├── README.md
├── centos
    ├── README.md
    └── openssh-7.4p1-obfuscate.patch
├── debian
    ├── 10.0p1.diff
    ├── 6.7p1-5+deb8u2.diff
    ├── 7.4p1-10+deb9u7.diff
    ├── 7.9p1-10+deb10u2.diff
    ├── 8.3p1.diff
    ├── 8.4p1.diff
    ├── 8.9p1.diff
    ├── 9.0p1.diff
    ├── 9.2p1.diff
    ├── 9.6p1.diff
    ├── 9.7p1.diff
    ├── 9.8p1.diff
    └── 9.9p1.diff
├── openbsd
    └── 8.0.diff
├── portable
    ├── 10.0.diff
    ├── 6.1.diff
    ├── 6.2.diff
    ├── 6.3_6.4.diff
    ├── 6.5.diff
    ├── 6.6.diff
    ├── 6.7.diff
    ├── 6.8.diff
    ├── 6.9.diff
    ├── 7.0_7.1.diff
    ├── 7.2.diff
    ├── 7.3.diff
    ├── 7.4.diff
    ├── 7.5.diff
    ├── 7.6.diff
    ├── 7.7.diff
    ├── 7.8.diff
    ├── 7.9.diff
    ├── 8.0.diff
    ├── 8.1.diff
    ├── 8.2.diff
    ├── 8.3.diff
    ├── 8.4.diff
    ├── 8.5_8.6.diff
    ├── 8.7.diff
    ├── 8.8_8.9.diff
    ├── 9.0.diff
    ├── 9.1.diff
    ├── 9.2.diff
    ├── 9.3.diff
    ├── 9.4.diff
    ├── 9.5.diff
    ├── 9.6.diff
    ├── 9.7.diff
    ├── 9.8.diff
    └── 9.9.diff
└── ubuntu
    ├── 5.9p1-5ubuntu1.7.diff
    ├── 6.6p1-2ubuntu2.12.patch
    ├── 6.6p1-2ubuntu2.3.patch
    ├── 6.7p1-5ubuntu1.3.patch
    ├── 6.9p1-2.patch
    ├── 7.1p1-4.patch
    ├── 7.2p2-4.patch
    ├── 7.2p2-4ubuntu2.7.patch
    ├── 7.4p1.patch
    ├── 7.5p1.patch
    ├── 7.6p1.patch
    ├── 7.7p1.patch
    ├── 7.9p1.diff
    ├── 8.0p1.patch
    ├── 8.1p1.patch
    ├── 8.2p1.patch
    ├── 8.9p1.patch
    ├── 9.3p1.patch
    ├── 9.6p1.patch
    └── 9.7p1.patch


/README.md:
--------------------------------------------------------------------------------
 1 | # obfuscated-openssh-patches
 2 | ### Patches for adding handshake obfuscation to OpenSSH
 3 | 
 4 | 
 5 | ### Not fully tested.
 6 | 
 7 | 
 8 | ### [Usage Info](https://zinglau.com/projects/ObfuscatedOpenSSHPatches.html)
 9 | 
10 | 
11 | ### [Ubuntu PPA](https://launchpad.net/~zinglau/+archive/ubuntu/obfuscated-openssh)
12 | 
13 | 
14 | ### [Debian Archive](https://deb.zinglau.com/)
15 | 
16 | 
17 | ### Acknowledgements
18 | - [brl](https://github.com/brl) developed the initial concept and authored the handshake obfuscattion patch
19 |  for openssh-5.2 ([repo](https://github.com/brl/obfuscated-openssh)).
20 | - [aligo](https://github.com/aligo) ported the patch to openssh-6.1 ([repo](https://github.com/aligo/obfuscated-openssh)).
21 | 
22 | #### [Donate using LiberaPay](https://liberapay.com/ZingLau2015/donate)
23 | [![Donate using LiberaPay](https://liberapay.com/assets/widgets/donate.svg)](https://liberapay.com/ZingLau2015/donate)
24 | 


--------------------------------------------------------------------------------
/centos/README.md:
--------------------------------------------------------------------------------
 1 | How to use
 2 | ======
 3 | 
 4 | 1. Clone source repository from CentOS
 5 |     ```Bash
 6 |     git clone https://git.centos.org/r/rpms/openssh.git
 7 |     ```
 8 | 
 9 | 2. Checkout the corresponding version tag. For full list of tags and branches, check [here](https://git.centos.org/summary/rpms!openssh.git).
10 |     ```Bash
11 |     cd openssh
12 |     # git checkout tags/<tag> -b <branch>
13 |     git checkout tags/imports/c7/openssh-7.4p1-16.el7 -b c7
14 |     ```
15 | 
16 | 3. Download the patch for corresponding version and save to `SOURCES/`
17 | 
18 | 4. Modify `SPECS/openssh.spec` accordingly. This may include:
19 |     * Changing `openssh_ver` or `openssh_rel` variable to indicate modification
20 |         ```diff
21 |          %define openssh_ver 7.4p1
22 |         -%define openssh_rel 16
23 |         +%define openssh_rel 16.obfs
24 |          %define pam_ssh_agent_ver 0.10.3
25 |          %define pam_ssh_agent_rel 2
26 |         ```
27 |     * Add the patch to patch list, and execute it **after all other patches**
28 |         ```diff
29 |          # Internal debug
30 |          Patch0: openssh-5.9p1-wIm.patch
31 |         +Patch1: openssh-7.4p1-obfuscate.patch
32 |         
33 |          #?
34 |          Patch100: openssh-7.4p1-coverity.patch
35 |         ```
36 |         ```diff
37 |          %patch700 -p1 -b .fips
38 |         
39 |          %patch100 -p1 -b .coverity
40 |         +%patch1 -p1 -b .obfuscate
41 |         
42 |          %if 0
43 |          # Nothing here yet
44 |         ```
45 | 
46 | 5. Build RPM
47 |     ```Bash
48 |     # You may need to install build dependencies first
49 |     yum-builddep openssh
50 |     # Test build (Executes the "%prep" stage. Normally this involves unpacking the sources and applying any patches.)
51 |     rpmbuild -bp SPECS/openssh.spec
52 |     # Build binary and source packages
53 |     rpmbuild -ba SPECS/openssh.spec
54 |     ```
55 | 
56 | 6. If all finished without error, you would now have RPM packages in `RPMS/` that can be used. On a system with both `openssh-server` and `openssh-clients` installed, you have to update both packages plus `openssh`, or you would break dependencies. Otherwise, just install the package you need, e.g. `openssh-server` with `openssh` as dependency.
57 |     ```Bash
58 |     # cd RPMS/<arch>
59 |     cd RPMS/x86_64
60 |     yum localinstall openssh-7.4p1-16.obfs.el7.x86_64.rpm openssh-clients-7.4p1-16.obfs.el7.x86_64.rpm openssh-server-7.4p1-16.obfs.el7.x86_64.rpm
61 |     ```
62 | 
63 | 7. Modify your existing `sshd_config`. (You can use `sshd_config.rpmnew` as a reference)
64 |     ```Bash
65 |     vi /etc/ssh/sshd_config
66 |     ```
67 | 
68 | 8. If you specified a port other than 22 as either the default port (not obfuscated), or the obfuscated port, you would have to update your SELinux config (if SELinux config is enabled)
69 |     ```Bash
70 |     semanage port -l | grep ssh
71 |     # ssh_port_t                     tcp      22
72 |     
73 |     # semanage port -a -t ssh_port_t -p tcp <your-port-number>
74 |     semanage port -a -t ssh_port_t -p tcp 222
75 |     ```
76 | 
77 | 9. Reload your `sshd.service`. **Make sure to test the new configuration before disconnecting you old SSH connection**, in case anything goes wrong, you can at least revert changes to `sshd_config` and possibly `yum reinstall openssh-server`.
78 |     ```Bash
79 |     systemctl reload sshd
80 |     ```
81 | 
82 | References
83 | ======
84 | 
85 | https://wiki.centos.org/PackageManagement/Rpm
86 | 
87 | https://blog.tinned-software.net/change-ssh-port-in-centos-with-selinux/
88 | 


--------------------------------------------------------------------------------
/debian/8.4p1.diff:
--------------------------------------------------------------------------------
  1 | Index: openssh-8.4p1/Makefile.in
  2 | ===================================================================
  3 | --- openssh-8.4p1.orig/Makefile.in	2021-02-14 19:49:28.000000000 +0800
  4 | +++ openssh-8.4p1/Makefile.in	2021-02-15 00:13:45.124094521 +0800
  5 | @@ -109,7 +109,7 @@
  6 |  	sntrup4591761.o kexsntrup4591761x25519.o kexgen.o \
  7 |  	kexgssc.o \
  8 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
  9 | -	sshbuf-io.o
 10 | +	sshbuf-io.o obfuscate.o
 11 |  
 12 |  SKOBJS=	ssh-sk-client.o
 13 |  
 14 | Index: openssh-8.4p1/kex.c
 15 | ===================================================================
 16 | --- openssh-8.4p1.orig/kex.c	2021-02-14 19:49:28.000000000 +0800
 17 | +++ openssh-8.4p1/kex.c	2021-02-15 00:13:45.124094521 +0800
 18 | @@ -59,6 +59,7 @@
 19 |  #include "monitor.h"
 20 |  #include "xmalloc.h"
 21 |  
 22 | +#include "obfuscate.h"
 23 |  #include "ssherr.h"
 24 |  #include "sshbuf.h"
 25 |  #include "digest.h"
 26 | @@ -517,9 +518,12 @@
 27 |  		return r;
 28 |  	debug("SSH2_MSG_NEWKEYS sent");
 29 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 30 | -	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
 31 | +	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0) {
 32 | +		sshpkt_disable_obfuscation(ssh);
 33 |  		if ((r = kex_send_ext_info(ssh)) != 0)
 34 |  			return r;
 35 | +		sshpkt_enable_obfuscation(ssh);
 36 | +	}
 37 |  	debug("expecting SSH2_MSG_NEWKEYS");
 38 |  	return 0;
 39 |  }
 40 | @@ -582,6 +586,7 @@
 41 |  	kex->flags &= ~KEX_INIT_SENT;
 42 |  	free(kex->name);
 43 |  	kex->name = NULL;
 44 | +	sshpkt_disable_obfuscation(ssh);
 45 |  	return 0;
 46 |  }
 47 |  
 48 | @@ -1252,14 +1257,42 @@
 49 |  		goto out;
 50 |  	}
 51 |  
 52 | +	/* Make copy and obfuscate the original */
 53 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 54 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 55 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 56 | +			r = SSH_ERR_ALLOC_FAIL;
 57 | +			goto out;
 58 | +		}
 59 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 60 | +	}
 61 | +
 62 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 63 |  	    sshbuf_mutable_ptr(our_version),
 64 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 65 |  		oerrno = errno;
 66 |  		debug("%s: write: %.100s", __func__, strerror(errno));
 67 |  		r = SSH_ERR_SYSTEM_ERROR;
 68 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 69 | +			free(cp);
 70 | +		}
 71 |  		goto out;
 72 |  	}
 73 | +
 74 | +	/* Restore the original */
 75 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 76 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 77 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 78 | +			free(cp);
 79 | +			goto out;
 80 | +		}
 81 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 82 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 83 | +			free(cp);
 84 | +			goto out;
 85 | +		}
 86 | +	}
 87 | +
 88 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 89 |  		oerrno = errno;
 90 |  		error("%s: sshbuf_consume_end: %s", __func__, ssh_err(r));
 91 | @@ -1319,6 +1352,8 @@
 92 |  				r = SSH_ERR_SYSTEM_ERROR;
 93 |  				goto out;
 94 |  			}
 95 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 96 | +			  obfuscate_input(&c, 1);
 97 |  			if (c == '\r') {
 98 |  				expect_nl = 1;
 99 |  				continue;
100 | Index: openssh-8.4p1/obfuscate.c
101 | ===================================================================
102 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
103 | +++ openssh-8.4p1/obfuscate.c	2021-02-15 00:13:45.124094521 +0800
104 | @@ -0,0 +1,220 @@
105 | +#include "includes.h"
106 | +#include <openssl/evp.h>
107 | +#include <openssl/rc4.h>
108 | +#include "openbsd-compat/openssl-compat.h"
109 | +#include <unistd.h>
110 | +#include <string.h>
111 | +#include "atomicio.h"
112 | +#include "canohost.h"
113 | +#include "xmalloc.h"
114 | +#include "log.h"
115 | +#include "packet.h"
116 | +#include "obfuscate.h"
117 | +
118 | +static RC4_KEY rc4_input;
119 | +static RC4_KEY rc4_output;
120 | +
121 | +static const char *obfuscate_keyword = NULL;
122 | +
123 | +#define OBFUSCATE_KEY_LENGTH 	16
124 | +#define OBFUSCATE_SEED_LENGTH	16
125 | +#define OBFUSCATE_HASH_ITERATIONS 6000
126 | +#define OBFUSCATE_MAX_PADDING	8192
127 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
128 | +
129 | +struct seed_msg {
130 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
131 | +	u_int32_t magic;
132 | +	u_int32_t padding_length;
133 | +	u_char padding[];
134 | +};
135 | +
136 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
137 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
138 | +static void set_keys(const u_char *, const u_char *);
139 | +static void initialize(const u_char *, int);
140 | +static void read_forever(int);
141 | +
142 | +
143 | +/*
144 | + * Server calls this
145 | + */
146 | +void
147 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
148 | +{
149 | +	struct seed_msg seed;
150 | +
151 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
152 | +	u_int len;
153 | +	u_int32_t padding_length;
154 | +
155 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
156 | +
157 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
158 | +	if(len != sizeof(struct seed_msg))
159 | +		fatal("obfuscate_receive_seed: read failed");
160 | +
161 | +	initialize(seed.seed_buffer, 1);
162 | +	obfuscate_input((u_char *)&seed.magic, 8);
163 | +
164 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
165 | +		logit("Magic value check failed (%u) on obfuscated handshake "
166 | + 			"from %.200s port %d", ntohl(seed.magic),
167 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
168 | +		read_forever(sock_in);
169 | +	}
170 | +	padding_length = ntohl(seed.padding_length);
171 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
172 | +		logit("Illegal padding length %d for obfuscated handshake "
173 | + 			"from %.200s port %d", ntohl(seed.padding_length),
174 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
175 | +		read_forever(sock_in);
176 | +	}
177 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
178 | +	if(len != padding_length)
179 | +		fatal("obfuscate_receive_seed: read failed");
180 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
181 | +	obfuscate_input(padding_drain, padding_length);
182 | +}
183 | +
184 | +/*
185 | + * Client calls this
186 | + */
187 | +void
188 | +obfuscate_send_seed(int sock_out)
189 | +{
190 | +	struct seed_msg *seed;
191 | +	int i;
192 | +	u_int32_t rnd = 0;
193 | +	u_int message_length;
194 | +	u_int padding_length;
195 | +
196 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
197 | +	message_length = padding_length + sizeof(struct seed_msg);
198 | +	seed = xmalloc(message_length);
199 | +
200 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
201 | +		if(i % 4 == 0)
202 | +			rnd = arc4random();
203 | +		seed->seed_buffer[i] = rnd & 0xff;
204 | +		rnd >>= 8;
205 | +	}
206 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
207 | +	seed->padding_length = htonl(padding_length);
208 | +	for(i = 0; i < (int)padding_length; i++) {
209 | +		if(i % 4 == 0)
210 | +			rnd = arc4random();
211 | +		seed->padding[i] = rnd & 0xff;
212 | +	}
213 | +	initialize(seed->seed_buffer, 0);
214 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
215 | +		message_length - OBFUSCATE_SEED_LENGTH);
216 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
217 | +	atomicio(vwrite, sock_out, seed, message_length);
218 | +	free(seed);
219 | +
220 | +}
221 | +
222 | +void
223 | +obfuscate_set_keyword(const char *keyword)
224 | +{
225 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
226 | +	obfuscate_keyword = keyword;
227 | +}
228 | +
229 | +void
230 | +obfuscate_input(u_char *buffer, u_int buffer_len)
231 | +{
232 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
233 | +}
234 | +
235 | +void
236 | +obfuscate_output(u_char *buffer, u_int buffer_len)
237 | +{
238 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
239 | +}
240 | +
241 | +static void
242 | +initialize(const u_char *seed, int server)
243 | +{
244 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
245 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
246 | +
247 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
248 | +
249 | +	if(server)
250 | +		set_keys(client_to_server_key, server_to_client_key);
251 | +	else
252 | +		set_keys(server_to_client_key, client_to_server_key);
253 | +}
254 | +
255 | +static void
256 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
257 | +{
258 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
259 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
260 | +}
261 | +
262 | +static void
263 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
264 | +{
265 | +	EVP_MD_CTX *ctx;
266 | +	u_char md_output[EVP_MAX_MD_SIZE];
267 | +	int md_len;
268 | +	int i;
269 | +	u_char *buffer;
270 | +	u_char *p;
271 | +	u_int buffer_length;
272 | +
273 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
274 | +		fatal("Cannot create new digest context");
275 | +
276 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
277 | +	if(obfuscate_keyword)
278 | +		buffer_length += strlen(obfuscate_keyword);
279 | +
280 | +	p = buffer = xmalloc(buffer_length);
281 | +
282 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
283 | +	p += OBFUSCATE_SEED_LENGTH;
284 | +
285 | +	if(obfuscate_keyword) {
286 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
287 | +		p += strlen(obfuscate_keyword);
288 | +	}
289 | +	memcpy(p, iv, iv_len);
290 | +
291 | +	EVP_DigestInit(ctx, EVP_sha1());
292 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
293 | +	EVP_DigestFinal(ctx, md_output, &md_len);
294 | +
295 | +	free(buffer);
296 | +
297 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
298 | +		EVP_DigestInit(ctx, EVP_sha1());
299 | +		EVP_DigestUpdate(ctx, md_output, md_len);
300 | +		EVP_DigestFinal(ctx, md_output, &md_len);
301 | +	}
302 | +
303 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
304 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
305 | +
306 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
307 | +}
308 | +
309 | +static void
310 | +set_keys(const u_char *input_key, const u_char *output_key)
311 | +{
312 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
313 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
314 | +}
315 | +
316 | +static void
317 | +read_forever(int sock_in)
318 | +{
319 | +	u_char discard_buffer[1024];
320 | +
321 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
322 | +		;
323 | +	cleanup_exit(255);
324 | +}
325 | Index: openssh-8.4p1/obfuscate.h
326 | ===================================================================
327 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
328 | +++ openssh-8.4p1/obfuscate.h	2021-02-15 00:13:45.124094521 +0800
329 | @@ -0,0 +1,10 @@
330 | +#ifndef _OBFUSCATE_H
331 | +#define _OBFUSCATE_H
332 | +
333 | +void obfuscate_receive_seed(struct ssh *, int);
334 | +void obfuscate_send_seed(int);
335 | +void obfuscate_set_keyword(const char *);
336 | +void obfuscate_input(u_char *, u_int);
337 | +void obfuscate_output(u_char *, u_int);
338 | +
339 | +#endif
340 | Index: openssh-8.4p1/packet.c
341 | ===================================================================
342 | --- openssh-8.4p1.orig/packet.c	2020-09-27 15:25:01.000000000 +0800
343 | +++ openssh-8.4p1/packet.c	2021-02-15 00:13:45.124094521 +0800
344 | @@ -94,6 +94,7 @@
345 |  #include "channels.h"
346 |  #include "ssh.h"
347 |  #include "packet.h"
348 | +#include "obfuscate.h"
349 |  #include "ssherr.h"
350 |  #include "sshbuf.h"
351 |  
352 | @@ -177,6 +178,8 @@
353 |  	/* Set to true if we are authenticated. */
354 |  	int after_authentication;
355 |  
356 | +	int obfuscation;
357 | +
358 |  	int keep_alive_timeouts;
359 |  
360 |  	/* The maximum time that we will wait to send or receive a packet */
361 | @@ -1203,6 +1206,8 @@
362 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
363 |  			goto out;
364 |  	}
365 | +	if(state->obfuscation)
366 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
367 |  #ifdef PACKET_DEBUG
368 |  	fprintf(stderr, "encrypted: ");
369 |  	sshbuf_dump(state->output, stderr);
370 | @@ -1545,6 +1550,8 @@
371 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
372 |  		    &cp)) != 0)
373 |  			goto out;
374 | +		if(state->obfuscation)
375 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
376 |  		if ((r = cipher_crypt(state->receive_context,
377 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
378 |  		    block_size, 0, 0)) != 0)
379 | @@ -1610,6 +1617,8 @@
380 |  			goto out;
381 |  		}
382 |  	}
383 | +	if(state->obfuscation)
384 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
385 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
386 |  	    &cp)) != 0)
387 |  		goto out;
388 | @@ -2745,3 +2754,25 @@
389 |  	ssh->state->extra_pad = pad;
390 |  	return 0;
391 |  }
392 | +
393 | +void
394 | +sshpkt_enable_obfuscation(struct ssh *ssh)
395 | +{
396 | +	debug("Obfuscation enabled");
397 | +	ssh->state->obfuscation = 1;
398 | +}
399 | +
400 | +void
401 | +sshpkt_disable_obfuscation(struct ssh *ssh)
402 | +{
403 | +	if(ssh->state->obfuscation) {
404 | +		debug("Obfuscation disabled");
405 | +		ssh->state->obfuscation = 0;
406 | +	}
407 | +}
408 | +
409 | +int
410 | +sshpkt_get_obfuscation(struct ssh *ssh)
411 | +{
412 | +	return ssh->state->obfuscation;
413 | +}
414 | Index: openssh-8.4p1/packet.h
415 | ===================================================================
416 | --- openssh-8.4p1.orig/packet.h	2020-09-27 15:25:01.000000000 +0800
417 | +++ openssh-8.4p1/packet.h	2021-02-15 00:13:45.124094521 +0800
418 | @@ -180,6 +180,9 @@
419 |  	    __attribute__((format(printf, 3, 4)))
420 |  	    __attribute__((noreturn));
421 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
422 | +void	sshpkt_enable_obfuscation(struct ssh *);
423 | +void	sshpkt_disable_obfuscation(struct ssh *);
424 | +int sshpkt_get_obfuscation(struct ssh *);
425 |  
426 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
427 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
428 | Index: openssh-8.4p1/readconf.c
429 | ===================================================================
430 | --- openssh-8.4p1.orig/readconf.c	2021-02-14 19:49:28.000000000 +0800
431 | +++ openssh-8.4p1/readconf.c	2021-02-15 00:13:45.124094521 +0800
432 | @@ -144,7 +144,7 @@
433 |  	oBadOption,
434 |  	oHost, oMatch, oInclude,
435 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
436 | -	oGatewayPorts, oExitOnForwardFailure,
437 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
438 |  	oPasswordAuthentication,
439 |  	oChallengeResponseAuthentication, oXAuthLocation,
440 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
441 | @@ -329,6 +329,8 @@
442 |  	{ "securitykeyprovider", oSecurityKeyProvider },
443 |  	{ "protocolkeepalives", oProtocolKeepAlives },
444 |  	{ "setuptimeout", oSetupTimeOut },
445 | +	{ "obfuscatehandshake", oObfuscateHandshake },
446 | +	{ "obfuscatekeyword", oObfuscateKeyword },
447 |  
448 |  	{ NULL, oBadOption }
449 |  };
450 | @@ -1906,6 +1908,16 @@
451 |  			*charptr = xstrdup(arg);
452 |  		break;
453 |  
454 | +	case oObfuscateHandshake:
455 | +		intptr = &options->obfuscate_handshake;
456 | +		goto parse_flag;
457 | +
458 | +	case oObfuscateKeyword:
459 | +		if (*activep)
460 | +			options->obfuscate_handshake = 1;
461 | +		charptr = &options->obfuscate_keyword;
462 | +		goto parse_string;
463 | +
464 |  	case oDeprecated:
465 |  		debug("%s line %d: Deprecated option \"%s\"",
466 |  		    filename, linenum, keyword);
467 | @@ -2105,6 +2117,8 @@
468 |  	options->add_keys_to_agent_lifespan = -1;
469 |  	options->identity_agent = NULL;
470 |  	options->visual_host_key = -1;
471 | +	options->obfuscate_handshake = 0;
472 | +	options->obfuscate_keyword = NULL;
473 |  	options->ip_qos_interactive = -1;
474 |  	options->ip_qos_bulk = -1;
475 |  	options->request_tty = -1;
476 | Index: openssh-8.4p1/readconf.h
477 | ===================================================================
478 | --- openssh-8.4p1.orig/readconf.h	2021-02-14 19:49:28.000000000 +0800
479 | +++ openssh-8.4p1/readconf.h	2021-02-15 00:13:45.124094521 +0800
480 | @@ -147,6 +147,8 @@
481 |  	int	permit_local_command;
482 |  	char	*remote_command;
483 |  	int	visual_host_key;
484 | +	int obfuscate_handshake;
485 | +	char *obfuscate_keyword;
486 |  
487 |  	int	request_tty;
488 |  
489 | Index: openssh-8.4p1/scp.c
490 | ===================================================================
491 | --- openssh-8.4p1.orig/scp.c	2021-02-14 19:49:28.000000000 +0800
492 | +++ openssh-8.4p1/scp.c	2021-02-15 00:16:52.039545456 +0800
493 | @@ -440,7 +440,7 @@
494 |  
495 |  	fflag = Tflag = tflag = 0;
496 |  	while ((ch = getopt(argc, argv,
497 | -	    "12346ABCTdfpqrtvF:J:P:S:c:i:l:o:")) != -1) {
498 | +	    "12346ABCTdfpqrtvF:J:P:S:c:i:l:o:zZ:")) != -1) {
499 |  		switch (ch) {
500 |  		/* User-visible flags. */
501 |  		case '1':
502 | @@ -453,6 +453,7 @@
503 |  		case '4':
504 |  		case '6':
505 |  		case 'C':
506 | +		case 'z':
507 |  			addargs(&args, "-%c", ch);
508 |  			addargs(&remote_remote_args, "-%c", ch);
509 |  			break;
510 | @@ -464,6 +465,7 @@
511 |  		case 'i':
512 |  		case 'F':
513 |  		case 'J':
514 | +		case 'Z':
515 |  			addargs(&remote_remote_args, "-%c", ch);
516 |  			addargs(&remote_remote_args, "%s", optarg);
517 |  			addargs(&args, "-%c", ch);
518 | Index: openssh-8.4p1/servconf.c
519 | ===================================================================
520 | --- openssh-8.4p1.orig/servconf.c	2021-02-14 19:49:28.000000000 +0800
521 | +++ openssh-8.4p1/servconf.c	2021-02-15 00:13:45.128094509 +0800
522 | @@ -96,6 +96,7 @@
523 |  
524 |  	/* Standard Options */
525 |  	options->num_ports = 0;
526 | +	options->num_obfuscated_ports = 0;
527 |  	options->ports_from_cmdline = 0;
528 |  	options->queued_listen_addrs = NULL;
529 |  	options->num_queued_listens = 0;
530 | @@ -181,6 +182,7 @@
531 |  	options->permitted_listens = NULL;
532 |  	options->adm_forced_command = NULL;
533 |  	options->chroot_directory = NULL;
534 | +	options->obfuscate_keyword = NULL;
535 |  	options->authorized_keys_command = NULL;
536 |  	options->authorized_keys_command_user = NULL;
537 |  	options->revoked_keys_file = NULL;
538 | @@ -323,7 +325,7 @@
539 |  #endif /* WITH_XMSS */
540 |  	}
541 |  	/* No certificates by default */
542 | -	if (options->num_ports == 0)
543 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
544 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
545 |  	if (options->address_family == -1)
546 |  		options->address_family = AF_UNSPEC;
547 | @@ -518,7 +520,7 @@
548 |  	/* Portable-specific options */
549 |  	sUsePAM,
550 |  	/* Standard Options */
551 | -	sPort, sHostKeyFile, sLoginGraceTime,
552 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
553 |  	sPermitRootLogin, sLogFacility, sLogLevel,
554 |  	sRhostsRSAAuthentication, sRSAAuthentication,
555 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
556 | @@ -576,6 +578,8 @@
557 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
558 |  	/* Standard Options */
559 |  	{ "port", sPort, SSHCFG_GLOBAL },
560 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
561 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
562 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
563 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
564 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
565 | @@ -796,6 +800,10 @@
566 |  			add_one_listen_addr(options, addr, rdomain,
567 |  			    options->ports[i]);
568 |  		}
569 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
570 | +			add_one_listen_addr(options, addr, rdomain,
571 | +				options->obfuscated_ports[i]);
572 | +		}
573 |  	}
574 |  }
575 |  
576 | @@ -910,7 +918,7 @@
577 |  	u_int i;
578 |  	struct queued_listenaddr *qla;
579 |  
580 | -	if (options->num_ports == 0)
581 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
582 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
583 |  	if (options->address_family == -1)
584 |  		options->address_family = AF_UNSPEC;
585 | @@ -1368,6 +1376,30 @@
586 |  			    filename, linenum);
587 |  		break;
588 |  
589 | +	case sObfuscatedPort:
590 | +		if(options->ports_from_cmdline)
591 | +			return 0;
592 | +		if(options->listen_addrs != NULL)
593 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
594 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
595 | +			fatal("%s line %d: too many ports.", filename, linenum);
596 | +		arg = strdelim(&cp);
597 | +		if(!arg || *arg == '\0')
598 | +			fatal("%s line %d: missing port number.", filename, linenum);
599 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
600 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
601 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
602 | +		break;
603 | +	case sObfuscateKeyword:
604 | +		charptr = &options->obfuscate_keyword;
605 | +		arg = strdelim(&cp);
606 | +		if(!arg || *arg == '\0')
607 | +			fatal("%s line %d: missing keyword argument.",
608 | +					filename, linenum);
609 | +		if(*activep && *charptr == NULL)
610 | +			*charptr = xstrdup(arg);
611 | +		break;
612 | +
613 |  	case sLoginGraceTime:
614 |  		intptr = &options->login_grace_time;
615 |   parse_time:
616 | Index: openssh-8.4p1/servconf.h
617 | ===================================================================
618 | --- openssh-8.4p1.orig/servconf.h	2021-02-14 19:49:28.000000000 +0800
619 | +++ openssh-8.4p1/servconf.h	2021-02-15 00:13:45.128094509 +0800
620 | @@ -207,6 +207,11 @@
621 |  	u_int   num_permitted_listens;
622 |  
623 |  	char   *chroot_directory;
624 | +
625 | +	int obfuscated_ports[MAX_PORTS];
626 | +	u_int num_obfuscated_ports;
627 | +	char *obfuscate_keyword;
628 | +
629 |  	char   *revoked_keys_file;
630 |  	char   *trusted_user_ca_keys;
631 |  	char   *authorized_keys_command;
632 | Index: openssh-8.4p1/sftp.c
633 | ===================================================================
634 | --- openssh-8.4p1.orig/sftp.c	2020-09-27 15:25:01.000000000 +0800
635 | +++ openssh-8.4p1/sftp.c	2021-02-15 00:18:28.247249714 +0800
636 | @@ -2408,13 +2408,14 @@
637 |  	infile = stdin;
638 |  
639 |  	while ((ch = getopt(argc, argv,
640 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:")) != -1) {
641 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:zZ:")) != -1) {
642 |  		switch (ch) {
643 |  		/* Passed through to ssh(1) */
644 |  		case 'A':
645 |  		case '4':
646 |  		case '6':
647 |  		case 'C':
648 | +		case 'z':
649 |  			addargs(&args, "-%c", ch);
650 |  			break;
651 |  		/* Passed through to ssh(1) with argument */
652 | @@ -2423,6 +2424,7 @@
653 |  		case 'c':
654 |  		case 'i':
655 |  		case 'o':
656 | +		case 'Z':
657 |  			addargs(&args, "-%c", ch);
658 |  			addargs(&args, "%s", optarg);
659 |  			break;
660 | Index: openssh-8.4p1/ssh.c
661 | ===================================================================
662 | --- openssh-8.4p1.orig/ssh.c	2021-02-14 19:49:28.000000000 +0800
663 | +++ openssh-8.4p1/ssh.c	2021-02-15 00:13:45.128094509 +0800
664 | @@ -203,13 +203,14 @@
665 |  usage(void)
666 |  {
667 |  	fprintf(stderr,
668 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
669 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface]\n"
670 |  "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
671 |  "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
672 |  "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
673 |  "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
674 |  "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
675 | -"           [-w local_tun[:remote_tun]] destination [command]\n"
676 | +"           [-w local_tun[:remote_tun]] [-Z obfuscate_keyword]\n"
677 | +"			destination [command]\n"
678 |  	);
679 |  	exit(255);
680 |  }
681 | @@ -722,7 +723,7 @@
682 |  
683 |   again:
684 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
685 | -	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
686 | +	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYyzZ:")) != -1) {
687 |  		switch (opt) {
688 |  		case '1':
689 |  			fatal("SSH protocol v.1 is no longer supported");
690 | @@ -1068,6 +1069,13 @@
691 |  		case 'F':
692 |  			config = optarg;
693 |  			break;
694 | +		case 'z':
695 | +			options.obfuscate_handshake = 1;
696 | +			break;
697 | +		case 'Z':
698 | +			options.obfuscate_handshake = 1;
699 | +			options.obfuscate_keyword = optarg;
700 | +			break;
701 |  		default:
702 |  			usage();
703 |  		}
704 | Index: openssh-8.4p1/sshconnect.c
705 | ===================================================================
706 | --- openssh-8.4p1.orig/sshconnect.c	2021-02-14 19:49:28.000000000 +0800
707 | +++ openssh-8.4p1/sshconnect.c	2021-02-15 00:13:45.128094509 +0800
708 | @@ -64,6 +64,7 @@
709 |  #include "monitor_fdpass.h"
710 |  #include "ssh2.h"
711 |  #include "version.h"
712 | +#include "obfuscate.h"
713 |  #include "authfile.h"
714 |  #include "ssherr.h"
715 |  #include "authfd.h"
716 | @@ -284,6 +285,12 @@
717 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
718 |  		return -1; /* ssh_packet_set_connection logs error */
719 |  
720 | +	if(options.obfuscate_handshake) {
721 | +		if(options.obfuscate_keyword)
722 | +			obfuscate_set_keyword(options.obfuscate_keyword);
723 | +		sshpkt_enable_obfuscation(ssh);
724 | +	}
725 | +
726 |  	return 0;
727 |  }
728 |  
729 | @@ -544,6 +551,11 @@
730 |  	/* Set the connection. */
731 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
732 |  		return -1; /* ssh_packet_set_connection logs error */
733 | +	if(options.obfuscate_handshake) {
734 | +		if(options.obfuscate_keyword)
735 | +			obfuscate_set_keyword(options.obfuscate_keyword);
736 | +		sshpkt_enable_obfuscation(ssh);
737 | +	}
738 |  
739 |  	return 0;
740 |  }
741 | @@ -1295,6 +1307,9 @@
742 |  	host = xstrdup(orighost);
743 |  	lowercase(host);
744 |  
745 | +	if(options.obfuscate_handshake)
746 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
747 | +
748 |  	/* Exchange protocol version identification strings with the server. */
749 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, 1, NULL)) != 0)
750 |  		sshpkt_fatal(ssh, r, "banner exchange");
751 | Index: openssh-8.4p1/sshd.c
752 | ===================================================================
753 | --- openssh-8.4p1.orig/sshd.c	2021-02-14 19:49:28.000000000 +0800
754 | +++ openssh-8.4p1/sshd.c	2021-02-15 00:13:45.128094509 +0800
755 | @@ -122,6 +122,7 @@
756 |  #include "ssh-gss.h"
757 |  #endif
758 |  #include "monitor_wrap.h"
759 | +#include "obfuscate.h"
760 |  #include "ssh-sandbox.h"
761 |  #include "auth-options.h"
762 |  #include "version.h"
763 | @@ -268,6 +269,9 @@
764 |  /* message to be displayed after login */
765 |  struct sshbuf *loginmsg;
766 |  
767 | +/* Enable handshake obfuscation */
768 | +int use_obfuscation = 0;
769 | +
770 |  /* Unprivileged user */
771 |  struct passwd *privsep_pw = NULL;
772 |  
773 | @@ -1540,7 +1544,7 @@
774 |  	struct ssh *ssh = NULL;
775 |  	extern char *optarg;
776 |  	extern int optind;
777 | -	int r, opt, on = 1, already_daemon, remote_port;
778 | +	int r, opt, on = 1, already_daemon, remote_port, local_port;
779 |  	int sock_in = -1, sock_out = -1, newsock = -1;
780 |  	const char *remote_ip, *rdomain;
781 |  	char *fp, *line, *laddr, *logfile = NULL;
782 | @@ -2176,6 +2180,14 @@
783 |  	channel_set_af(ssh, options.address_family);
784 |  	process_permitopen(ssh, &options);
785 |  
786 | +	local_port = ssh_local_port(ssh);
787 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
788 | +		if(options.obfuscated_ports[i] == local_port) {
789 | +			use_obfuscation = 1;
790 | +			break;
791 | +		}
792 | +	}
793 | +
794 |  	/* Set SO_KEEPALIVE if requested. */
795 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
796 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
797 | @@ -2241,6 +2253,13 @@
798 |  	if (!debug_flag)
799 |  		alarm(options.login_grace_time);
800 |  
801 | +	if (use_obfuscation) {
802 | +		if (options.obfuscate_keyword)
803 | +			obfuscate_set_keyword(options.obfuscate_keyword);
804 | +		sshpkt_enable_obfuscation(ssh);
805 | +		obfuscate_receive_seed(ssh, sock_in);
806 | +	}
807 | +
808 |  	if ((r = kex_exchange_identification(ssh, -1, options.debian_banner,
809 |  	    options.version_addendum)) != 0)
810 |  		sshpkt_fatal(ssh, r, "banner exchange");
811 | @@ -2266,8 +2285,12 @@
812 |  	auth_debug_reset();
813 |  
814 |  	if (use_privsep) {
815 | -		if (privsep_preauth(ssh) == 1)
816 | +
817 | +		if (privsep_preauth(ssh) == 1) {
818 | +			if(use_obfuscation)
819 | +				sshpkt_disable_obfuscation(ssh);
820 |  			goto authenticated;
821 | +		}
822 |  	} else if (have_agent) {
823 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
824 |  			error("Unable to get agent socket: %s", ssh_err(r));
825 | Index: openssh-8.4p1/sshd_config
826 | ===================================================================
827 | --- openssh-8.4p1.orig/sshd_config	2021-02-14 19:49:28.000000000 +0800
828 | +++ openssh-8.4p1/sshd_config	2021-02-15 00:13:45.128094509 +0800
829 | @@ -13,6 +13,8 @@
830 |  Include /etc/ssh/sshd_config.d/*.conf
831 |  
832 |  #Port 22
833 | +#ObfuscatedPort 222
834 | +#ObfuscateKeyword key
835 |  #AddressFamily any
836 |  #ListenAddress 0.0.0.0
837 |  #ListenAddress ::
838 | 


--------------------------------------------------------------------------------
/debian/9.2p1.diff:
--------------------------------------------------------------------------------
  1 | Index: openssh-9.2p1/Makefile.in
  2 | ===================================================================
  3 | --- openssh-9.2p1.orig/Makefile.in	2023-02-24 10:54:30.000000000 +0800
  4 | +++ openssh-9.2p1/Makefile.in	2023-02-24 10:55:06.821149662 +0800
  5 | @@ -112,7 +112,7 @@
  6 |  	kexsntrup761x25519.o sntrup761.o kexgen.o \
  7 |  	kexgssc.o \
  8 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
  9 | -	sshbuf-io.o
 10 | +	sshbuf-io.o obfuscate.o
 11 |  
 12 |  SKOBJS=	ssh-sk-client.o
 13 |  
 14 | Index: openssh-9.2p1/kex.c
 15 | ===================================================================
 16 | --- openssh-9.2p1.orig/kex.c	2023-02-24 10:54:30.000000000 +0800
 17 | +++ openssh-9.2p1/kex.c	2023-02-24 10:55:06.821149662 +0800
 18 | @@ -59,6 +59,7 @@
 19 |  #include "monitor.h"
 20 |  #include "xmalloc.h"
 21 |  
 22 | +#include "obfuscate.h"
 23 |  #include "ssherr.h"
 24 |  #include "sshbuf.h"
 25 |  #include "digest.h"
 26 | @@ -521,9 +522,12 @@
 27 |  		return r;
 28 |  	debug("SSH2_MSG_NEWKEYS sent");
 29 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 30 | -	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
 31 | +	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0) {
 32 | +		sshpkt_disable_obfuscation(ssh);
 33 |  		if ((r = kex_send_ext_info(ssh)) != 0)
 34 |  			return r;
 35 | +		sshpkt_enable_obfuscation(ssh);
 36 | +	}
 37 |  	debug("expecting SSH2_MSG_NEWKEYS");
 38 |  	return 0;
 39 |  }
 40 | @@ -601,6 +605,7 @@
 41 |  	kex->flags &= ~KEX_INIT_SENT;
 42 |  	free(kex->name);
 43 |  	kex->name = NULL;
 44 | +	sshpkt_disable_obfuscation(ssh);
 45 |  	return 0;
 46 |  }
 47 |  
 48 | @@ -1299,14 +1304,42 @@
 49 |  		goto out;
 50 |  	}
 51 |  
 52 | +	/* Make copy and obfuscate the original */
 53 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 54 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 55 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 56 | +			r = SSH_ERR_ALLOC_FAIL;
 57 | +			goto out;
 58 | +		}
 59 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 60 | +	}
 61 | +
 62 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 63 |  	    sshbuf_mutable_ptr(our_version),
 64 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 65 |  		oerrno = errno;
 66 |  		debug_f("write: %.100s", strerror(errno));
 67 |  		r = SSH_ERR_SYSTEM_ERROR;
 68 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 69 | +			free(cp);
 70 | +		}
 71 |  		goto out;
 72 |  	}
 73 | +
 74 | +	/* Restore the original */
 75 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 76 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 77 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 78 | +			free(cp);
 79 | +			goto out;
 80 | +		}
 81 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 82 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 83 | +			free(cp);
 84 | +			goto out;
 85 | +		}
 86 | +	}
 87 | +
 88 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 89 |  		oerrno = errno;
 90 |  		error_fr(r, "sshbuf_consume_end");
 91 | @@ -1363,6 +1396,8 @@
 92 |  				r = SSH_ERR_SYSTEM_ERROR;
 93 |  				goto out;
 94 |  			}
 95 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 96 | +			  obfuscate_input(&c, 1);
 97 |  			if (c == '\r') {
 98 |  				expect_nl = 1;
 99 |  				continue;
100 | Index: openssh-9.2p1/obfuscate.c
101 | ===================================================================
102 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
103 | +++ openssh-9.2p1/obfuscate.c	2023-02-24 10:55:06.821149662 +0800
104 | @@ -0,0 +1,220 @@
105 | +#include "includes.h"
106 | +#include <openssl/evp.h>
107 | +#include <openssl/rc4.h>
108 | +#include "openbsd-compat/openssl-compat.h"
109 | +#include <unistd.h>
110 | +#include <string.h>
111 | +#include "atomicio.h"
112 | +#include "canohost.h"
113 | +#include "xmalloc.h"
114 | +#include "log.h"
115 | +#include "packet.h"
116 | +#include "obfuscate.h"
117 | +
118 | +static RC4_KEY rc4_input;
119 | +static RC4_KEY rc4_output;
120 | +
121 | +static const char *obfuscate_keyword = NULL;
122 | +
123 | +#define OBFUSCATE_KEY_LENGTH 	16
124 | +#define OBFUSCATE_SEED_LENGTH	16
125 | +#define OBFUSCATE_HASH_ITERATIONS 6000
126 | +#define OBFUSCATE_MAX_PADDING	8192
127 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
128 | +
129 | +struct seed_msg {
130 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
131 | +	u_int32_t magic;
132 | +	u_int32_t padding_length;
133 | +	u_char padding[];
134 | +};
135 | +
136 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
137 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
138 | +static void set_keys(const u_char *, const u_char *);
139 | +static void initialize(const u_char *, int);
140 | +static void read_forever(int);
141 | +
142 | +
143 | +/*
144 | + * Server calls this
145 | + */
146 | +void
147 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
148 | +{
149 | +	struct seed_msg seed;
150 | +
151 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
152 | +	u_int len;
153 | +	u_int32_t padding_length;
154 | +
155 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
156 | +
157 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
158 | +	if(len != sizeof(struct seed_msg))
159 | +		fatal("obfuscate_receive_seed: read failed");
160 | +
161 | +	initialize(seed.seed_buffer, 1);
162 | +	obfuscate_input((u_char *)&seed.magic, 8);
163 | +
164 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
165 | +		logit("Magic value check failed (%u) on obfuscated handshake "
166 | + 			"from %.200s port %d", ntohl(seed.magic),
167 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
168 | +		read_forever(sock_in);
169 | +	}
170 | +	padding_length = ntohl(seed.padding_length);
171 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
172 | +		logit("Illegal padding length %d for obfuscated handshake "
173 | + 			"from %.200s port %d", ntohl(seed.padding_length),
174 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
175 | +		read_forever(sock_in);
176 | +	}
177 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
178 | +	if(len != padding_length)
179 | +		fatal("obfuscate_receive_seed: read failed");
180 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
181 | +	obfuscate_input(padding_drain, padding_length);
182 | +}
183 | +
184 | +/*
185 | + * Client calls this
186 | + */
187 | +void
188 | +obfuscate_send_seed(int sock_out)
189 | +{
190 | +	struct seed_msg *seed;
191 | +	int i;
192 | +	u_int32_t rnd = 0;
193 | +	u_int message_length;
194 | +	u_int padding_length;
195 | +
196 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
197 | +	message_length = padding_length + sizeof(struct seed_msg);
198 | +	seed = xmalloc(message_length);
199 | +
200 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
201 | +		if(i % 4 == 0)
202 | +			rnd = arc4random();
203 | +		seed->seed_buffer[i] = rnd & 0xff;
204 | +		rnd >>= 8;
205 | +	}
206 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
207 | +	seed->padding_length = htonl(padding_length);
208 | +	for(i = 0; i < (int)padding_length; i++) {
209 | +		if(i % 4 == 0)
210 | +			rnd = arc4random();
211 | +		seed->padding[i] = rnd & 0xff;
212 | +	}
213 | +	initialize(seed->seed_buffer, 0);
214 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
215 | +		message_length - OBFUSCATE_SEED_LENGTH);
216 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
217 | +	atomicio(vwrite, sock_out, seed, message_length);
218 | +	free(seed);
219 | +
220 | +}
221 | +
222 | +void
223 | +obfuscate_set_keyword(const char *keyword)
224 | +{
225 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
226 | +	obfuscate_keyword = keyword;
227 | +}
228 | +
229 | +void
230 | +obfuscate_input(u_char *buffer, u_int buffer_len)
231 | +{
232 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
233 | +}
234 | +
235 | +void
236 | +obfuscate_output(u_char *buffer, u_int buffer_len)
237 | +{
238 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
239 | +}
240 | +
241 | +static void
242 | +initialize(const u_char *seed, int server)
243 | +{
244 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
245 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
246 | +
247 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
248 | +
249 | +	if(server)
250 | +		set_keys(client_to_server_key, server_to_client_key);
251 | +	else
252 | +		set_keys(server_to_client_key, client_to_server_key);
253 | +}
254 | +
255 | +static void
256 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
257 | +{
258 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
259 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
260 | +}
261 | +
262 | +static void
263 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
264 | +{
265 | +	EVP_MD_CTX *ctx;
266 | +	u_char md_output[EVP_MAX_MD_SIZE];
267 | +	int md_len;
268 | +	int i;
269 | +	u_char *buffer;
270 | +	u_char *p;
271 | +	u_int buffer_length;
272 | +
273 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
274 | +		fatal("Cannot create new digest context");
275 | +
276 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
277 | +	if(obfuscate_keyword)
278 | +		buffer_length += strlen(obfuscate_keyword);
279 | +
280 | +	p = buffer = xmalloc(buffer_length);
281 | +
282 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
283 | +	p += OBFUSCATE_SEED_LENGTH;
284 | +
285 | +	if(obfuscate_keyword) {
286 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
287 | +		p += strlen(obfuscate_keyword);
288 | +	}
289 | +	memcpy(p, iv, iv_len);
290 | +
291 | +	EVP_DigestInit(ctx, EVP_sha1());
292 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
293 | +	EVP_DigestFinal(ctx, md_output, &md_len);
294 | +
295 | +	free(buffer);
296 | +
297 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
298 | +		EVP_DigestInit(ctx, EVP_sha1());
299 | +		EVP_DigestUpdate(ctx, md_output, md_len);
300 | +		EVP_DigestFinal(ctx, md_output, &md_len);
301 | +	}
302 | +
303 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
304 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
305 | +
306 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
307 | +}
308 | +
309 | +static void
310 | +set_keys(const u_char *input_key, const u_char *output_key)
311 | +{
312 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
313 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
314 | +}
315 | +
316 | +static void
317 | +read_forever(int sock_in)
318 | +{
319 | +	u_char discard_buffer[1024];
320 | +
321 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
322 | +		;
323 | +	cleanup_exit(255);
324 | +}
325 | Index: openssh-9.2p1/obfuscate.h
326 | ===================================================================
327 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
328 | +++ openssh-9.2p1/obfuscate.h	2023-02-24 10:55:06.821149662 +0800
329 | @@ -0,0 +1,10 @@
330 | +#ifndef _OBFUSCATE_H
331 | +#define _OBFUSCATE_H
332 | +
333 | +void obfuscate_receive_seed(struct ssh *, int);
334 | +void obfuscate_send_seed(int);
335 | +void obfuscate_set_keyword(const char *);
336 | +void obfuscate_input(u_char *, u_int);
337 | +void obfuscate_output(u_char *, u_int);
338 | +
339 | +#endif
340 | Index: openssh-9.2p1/packet.c
341 | ===================================================================
342 | --- openssh-9.2p1.orig/packet.c	2023-02-02 20:21:54.000000000 +0800
343 | +++ openssh-9.2p1/packet.c	2023-02-24 10:55:06.821149662 +0800
344 | @@ -94,6 +94,7 @@
345 |  #include "channels.h"
346 |  #include "ssh.h"
347 |  #include "packet.h"
348 | +#include "obfuscate.h"
349 |  #include "ssherr.h"
350 |  #include "sshbuf.h"
351 |  
352 | @@ -177,6 +178,8 @@
353 |  	/* Set to true if we are authenticated. */
354 |  	int after_authentication;
355 |  
356 | +	int obfuscation;
357 | +
358 |  	int keep_alive_timeouts;
359 |  
360 |  	/* The maximum time that we will wait to send or receive a packet */
361 | @@ -1200,6 +1203,8 @@
362 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
363 |  			goto out;
364 |  	}
365 | +	if(state->obfuscation)
366 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
367 |  #ifdef PACKET_DEBUG
368 |  	fprintf(stderr, "encrypted: ");
369 |  	sshbuf_dump(state->output, stderr);
370 | @@ -1534,6 +1539,8 @@
371 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
372 |  		    &cp)) != 0)
373 |  			goto out;
374 | +		if(state->obfuscation)
375 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
376 |  		if ((r = cipher_crypt(state->receive_context,
377 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
378 |  		    block_size, 0, 0)) != 0)
379 | @@ -1599,6 +1606,8 @@
380 |  			goto out;
381 |  		}
382 |  	}
383 | +	if(state->obfuscation)
384 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
385 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
386 |  	    &cp)) != 0)
387 |  		goto out;
388 | @@ -2717,3 +2726,25 @@
389 |  	ssh->state->extra_pad = pad;
390 |  	return 0;
391 |  }
392 | +
393 | +void
394 | +sshpkt_enable_obfuscation(struct ssh *ssh)
395 | +{
396 | +	debug("Obfuscation enabled");
397 | +	ssh->state->obfuscation = 1;
398 | +}
399 | +
400 | +void
401 | +sshpkt_disable_obfuscation(struct ssh *ssh)
402 | +{
403 | +	if(ssh->state->obfuscation) {
404 | +		debug("Obfuscation disabled");
405 | +		ssh->state->obfuscation = 0;
406 | +	}
407 | +}
408 | +
409 | +int
410 | +sshpkt_get_obfuscation(struct ssh *ssh)
411 | +{
412 | +	return ssh->state->obfuscation;
413 | +}
414 | Index: openssh-9.2p1/packet.h
415 | ===================================================================
416 | --- openssh-9.2p1.orig/packet.h	2023-02-02 20:21:54.000000000 +0800
417 | +++ openssh-9.2p1/packet.h	2023-02-24 10:55:06.821149662 +0800
418 | @@ -182,6 +182,9 @@
419 |  	    __attribute__((format(printf, 3, 4)))
420 |  	    __attribute__((noreturn));
421 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
422 | +void	sshpkt_enable_obfuscation(struct ssh *);
423 | +void	sshpkt_disable_obfuscation(struct ssh *);
424 | +int sshpkt_get_obfuscation(struct ssh *);
425 |  
426 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
427 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
428 | Index: openssh-9.2p1/readconf.c
429 | ===================================================================
430 | --- openssh-9.2p1.orig/readconf.c	2023-02-24 10:54:30.000000000 +0800
431 | +++ openssh-9.2p1/readconf.c	2023-02-24 10:57:04.041464823 +0800
432 | @@ -144,7 +144,7 @@
433 |  	oBadOption,
434 |  	oHost, oMatch, oInclude,
435 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
436 | -	oGatewayPorts, oExitOnForwardFailure,
437 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
438 |  	oPasswordAuthentication,
439 |  	oXAuthLocation,
440 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
441 | @@ -342,6 +342,8 @@
442 |  	{ "enableescapecommandline", oEnableEscapeCommandline },
443 |  	{ "protocolkeepalives", oProtocolKeepAlives },
444 |  	{ "setuptimeout", oSetupTimeOut },
445 | +	{ "obfuscatehandshake", oObfuscateHandshake },
446 | +	{ "obfuscatekeyword", oObfuscateKeyword },
447 |  
448 |  	{ NULL, oBadOption }
449 |  };
450 | @@ -2248,6 +2250,16 @@
451 |  		intptr = &options->required_rsa_size;
452 |  		goto parse_int;
453 |  
454 | +	case oObfuscateHandshake:
455 | +		intptr = &options->obfuscate_handshake;
456 | +		goto parse_flag;
457 | +
458 | +	case oObfuscateKeyword:
459 | +		if (*activep)
460 | +			options->obfuscate_handshake = 1;
461 | +		charptr = &options->obfuscate_keyword;
462 | +		goto parse_string;
463 | +
464 |  	case oDeprecated:
465 |  		debug("%s line %d: Deprecated option \"%s\"",
466 |  		    filename, linenum, keyword);
467 | @@ -2482,6 +2494,8 @@
468 |  	options->add_keys_to_agent_lifespan = -1;
469 |  	options->identity_agent = NULL;
470 |  	options->visual_host_key = -1;
471 | +	options->obfuscate_handshake = 0;
472 | +	options->obfuscate_keyword = NULL;
473 |  	options->ip_qos_interactive = -1;
474 |  	options->ip_qos_bulk = -1;
475 |  	options->request_tty = -1;
476 | Index: openssh-9.2p1/readconf.h
477 | ===================================================================
478 | --- openssh-9.2p1.orig/readconf.h	2023-02-24 10:54:30.000000000 +0800
479 | +++ openssh-9.2p1/readconf.h	2023-02-24 10:55:06.821149662 +0800
480 | @@ -151,6 +151,8 @@
481 |  	int	permit_local_command;
482 |  	char	*remote_command;
483 |  	int	visual_host_key;
484 | +	int obfuscate_handshake;
485 | +	char *obfuscate_keyword;
486 |  
487 |  	int	request_tty;
488 |  	int	session_type;
489 | Index: openssh-9.2p1/scp.c
490 | ===================================================================
491 | --- openssh-9.2p1.orig/scp.c	2023-02-24 10:54:30.000000000 +0800
492 | +++ openssh-9.2p1/scp.c	2023-02-24 10:55:06.821149662 +0800
493 | @@ -512,7 +512,7 @@
494 |  
495 |  	fflag = Tflag = tflag = 0;
496 |  	while ((ch = getopt(argc, argv,
497 | -	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:")) != -1) {
498 | +	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:zZ:")) != -1) {
499 |  		switch (ch) {
500 |  		/* User-visible flags. */
501 |  		case '1':
502 | @@ -525,6 +525,7 @@
503 |  		case '4':
504 |  		case '6':
505 |  		case 'C':
506 | +		case 'z':
507 |  			addargs(&args, "-%c", ch);
508 |  			addargs(&remote_remote_args, "-%c", ch);
509 |  			break;
510 | @@ -542,6 +543,7 @@
511 |  		case 'i':
512 |  		case 'F':
513 |  		case 'J':
514 | +		case 'Z':
515 |  			addargs(&remote_remote_args, "-%c", ch);
516 |  			addargs(&remote_remote_args, "%s", optarg);
517 |  			addargs(&args, "-%c", ch);
518 | Index: openssh-9.2p1/servconf.c
519 | ===================================================================
520 | --- openssh-9.2p1.orig/servconf.c	2023-02-24 10:54:30.000000000 +0800
521 | +++ openssh-9.2p1/servconf.c	2023-02-24 10:55:06.821149662 +0800
522 | @@ -96,6 +96,7 @@
523 |  
524 |  	/* Standard Options */
525 |  	options->num_ports = 0;
526 | +	options->num_obfuscated_ports = 0;
527 |  	options->ports_from_cmdline = 0;
528 |  	options->queued_listen_addrs = NULL;
529 |  	options->num_queued_listens = 0;
530 | @@ -185,6 +186,7 @@
531 |  	options->permitted_listens = NULL;
532 |  	options->adm_forced_command = NULL;
533 |  	options->chroot_directory = NULL;
534 | +	options->obfuscate_keyword = NULL;
535 |  	options->authorized_keys_command = NULL;
536 |  	options->authorized_keys_command_user = NULL;
537 |  	options->revoked_keys_file = NULL;
538 | @@ -305,7 +307,7 @@
539 |  #endif /* WITH_XMSS */
540 |  	}
541 |  	/* No certificates by default */
542 | -	if (options->num_ports == 0)
543 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
544 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
545 |  	if (options->address_family == -1)
546 |  		options->address_family = AF_UNSPEC;
547 | @@ -517,7 +519,7 @@
548 |  	/* Portable-specific options */
549 |  	sUsePAM,
550 |  	/* Standard Options */
551 | -	sPort, sHostKeyFile, sLoginGraceTime,
552 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
553 |  	sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
554 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
555 |  	sKerberosGetAFSToken, sPasswordAuthentication,
556 | @@ -574,6 +576,8 @@
557 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
558 |  	/* Standard Options */
559 |  	{ "port", sPort, SSHCFG_GLOBAL },
560 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
561 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
562 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
563 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
564 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
565 | @@ -803,6 +807,10 @@
566 |  			add_one_listen_addr(options, addr, rdomain,
567 |  			    options->ports[i]);
568 |  		}
569 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
570 | +			add_one_listen_addr(options, addr, rdomain,
571 | +				options->obfuscated_ports[i]);
572 | +		}
573 |  	}
574 |  }
575 |  
576 | @@ -917,7 +925,7 @@
577 |  	u_int i;
578 |  	struct queued_listenaddr *qla;
579 |  
580 | -	if (options->num_ports == 0)
581 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
582 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
583 |  	if (options->address_family == -1)
584 |  		options->address_family = AF_UNSPEC;
585 | @@ -1453,6 +1461,30 @@
586 |  			    filename, linenum);
587 |  		break;
588 |  
589 | +	case sObfuscatedPort:
590 | +		if(options->ports_from_cmdline)
591 | +			return 0;
592 | +		if(options->listen_addrs != NULL)
593 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
594 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
595 | +			fatal("%s line %d: too many ports.", filename, linenum);
596 | +		arg = argv_next(&ac, &av);
597 | +		if(!arg || *arg == '\0')
598 | +			fatal("%s line %d: missing port number.", filename, linenum);
599 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
600 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
601 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
602 | +		break;
603 | +	case sObfuscateKeyword:
604 | +		charptr = &options->obfuscate_keyword;
605 | +		arg = argv_next(&ac, &av);
606 | +		if(!arg || *arg == '\0')
607 | +			fatal("%s line %d: missing keyword argument.",
608 | +					filename, linenum);
609 | +		if(*activep && *charptr == NULL)
610 | +			*charptr = xstrdup(arg);
611 | +		break;
612 | +
613 |  	case sLoginGraceTime:
614 |  		intptr = &options->login_grace_time;
615 |   parse_time:
616 | Index: openssh-9.2p1/servconf.h
617 | ===================================================================
618 | --- openssh-9.2p1.orig/servconf.h	2023-02-24 10:54:30.000000000 +0800
619 | +++ openssh-9.2p1/servconf.h	2023-02-24 10:55:06.825149661 +0800
620 | @@ -212,6 +212,11 @@
621 |  	u_int   num_permitted_listens;
622 |  
623 |  	char   *chroot_directory;
624 | +
625 | +	int obfuscated_ports[MAX_PORTS];
626 | +	u_int num_obfuscated_ports;
627 | +	char *obfuscate_keyword;
628 | +
629 |  	char   *revoked_keys_file;
630 |  	char   *trusted_user_ca_keys;
631 |  	char   *authorized_keys_command;
632 | Index: openssh-9.2p1/sftp.c
633 | ===================================================================
634 | --- openssh-9.2p1.orig/sftp.c	2023-02-02 20:21:54.000000000 +0800
635 | +++ openssh-9.2p1/sftp.c	2023-02-24 10:55:06.825149661 +0800
636 | @@ -2450,13 +2450,14 @@
637 |  	infile = stdin;
638 |  
639 |  	while ((ch = getopt(argc, argv,
640 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:")) != -1) {
641 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:zZ:")) != -1) {
642 |  		switch (ch) {
643 |  		/* Passed through to ssh(1) */
644 |  		case 'A':
645 |  		case '4':
646 |  		case '6':
647 |  		case 'C':
648 | +		case 'z':
649 |  			addargs(&args, "-%c", ch);
650 |  			break;
651 |  		/* Passed through to ssh(1) with argument */
652 | @@ -2465,6 +2466,7 @@
653 |  		case 'c':
654 |  		case 'i':
655 |  		case 'o':
656 | +		case 'Z':
657 |  			addargs(&args, "-%c", ch);
658 |  			addargs(&args, "%s", optarg);
659 |  			break;
660 | Index: openssh-9.2p1/ssh.c
661 | ===================================================================
662 | --- openssh-9.2p1.orig/ssh.c	2023-02-24 10:54:30.000000000 +0800
663 | +++ openssh-9.2p1/ssh.c	2023-02-24 10:55:06.825149661 +0800
664 | @@ -179,13 +179,14 @@
665 |  usage(void)
666 |  {
667 |  	fprintf(stderr,
668 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
669 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface]\n"
670 |  "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
671 |  "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
672 |  "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
673 |  "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
674 |  "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
675 |  "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
676 | +"           [-Z obfuscate_keyword]\n"
677 |  	);
678 |  	exit(255);
679 |  }
680 | @@ -708,7 +709,7 @@
681 |  
682 |   again:
683 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
684 | -	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
685 | +	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYyzZ:")) != -1) { /* HUZdhjruz */
686 |  		switch (opt) {
687 |  		case '1':
688 |  			fatal("SSH protocol v.1 is no longer supported");
689 | @@ -1055,6 +1056,13 @@
690 |  		case 'F':
691 |  			config = optarg;
692 |  			break;
693 | +		case 'z':
694 | +			options.obfuscate_handshake = 1;
695 | +			break;
696 | +		case 'Z':
697 | +			options.obfuscate_handshake = 1;
698 | +			options.obfuscate_keyword = optarg;
699 | +			break;
700 |  		default:
701 |  			usage();
702 |  		}
703 | Index: openssh-9.2p1/sshconnect.c
704 | ===================================================================
705 | --- openssh-9.2p1.orig/sshconnect.c	2023-02-24 10:54:30.000000000 +0800
706 | +++ openssh-9.2p1/sshconnect.c	2023-02-24 10:55:06.825149661 +0800
707 | @@ -65,6 +65,7 @@
708 |  #include "monitor_fdpass.h"
709 |  #include "ssh2.h"
710 |  #include "version.h"
711 | +#include "obfuscate.h"
712 |  #include "authfile.h"
713 |  #include "ssherr.h"
714 |  #include "authfd.h"
715 | @@ -269,6 +270,12 @@
716 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
717 |  		return -1; /* ssh_packet_set_connection logs error */
718 |  
719 | +	if(options.obfuscate_handshake) {
720 | +		if(options.obfuscate_keyword)
721 | +			obfuscate_set_keyword(options.obfuscate_keyword);
722 | +		sshpkt_enable_obfuscation(ssh);
723 | +	}
724 | +
725 |  	return 0;
726 |  }
727 |  
728 | @@ -530,6 +537,11 @@
729 |  	/* Set the connection. */
730 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
731 |  		return -1; /* ssh_packet_set_connection logs error */
732 | +	if(options.obfuscate_handshake) {
733 | +		if(options.obfuscate_keyword)
734 | +			obfuscate_set_keyword(options.obfuscate_keyword);
735 | +		sshpkt_enable_obfuscation(ssh);
736 | +	}
737 |  
738 |  	return 0;
739 |  }
740 | @@ -1573,6 +1585,9 @@
741 |  	host = xstrdup(orighost);
742 |  	lowercase(host);
743 |  
744 | +	if(options.obfuscate_handshake)
745 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
746 | +
747 |  	/* Exchange protocol version identification strings with the server. */
748 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, 1, NULL)) != 0)
749 |  		sshpkt_fatal(ssh, r, "banner exchange");
750 | Index: openssh-9.2p1/sshd.c
751 | ===================================================================
752 | --- openssh-9.2p1.orig/sshd.c	2023-02-24 10:54:30.000000000 +0800
753 | +++ openssh-9.2p1/sshd.c	2023-02-24 10:58:30.305962876 +0800
754 | @@ -125,6 +125,7 @@
755 |  #include "ssh-gss.h"
756 |  #endif
757 |  #include "monitor_wrap.h"
758 | +#include "obfuscate.h"
759 |  #include "ssh-sandbox.h"
760 |  #include "auth-options.h"
761 |  #include "version.h"
762 | @@ -272,6 +273,9 @@
763 |  /* message to be displayed after login */
764 |  struct sshbuf *loginmsg;
765 |  
766 | +/* Enable handshake obfuscation */
767 | +int use_obfuscation = 0;
768 | +
769 |  /* Unprivileged user */
770 |  struct passwd *privsep_pw = NULL;
771 |  
772 | @@ -1605,7 +1609,7 @@
773 |  	struct ssh *ssh = NULL;
774 |  	extern char *optarg;
775 |  	extern int optind;
776 | -	int r, opt, on = 1, already_daemon, remote_port;
777 | +	int r, opt, on = 1, already_daemon, remote_port, local_port;
778 |  	int sock_in = -1, sock_out = -1, newsock = -1;
779 |  	const char *remote_ip, *rdomain;
780 |  	char *fp, *line, *laddr, *logfile = NULL;
781 | @@ -2243,6 +2247,14 @@
782 |  	process_channel_timeouts(ssh, &options);
783 |  	process_permitopen(ssh, &options);
784 |  
785 | +	local_port = ssh_local_port(ssh);
786 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
787 | +		if(options.obfuscated_ports[i] == local_port) {
788 | +			use_obfuscation = 1;
789 | +			break;
790 | +		}
791 | +	}
792 | +
793 |  	/* Set SO_KEEPALIVE if requested. */
794 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
795 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
796 | @@ -2308,6 +2320,13 @@
797 |  	if (!debug_flag)
798 |  		alarm(options.login_grace_time);
799 |  
800 | +	if(use_obfuscation) {
801 | +		if(options.obfuscate_keyword)
802 | +			obfuscate_set_keyword(options.obfuscate_keyword);
803 | +		sshpkt_enable_obfuscation(ssh);
804 | +		obfuscate_receive_seed(ssh, sock_in);
805 | +	}
806 | +
807 |  	if ((r = kex_exchange_identification(ssh, -1, options.debian_banner,
808 |  	    options.version_addendum)) != 0)
809 |  		sshpkt_fatal(ssh, r, "banner exchange");
810 | @@ -2333,8 +2352,12 @@
811 |  	auth_debug_reset();
812 |  
813 |  	if (use_privsep) {
814 | -		if (privsep_preauth(ssh) == 1)
815 | +
816 | +		if (privsep_preauth(ssh) == 1) {
817 | +			if(use_obfuscation)
818 | +				sshpkt_disable_obfuscation(ssh);
819 |  			goto authenticated;
820 | +		}
821 |  	} else if (have_agent) {
822 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
823 |  			error_r(r, "Unable to get agent socket");
824 | Index: openssh-9.2p1/sshd_config
825 | ===================================================================
826 | --- openssh-9.2p1.orig/sshd_config	2023-02-24 10:54:30.000000000 +0800
827 | +++ openssh-9.2p1/sshd_config	2023-02-24 10:55:06.825149661 +0800
828 | @@ -13,6 +13,8 @@
829 |  Include /etc/ssh/sshd_config.d/*.conf
830 |  
831 |  #Port 22
832 | +#ObfuscatedPort 222
833 | +#ObfuscateKeyword key
834 |  #AddressFamily any
835 |  #ListenAddress 0.0.0.0
836 |  #ListenAddress ::
837 | 


--------------------------------------------------------------------------------
/debian/9.7p1.diff:
--------------------------------------------------------------------------------
1 | 9.6p1.diff


--------------------------------------------------------------------------------
/debian/9.9p1.diff:
--------------------------------------------------------------------------------
1 | 9.8p1.diff


--------------------------------------------------------------------------------
/portable/8.4.diff:
--------------------------------------------------------------------------------
  1 | diff --git a/Makefile.in b/Makefile.in
  2 | index acfb919..957dd38 100644
  3 | --- a/Makefile.in
  4 | +++ b/Makefile.in
  5 | @@ -108,7 +108,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
  6 |  	kexgexc.o kexgexs.o \
  7 |  	sntrup4591761.o kexsntrup4591761x25519.o kexgen.o \
  8 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
  9 | -	sshbuf-io.o
 10 | +	sshbuf-io.o obfuscate.o
 11 |  
 12 |  SKOBJS=	ssh-sk-client.o
 13 |  
 14 | diff --git a/kex.c b/kex.c
 15 | index aecb939..bc75213 100644
 16 | --- a/kex.c
 17 | +++ b/kex.c
 18 | @@ -58,6 +58,7 @@
 19 |  #include "dispatch.h"
 20 |  #include "monitor.h"
 21 |  
 22 | +#include "obfuscate.h"
 23 |  #include "ssherr.h"
 24 |  #include "sshbuf.h"
 25 |  #include "digest.h"
 26 | @@ -460,9 +461,12 @@ kex_send_newkeys(struct ssh *ssh)
 27 |  		return r;
 28 |  	debug("SSH2_MSG_NEWKEYS sent");
 29 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 30 | -	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
 31 | +	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0) {
 32 | +		sshpkt_disable_obfuscation(ssh);
 33 |  		if ((r = kex_send_ext_info(ssh)) != 0)
 34 |  			return r;
 35 | +		sshpkt_enable_obfuscation(ssh);
 36 | +	}
 37 |  	debug("expecting SSH2_MSG_NEWKEYS");
 38 |  	return 0;
 39 |  }
 40 | @@ -525,6 +529,7 @@ kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh)
 41 |  	kex->flags &= ~KEX_INIT_SENT;
 42 |  	free(kex->name);
 43 |  	kex->name = NULL;
 44 | +	sshpkt_disable_obfuscation(ssh);
 45 |  	return 0;
 46 |  }
 47 |  
 48 | @@ -1191,14 +1196,42 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
 49 |  		goto out;
 50 |  	}
 51 |  
 52 | +	/* Make copy and obfuscate the original */
 53 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 54 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 55 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 56 | +			r = SSH_ERR_ALLOC_FAIL;
 57 | +			goto out;
 58 | +		}
 59 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 60 | +	}
 61 | +
 62 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 63 |  	    sshbuf_mutable_ptr(our_version),
 64 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 65 |  		oerrno = errno;
 66 |  		debug("%s: write: %.100s", __func__, strerror(errno));
 67 |  		r = SSH_ERR_SYSTEM_ERROR;
 68 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 69 | +			free(cp);
 70 | +		}
 71 |  		goto out;
 72 |  	}
 73 | +
 74 | +	/* Restore the original */
 75 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 76 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 77 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 78 | +			free(cp);
 79 | +			goto out;
 80 | +		}
 81 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 82 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 83 | +			free(cp);
 84 | +			goto out;
 85 | +		}
 86 | +	}
 87 | +
 88 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 89 |  		oerrno = errno;
 90 |  		error("%s: sshbuf_consume_end: %s", __func__, ssh_err(r));
 91 | @@ -1258,6 +1291,8 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
 92 |  				r = SSH_ERR_SYSTEM_ERROR;
 93 |  				goto out;
 94 |  			}
 95 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 96 | +			  obfuscate_input(&c, 1);
 97 |  			if (c == '\r') {
 98 |  				expect_nl = 1;
 99 |  				continue;
100 | diff --git a/obfuscate.c b/obfuscate.c
101 | new file mode 100644
102 | index 0000000..eb202a2
103 | --- /dev/null
104 | +++ b/obfuscate.c
105 | @@ -0,0 +1,220 @@
106 | +#include "includes.h"
107 | +#include <openssl/evp.h>
108 | +#include <openssl/rc4.h>
109 | +#include "openbsd-compat/openssl-compat.h"
110 | +#include <unistd.h>
111 | +#include <string.h>
112 | +#include "atomicio.h"
113 | +#include "canohost.h"
114 | +#include "xmalloc.h"
115 | +#include "log.h"
116 | +#include "packet.h"
117 | +#include "obfuscate.h"
118 | +
119 | +static RC4_KEY rc4_input;
120 | +static RC4_KEY rc4_output;
121 | +
122 | +static const char *obfuscate_keyword = NULL;
123 | +
124 | +#define OBFUSCATE_KEY_LENGTH 	16
125 | +#define OBFUSCATE_SEED_LENGTH	16
126 | +#define OBFUSCATE_HASH_ITERATIONS 6000
127 | +#define OBFUSCATE_MAX_PADDING	8192
128 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
129 | +
130 | +struct seed_msg {
131 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
132 | +	u_int32_t magic;
133 | +	u_int32_t padding_length;
134 | +	u_char padding[];
135 | +};
136 | +
137 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
138 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
139 | +static void set_keys(const u_char *, const u_char *);
140 | +static void initialize(const u_char *, int);
141 | +static void read_forever(int);
142 | +
143 | +
144 | +/*
145 | + * Server calls this
146 | + */
147 | +void
148 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
149 | +{
150 | +	struct seed_msg seed;
151 | +
152 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
153 | +	u_int len;
154 | +	u_int32_t padding_length;
155 | +
156 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
157 | +
158 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
159 | +	if(len != sizeof(struct seed_msg))
160 | +		fatal("obfuscate_receive_seed: read failed");
161 | +
162 | +	initialize(seed.seed_buffer, 1);
163 | +	obfuscate_input((u_char *)&seed.magic, 8);
164 | +
165 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
166 | +		logit("Magic value check failed (%u) on obfuscated handshake "
167 | + 			"from %.200s port %d", ntohl(seed.magic),
168 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
169 | +		read_forever(sock_in);
170 | +	}
171 | +	padding_length = ntohl(seed.padding_length);
172 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
173 | +		logit("Illegal padding length %d for obfuscated handshake "
174 | + 			"from %.200s port %d", ntohl(seed.padding_length),
175 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
176 | +		read_forever(sock_in);
177 | +	}
178 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
179 | +	if(len != padding_length)
180 | +		fatal("obfuscate_receive_seed: read failed");
181 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
182 | +	obfuscate_input(padding_drain, padding_length);
183 | +}
184 | +
185 | +/*
186 | + * Client calls this
187 | + */
188 | +void
189 | +obfuscate_send_seed(int sock_out)
190 | +{
191 | +	struct seed_msg *seed;
192 | +	int i;
193 | +	u_int32_t rnd = 0;
194 | +	u_int message_length;
195 | +	u_int padding_length;
196 | +
197 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
198 | +	message_length = padding_length + sizeof(struct seed_msg);
199 | +	seed = xmalloc(message_length);
200 | +
201 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
202 | +		if(i % 4 == 0)
203 | +			rnd = arc4random();
204 | +		seed->seed_buffer[i] = rnd & 0xff;
205 | +		rnd >>= 8;
206 | +	}
207 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
208 | +	seed->padding_length = htonl(padding_length);
209 | +	for(i = 0; i < (int)padding_length; i++) {
210 | +		if(i % 4 == 0)
211 | +			rnd = arc4random();
212 | +		seed->padding[i] = rnd & 0xff;
213 | +	}
214 | +	initialize(seed->seed_buffer, 0);
215 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
216 | +		message_length - OBFUSCATE_SEED_LENGTH);
217 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
218 | +	atomicio(vwrite, sock_out, seed, message_length);
219 | +	free(seed);
220 | +
221 | +}
222 | +
223 | +void
224 | +obfuscate_set_keyword(const char *keyword)
225 | +{
226 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
227 | +	obfuscate_keyword = keyword;
228 | +}
229 | +
230 | +void
231 | +obfuscate_input(u_char *buffer, u_int buffer_len)
232 | +{
233 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
234 | +}
235 | +
236 | +void
237 | +obfuscate_output(u_char *buffer, u_int buffer_len)
238 | +{
239 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
240 | +}
241 | +
242 | +static void
243 | +initialize(const u_char *seed, int server)
244 | +{
245 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
246 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
247 | +
248 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
249 | +
250 | +	if(server)
251 | +		set_keys(client_to_server_key, server_to_client_key);
252 | +	else
253 | +		set_keys(server_to_client_key, client_to_server_key);
254 | +}
255 | +
256 | +static void
257 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
258 | +{
259 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
260 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
261 | +}
262 | +
263 | +static void
264 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
265 | +{
266 | +	EVP_MD_CTX *ctx;
267 | +	u_char md_output[EVP_MAX_MD_SIZE];
268 | +	int md_len;
269 | +	int i;
270 | +	u_char *buffer;
271 | +	u_char *p;
272 | +	u_int buffer_length;
273 | +
274 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
275 | +		fatal("Cannot create new digest context");
276 | +
277 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
278 | +	if(obfuscate_keyword)
279 | +		buffer_length += strlen(obfuscate_keyword);
280 | +
281 | +	p = buffer = xmalloc(buffer_length);
282 | +
283 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
284 | +	p += OBFUSCATE_SEED_LENGTH;
285 | +
286 | +	if(obfuscate_keyword) {
287 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
288 | +		p += strlen(obfuscate_keyword);
289 | +	}
290 | +	memcpy(p, iv, iv_len);
291 | +
292 | +	EVP_DigestInit(ctx, EVP_sha1());
293 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
294 | +	EVP_DigestFinal(ctx, md_output, &md_len);
295 | +
296 | +	free(buffer);
297 | +
298 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
299 | +		EVP_DigestInit(ctx, EVP_sha1());
300 | +		EVP_DigestUpdate(ctx, md_output, md_len);
301 | +		EVP_DigestFinal(ctx, md_output, &md_len);
302 | +	}
303 | +
304 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
305 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
306 | +
307 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
308 | +}
309 | +
310 | +static void
311 | +set_keys(const u_char *input_key, const u_char *output_key)
312 | +{
313 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
314 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
315 | +}
316 | +
317 | +static void
318 | +read_forever(int sock_in)
319 | +{
320 | +	u_char discard_buffer[1024];
321 | +
322 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
323 | +		;
324 | +	cleanup_exit(255);
325 | +}
326 | diff --git a/obfuscate.h b/obfuscate.h
327 | new file mode 100644
328 | index 0000000..d5fb92b
329 | --- /dev/null
330 | +++ b/obfuscate.h
331 | @@ -0,0 +1,10 @@
332 | +#ifndef _OBFUSCATE_H
333 | +#define _OBFUSCATE_H
334 | +
335 | +void obfuscate_receive_seed(struct ssh *, int);
336 | +void obfuscate_send_seed(int);
337 | +void obfuscate_set_keyword(const char *);
338 | +void obfuscate_input(u_char *, u_int);
339 | +void obfuscate_output(u_char *, u_int);
340 | +
341 | +#endif
342 | diff --git a/packet.c b/packet.c
343 | index 00e3180..859cf57 100644
344 | --- a/packet.c
345 | +++ b/packet.c
346 | @@ -94,6 +94,7 @@
347 |  #include "channels.h"
348 |  #include "ssh.h"
349 |  #include "packet.h"
350 | +#include "obfuscate.h"
351 |  #include "ssherr.h"
352 |  #include "sshbuf.h"
353 |  
354 | @@ -177,6 +178,8 @@ struct session_state {
355 |  	/* Set to true if we are authenticated. */
356 |  	int after_authentication;
357 |  
358 | +	int obfuscation;
359 | +
360 |  	int keep_alive_timeouts;
361 |  
362 |  	/* The maximum time that we will wait to send or receive a packet */
363 | @@ -1203,6 +1206,8 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
364 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
365 |  			goto out;
366 |  	}
367 | +	if(state->obfuscation)
368 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
369 |  #ifdef PACKET_DEBUG
370 |  	fprintf(stderr, "encrypted: ");
371 |  	sshbuf_dump(state->output, stderr);
372 | @@ -1545,6 +1550,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
373 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
374 |  		    &cp)) != 0)
375 |  			goto out;
376 | +		if(state->obfuscation)
377 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
378 |  		if ((r = cipher_crypt(state->receive_context,
379 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
380 |  		    block_size, 0, 0)) != 0)
381 | @@ -1610,6 +1617,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
382 |  			goto out;
383 |  		}
384 |  	}
385 | +	if(state->obfuscation)
386 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
387 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
388 |  	    &cp)) != 0)
389 |  		goto out;
390 | @@ -2745,3 +2754,25 @@ sshpkt_add_padding(struct ssh *ssh, u_char pad)
391 |  	ssh->state->extra_pad = pad;
392 |  	return 0;
393 |  }
394 | +
395 | +void
396 | +sshpkt_enable_obfuscation(struct ssh *ssh)
397 | +{
398 | +	debug("Obfuscation enabled");
399 | +	ssh->state->obfuscation = 1;
400 | +}
401 | +
402 | +void
403 | +sshpkt_disable_obfuscation(struct ssh *ssh)
404 | +{
405 | +	if(ssh->state->obfuscation) {
406 | +		debug("Obfuscation disabled");
407 | +		ssh->state->obfuscation = 0;
408 | +	}
409 | +}
410 | +
411 | +int
412 | +sshpkt_get_obfuscation(struct ssh *ssh)
413 | +{
414 | +	return ssh->state->obfuscation;
415 | +}
416 | diff --git a/packet.h b/packet.h
417 | index c2544bd..b54cf9c 100644
418 | --- a/packet.h
419 | +++ b/packet.h
420 | @@ -180,6 +180,9 @@ void	sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
421 |  	    __attribute__((format(printf, 3, 4)))
422 |  	    __attribute__((noreturn));
423 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
424 | +void	sshpkt_enable_obfuscation(struct ssh *);
425 | +void	sshpkt_disable_obfuscation(struct ssh *);
426 | +int sshpkt_get_obfuscation(struct ssh *);
427 |  
428 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
429 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
430 | diff --git a/readconf.c b/readconf.c
431 | index 554efd7..7515c6f 100644
432 | --- a/readconf.c
433 | +++ b/readconf.c
434 | @@ -143,7 +143,7 @@ typedef enum {
435 |  	oBadOption,
436 |  	oHost, oMatch, oInclude,
437 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
438 | -	oGatewayPorts, oExitOnForwardFailure,
439 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
440 |  	oPasswordAuthentication,
441 |  	oChallengeResponseAuthentication, oXAuthLocation,
442 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
443 | @@ -310,6 +310,8 @@ static struct {
444 |  	{ "ignoreunknown", oIgnoreUnknown },
445 |  	{ "proxyjump", oProxyJump },
446 |  	{ "securitykeyprovider", oSecurityKeyProvider },
447 | +	{ "obfuscatehandshake", oObfuscateHandshake },
448 | +	{ "obfuscatekeyword", oObfuscateKeyword },
449 |  
450 |  	{ NULL, oBadOption }
451 |  };
452 | @@ -1853,6 +1855,16 @@ parse_keytypes:
453 |  			*charptr = xstrdup(arg);
454 |  		break;
455 |  
456 | +	case oObfuscateHandshake:
457 | +		intptr = &options->obfuscate_handshake;
458 | +		goto parse_flag;
459 | +
460 | +	case oObfuscateKeyword:
461 | +		if (*activep)
462 | +			options->obfuscate_handshake = 1;
463 | +		charptr = &options->obfuscate_keyword;
464 | +		goto parse_string;
465 | +
466 |  	case oDeprecated:
467 |  		debug("%s line %d: Deprecated option \"%s\"",
468 |  		    filename, linenum, keyword);
469 | @@ -2047,6 +2059,8 @@ initialize_options(Options * options)
470 |  	options->add_keys_to_agent_lifespan = -1;
471 |  	options->identity_agent = NULL;
472 |  	options->visual_host_key = -1;
473 | +	options->obfuscate_handshake = 0;
474 | +	options->obfuscate_keyword = NULL;
475 |  	options->ip_qos_interactive = -1;
476 |  	options->ip_qos_bulk = -1;
477 |  	options->request_tty = -1;
478 | diff --git a/readconf.h b/readconf.h
479 | index d6a1555..5d93b1e 100644
480 | --- a/readconf.h
481 | +++ b/readconf.h
482 | @@ -141,6 +141,8 @@ typedef struct {
483 |  	int	permit_local_command;
484 |  	char	*remote_command;
485 |  	int	visual_host_key;
486 | +	int obfuscate_handshake;
487 | +	char *obfuscate_keyword;
488 |  
489 |  	int	request_tty;
490 |  
491 | diff --git a/scp.c b/scp.c
492 | index 6ae1706..ce6f323 100644
493 | --- a/scp.c
494 | +++ b/scp.c
495 | @@ -432,7 +432,7 @@ main(int argc, char **argv)
496 |  
497 |  	fflag = Tflag = tflag = 0;
498 |  	while ((ch = getopt(argc, argv,
499 | -	    "12346ABCTdfpqrtvF:J:P:S:c:i:l:o:")) != -1) {
500 | +	    "12346ABCTdfpqrtvF:J:P:S:c:i:l:o:zZ:")) != -1) {
501 |  		switch (ch) {
502 |  		/* User-visible flags. */
503 |  		case '1':
504 | @@ -445,6 +445,7 @@ main(int argc, char **argv)
505 |  		case '4':
506 |  		case '6':
507 |  		case 'C':
508 | +		case 'z':
509 |  			addargs(&args, "-%c", ch);
510 |  			addargs(&remote_remote_args, "-%c", ch);
511 |  			break;
512 | @@ -456,6 +457,7 @@ main(int argc, char **argv)
513 |  		case 'i':
514 |  		case 'F':
515 |  		case 'J':
516 | +		case 'Z':
517 |  			addargs(&remote_remote_args, "-%c", ch);
518 |  			addargs(&remote_remote_args, "%s", optarg);
519 |  			addargs(&args, "-%c", ch);
520 | diff --git a/servconf.c b/servconf.c
521 | index f08e374..7c16cca 100644
522 | --- a/servconf.c
523 | +++ b/servconf.c
524 | @@ -95,6 +95,7 @@ initialize_server_options(ServerOptions *options)
525 |  
526 |  	/* Standard Options */
527 |  	options->num_ports = 0;
528 | +	options->num_obfuscated_ports = 0;
529 |  	options->ports_from_cmdline = 0;
530 |  	options->queued_listen_addrs = NULL;
531 |  	options->num_queued_listens = 0;
532 | @@ -177,6 +178,7 @@ initialize_server_options(ServerOptions *options)
533 |  	options->permitted_listens = NULL;
534 |  	options->adm_forced_command = NULL;
535 |  	options->chroot_directory = NULL;
536 | +	options->obfuscate_keyword = NULL;
537 |  	options->authorized_keys_command = NULL;
538 |  	options->authorized_keys_command_user = NULL;
539 |  	options->revoked_keys_file = NULL;
540 | @@ -318,7 +320,7 @@ fill_default_server_options(ServerOptions *options)
541 |  #endif /* WITH_XMSS */
542 |  	}
543 |  	/* No certificates by default */
544 | -	if (options->num_ports == 0)
545 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
546 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
547 |  	if (options->address_family == -1)
548 |  		options->address_family = AF_UNSPEC;
549 | @@ -503,7 +505,7 @@ typedef enum {
550 |  	/* Portable-specific options */
551 |  	sUsePAM,
552 |  	/* Standard Options */
553 | -	sPort, sHostKeyFile, sLoginGraceTime,
554 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
555 |  	sPermitRootLogin, sLogFacility, sLogLevel,
556 |  	sRhostsRSAAuthentication, sRSAAuthentication,
557 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
558 | @@ -559,6 +561,8 @@ static struct {
559 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
560 |  	/* Standard Options */
561 |  	{ "port", sPort, SSHCFG_GLOBAL },
562 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
563 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
564 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
565 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
566 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
567 | @@ -767,6 +771,10 @@ add_listen_addr(ServerOptions *options, const char *addr,
568 |  			add_one_listen_addr(options, addr, rdomain,
569 |  			    options->ports[i]);
570 |  		}
571 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
572 | +			add_one_listen_addr(options, addr, rdomain,
573 | +				options->obfuscated_ports[i]);
574 | +		}
575 |  	}
576 |  }
577 |  
578 | @@ -881,7 +889,7 @@ process_queued_listen_addrs(ServerOptions *options)
579 |  	u_int i;
580 |  	struct queued_listenaddr *qla;
581 |  
582 | -	if (options->num_ports == 0)
583 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
584 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
585 |  	if (options->address_family == -1)
586 |  		options->address_family = AF_UNSPEC;
587 | @@ -1339,6 +1347,30 @@ process_server_config_line_depth(ServerOptions *options, char *line,
588 |  			    filename, linenum);
589 |  		break;
590 |  
591 | +	case sObfuscatedPort:
592 | +		if(options->ports_from_cmdline)
593 | +			return 0;
594 | +		if(options->listen_addrs != NULL)
595 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
596 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
597 | +			fatal("%s line %d: too many ports.", filename, linenum);
598 | +		arg = strdelim(&cp);
599 | +		if(!arg || *arg == '\0')
600 | +			fatal("%s line %d: missing port number.", filename, linenum);
601 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
602 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
603 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
604 | +		break;
605 | +	case sObfuscateKeyword:
606 | +		charptr = &options->obfuscate_keyword;
607 | +		arg = strdelim(&cp);
608 | +		if(!arg || *arg == '\0')
609 | +			fatal("%s line %d: missing keyword argument.",
610 | +					filename, linenum);
611 | +		if(*activep && *charptr == NULL)
612 | +			*charptr = xstrdup(arg);
613 | +		break;
614 | +
615 |  	case sLoginGraceTime:
616 |  		intptr = &options->login_grace_time;
617 |   parse_time:
618 | diff --git a/servconf.h b/servconf.h
619 | index 1df8f3d..060a4e1 100644
620 | --- a/servconf.h
621 | +++ b/servconf.h
622 | @@ -204,6 +204,11 @@ typedef struct {
623 |  	u_int   num_permitted_listens;
624 |  
625 |  	char   *chroot_directory;
626 | +
627 | +	int obfuscated_ports[MAX_PORTS];
628 | +	u_int num_obfuscated_ports;
629 | +	char *obfuscate_keyword;
630 | +
631 |  	char   *revoked_keys_file;
632 |  	char   *trusted_user_ca_keys;
633 |  	char   *authorized_keys_command;
634 | diff --git a/sftp.c b/sftp.c
635 | index c88c861..a57f466 100644
636 | --- a/sftp.c
637 | +++ b/sftp.c
638 | @@ -2408,13 +2408,14 @@ main(int argc, char **argv)
639 |  	infile = stdin;
640 |  
641 |  	while ((ch = getopt(argc, argv,
642 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:")) != -1) {
643 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:zZ:")) != -1) {
644 |  		switch (ch) {
645 |  		/* Passed through to ssh(1) */
646 |  		case 'A':
647 |  		case '4':
648 |  		case '6':
649 |  		case 'C':
650 | +		case 'z':
651 |  			addargs(&args, "-%c", ch);
652 |  			break;
653 |  		/* Passed through to ssh(1) with argument */
654 | @@ -2423,6 +2424,7 @@ main(int argc, char **argv)
655 |  		case 'c':
656 |  		case 'i':
657 |  		case 'o':
658 | +		case 'Z':
659 |  			addargs(&args, "-%c", ch);
660 |  			addargs(&args, "%s", optarg);
661 |  			break;
662 | diff --git a/ssh.c b/ssh.c
663 | index f34ca0d..66dd0ff 100644
664 | --- a/ssh.c
665 | +++ b/ssh.c
666 | @@ -203,13 +203,14 @@ static void
667 |  usage(void)
668 |  {
669 |  	fprintf(stderr,
670 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
671 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface]\n"
672 |  "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
673 |  "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
674 |  "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
675 |  "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
676 |  "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
677 | -"           [-w local_tun[:remote_tun]] destination [command]\n"
678 | +"           [-w local_tun[:remote_tun]] [-Z obfuscate_keyword]\n"
679 | +"			destination [command]\n"
680 |  	);
681 |  	exit(255);
682 |  }
683 | @@ -722,7 +723,7 @@ main(int ac, char **av)
684 |  
685 |   again:
686 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
687 | -	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
688 | +	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYyzZ:")) != -1) {
689 |  		switch (opt) {
690 |  		case '1':
691 |  			fatal("SSH protocol v.1 is no longer supported");
692 | @@ -1066,6 +1067,13 @@ main(int ac, char **av)
693 |  		case 'F':
694 |  			config = optarg;
695 |  			break;
696 | +		case 'z':
697 | +			options.obfuscate_handshake = 1;
698 | +			break;
699 | +		case 'Z':
700 | +			options.obfuscate_handshake = 1;
701 | +			options.obfuscate_keyword = optarg;
702 | +			break;
703 |  		default:
704 |  			usage();
705 |  		}
706 | diff --git a/sshconnect.c b/sshconnect.c
707 | index 9ec0618..6f34f36 100644
708 | --- a/sshconnect.c
709 | +++ b/sshconnect.c
710 | @@ -64,6 +64,7 @@
711 |  #include "monitor_fdpass.h"
712 |  #include "ssh2.h"
713 |  #include "version.h"
714 | +#include "obfuscate.h"
715 |  #include "authfile.h"
716 |  #include "ssherr.h"
717 |  #include "authfd.h"
718 | @@ -284,6 +285,12 @@ ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
719 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
720 |  		return -1; /* ssh_packet_set_connection logs error */
721 |  
722 | +	if(options.obfuscate_handshake) {
723 | +		if(options.obfuscate_keyword)
724 | +			obfuscate_set_keyword(options.obfuscate_keyword);
725 | +		sshpkt_enable_obfuscation(ssh);
726 | +	}
727 | +
728 |  	return 0;
729 |  }
730 |  
731 | @@ -544,6 +551,11 @@ ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
732 |  	/* Set the connection. */
733 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
734 |  		return -1; /* ssh_packet_set_connection logs error */
735 | +	if(options.obfuscate_handshake) {
736 | +		if(options.obfuscate_keyword)
737 | +			obfuscate_set_keyword(options.obfuscate_keyword);
738 | +		sshpkt_enable_obfuscation(ssh);
739 | +	}
740 |  
741 |  	return 0;
742 |  }
743 | @@ -1288,6 +1300,9 @@ ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
744 |  	host = xstrdup(orighost);
745 |  	lowercase(host);
746 |  
747 | +	if(options.obfuscate_handshake)
748 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
749 | +
750 |  	/* Exchange protocol version identification strings with the server. */
751 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
752 |  		sshpkt_fatal(ssh, r, "banner exchange");
753 | diff --git a/sshd.c b/sshd.c
754 | index 8de4a9c..a5ad0f1 100644
755 | --- a/sshd.c
756 | +++ b/sshd.c
757 | @@ -118,6 +118,7 @@
758 |  #include "ssh-gss.h"
759 |  #endif
760 |  #include "monitor_wrap.h"
761 | +#include "obfuscate.h"
762 |  #include "ssh-sandbox.h"
763 |  #include "auth-options.h"
764 |  #include "version.h"
765 | @@ -257,6 +258,9 @@ struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
766 |  /* message to be displayed after login */
767 |  struct sshbuf *loginmsg;
768 |  
769 | +/* Enable handshake obfuscation */
770 | +int use_obfuscation = 0;
771 | +
772 |  /* Unprivileged user */
773 |  struct passwd *privsep_pw = NULL;
774 |  
775 | @@ -1536,7 +1540,7 @@ main(int ac, char **av)
776 |  	struct ssh *ssh = NULL;
777 |  	extern char *optarg;
778 |  	extern int optind;
779 | -	int r, opt, on = 1, already_daemon, remote_port;
780 | +	int r, opt, on = 1, already_daemon, remote_port, local_port;
781 |  	int sock_in = -1, sock_out = -1, newsock = -1;
782 |  	const char *remote_ip, *rdomain;
783 |  	char *fp, *line, *laddr, *logfile = NULL;
784 | @@ -2166,6 +2170,14 @@ main(int ac, char **av)
785 |  	channel_set_af(ssh, options.address_family);
786 |  	process_permitopen(ssh, &options);
787 |  
788 | +	local_port = ssh_local_port(ssh);
789 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
790 | +		if(options.obfuscated_ports[i] == local_port) {
791 | +			use_obfuscation = 1;
792 | +			break;
793 | +		}
794 | +	}
795 | +
796 |  	/* Set SO_KEEPALIVE if requested. */
797 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
798 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
799 | @@ -2213,6 +2225,13 @@ main(int ac, char **av)
800 |  	if (!debug_flag)
801 |  		alarm(options.login_grace_time);
802 |  
803 | +	if(use_obfuscation) {
804 | +		if(options.obfuscate_keyword)
805 | +			obfuscate_set_keyword(options.obfuscate_keyword);
806 | +		sshpkt_enable_obfuscation(ssh);
807 | +		obfuscate_receive_seed(ssh, sock_in);
808 | +	}
809 | +
810 |  	if ((r = kex_exchange_identification(ssh, -1,
811 |  	    options.version_addendum)) != 0)
812 |  		sshpkt_fatal(ssh, r, "banner exchange");
813 | @@ -2238,8 +2257,12 @@ main(int ac, char **av)
814 |  	auth_debug_reset();
815 |  
816 |  	if (use_privsep) {
817 | -		if (privsep_preauth(ssh) == 1)
818 | +
819 | +		if (privsep_preauth(ssh) == 1) {
820 | +			if(use_obfuscation)
821 | +				sshpkt_disable_obfuscation(ssh);
822 |  			goto authenticated;
823 | +		}
824 |  	} else if (have_agent) {
825 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
826 |  			error("Unable to get agent socket: %s", ssh_err(r));
827 | diff --git a/sshd_config b/sshd_config
828 | index 19b7c91..21c4ffc 100644
829 | --- a/sshd_config
830 | +++ b/sshd_config
831 | @@ -11,6 +11,8 @@
832 |  # default value.
833 |  
834 |  #Port 22
835 | +#ObfuscatedPort 222
836 | +#ObfuscateKeyword key
837 |  #AddressFamily any
838 |  #ListenAddress 0.0.0.0
839 |  #ListenAddress ::
840 | 


--------------------------------------------------------------------------------
/portable/9.2.diff:
--------------------------------------------------------------------------------
  1 | diff --git a/Makefile.in b/Makefile.in
  2 | index c0ebfa04..678f6315 100644
  3 | --- a/Makefile.in
  4 | +++ b/Makefile.in
  5 | @@ -111,7 +111,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
  6 |  	kexgexc.o kexgexs.o \
  7 |  	kexsntrup761x25519.o sntrup761.o kexgen.o \
  8 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
  9 | -	sshbuf-io.o
 10 | +	sshbuf-io.o obfuscate.o
 11 |  
 12 |  SKOBJS=	ssh-sk-client.o
 13 |  
 14 | diff --git a/kex.c b/kex.c
 15 | index 8cdefcf7..9612f17b 100644
 16 | --- a/kex.c
 17 | +++ b/kex.c
 18 | @@ -58,6 +58,7 @@
 19 |  #include "dispatch.h"
 20 |  #include "monitor.h"
 21 |  
 22 | +#include "obfuscate.h"
 23 |  #include "ssherr.h"
 24 |  #include "sshbuf.h"
 25 |  #include "digest.h"
 26 | @@ -464,9 +465,12 @@ kex_send_newkeys(struct ssh *ssh)
 27 |  		return r;
 28 |  	debug("SSH2_MSG_NEWKEYS sent");
 29 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 30 | -	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
 31 | +	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0) {
 32 | +		sshpkt_disable_obfuscation(ssh);
 33 |  		if ((r = kex_send_ext_info(ssh)) != 0)
 34 |  			return r;
 35 | +		sshpkt_enable_obfuscation(ssh);
 36 | +	}
 37 |  	debug("expecting SSH2_MSG_NEWKEYS");
 38 |  	return 0;
 39 |  }
 40 | @@ -544,6 +548,7 @@ kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh)
 41 |  	kex->flags &= ~KEX_INIT_SENT;
 42 |  	free(kex->name);
 43 |  	kex->name = NULL;
 44 | +	sshpkt_disable_obfuscation(ssh);
 45 |  	return 0;
 46 |  }
 47 |  
 48 | @@ -1238,14 +1243,42 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
 49 |  		goto out;
 50 |  	}
 51 |  
 52 | +	/* Make copy and obfuscate the original */
 53 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 54 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 55 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 56 | +			r = SSH_ERR_ALLOC_FAIL;
 57 | +			goto out;
 58 | +		}
 59 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 60 | +	}
 61 | +
 62 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 63 |  	    sshbuf_mutable_ptr(our_version),
 64 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 65 |  		oerrno = errno;
 66 |  		debug_f("write: %.100s", strerror(errno));
 67 |  		r = SSH_ERR_SYSTEM_ERROR;
 68 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 69 | +			free(cp);
 70 | +		}
 71 |  		goto out;
 72 |  	}
 73 | +
 74 | +	/* Restore the original */
 75 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 76 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 77 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 78 | +			free(cp);
 79 | +			goto out;
 80 | +		}
 81 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 82 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 83 | +			free(cp);
 84 | +			goto out;
 85 | +		}
 86 | +	}
 87 | +
 88 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 89 |  		oerrno = errno;
 90 |  		error_fr(r, "sshbuf_consume_end");
 91 | @@ -1302,6 +1335,8 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
 92 |  				r = SSH_ERR_SYSTEM_ERROR;
 93 |  				goto out;
 94 |  			}
 95 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 96 | +			  obfuscate_input(&c, 1);
 97 |  			if (c == '\r') {
 98 |  				expect_nl = 1;
 99 |  				continue;
100 | diff --git a/obfuscate.c b/obfuscate.c
101 | new file mode 100644
102 | index 00000000..eb202a2d
103 | --- /dev/null
104 | +++ b/obfuscate.c
105 | @@ -0,0 +1,220 @@
106 | +#include "includes.h"
107 | +#include <openssl/evp.h>
108 | +#include <openssl/rc4.h>
109 | +#include "openbsd-compat/openssl-compat.h"
110 | +#include <unistd.h>
111 | +#include <string.h>
112 | +#include "atomicio.h"
113 | +#include "canohost.h"
114 | +#include "xmalloc.h"
115 | +#include "log.h"
116 | +#include "packet.h"
117 | +#include "obfuscate.h"
118 | +
119 | +static RC4_KEY rc4_input;
120 | +static RC4_KEY rc4_output;
121 | +
122 | +static const char *obfuscate_keyword = NULL;
123 | +
124 | +#define OBFUSCATE_KEY_LENGTH 	16
125 | +#define OBFUSCATE_SEED_LENGTH	16
126 | +#define OBFUSCATE_HASH_ITERATIONS 6000
127 | +#define OBFUSCATE_MAX_PADDING	8192
128 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
129 | +
130 | +struct seed_msg {
131 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
132 | +	u_int32_t magic;
133 | +	u_int32_t padding_length;
134 | +	u_char padding[];
135 | +};
136 | +
137 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
138 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
139 | +static void set_keys(const u_char *, const u_char *);
140 | +static void initialize(const u_char *, int);
141 | +static void read_forever(int);
142 | +
143 | +
144 | +/*
145 | + * Server calls this
146 | + */
147 | +void
148 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
149 | +{
150 | +	struct seed_msg seed;
151 | +
152 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
153 | +	u_int len;
154 | +	u_int32_t padding_length;
155 | +
156 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
157 | +
158 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
159 | +	if(len != sizeof(struct seed_msg))
160 | +		fatal("obfuscate_receive_seed: read failed");
161 | +
162 | +	initialize(seed.seed_buffer, 1);
163 | +	obfuscate_input((u_char *)&seed.magic, 8);
164 | +
165 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
166 | +		logit("Magic value check failed (%u) on obfuscated handshake "
167 | + 			"from %.200s port %d", ntohl(seed.magic),
168 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
169 | +		read_forever(sock_in);
170 | +	}
171 | +	padding_length = ntohl(seed.padding_length);
172 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
173 | +		logit("Illegal padding length %d for obfuscated handshake "
174 | + 			"from %.200s port %d", ntohl(seed.padding_length),
175 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
176 | +		read_forever(sock_in);
177 | +	}
178 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
179 | +	if(len != padding_length)
180 | +		fatal("obfuscate_receive_seed: read failed");
181 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
182 | +	obfuscate_input(padding_drain, padding_length);
183 | +}
184 | +
185 | +/*
186 | + * Client calls this
187 | + */
188 | +void
189 | +obfuscate_send_seed(int sock_out)
190 | +{
191 | +	struct seed_msg *seed;
192 | +	int i;
193 | +	u_int32_t rnd = 0;
194 | +	u_int message_length;
195 | +	u_int padding_length;
196 | +
197 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
198 | +	message_length = padding_length + sizeof(struct seed_msg);
199 | +	seed = xmalloc(message_length);
200 | +
201 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
202 | +		if(i % 4 == 0)
203 | +			rnd = arc4random();
204 | +		seed->seed_buffer[i] = rnd & 0xff;
205 | +		rnd >>= 8;
206 | +	}
207 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
208 | +	seed->padding_length = htonl(padding_length);
209 | +	for(i = 0; i < (int)padding_length; i++) {
210 | +		if(i % 4 == 0)
211 | +			rnd = arc4random();
212 | +		seed->padding[i] = rnd & 0xff;
213 | +	}
214 | +	initialize(seed->seed_buffer, 0);
215 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
216 | +		message_length - OBFUSCATE_SEED_LENGTH);
217 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
218 | +	atomicio(vwrite, sock_out, seed, message_length);
219 | +	free(seed);
220 | +
221 | +}
222 | +
223 | +void
224 | +obfuscate_set_keyword(const char *keyword)
225 | +{
226 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
227 | +	obfuscate_keyword = keyword;
228 | +}
229 | +
230 | +void
231 | +obfuscate_input(u_char *buffer, u_int buffer_len)
232 | +{
233 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
234 | +}
235 | +
236 | +void
237 | +obfuscate_output(u_char *buffer, u_int buffer_len)
238 | +{
239 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
240 | +}
241 | +
242 | +static void
243 | +initialize(const u_char *seed, int server)
244 | +{
245 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
246 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
247 | +
248 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
249 | +
250 | +	if(server)
251 | +		set_keys(client_to_server_key, server_to_client_key);
252 | +	else
253 | +		set_keys(server_to_client_key, client_to_server_key);
254 | +}
255 | +
256 | +static void
257 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
258 | +{
259 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
260 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
261 | +}
262 | +
263 | +static void
264 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
265 | +{
266 | +	EVP_MD_CTX *ctx;
267 | +	u_char md_output[EVP_MAX_MD_SIZE];
268 | +	int md_len;
269 | +	int i;
270 | +	u_char *buffer;
271 | +	u_char *p;
272 | +	u_int buffer_length;
273 | +
274 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
275 | +		fatal("Cannot create new digest context");
276 | +
277 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
278 | +	if(obfuscate_keyword)
279 | +		buffer_length += strlen(obfuscate_keyword);
280 | +
281 | +	p = buffer = xmalloc(buffer_length);
282 | +
283 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
284 | +	p += OBFUSCATE_SEED_LENGTH;
285 | +
286 | +	if(obfuscate_keyword) {
287 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
288 | +		p += strlen(obfuscate_keyword);
289 | +	}
290 | +	memcpy(p, iv, iv_len);
291 | +
292 | +	EVP_DigestInit(ctx, EVP_sha1());
293 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
294 | +	EVP_DigestFinal(ctx, md_output, &md_len);
295 | +
296 | +	free(buffer);
297 | +
298 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
299 | +		EVP_DigestInit(ctx, EVP_sha1());
300 | +		EVP_DigestUpdate(ctx, md_output, md_len);
301 | +		EVP_DigestFinal(ctx, md_output, &md_len);
302 | +	}
303 | +
304 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
305 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
306 | +
307 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
308 | +}
309 | +
310 | +static void
311 | +set_keys(const u_char *input_key, const u_char *output_key)
312 | +{
313 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
314 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
315 | +}
316 | +
317 | +static void
318 | +read_forever(int sock_in)
319 | +{
320 | +	u_char discard_buffer[1024];
321 | +
322 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
323 | +		;
324 | +	cleanup_exit(255);
325 | +}
326 | diff --git a/obfuscate.h b/obfuscate.h
327 | new file mode 100644
328 | index 00000000..d5fb92b4
329 | --- /dev/null
330 | +++ b/obfuscate.h
331 | @@ -0,0 +1,10 @@
332 | +#ifndef _OBFUSCATE_H
333 | +#define _OBFUSCATE_H
334 | +
335 | +void obfuscate_receive_seed(struct ssh *, int);
336 | +void obfuscate_send_seed(int);
337 | +void obfuscate_set_keyword(const char *);
338 | +void obfuscate_input(u_char *, u_int);
339 | +void obfuscate_output(u_char *, u_int);
340 | +
341 | +#endif
342 | diff --git a/packet.c b/packet.c
343 | index 3f64d2d3..13699f9d 100644
344 | --- a/packet.c
345 | +++ b/packet.c
346 | @@ -94,6 +94,7 @@
347 |  #include "channels.h"
348 |  #include "ssh.h"
349 |  #include "packet.h"
350 | +#include "obfuscate.h"
351 |  #include "ssherr.h"
352 |  #include "sshbuf.h"
353 |  
354 | @@ -177,6 +178,8 @@ struct session_state {
355 |  	/* Set to true if we are authenticated. */
356 |  	int after_authentication;
357 |  
358 | +	int obfuscation;
359 | +
360 |  	int keep_alive_timeouts;
361 |  
362 |  	/* The maximum time that we will wait to send or receive a packet */
363 | @@ -1200,6 +1203,8 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
364 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
365 |  			goto out;
366 |  	}
367 | +	if(state->obfuscation)
368 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
369 |  #ifdef PACKET_DEBUG
370 |  	fprintf(stderr, "encrypted: ");
371 |  	sshbuf_dump(state->output, stderr);
372 | @@ -1534,6 +1539,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
373 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
374 |  		    &cp)) != 0)
375 |  			goto out;
376 | +		if(state->obfuscation)
377 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
378 |  		if ((r = cipher_crypt(state->receive_context,
379 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
380 |  		    block_size, 0, 0)) != 0)
381 | @@ -1599,6 +1606,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
382 |  			goto out;
383 |  		}
384 |  	}
385 | +	if(state->obfuscation)
386 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
387 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
388 |  	    &cp)) != 0)
389 |  		goto out;
390 | @@ -2717,3 +2726,25 @@ sshpkt_add_padding(struct ssh *ssh, u_char pad)
391 |  	ssh->state->extra_pad = pad;
392 |  	return 0;
393 |  }
394 | +
395 | +void
396 | +sshpkt_enable_obfuscation(struct ssh *ssh)
397 | +{
398 | +	debug("Obfuscation enabled");
399 | +	ssh->state->obfuscation = 1;
400 | +}
401 | +
402 | +void
403 | +sshpkt_disable_obfuscation(struct ssh *ssh)
404 | +{
405 | +	if(ssh->state->obfuscation) {
406 | +		debug("Obfuscation disabled");
407 | +		ssh->state->obfuscation = 0;
408 | +	}
409 | +}
410 | +
411 | +int
412 | +sshpkt_get_obfuscation(struct ssh *ssh)
413 | +{
414 | +	return ssh->state->obfuscation;
415 | +}
416 | diff --git a/packet.h b/packet.h
417 | index 176488b1..87864a7d 100644
418 | --- a/packet.h
419 | +++ b/packet.h
420 | @@ -182,6 +182,9 @@ void	sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
421 |  	    __attribute__((format(printf, 3, 4)))
422 |  	    __attribute__((noreturn));
423 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
424 | +void	sshpkt_enable_obfuscation(struct ssh *);
425 | +void	sshpkt_disable_obfuscation(struct ssh *);
426 | +int sshpkt_get_obfuscation(struct ssh *);
427 |  
428 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
429 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
430 | diff --git a/readconf.c b/readconf.c
431 | index cf794988..c4f288c7 100644
432 | --- a/readconf.c
433 | +++ b/readconf.c
434 | @@ -143,7 +143,7 @@ typedef enum {
435 |  	oBadOption,
436 |  	oHost, oMatch, oInclude,
437 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
438 | -	oGatewayPorts, oExitOnForwardFailure,
439 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
440 |  	oPasswordAuthentication,
441 |  	oXAuthLocation,
442 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
443 | @@ -323,6 +323,8 @@ static struct {
444 |  	{ "knownhostscommand", oKnownHostsCommand },
445 |  	{ "requiredrsasize", oRequiredRSASize },
446 |  	{ "enableescapecommandline", oEnableEscapeCommandline },
447 | +	{ "obfuscatehandshake", oObfuscateHandshake },
448 | +	{ "obfuscatekeyword", oObfuscateKeyword },
449 |  
450 |  	{ NULL, oBadOption }
451 |  };
452 | @@ -2191,6 +2193,16 @@ parse_pubkey_algos:
453 |  		intptr = &options->required_rsa_size;
454 |  		goto parse_int;
455 |  
456 | +	case oObfuscateHandshake:
457 | +		intptr = &options->obfuscate_handshake;
458 | +		goto parse_flag;
459 | +
460 | +	case oObfuscateKeyword:
461 | +		if (*activep)
462 | +			options->obfuscate_handshake = 1;
463 | +		charptr = &options->obfuscate_keyword;
464 | +		goto parse_string;
465 | +
466 |  	case oDeprecated:
467 |  		debug("%s line %d: Deprecated option \"%s\"",
468 |  		    filename, linenum, keyword);
469 | @@ -2420,6 +2432,8 @@ initialize_options(Options * options)
470 |  	options->add_keys_to_agent_lifespan = -1;
471 |  	options->identity_agent = NULL;
472 |  	options->visual_host_key = -1;
473 | +	options->obfuscate_handshake = 0;
474 | +	options->obfuscate_keyword = NULL;
475 |  	options->ip_qos_interactive = -1;
476 |  	options->ip_qos_bulk = -1;
477 |  	options->request_tty = -1;
478 | diff --git a/readconf.h b/readconf.h
479 | index 2ce1b4c3..cdd7d335 100644
480 | --- a/readconf.h
481 | +++ b/readconf.h
482 | @@ -145,6 +145,8 @@ typedef struct {
483 |  	int	permit_local_command;
484 |  	char	*remote_command;
485 |  	int	visual_host_key;
486 | +	int obfuscate_handshake;
487 | +	char *obfuscate_keyword;
488 |  
489 |  	int	request_tty;
490 |  	int	session_type;
491 | diff --git a/scp.c b/scp.c
492 | index 1adff5ce..6e6f0285 100644
493 | --- a/scp.c
494 | +++ b/scp.c
495 | @@ -504,7 +504,7 @@ main(int argc, char **argv)
496 |  
497 |  	fflag = Tflag = tflag = 0;
498 |  	while ((ch = getopt(argc, argv,
499 | -	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:")) != -1) {
500 | +	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:zZ:")) != -1) {
501 |  		switch (ch) {
502 |  		/* User-visible flags. */
503 |  		case '1':
504 | @@ -517,6 +517,7 @@ main(int argc, char **argv)
505 |  		case '4':
506 |  		case '6':
507 |  		case 'C':
508 | +		case 'z':
509 |  			addargs(&args, "-%c", ch);
510 |  			addargs(&remote_remote_args, "-%c", ch);
511 |  			break;
512 | @@ -534,6 +535,7 @@ main(int argc, char **argv)
513 |  		case 'i':
514 |  		case 'F':
515 |  		case 'J':
516 | +		case 'Z':
517 |  			addargs(&remote_remote_args, "-%c", ch);
518 |  			addargs(&remote_remote_args, "%s", optarg);
519 |  			addargs(&args, "-%c", ch);
520 | diff --git a/servconf.c b/servconf.c
521 | index 2e039da8..d87ae19a 100644
522 | --- a/servconf.c
523 | +++ b/servconf.c
524 | @@ -95,6 +95,7 @@ initialize_server_options(ServerOptions *options)
525 |  
526 |  	/* Standard Options */
527 |  	options->num_ports = 0;
528 | +	options->num_obfuscated_ports = 0;
529 |  	options->ports_from_cmdline = 0;
530 |  	options->queued_listen_addrs = NULL;
531 |  	options->num_queued_listens = 0;
532 | @@ -181,6 +182,7 @@ initialize_server_options(ServerOptions *options)
533 |  	options->permitted_listens = NULL;
534 |  	options->adm_forced_command = NULL;
535 |  	options->chroot_directory = NULL;
536 | +	options->obfuscate_keyword = NULL;
537 |  	options->authorized_keys_command = NULL;
538 |  	options->authorized_keys_command_user = NULL;
539 |  	options->revoked_keys_file = NULL;
540 | @@ -300,7 +302,7 @@ fill_default_server_options(ServerOptions *options)
541 |  #endif /* WITH_XMSS */
542 |  	}
543 |  	/* No certificates by default */
544 | -	if (options->num_ports == 0)
545 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
546 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
547 |  	if (options->address_family == -1)
548 |  		options->address_family = AF_UNSPEC;
549 | @@ -502,7 +504,7 @@ typedef enum {
550 |  	/* Portable-specific options */
551 |  	sUsePAM,
552 |  	/* Standard Options */
553 | -	sPort, sHostKeyFile, sLoginGraceTime,
554 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
555 |  	sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
556 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
557 |  	sKerberosGetAFSToken, sPasswordAuthentication,
558 | @@ -557,6 +559,8 @@ static struct {
559 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
560 |  	/* Standard Options */
561 |  	{ "port", sPort, SSHCFG_GLOBAL },
562 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
563 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
564 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
565 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
566 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
567 | @@ -774,6 +778,10 @@ add_listen_addr(ServerOptions *options, const char *addr,
568 |  			add_one_listen_addr(options, addr, rdomain,
569 |  			    options->ports[i]);
570 |  		}
571 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
572 | +			add_one_listen_addr(options, addr, rdomain,
573 | +				options->obfuscated_ports[i]);
574 | +		}
575 |  	}
576 |  }
577 |  
578 | @@ -888,7 +896,7 @@ process_queued_listen_addrs(ServerOptions *options)
579 |  	u_int i;
580 |  	struct queued_listenaddr *qla;
581 |  
582 | -	if (options->num_ports == 0)
583 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
584 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
585 |  	if (options->address_family == -1)
586 |  		options->address_family = AF_UNSPEC;
587 | @@ -1424,6 +1432,30 @@ process_server_config_line_depth(ServerOptions *options, char *line,
588 |  			    filename, linenum);
589 |  		break;
590 |  
591 | +	case sObfuscatedPort:
592 | +		if(options->ports_from_cmdline)
593 | +			return 0;
594 | +		if(options->listen_addrs != NULL)
595 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
596 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
597 | +			fatal("%s line %d: too many ports.", filename, linenum);
598 | +		arg = argv_next(&ac, &av);
599 | +		if(!arg || *arg == '\0')
600 | +			fatal("%s line %d: missing port number.", filename, linenum);
601 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
602 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
603 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
604 | +		break;
605 | +	case sObfuscateKeyword:
606 | +		charptr = &options->obfuscate_keyword;
607 | +		arg = argv_next(&ac, &av);
608 | +		if(!arg || *arg == '\0')
609 | +			fatal("%s line %d: missing keyword argument.",
610 | +					filename, linenum);
611 | +		if(*activep && *charptr == NULL)
612 | +			*charptr = xstrdup(arg);
613 | +		break;
614 | +
615 |  	case sLoginGraceTime:
616 |  		intptr = &options->login_grace_time;
617 |   parse_time:
618 | diff --git a/servconf.h b/servconf.h
619 | index 7ad43de8..7ab1c624 100644
620 | --- a/servconf.h
621 | +++ b/servconf.h
622 | @@ -209,6 +209,11 @@ typedef struct {
623 |  	u_int   num_permitted_listens;
624 |  
625 |  	char   *chroot_directory;
626 | +
627 | +	int obfuscated_ports[MAX_PORTS];
628 | +	u_int num_obfuscated_ports;
629 | +	char *obfuscate_keyword;
630 | +
631 |  	char   *revoked_keys_file;
632 |  	char   *trusted_user_ca_keys;
633 |  	char   *authorized_keys_command;
634 | diff --git a/sftp.c b/sftp.c
635 | index b3616c15..4b84d542 100644
636 | --- a/sftp.c
637 | +++ b/sftp.c
638 | @@ -2450,13 +2450,14 @@ main(int argc, char **argv)
639 |  	infile = stdin;
640 |  
641 |  	while ((ch = getopt(argc, argv,
642 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:")) != -1) {
643 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:zZ:")) != -1) {
644 |  		switch (ch) {
645 |  		/* Passed through to ssh(1) */
646 |  		case 'A':
647 |  		case '4':
648 |  		case '6':
649 |  		case 'C':
650 | +		case 'z':
651 |  			addargs(&args, "-%c", ch);
652 |  			break;
653 |  		/* Passed through to ssh(1) with argument */
654 | @@ -2465,6 +2466,7 @@ main(int argc, char **argv)
655 |  		case 'c':
656 |  		case 'i':
657 |  		case 'o':
658 | +		case 'Z':
659 |  			addargs(&args, "-%c", ch);
660 |  			addargs(&args, "%s", optarg);
661 |  			break;
662 | diff --git a/ssh.c b/ssh.c
663 | index 87454b84..c2b55079 100644
664 | --- a/ssh.c
665 | +++ b/ssh.c
666 | @@ -179,13 +179,14 @@ static void
667 |  usage(void)
668 |  {
669 |  	fprintf(stderr,
670 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
671 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface]\n"
672 |  "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
673 |  "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
674 |  "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
675 |  "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
676 |  "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
677 |  "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
678 | +"           [-Z obfuscate_keyword]\n"
679 |  	);
680 |  	exit(255);
681 |  }
682 | @@ -708,7 +709,7 @@ main(int ac, char **av)
683 |  
684 |   again:
685 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
686 | -	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
687 | +	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYyzZ:")) != -1) { /* HUZdhjruz */
688 |  		switch (opt) {
689 |  		case '1':
690 |  			fatal("SSH protocol v.1 is no longer supported");
691 | @@ -1053,6 +1054,13 @@ main(int ac, char **av)
692 |  		case 'F':
693 |  			config = optarg;
694 |  			break;
695 | +		case 'z':
696 | +			options.obfuscate_handshake = 1;
697 | +			break;
698 | +		case 'Z':
699 | +			options.obfuscate_handshake = 1;
700 | +			options.obfuscate_keyword = optarg;
701 | +			break;
702 |  		default:
703 |  			usage();
704 |  		}
705 | diff --git a/sshconnect.c b/sshconnect.c
706 | index 792bc34b..d6d8b51f 100644
707 | --- a/sshconnect.c
708 | +++ b/sshconnect.c
709 | @@ -65,6 +65,7 @@
710 |  #include "monitor_fdpass.h"
711 |  #include "ssh2.h"
712 |  #include "version.h"
713 | +#include "obfuscate.h"
714 |  #include "authfile.h"
715 |  #include "ssherr.h"
716 |  #include "authfd.h"
717 | @@ -269,6 +270,12 @@ ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
718 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
719 |  		return -1; /* ssh_packet_set_connection logs error */
720 |  
721 | +	if(options.obfuscate_handshake) {
722 | +		if(options.obfuscate_keyword)
723 | +			obfuscate_set_keyword(options.obfuscate_keyword);
724 | +		sshpkt_enable_obfuscation(ssh);
725 | +	}
726 | +
727 |  	return 0;
728 |  }
729 |  
730 | @@ -530,6 +537,11 @@ ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
731 |  	/* Set the connection. */
732 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
733 |  		return -1; /* ssh_packet_set_connection logs error */
734 | +	if(options.obfuscate_handshake) {
735 | +		if(options.obfuscate_keyword)
736 | +			obfuscate_set_keyword(options.obfuscate_keyword);
737 | +		sshpkt_enable_obfuscation(ssh);
738 | +	}
739 |  
740 |  	return 0;
741 |  }
742 | @@ -1566,6 +1578,9 @@ ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
743 |  	host = xstrdup(orighost);
744 |  	lowercase(host);
745 |  
746 | +	if(options.obfuscate_handshake)
747 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
748 | +
749 |  	/* Exchange protocol version identification strings with the server. */
750 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
751 |  		sshpkt_fatal(ssh, r, "banner exchange");
752 | diff --git a/sshd.c b/sshd.c
753 | index 6321936c..e3ee3301 100644
754 | --- a/sshd.c
755 | +++ b/sshd.c
756 | @@ -121,6 +121,7 @@
757 |  #include "ssh-gss.h"
758 |  #endif
759 |  #include "monitor_wrap.h"
760 | +#include "obfuscate.h"
761 |  #include "ssh-sandbox.h"
762 |  #include "auth-options.h"
763 |  #include "version.h"
764 | @@ -255,6 +256,9 @@ struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
765 |  /* message to be displayed after login */
766 |  struct sshbuf *loginmsg;
767 |  
768 | +/* Enable handshake obfuscation */
769 | +int use_obfuscation = 0;
770 | +
771 |  /* Unprivileged user */
772 |  struct passwd *privsep_pw = NULL;
773 |  
774 | @@ -1533,7 +1537,7 @@ main(int ac, char **av)
775 |  	struct ssh *ssh = NULL;
776 |  	extern char *optarg;
777 |  	extern int optind;
778 | -	int r, opt, on = 1, already_daemon, remote_port;
779 | +	int r, opt, on = 1, already_daemon, remote_port, local_port;
780 |  	int sock_in = -1, sock_out = -1, newsock = -1;
781 |  	const char *remote_ip, *rdomain;
782 |  	char *fp, *line, *laddr, *logfile = NULL;
783 | @@ -2165,6 +2169,14 @@ main(int ac, char **av)
784 |  	process_channel_timeouts(ssh, &options);
785 |  	process_permitopen(ssh, &options);
786 |  
787 | +	local_port = ssh_local_port(ssh);
788 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
789 | +		if(options.obfuscated_ports[i] == local_port) {
790 | +			use_obfuscation = 1;
791 | +			break;
792 | +		}
793 | +	}
794 | +
795 |  	/* Set SO_KEEPALIVE if requested. */
796 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
797 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
798 | @@ -2212,6 +2224,13 @@ main(int ac, char **av)
799 |  	if (!debug_flag)
800 |  		alarm(options.login_grace_time);
801 |  
802 | +	if(use_obfuscation) {
803 | +		if(options.obfuscate_keyword)
804 | +			obfuscate_set_keyword(options.obfuscate_keyword);
805 | +		sshpkt_enable_obfuscation(ssh);
806 | +		obfuscate_receive_seed(ssh, sock_in);
807 | +	}
808 | +
809 |  	if ((r = kex_exchange_identification(ssh, -1,
810 |  	    options.version_addendum)) != 0)
811 |  		sshpkt_fatal(ssh, r, "banner exchange");
812 | @@ -2237,8 +2256,12 @@ main(int ac, char **av)
813 |  	auth_debug_reset();
814 |  
815 |  	if (use_privsep) {
816 | -		if (privsep_preauth(ssh) == 1)
817 | +
818 | +		if (privsep_preauth(ssh) == 1) {
819 | +			if(use_obfuscation)
820 | +				sshpkt_disable_obfuscation(ssh);
821 |  			goto authenticated;
822 | +		}
823 |  	} else if (have_agent) {
824 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
825 |  			error_r(r, "Unable to get agent socket");
826 | diff --git a/sshd_config b/sshd_config
827 | index 36894ace..5dfb1c68 100644
828 | --- a/sshd_config
829 | +++ b/sshd_config
830 | @@ -11,6 +11,8 @@
831 |  # default value.
832 |  
833 |  #Port 22
834 | +#ObfuscatedPort 222
835 | +#ObfuscateKeyword key
836 |  #AddressFamily any
837 |  #ListenAddress 0.0.0.0
838 |  #ListenAddress ::
839 | 


--------------------------------------------------------------------------------
/portable/9.7.diff:
--------------------------------------------------------------------------------
1 | 9.6.diff


--------------------------------------------------------------------------------
/portable/9.8.diff:
--------------------------------------------------------------------------------
  1 | diff -Nupr openssh-9.8p1/kex.c ob/kex.c
  2 | --- openssh-9.8p1/kex.c	2024-07-01 12:36:28.000000000 +0800
  3 | +++ ob/kex.c	2024-07-01 23:59:55.288000539 +0800
  4 | @@ -59,6 +59,7 @@
  5 |  #include "monitor.h"
  6 |  #include "myproposal.h"
  7 |  
  8 | +#include "obfuscate.h"
  9 |  #include "ssherr.h"
 10 |  #include "sshbuf.h"
 11 |  #include "digest.h"
 12 | @@ -400,8 +401,10 @@ kex_send_newkeys(struct ssh *ssh)
 13 |  		return r;
 14 |  	debug("SSH2_MSG_NEWKEYS sent");
 15 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 16 | +	sshpkt_disable_obfuscation(ssh);
 17 |  	if ((r = kex_maybe_send_ext_info(ssh)) != 0)
 18 |  		return r;
 19 | +	sshpkt_enable_obfuscation(ssh);
 20 |  	debug("expecting SSH2_MSG_NEWKEYS");
 21 |  	return 0;
 22 |  }
 23 | @@ -565,6 +568,7 @@ kex_input_newkeys(int type, u_int32_t se
 24 |  	kex->flags &= ~KEX_INIT_SENT;
 25 |  	free(kex->name);
 26 |  	kex->name = NULL;
 27 | +	sshpkt_disable_obfuscation(ssh);
 28 |  	return 0;
 29 |  }
 30 |  
 31 | @@ -1261,14 +1265,42 @@ kex_exchange_identification(struct ssh *
 32 |  		goto out;
 33 |  	}
 34 |  
 35 | +	/* Make copy and obfuscate the original */
 36 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 37 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 38 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 39 | +			r = SSH_ERR_ALLOC_FAIL;
 40 | +			goto out;
 41 | +		}
 42 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 43 | +	}
 44 | +
 45 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 46 |  	    sshbuf_mutable_ptr(our_version),
 47 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 48 |  		oerrno = errno;
 49 |  		debug_f("write: %.100s", strerror(errno));
 50 |  		r = SSH_ERR_SYSTEM_ERROR;
 51 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 52 | +			free(cp);
 53 | +		}
 54 |  		goto out;
 55 |  	}
 56 | +
 57 | +	/* Restore the original */
 58 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 59 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 60 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 61 | +			free(cp);
 62 | +			goto out;
 63 | +		}
 64 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 65 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 66 | +			free(cp);
 67 | +			goto out;
 68 | +		}
 69 | +	}
 70 | +
 71 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 72 |  		oerrno = errno;
 73 |  		error_fr(r, "sshbuf_consume_end");
 74 | @@ -1325,6 +1357,8 @@ kex_exchange_identification(struct ssh *
 75 |  				r = SSH_ERR_SYSTEM_ERROR;
 76 |  				goto out;
 77 |  			}
 78 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 79 | +			  obfuscate_input(&c, 1);
 80 |  			if (c == '\r') {
 81 |  				expect_nl = 1;
 82 |  				continue;
 83 | diff -Nupr openssh-9.8p1/Makefile.in ob/Makefile.in
 84 | --- openssh-9.8p1/Makefile.in	2024-07-01 12:36:28.000000000 +0800
 85 | +++ ob/Makefile.in	2024-07-01 23:59:55.288000539 +0800
 86 | @@ -113,7 +113,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
 87 |  	kexgexc.o kexgexs.o \
 88 |  	kexsntrup761x25519.o sntrup761.o kexgen.o \
 89 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
 90 | -	sshbuf-io.o
 91 | +	sshbuf-io.o obfuscate.o
 92 |  
 93 |  SKOBJS=	ssh-sk-client.o
 94 |  
 95 | diff -Nupr openssh-9.8p1/obfuscate.c ob/obfuscate.c
 96 | --- openssh-9.8p1/obfuscate.c	1970-01-01 08:00:00.000000000 +0800
 97 | +++ ob/obfuscate.c	2024-07-01 23:59:55.288000539 +0800
 98 | @@ -0,0 +1,220 @@
 99 | +#include "includes.h"
100 | +#include <openssl/evp.h>
101 | +#include <openssl/rc4.h>
102 | +#include "openbsd-compat/openssl-compat.h"
103 | +#include <unistd.h>
104 | +#include <string.h>
105 | +#include "atomicio.h"
106 | +#include "canohost.h"
107 | +#include "xmalloc.h"
108 | +#include "log.h"
109 | +#include "packet.h"
110 | +#include "obfuscate.h"
111 | +
112 | +static RC4_KEY rc4_input;
113 | +static RC4_KEY rc4_output;
114 | +
115 | +static const char *obfuscate_keyword = NULL;
116 | +
117 | +#define OBFUSCATE_KEY_LENGTH 	16
118 | +#define OBFUSCATE_SEED_LENGTH	16
119 | +#define OBFUSCATE_HASH_ITERATIONS 6000
120 | +#define OBFUSCATE_MAX_PADDING	8192
121 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
122 | +
123 | +struct seed_msg {
124 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
125 | +	u_int32_t magic;
126 | +	u_int32_t padding_length;
127 | +	u_char padding[];
128 | +};
129 | +
130 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
131 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
132 | +static void set_keys(const u_char *, const u_char *);
133 | +static void initialize(const u_char *, int);
134 | +static void read_forever(int);
135 | +
136 | +
137 | +/*
138 | + * Server calls this
139 | + */
140 | +void
141 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
142 | +{
143 | +	struct seed_msg seed;
144 | +
145 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
146 | +	u_int len;
147 | +	u_int32_t padding_length;
148 | +
149 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
150 | +
151 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
152 | +	if(len != sizeof(struct seed_msg))
153 | +		fatal("obfuscate_receive_seed: read failed");
154 | +
155 | +	initialize(seed.seed_buffer, 1);
156 | +	obfuscate_input((u_char *)&seed.magic, 8);
157 | +
158 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
159 | +		logit("Magic value check failed (%u) on obfuscated handshake "
160 | + 			"from %.200s port %d", ntohl(seed.magic),
161 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
162 | +		read_forever(sock_in);
163 | +	}
164 | +	padding_length = ntohl(seed.padding_length);
165 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
166 | +		logit("Illegal padding length %d for obfuscated handshake "
167 | + 			"from %.200s port %d", ntohl(seed.padding_length),
168 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
169 | +		read_forever(sock_in);
170 | +	}
171 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
172 | +	if(len != padding_length)
173 | +		fatal("obfuscate_receive_seed: read failed");
174 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
175 | +	obfuscate_input(padding_drain, padding_length);
176 | +}
177 | +
178 | +/*
179 | + * Client calls this
180 | + */
181 | +void
182 | +obfuscate_send_seed(int sock_out)
183 | +{
184 | +	struct seed_msg *seed;
185 | +	int i;
186 | +	u_int32_t rnd = 0;
187 | +	u_int message_length;
188 | +	u_int padding_length;
189 | +
190 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
191 | +	message_length = padding_length + sizeof(struct seed_msg);
192 | +	seed = xmalloc(message_length);
193 | +
194 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
195 | +		if(i % 4 == 0)
196 | +			rnd = arc4random();
197 | +		seed->seed_buffer[i] = rnd & 0xff;
198 | +		rnd >>= 8;
199 | +	}
200 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
201 | +	seed->padding_length = htonl(padding_length);
202 | +	for(i = 0; i < (int)padding_length; i++) {
203 | +		if(i % 4 == 0)
204 | +			rnd = arc4random();
205 | +		seed->padding[i] = rnd & 0xff;
206 | +	}
207 | +	initialize(seed->seed_buffer, 0);
208 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
209 | +		message_length - OBFUSCATE_SEED_LENGTH);
210 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
211 | +	atomicio(vwrite, sock_out, seed, message_length);
212 | +	free(seed);
213 | +
214 | +}
215 | +
216 | +void
217 | +obfuscate_set_keyword(const char *keyword)
218 | +{
219 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
220 | +	obfuscate_keyword = keyword;
221 | +}
222 | +
223 | +void
224 | +obfuscate_input(u_char *buffer, u_int buffer_len)
225 | +{
226 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
227 | +}
228 | +
229 | +void
230 | +obfuscate_output(u_char *buffer, u_int buffer_len)
231 | +{
232 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
233 | +}
234 | +
235 | +static void
236 | +initialize(const u_char *seed, int server)
237 | +{
238 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
239 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
240 | +
241 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
242 | +
243 | +	if(server)
244 | +		set_keys(client_to_server_key, server_to_client_key);
245 | +	else
246 | +		set_keys(server_to_client_key, client_to_server_key);
247 | +}
248 | +
249 | +static void
250 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
251 | +{
252 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
253 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
254 | +}
255 | +
256 | +static void
257 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
258 | +{
259 | +	EVP_MD_CTX *ctx;
260 | +	u_char md_output[EVP_MAX_MD_SIZE];
261 | +	int md_len;
262 | +	int i;
263 | +	u_char *buffer;
264 | +	u_char *p;
265 | +	u_int buffer_length;
266 | +
267 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
268 | +		fatal("Cannot create new digest context");
269 | +
270 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
271 | +	if(obfuscate_keyword)
272 | +		buffer_length += strlen(obfuscate_keyword);
273 | +
274 | +	p = buffer = xmalloc(buffer_length);
275 | +
276 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
277 | +	p += OBFUSCATE_SEED_LENGTH;
278 | +
279 | +	if(obfuscate_keyword) {
280 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
281 | +		p += strlen(obfuscate_keyword);
282 | +	}
283 | +	memcpy(p, iv, iv_len);
284 | +
285 | +	EVP_DigestInit(ctx, EVP_sha1());
286 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
287 | +	EVP_DigestFinal(ctx, md_output, &md_len);
288 | +
289 | +	free(buffer);
290 | +
291 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
292 | +		EVP_DigestInit(ctx, EVP_sha1());
293 | +		EVP_DigestUpdate(ctx, md_output, md_len);
294 | +		EVP_DigestFinal(ctx, md_output, &md_len);
295 | +	}
296 | +
297 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
298 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
299 | +
300 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
301 | +}
302 | +
303 | +static void
304 | +set_keys(const u_char *input_key, const u_char *output_key)
305 | +{
306 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
307 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
308 | +}
309 | +
310 | +static void
311 | +read_forever(int sock_in)
312 | +{
313 | +	u_char discard_buffer[1024];
314 | +
315 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
316 | +		;
317 | +	cleanup_exit(255);
318 | +}
319 | diff -Nupr openssh-9.8p1/obfuscate.h ob/obfuscate.h
320 | --- openssh-9.8p1/obfuscate.h	1970-01-01 08:00:00.000000000 +0800
321 | +++ ob/obfuscate.h	2024-07-01 23:59:55.288000539 +0800
322 | @@ -0,0 +1,10 @@
323 | +#ifndef _OBFUSCATE_H
324 | +#define _OBFUSCATE_H
325 | +
326 | +void obfuscate_receive_seed(struct ssh *, int);
327 | +void obfuscate_send_seed(int);
328 | +void obfuscate_set_keyword(const char *);
329 | +void obfuscate_input(u_char *, u_int);
330 | +void obfuscate_output(u_char *, u_int);
331 | +
332 | +#endif
333 | diff -Nupr openssh-9.8p1/packet.c ob/packet.c
334 | --- openssh-9.8p1/packet.c	2024-07-01 12:36:28.000000000 +0800
335 | +++ ob/packet.c	2024-07-01 23:59:55.300000506 +0800
336 | @@ -94,6 +94,7 @@
337 |  #include "channels.h"
338 |  #include "ssh.h"
339 |  #include "packet.h"
340 | +#include "obfuscate.h"
341 |  #include "ssherr.h"
342 |  #include "sshbuf.h"
343 |  
344 | @@ -177,6 +178,8 @@ struct session_state {
345 |  	/* Set to true if we are authenticated. */
346 |  	int after_authentication;
347 |  
348 | +	int obfuscation;
349 | +
350 |  	int keep_alive_timeouts;
351 |  
352 |  	/* The maximum time that we will wait to send or receive a packet */
353 | @@ -1294,6 +1297,8 @@ ssh_packet_send2_wrapped(struct ssh *ssh
354 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
355 |  			goto out;
356 |  	}
357 | +	if(state->obfuscation)
358 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
359 |  #ifdef PACKET_DEBUG
360 |  	fprintf(stderr, "encrypted: ");
361 |  	sshbuf_dump(state->output, stderr);
362 | @@ -1614,6 +1619,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u
363 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
364 |  		    &cp)) != 0)
365 |  			goto out;
366 | +		if(state->obfuscation)
367 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
368 |  		if ((r = cipher_crypt(state->receive_context,
369 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
370 |  		    block_size, 0, 0)) != 0)
371 | @@ -1679,6 +1686,8 @@ ssh_packet_read_poll2(struct ssh *ssh, u
372 |  			goto out;
373 |  		}
374 |  	}
375 | +	if(state->obfuscation)
376 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
377 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
378 |  	    &cp)) != 0)
379 |  		goto out;
380 | @@ -2855,3 +2864,25 @@ sshpkt_add_padding(struct ssh *ssh, u_ch
381 |  	ssh->state->extra_pad = pad;
382 |  	return 0;
383 |  }
384 | +
385 | +void
386 | +sshpkt_enable_obfuscation(struct ssh *ssh)
387 | +{
388 | +	debug("Obfuscation enabled");
389 | +	ssh->state->obfuscation = 1;
390 | +}
391 | +
392 | +void
393 | +sshpkt_disable_obfuscation(struct ssh *ssh)
394 | +{
395 | +	if(ssh->state->obfuscation) {
396 | +		debug("Obfuscation disabled");
397 | +		ssh->state->obfuscation = 0;
398 | +	}
399 | +}
400 | +
401 | +int
402 | +sshpkt_get_obfuscation(struct ssh *ssh)
403 | +{
404 | +	return ssh->state->obfuscation;
405 | +}
406 | diff -Nupr openssh-9.8p1/packet.h ob/packet.h
407 | --- openssh-9.8p1/packet.h	2024-07-01 12:36:28.000000000 +0800
408 | +++ ob/packet.h	2024-07-01 23:59:55.300000506 +0800
409 | @@ -181,6 +181,9 @@ void	sshpkt_fatal(struct ssh *ssh, int r
410 |  	    __attribute__((format(printf, 3, 4)))
411 |  	    __attribute__((noreturn));
412 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
413 | +void	sshpkt_enable_obfuscation(struct ssh *);
414 | +void	sshpkt_disable_obfuscation(struct ssh *);
415 | +int sshpkt_get_obfuscation(struct ssh *);
416 |  
417 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
418 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
419 | diff -Nupr openssh-9.8p1/readconf.c ob/readconf.c
420 | --- openssh-9.8p1/readconf.c	2024-07-01 12:36:28.000000000 +0800
421 | +++ ob/readconf.c	2024-07-01 23:59:55.300000506 +0800
422 | @@ -146,7 +146,7 @@ typedef enum {
423 |  	oBadOption,
424 |  	oHost, oMatch, oInclude, oTag,
425 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
426 | -	oGatewayPorts, oExitOnForwardFailure,
427 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
428 |  	oPasswordAuthentication,
429 |  	oXAuthLocation,
430 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
431 | @@ -329,6 +329,8 @@ static struct {
432 |  	{ "enableescapecommandline", oEnableEscapeCommandline },
433 |  	{ "obscurekeystroketiming", oObscureKeystrokeTiming },
434 |  	{ "channeltimeout", oChannelTimeout },
435 | +	{ "obfuscatehandshake", oObfuscateHandshake },
436 | +	{ "obfuscatekeyword", oObfuscateKeyword },
437 |  
438 |  	{ NULL, oBadOption }
439 |  };
440 | @@ -2388,6 +2390,16 @@ parse_pubkey_algos:
441 |  		}
442 |  		break;
443 |  
444 | +	case oObfuscateHandshake:
445 | +		intptr = &options->obfuscate_handshake;
446 | +		goto parse_flag;
447 | +
448 | +	case oObfuscateKeyword:
449 | +		if (*activep)
450 | +			options->obfuscate_handshake = 1;
451 | +		charptr = &options->obfuscate_keyword;
452 | +		goto parse_string;
453 | +
454 |  	case oDeprecated:
455 |  		debug("%s line %d: Deprecated option \"%s\"",
456 |  		    filename, linenum, keyword);
457 | @@ -2619,6 +2631,8 @@ initialize_options(Options * options)
458 |  	options->add_keys_to_agent_lifespan = -1;
459 |  	options->identity_agent = NULL;
460 |  	options->visual_host_key = -1;
461 | +	options->obfuscate_handshake = 0;
462 | +	options->obfuscate_keyword = NULL;
463 |  	options->ip_qos_interactive = -1;
464 |  	options->ip_qos_bulk = -1;
465 |  	options->request_tty = -1;
466 | diff -Nupr openssh-9.8p1/readconf.h ob/readconf.h
467 | --- openssh-9.8p1/readconf.h	2024-07-01 12:36:28.000000000 +0800
468 | +++ ob/readconf.h	2024-07-01 23:59:55.300000506 +0800
469 | @@ -146,6 +146,8 @@ typedef struct {
470 |  	int	permit_local_command;
471 |  	char	*remote_command;
472 |  	int	visual_host_key;
473 | +	int obfuscate_handshake;
474 | +	char *obfuscate_keyword;
475 |  
476 |  	int	request_tty;
477 |  	int	session_type;
478 | diff -Nupr openssh-9.8p1/scp.c ob/scp.c
479 | --- openssh-9.8p1/scp.c	2024-07-01 12:36:28.000000000 +0800
480 | +++ ob/scp.c	2024-07-01 23:59:55.312000470 +0800
481 | @@ -508,7 +508,7 @@ main(int argc, char **argv)
482 |  
483 |  	fflag = Tflag = tflag = 0;
484 |  	while ((ch = getopt(argc, argv,
485 | -	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:")) != -1) {
486 | +	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:zZ:")) != -1) {
487 |  		switch (ch) {
488 |  		/* User-visible flags. */
489 |  		case '1':
490 | @@ -521,6 +521,7 @@ main(int argc, char **argv)
491 |  		case '4':
492 |  		case '6':
493 |  		case 'C':
494 | +		case 'z':
495 |  			addargs(&args, "-%c", ch);
496 |  			addargs(&remote_remote_args, "-%c", ch);
497 |  			break;
498 | @@ -538,6 +539,7 @@ main(int argc, char **argv)
499 |  		case 'i':
500 |  		case 'F':
501 |  		case 'J':
502 | +		case 'Z':
503 |  			addargs(&remote_remote_args, "-%c", ch);
504 |  			addargs(&remote_remote_args, "%s", optarg);
505 |  			addargs(&args, "-%c", ch);
506 | diff -Nupr openssh-9.8p1/servconf.c ob/servconf.c
507 | --- openssh-9.8p1/servconf.c	2024-07-01 12:36:28.000000000 +0800
508 | +++ ob/servconf.c	2024-07-01 23:59:55.312000470 +0800
509 | @@ -96,6 +96,7 @@ initialize_server_options(ServerOptions
510 |  
511 |  	/* Standard Options */
512 |  	options->num_ports = 0;
513 | +	options->num_obfuscated_ports = 0;
514 |  	options->ports_from_cmdline = 0;
515 |  	options->queued_listen_addrs = NULL;
516 |  	options->num_queued_listens = 0;
517 | @@ -194,6 +195,7 @@ initialize_server_options(ServerOptions
518 |  	options->permitted_listens = NULL;
519 |  	options->adm_forced_command = NULL;
520 |  	options->chroot_directory = NULL;
521 | +	options->obfuscate_keyword = NULL;
522 |  	options->authorized_keys_command = NULL;
523 |  	options->authorized_keys_command_user = NULL;
524 |  	options->revoked_keys_file = NULL;
525 | @@ -316,7 +318,7 @@ fill_default_server_options(ServerOption
526 |  #endif /* WITH_XMSS */
527 |  	}
528 |  	/* No certificates by default */
529 | -	if (options->num_ports == 0)
530 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
531 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
532 |  	if (options->address_family == -1)
533 |  		options->address_family = AF_UNSPEC;
534 | @@ -539,7 +541,7 @@ typedef enum {
535 |  	/* Portable-specific options */
536 |  	sUsePAM, sPAMServiceName,
537 |  	/* Standard Options */
538 | -	sPort, sHostKeyFile, sLoginGraceTime,
539 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
540 |  	sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
541 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
542 |  	sKerberosGetAFSToken, sPasswordAuthentication,
543 | @@ -598,6 +600,8 @@ static struct {
544 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
545 |  	/* Standard Options */
546 |  	{ "port", sPort, SSHCFG_GLOBAL },
547 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
548 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
549 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
550 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
551 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
552 | @@ -818,6 +822,10 @@ add_listen_addr(ServerOptions *options,
553 |  			add_one_listen_addr(options, addr, rdomain,
554 |  			    options->ports[i]);
555 |  		}
556 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
557 | +			add_one_listen_addr(options, addr, rdomain,
558 | +				options->obfuscated_ports[i]);
559 | +		}
560 |  	}
561 |  }
562 |  
563 | @@ -932,7 +940,7 @@ process_queued_listen_addrs(ServerOption
564 |  	u_int i;
565 |  	struct queued_listenaddr *qla;
566 |  
567 | -	if (options->num_ports == 0)
568 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
569 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
570 |  	if (options->address_family == -1)
571 |  		options->address_family = AF_UNSPEC;
572 | @@ -1360,6 +1368,30 @@ process_server_config_line_depth(ServerO
573 |  			    filename, linenum);
574 |  		break;
575 |  
576 | +	case sObfuscatedPort:
577 | +		if(options->ports_from_cmdline)
578 | +			return 0;
579 | +		if(options->listen_addrs != NULL)
580 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
581 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
582 | +			fatal("%s line %d: too many ports.", filename, linenum);
583 | +		arg = argv_next(&ac, &av);
584 | +		if(!arg || *arg == '\0')
585 | +			fatal("%s line %d: missing port number.", filename, linenum);
586 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
587 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
588 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
589 | +		break;
590 | +	case sObfuscateKeyword:
591 | +		charptr = &options->obfuscate_keyword;
592 | +		arg = argv_next(&ac, &av);
593 | +		if(!arg || *arg == '\0')
594 | +			fatal("%s line %d: missing keyword argument.",
595 | +					filename, linenum);
596 | +		if(*activep && *charptr == NULL)
597 | +			*charptr = xstrdup(arg);
598 | +		break;
599 | +
600 |  	case sLoginGraceTime:
601 |  		intptr = &options->login_grace_time;
602 |   parse_time:
603 | diff -Nupr openssh-9.8p1/servconf.h ob/servconf.h
604 | --- openssh-9.8p1/servconf.h	2024-07-01 12:36:28.000000000 +0800
605 | +++ ob/servconf.h	2024-07-01 23:59:55.312000470 +0800
606 | @@ -220,6 +220,11 @@ typedef struct {
607 |  	u_int   num_permitted_listens;
608 |  
609 |  	char   *chroot_directory;
610 | +
611 | +	int obfuscated_ports[MAX_PORTS];
612 | +	u_int num_obfuscated_ports;
613 | +	char *obfuscate_keyword;
614 | +
615 |  	char   *revoked_keys_file;
616 |  	char   *trusted_user_ca_keys;
617 |  	char   *authorized_keys_command;
618 | diff -Nupr openssh-9.8p1/sftp.c ob/sftp.c
619 | --- openssh-9.8p1/sftp.c	2024-07-01 12:36:28.000000000 +0800
620 | +++ ob/sftp.c	2024-07-01 23:59:55.312000470 +0800
621 | @@ -2468,13 +2468,14 @@ main(int argc, char **argv)
622 |  	infile = stdin;
623 |  
624 |  	while ((ch = getopt(argc, argv,
625 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:")) != -1) {
626 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:zZ:")) != -1) {
627 |  		switch (ch) {
628 |  		/* Passed through to ssh(1) */
629 |  		case 'A':
630 |  		case '4':
631 |  		case '6':
632 |  		case 'C':
633 | +		case 'z':
634 |  			addargs(&args, "-%c", ch);
635 |  			break;
636 |  		/* Passed through to ssh(1) with argument */
637 | @@ -2483,6 +2484,7 @@ main(int argc, char **argv)
638 |  		case 'c':
639 |  		case 'i':
640 |  		case 'o':
641 | +		case 'Z':
642 |  			addargs(&args, "-%c", ch);
643 |  			addargs(&args, "%s", optarg);
644 |  			break;
645 | diff -Nupr openssh-9.8p1/ssh.c ob/ssh.c
646 | --- openssh-9.8p1/ssh.c	2024-07-01 12:36:28.000000000 +0800
647 | +++ ob/ssh.c	2024-07-01 23:59:55.316000458 +0800
648 | @@ -180,12 +180,13 @@ static void
649 |  usage(void)
650 |  {
651 |  	fprintf(stderr,
652 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] [-b bind_address]\n"
653 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface] [-b bind_address]\n"
654 |  "           [-c cipher_spec] [-D [bind_address:]port] [-E log_file]\n"
655 |  "           [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file]\n"
656 |  "           [-J destination] [-L address] [-l login_name] [-m mac_spec]\n"
657 |  "           [-O ctl_cmd] [-o option] [-P tag] [-p port] [-R address]\n"
658 |  "           [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
659 | +"           [-Z obfuscate_keyword]\n"
660 |  "           destination [command [argument ...]]\n"
661 |  "       ssh [-Q query_option]\n"
662 |  	);
663 | @@ -746,7 +747,7 @@ main(int ac, char **av)
664 |  
665 |   again:
666 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
667 | -	    "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
668 | +	    "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYyzZ:")) != -1) { /* HUZdhjruz */
669 |  		switch (opt) {
670 |  		case '1':
671 |  			fatal("SSH protocol v.1 is no longer supported");
672 | @@ -1098,6 +1099,13 @@ main(int ac, char **av)
673 |  		case 'F':
674 |  			config = optarg;
675 |  			break;
676 | +		case 'z':
677 | +			options.obfuscate_handshake = 1;
678 | +			break;
679 | +		case 'Z':
680 | +			options.obfuscate_handshake = 1;
681 | +			options.obfuscate_keyword = optarg;
682 | +			break;
683 |  		default:
684 |  			usage();
685 |  		}
686 | diff -Nupr openssh-9.8p1/sshconnect.c ob/sshconnect.c
687 | --- openssh-9.8p1/sshconnect.c	2024-07-01 12:36:28.000000000 +0800
688 | +++ ob/sshconnect.c	2024-07-01 23:59:55.316000458 +0800
689 | @@ -65,6 +65,7 @@
690 |  #include "monitor_fdpass.h"
691 |  #include "ssh2.h"
692 |  #include "version.h"
693 | +#include "obfuscate.h"
694 |  #include "authfile.h"
695 |  #include "ssherr.h"
696 |  #include "authfd.h"
697 | @@ -269,6 +270,12 @@ ssh_proxy_connect(struct ssh *ssh, const
698 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
699 |  		return -1; /* ssh_packet_set_connection logs error */
700 |  
701 | +	if(options.obfuscate_handshake) {
702 | +		if(options.obfuscate_keyword)
703 | +			obfuscate_set_keyword(options.obfuscate_keyword);
704 | +		sshpkt_enable_obfuscation(ssh);
705 | +	}
706 | +
707 |  	return 0;
708 |  }
709 |  
710 | @@ -538,6 +545,11 @@ ssh_connect_direct(struct ssh *ssh, cons
711 |  	/* Set the connection. */
712 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
713 |  		return -1; /* ssh_packet_set_connection logs error */
714 | +	if(options.obfuscate_handshake) {
715 | +		if(options.obfuscate_keyword)
716 | +			obfuscate_set_keyword(options.obfuscate_keyword);
717 | +		sshpkt_enable_obfuscation(ssh);
718 | +	}
719 |  
720 |  	return 0;
721 |  }
722 | @@ -1603,6 +1615,9 @@ ssh_login(struct ssh *ssh, Sensitive *se
723 |  	host = xstrdup(orighost);
724 |  	lowercase(host);
725 |  
726 | +	if(options.obfuscate_handshake)
727 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
728 | +
729 |  	/* Exchange protocol version identification strings with the server. */
730 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
731 |  		sshpkt_fatal(ssh, r, "banner exchange");
732 | diff -Nupr openssh-9.8p1/sshd_config ob/sshd_config
733 | --- openssh-9.8p1/sshd_config	2024-07-01 12:36:28.000000000 +0800
734 | +++ ob/sshd_config	2024-07-01 23:59:55.316000458 +0800
735 | @@ -11,6 +11,8 @@
736 |  # default value.
737 |  
738 |  #Port 22
739 | +#ObfuscatedPort 222
740 | +#ObfuscateKeyword key
741 |  #AddressFamily any
742 |  #ListenAddress 0.0.0.0
743 |  #ListenAddress ::
744 | diff -Nupr openssh-9.8p1/sshd-session.c ob/sshd-session.c
745 | --- openssh-9.8p1/sshd-session.c	2024-07-01 12:36:28.000000000 +0800
746 | +++ ob/sshd-session.c	2024-07-02 01:04:59.795478593 +0800
747 | @@ -102,6 +102,7 @@
748 |  #include "ssh-gss.h"
749 |  #endif
750 |  #include "monitor_wrap.h"
751 | +#include "obfuscate.h"
752 |  #include "ssh-sandbox.h"
753 |  #include "auth-options.h"
754 |  #include "version.h"
755 | @@ -190,6 +191,9 @@ struct include_list includes = TAILQ_HEA
756 |  /* message to be displayed after login */
757 |  struct sshbuf *loginmsg;
758 |  
759 | +/* Enable handshake obfuscation */
760 | +int use_obfuscation = 0;
761 | +
762 |  /* Prototypes for various functions defined later in this file. */
763 |  void destroy_sensitive_data(void);
764 |  void demote_sensitive_data(void);
765 | @@ -870,7 +874,7 @@ main(int ac, char **av)
766 |  	struct ssh *ssh = NULL;
767 |  	extern char *optarg;
768 |  	extern int optind;
769 | -	int r, opt, on = 1, remote_port;
770 | +	int r, opt, on = 1, remote_port, local_port;
771 |  	int sock_in = -1, sock_out = -1, rexeced_flag = 0, have_key = 0;
772 |  	const char *remote_ip, *rdomain;
773 |  	char *line, *laddr, *logfile = NULL;
774 | @@ -1234,6 +1238,14 @@ main(int ac, char **av)
775 |  	server_process_channel_timeouts(ssh);
776 |  	server_process_permitopen(ssh);
777 |  
778 | +	local_port = ssh_local_port(ssh);
779 | +	for (i = 0; i < options.num_obfuscated_ports; i++) {
780 | +		if (options.obfuscated_ports[i] == local_port) {
781 | +			use_obfuscation = 1;
782 | +			break;
783 | +		}
784 | +	}
785 | +
786 |  	/* Set SO_KEEPALIVE if requested. */
787 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
788 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
789 | @@ -1278,6 +1290,13 @@ main(int ac, char **av)
790 |  	if (!debug_flag)
791 |  		alarm(options.login_grace_time);
792 |  
793 | +	if (use_obfuscation) {
794 | +		if (options.obfuscate_keyword)
795 | +			obfuscate_set_keyword(options.obfuscate_keyword);
796 | +		sshpkt_enable_obfuscation(ssh);
797 | +		obfuscate_receive_seed(ssh, sock_in);
798 | +	}
799 | +
800 |  	if ((r = kex_exchange_identification(ssh, -1,
801 |  	    options.version_addendum)) != 0)
802 |  		sshpkt_fatal(ssh, r, "banner exchange");
803 | @@ -1300,8 +1319,11 @@ main(int ac, char **av)
804 |  		fatal("sshbuf_new loginmsg failed");
805 |  	auth_debug_reset();
806 |  
807 | -	if (privsep_preauth(ssh) == 1)
808 | -		goto authenticated;
809 | +	if (privsep_preauth(ssh) == 1) {
810 | +		if(use_obfuscation)
811 | +			sshpkt_disable_obfuscation(ssh);
812 | + 		goto authenticated;
813 | +	}
814 |  
815 |  	/* perform the key exchange */
816 |  	/* authenticate user and start session */
817 | 


--------------------------------------------------------------------------------
/portable/9.9.diff:
--------------------------------------------------------------------------------
1 | 9.8.diff


--------------------------------------------------------------------------------
/ubuntu/8.9p1.patch:
--------------------------------------------------------------------------------
  1 | Description: Add handshake obfuscation
  2 | Author: zinglau <zinglau2015@gmail.com>
  3 | Index: openssh-8.9p1/Makefile.in
  4 | ===================================================================
  5 | --- openssh-8.9p1.orig/Makefile.in	2023-12-25 12:09:32.000000000 +0800
  6 | +++ openssh-8.9p1/Makefile.in	2023-12-25 12:09:32.000000000 +0800
  7 | @@ -112,7 +112,7 @@
  8 |  	kexsntrup761x25519.o sntrup761.o kexgen.o \
  9 |  	kexgssc.o \
 10 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
 11 | -	sshbuf-io.o
 12 | +	sshbuf-io.o obfuscate.o
 13 |  
 14 |  SKOBJS=	ssh-sk-client.o
 15 |  
 16 | Index: openssh-8.9p1/kex.c
 17 | ===================================================================
 18 | --- openssh-8.9p1.orig/kex.c	2023-12-25 12:09:32.000000000 +0800
 19 | +++ openssh-8.9p1/kex.c	2023-12-25 12:09:32.000000000 +0800
 20 | @@ -59,6 +59,7 @@
 21 |  #include "monitor.h"
 22 |  #include "xmalloc.h"
 23 |  
 24 | +#include "obfuscate.h"
 25 |  #include "ssherr.h"
 26 |  #include "sshbuf.h"
 27 |  #include "digest.h"
 28 | @@ -521,9 +522,12 @@
 29 |  		return r;
 30 |  	debug("SSH2_MSG_NEWKEYS sent");
 31 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 32 | -	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
 33 | +	if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0) {
 34 | +		sshpkt_disable_obfuscation(ssh);
 35 |  		if ((r = kex_send_ext_info(ssh)) != 0)
 36 |  			return r;
 37 | +		sshpkt_enable_obfuscation(ssh);
 38 | +	}
 39 |  	debug("expecting SSH2_MSG_NEWKEYS");
 40 |  	return 0;
 41 |  }
 42 | @@ -601,6 +605,7 @@
 43 |  	kex->flags &= ~KEX_INIT_SENT;
 44 |  	free(kex->name);
 45 |  	kex->name = NULL;
 46 | +	sshpkt_disable_obfuscation(ssh);
 47 |  	return 0;
 48 |  }
 49 |  
 50 | @@ -1299,14 +1304,42 @@
 51 |  		goto out;
 52 |  	}
 53 |  
 54 | +	/* Make copy and obfuscate the original */
 55 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 56 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 57 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 58 | +			r = SSH_ERR_ALLOC_FAIL;
 59 | +			goto out;
 60 | +		}
 61 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 62 | +	}
 63 | +
 64 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 65 |  	    sshbuf_mutable_ptr(our_version),
 66 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 67 |  		oerrno = errno;
 68 |  		debug_f("write: %.100s", strerror(errno));
 69 |  		r = SSH_ERR_SYSTEM_ERROR;
 70 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 71 | +			free(cp);
 72 | +		}
 73 |  		goto out;
 74 |  	}
 75 | +
 76 | +	/* Restore the original */
 77 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 78 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 79 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 80 | +			free(cp);
 81 | +			goto out;
 82 | +		}
 83 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 84 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 85 | +			free(cp);
 86 | +			goto out;
 87 | +		}
 88 | +	}
 89 | +
 90 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 91 |  		oerrno = errno;
 92 |  		error_fr(r, "sshbuf_consume_end");
 93 | @@ -1363,6 +1396,8 @@
 94 |  				r = SSH_ERR_SYSTEM_ERROR;
 95 |  				goto out;
 96 |  			}
 97 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 98 | +			  obfuscate_input(&c, 1);
 99 |  			if (c == '\r') {
100 |  				expect_nl = 1;
101 |  				continue;
102 | Index: openssh-8.9p1/obfuscate.c
103 | ===================================================================
104 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
105 | +++ openssh-8.9p1/obfuscate.c	2023-12-25 12:09:32.000000000 +0800
106 | @@ -0,0 +1,220 @@
107 | +#include "includes.h"
108 | +#include <openssl/evp.h>
109 | +#include <openssl/rc4.h>
110 | +#include "openbsd-compat/openssl-compat.h"
111 | +#include <unistd.h>
112 | +#include <string.h>
113 | +#include "atomicio.h"
114 | +#include "canohost.h"
115 | +#include "xmalloc.h"
116 | +#include "log.h"
117 | +#include "packet.h"
118 | +#include "obfuscate.h"
119 | +
120 | +static RC4_KEY rc4_input;
121 | +static RC4_KEY rc4_output;
122 | +
123 | +static const char *obfuscate_keyword = NULL;
124 | +
125 | +#define OBFUSCATE_KEY_LENGTH 	16
126 | +#define OBFUSCATE_SEED_LENGTH	16
127 | +#define OBFUSCATE_HASH_ITERATIONS 6000
128 | +#define OBFUSCATE_MAX_PADDING	8192
129 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
130 | +
131 | +struct seed_msg {
132 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
133 | +	u_int32_t magic;
134 | +	u_int32_t padding_length;
135 | +	u_char padding[];
136 | +};
137 | +
138 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
139 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
140 | +static void set_keys(const u_char *, const u_char *);
141 | +static void initialize(const u_char *, int);
142 | +static void read_forever(int);
143 | +
144 | +
145 | +/*
146 | + * Server calls this
147 | + */
148 | +void
149 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
150 | +{
151 | +	struct seed_msg seed;
152 | +
153 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
154 | +	u_int len;
155 | +	u_int32_t padding_length;
156 | +
157 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
158 | +
159 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
160 | +	if(len != sizeof(struct seed_msg))
161 | +		fatal("obfuscate_receive_seed: read failed");
162 | +
163 | +	initialize(seed.seed_buffer, 1);
164 | +	obfuscate_input((u_char *)&seed.magic, 8);
165 | +
166 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
167 | +		logit("Magic value check failed (%u) on obfuscated handshake "
168 | + 			"from %.200s port %d", ntohl(seed.magic),
169 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
170 | +		read_forever(sock_in);
171 | +	}
172 | +	padding_length = ntohl(seed.padding_length);
173 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
174 | +		logit("Illegal padding length %d for obfuscated handshake "
175 | + 			"from %.200s port %d", ntohl(seed.padding_length),
176 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
177 | +		read_forever(sock_in);
178 | +	}
179 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
180 | +	if(len != padding_length)
181 | +		fatal("obfuscate_receive_seed: read failed");
182 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
183 | +	obfuscate_input(padding_drain, padding_length);
184 | +}
185 | +
186 | +/*
187 | + * Client calls this
188 | + */
189 | +void
190 | +obfuscate_send_seed(int sock_out)
191 | +{
192 | +	struct seed_msg *seed;
193 | +	int i;
194 | +	u_int32_t rnd = 0;
195 | +	u_int message_length;
196 | +	u_int padding_length;
197 | +
198 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
199 | +	message_length = padding_length + sizeof(struct seed_msg);
200 | +	seed = xmalloc(message_length);
201 | +
202 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
203 | +		if(i % 4 == 0)
204 | +			rnd = arc4random();
205 | +		seed->seed_buffer[i] = rnd & 0xff;
206 | +		rnd >>= 8;
207 | +	}
208 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
209 | +	seed->padding_length = htonl(padding_length);
210 | +	for(i = 0; i < (int)padding_length; i++) {
211 | +		if(i % 4 == 0)
212 | +			rnd = arc4random();
213 | +		seed->padding[i] = rnd & 0xff;
214 | +	}
215 | +	initialize(seed->seed_buffer, 0);
216 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
217 | +		message_length - OBFUSCATE_SEED_LENGTH);
218 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
219 | +	atomicio(vwrite, sock_out, seed, message_length);
220 | +	free(seed);
221 | +
222 | +}
223 | +
224 | +void
225 | +obfuscate_set_keyword(const char *keyword)
226 | +{
227 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
228 | +	obfuscate_keyword = keyword;
229 | +}
230 | +
231 | +void
232 | +obfuscate_input(u_char *buffer, u_int buffer_len)
233 | +{
234 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
235 | +}
236 | +
237 | +void
238 | +obfuscate_output(u_char *buffer, u_int buffer_len)
239 | +{
240 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
241 | +}
242 | +
243 | +static void
244 | +initialize(const u_char *seed, int server)
245 | +{
246 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
247 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
248 | +
249 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
250 | +
251 | +	if(server)
252 | +		set_keys(client_to_server_key, server_to_client_key);
253 | +	else
254 | +		set_keys(server_to_client_key, client_to_server_key);
255 | +}
256 | +
257 | +static void
258 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
259 | +{
260 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
261 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
262 | +}
263 | +
264 | +static void
265 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
266 | +{
267 | +	EVP_MD_CTX *ctx;
268 | +	u_char md_output[EVP_MAX_MD_SIZE];
269 | +	int md_len;
270 | +	int i;
271 | +	u_char *buffer;
272 | +	u_char *p;
273 | +	u_int buffer_length;
274 | +
275 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
276 | +		fatal("Cannot create new digest context");
277 | +
278 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
279 | +	if(obfuscate_keyword)
280 | +		buffer_length += strlen(obfuscate_keyword);
281 | +
282 | +	p = buffer = xmalloc(buffer_length);
283 | +
284 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
285 | +	p += OBFUSCATE_SEED_LENGTH;
286 | +
287 | +	if(obfuscate_keyword) {
288 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
289 | +		p += strlen(obfuscate_keyword);
290 | +	}
291 | +	memcpy(p, iv, iv_len);
292 | +
293 | +	EVP_DigestInit(ctx, EVP_sha1());
294 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
295 | +	EVP_DigestFinal(ctx, md_output, &md_len);
296 | +
297 | +	free(buffer);
298 | +
299 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
300 | +		EVP_DigestInit(ctx, EVP_sha1());
301 | +		EVP_DigestUpdate(ctx, md_output, md_len);
302 | +		EVP_DigestFinal(ctx, md_output, &md_len);
303 | +	}
304 | +
305 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
306 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
307 | +
308 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
309 | +}
310 | +
311 | +static void
312 | +set_keys(const u_char *input_key, const u_char *output_key)
313 | +{
314 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
315 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
316 | +}
317 | +
318 | +static void
319 | +read_forever(int sock_in)
320 | +{
321 | +	u_char discard_buffer[1024];
322 | +
323 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
324 | +		;
325 | +	cleanup_exit(255);
326 | +}
327 | Index: openssh-8.9p1/obfuscate.h
328 | ===================================================================
329 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
330 | +++ openssh-8.9p1/obfuscate.h	2023-12-25 12:09:32.000000000 +0800
331 | @@ -0,0 +1,10 @@
332 | +#ifndef _OBFUSCATE_H
333 | +#define _OBFUSCATE_H
334 | +
335 | +void obfuscate_receive_seed(struct ssh *, int);
336 | +void obfuscate_send_seed(int);
337 | +void obfuscate_set_keyword(const char *);
338 | +void obfuscate_input(u_char *, u_int);
339 | +void obfuscate_output(u_char *, u_int);
340 | +
341 | +#endif
342 | Index: openssh-8.9p1/packet.c
343 | ===================================================================
344 | --- openssh-8.9p1.orig/packet.c	2022-02-23 19:31:11.000000000 +0800
345 | +++ openssh-8.9p1/packet.c	2023-12-25 12:09:32.000000000 +0800
346 | @@ -94,6 +94,7 @@
347 |  #include "channels.h"
348 |  #include "ssh.h"
349 |  #include "packet.h"
350 | +#include "obfuscate.h"
351 |  #include "ssherr.h"
352 |  #include "sshbuf.h"
353 |  
354 | @@ -177,6 +178,8 @@
355 |  	/* Set to true if we are authenticated. */
356 |  	int after_authentication;
357 |  
358 | +	int obfuscation;
359 | +
360 |  	int keep_alive_timeouts;
361 |  
362 |  	/* The maximum time that we will wait to send or receive a packet */
363 | @@ -1200,6 +1203,8 @@
364 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
365 |  			goto out;
366 |  	}
367 | +	if(state->obfuscation)
368 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
369 |  #ifdef PACKET_DEBUG
370 |  	fprintf(stderr, "encrypted: ");
371 |  	sshbuf_dump(state->output, stderr);
372 | @@ -1534,6 +1539,8 @@
373 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
374 |  		    &cp)) != 0)
375 |  			goto out;
376 | +		if(state->obfuscation)
377 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
378 |  		if ((r = cipher_crypt(state->receive_context,
379 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
380 |  		    block_size, 0, 0)) != 0)
381 | @@ -1599,6 +1606,8 @@
382 |  			goto out;
383 |  		}
384 |  	}
385 | +	if(state->obfuscation)
386 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
387 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
388 |  	    &cp)) != 0)
389 |  		goto out;
390 | @@ -2717,3 +2726,25 @@
391 |  	ssh->state->extra_pad = pad;
392 |  	return 0;
393 |  }
394 | +
395 | +void
396 | +sshpkt_enable_obfuscation(struct ssh *ssh)
397 | +{
398 | +	debug("Obfuscation enabled");
399 | +	ssh->state->obfuscation = 1;
400 | +}
401 | +
402 | +void
403 | +sshpkt_disable_obfuscation(struct ssh *ssh)
404 | +{
405 | +	if(ssh->state->obfuscation) {
406 | +		debug("Obfuscation disabled");
407 | +		ssh->state->obfuscation = 0;
408 | +	}
409 | +}
410 | +
411 | +int
412 | +sshpkt_get_obfuscation(struct ssh *ssh)
413 | +{
414 | +	return ssh->state->obfuscation;
415 | +}
416 | Index: openssh-8.9p1/packet.h
417 | ===================================================================
418 | --- openssh-8.9p1.orig/packet.h	2022-02-23 19:31:11.000000000 +0800
419 | +++ openssh-8.9p1/packet.h	2023-12-25 12:09:32.000000000 +0800
420 | @@ -182,6 +182,9 @@
421 |  	    __attribute__((format(printf, 3, 4)))
422 |  	    __attribute__((noreturn));
423 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
424 | +void	sshpkt_enable_obfuscation(struct ssh *);
425 | +void	sshpkt_disable_obfuscation(struct ssh *);
426 | +int sshpkt_get_obfuscation(struct ssh *);
427 |  
428 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
429 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
430 | Index: openssh-8.9p1/readconf.c
431 | ===================================================================
432 | --- openssh-8.9p1.orig/readconf.c	2023-12-25 12:09:32.000000000 +0800
433 | +++ openssh-8.9p1/readconf.c	2023-12-25 12:09:32.000000000 +0800
434 | @@ -144,7 +144,7 @@
435 |  	oBadOption,
436 |  	oHost, oMatch, oInclude,
437 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
438 | -	oGatewayPorts, oExitOnForwardFailure,
439 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
440 |  	oPasswordAuthentication,
441 |  	oXAuthLocation,
442 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
443 | @@ -339,6 +339,8 @@
444 |  	{ "knownhostscommand", oKnownHostsCommand },
445 |  	{ "protocolkeepalives", oProtocolKeepAlives },
446 |  	{ "setuptimeout", oSetupTimeOut },
447 | +	{ "obfuscatehandshake", oObfuscateHandshake },
448 | +	{ "obfuscatekeyword", oObfuscateKeyword },
449 |  
450 |  	{ NULL, oBadOption }
451 |  };
452 | @@ -2248,6 +2250,16 @@
453 |  			*charptr = xstrdup(arg);
454 |  		break;
455 |  
456 | +	case oObfuscateHandshake:
457 | +		intptr = &options->obfuscate_handshake;
458 | +		goto parse_flag;
459 | +
460 | +	case oObfuscateKeyword:
461 | +		if (*activep)
462 | +			options->obfuscate_handshake = 1;
463 | +		charptr = &options->obfuscate_keyword;
464 | +		goto parse_string;
465 | +
466 |  	case oDeprecated:
467 |  		debug("%s line %d: Deprecated option \"%s\"",
468 |  		    filename, linenum, keyword);
469 | @@ -2481,6 +2493,8 @@
470 |  	options->add_keys_to_agent_lifespan = -1;
471 |  	options->identity_agent = NULL;
472 |  	options->visual_host_key = -1;
473 | +	options->obfuscate_handshake = 0;
474 | +	options->obfuscate_keyword = NULL;
475 |  	options->ip_qos_interactive = -1;
476 |  	options->ip_qos_bulk = -1;
477 |  	options->request_tty = -1;
478 | Index: openssh-8.9p1/readconf.h
479 | ===================================================================
480 | --- openssh-8.9p1.orig/readconf.h	2023-12-25 12:09:32.000000000 +0800
481 | +++ openssh-8.9p1/readconf.h	2023-12-25 12:09:32.000000000 +0800
482 | @@ -150,6 +150,8 @@
483 |  	int	permit_local_command;
484 |  	char	*remote_command;
485 |  	int	visual_host_key;
486 | +	int obfuscate_handshake;
487 | +	char *obfuscate_keyword;
488 |  
489 |  	int	request_tty;
490 |  	int	session_type;
491 | Index: openssh-8.9p1/scp.c
492 | ===================================================================
493 | --- openssh-8.9p1.orig/scp.c	2023-12-25 12:09:32.000000000 +0800
494 | +++ openssh-8.9p1/scp.c	2023-12-25 12:09:32.000000000 +0800
495 | @@ -490,7 +490,7 @@
496 |  
497 |  	fflag = Tflag = tflag = 0;
498 |  	while ((ch = getopt(argc, argv,
499 | -	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:")) != -1) {
500 | +	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:zZ:")) != -1) {
501 |  		switch (ch) {
502 |  		/* User-visible flags. */
503 |  		case '1':
504 | @@ -503,6 +503,7 @@
505 |  		case '4':
506 |  		case '6':
507 |  		case 'C':
508 | +		case 'z':
509 |  			addargs(&args, "-%c", ch);
510 |  			addargs(&remote_remote_args, "-%c", ch);
511 |  			break;
512 | @@ -520,6 +521,7 @@
513 |  		case 'i':
514 |  		case 'F':
515 |  		case 'J':
516 | +		case 'Z':
517 |  			addargs(&remote_remote_args, "-%c", ch);
518 |  			addargs(&remote_remote_args, "%s", optarg);
519 |  			addargs(&args, "-%c", ch);
520 | Index: openssh-8.9p1/servconf.c
521 | ===================================================================
522 | --- openssh-8.9p1.orig/servconf.c	2023-12-25 12:09:32.000000000 +0800
523 | +++ openssh-8.9p1/servconf.c	2023-12-25 12:09:32.000000000 +0800
524 | @@ -96,6 +96,7 @@
525 |  
526 |  	/* Standard Options */
527 |  	options->num_ports = 0;
528 | +	options->num_obfuscated_ports = 0;
529 |  	options->ports_from_cmdline = 0;
530 |  	options->queued_listen_addrs = NULL;
531 |  	options->num_queued_listens = 0;
532 | @@ -185,6 +186,7 @@
533 |  	options->permitted_listens = NULL;
534 |  	options->adm_forced_command = NULL;
535 |  	options->chroot_directory = NULL;
536 | +	options->obfuscate_keyword = NULL;
537 |  	options->authorized_keys_command = NULL;
538 |  	options->authorized_keys_command_user = NULL;
539 |  	options->revoked_keys_file = NULL;
540 | @@ -301,7 +303,7 @@
541 |  #endif /* WITH_XMSS */
542 |  	}
543 |  	/* No certificates by default */
544 | -	if (options->num_ports == 0)
545 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
546 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
547 |  	if (options->address_family == -1)
548 |  		options->address_family = AF_UNSPEC;
549 | @@ -502,7 +504,7 @@
550 |  	/* Portable-specific options */
551 |  	sUsePAM,
552 |  	/* Standard Options */
553 | -	sPort, sHostKeyFile, sLoginGraceTime,
554 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
555 |  	sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
556 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
557 |  	sKerberosGetAFSToken, sPasswordAuthentication,
558 | @@ -558,6 +560,8 @@
559 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
560 |  	/* Standard Options */
561 |  	{ "port", sPort, SSHCFG_GLOBAL },
562 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
563 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
564 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
565 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
566 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
567 | @@ -784,6 +788,10 @@
568 |  			add_one_listen_addr(options, addr, rdomain,
569 |  			    options->ports[i]);
570 |  		}
571 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
572 | +			add_one_listen_addr(options, addr, rdomain,
573 | +				options->obfuscated_ports[i]);
574 | +		}
575 |  	}
576 |  }
577 |  
578 | @@ -898,7 +906,7 @@
579 |  	u_int i;
580 |  	struct queued_listenaddr *qla;
581 |  
582 | -	if (options->num_ports == 0)
583 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
584 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
585 |  	if (options->address_family == -1)
586 |  		options->address_family = AF_UNSPEC;
587 | @@ -1382,6 +1390,30 @@
588 |  			    filename, linenum);
589 |  		break;
590 |  
591 | +	case sObfuscatedPort:
592 | +		if(options->ports_from_cmdline)
593 | +			return 0;
594 | +		if(options->listen_addrs != NULL)
595 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
596 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
597 | +			fatal("%s line %d: too many ports.", filename, linenum);
598 | +		arg = argv_next(&ac, &av);
599 | +		if(!arg || *arg == '\0')
600 | +			fatal("%s line %d: missing port number.", filename, linenum);
601 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
602 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
603 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
604 | +		break;
605 | +	case sObfuscateKeyword:
606 | +		charptr = &options->obfuscate_keyword;
607 | +		arg = argv_next(&ac, &av);
608 | +		if(!arg || *arg == '\0')
609 | +			fatal("%s line %d: missing keyword argument.",
610 | +					filename, linenum);
611 | +		if(*activep && *charptr == NULL)
612 | +			*charptr = xstrdup(arg);
613 | +		break;
614 | +
615 |  	case sLoginGraceTime:
616 |  		intptr = &options->login_grace_time;
617 |   parse_time:
618 | Index: openssh-8.9p1/servconf.h
619 | ===================================================================
620 | --- openssh-8.9p1.orig/servconf.h	2023-12-25 12:09:32.000000000 +0800
621 | +++ openssh-8.9p1/servconf.h	2023-12-25 12:09:32.000000000 +0800
622 | @@ -212,6 +212,11 @@
623 |  	u_int   num_permitted_listens;
624 |  
625 |  	char   *chroot_directory;
626 | +
627 | +	int obfuscated_ports[MAX_PORTS];
628 | +	u_int num_obfuscated_ports;
629 | +	char *obfuscate_keyword;
630 | +
631 |  	char   *revoked_keys_file;
632 |  	char   *trusted_user_ca_keys;
633 |  	char   *authorized_keys_command;
634 | Index: openssh-8.9p1/sftp.c
635 | ===================================================================
636 | --- openssh-8.9p1.orig/sftp.c	2022-02-23 19:31:11.000000000 +0800
637 | +++ openssh-8.9p1/sftp.c	2023-12-25 12:09:32.000000000 +0800
638 | @@ -2380,13 +2380,14 @@
639 |  	infile = stdin;
640 |  
641 |  	while ((ch = getopt(argc, argv,
642 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:")) != -1) {
643 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:zZ:")) != -1) {
644 |  		switch (ch) {
645 |  		/* Passed through to ssh(1) */
646 |  		case 'A':
647 |  		case '4':
648 |  		case '6':
649 |  		case 'C':
650 | +		case 'z':
651 |  			addargs(&args, "-%c", ch);
652 |  			break;
653 |  		/* Passed through to ssh(1) with argument */
654 | @@ -2395,6 +2396,7 @@
655 |  		case 'c':
656 |  		case 'i':
657 |  		case 'o':
658 | +		case 'Z':
659 |  			addargs(&args, "-%c", ch);
660 |  			addargs(&args, "%s", optarg);
661 |  			break;
662 | Index: openssh-8.9p1/ssh.c
663 | ===================================================================
664 | --- openssh-8.9p1.orig/ssh.c	2023-12-25 12:09:32.000000000 +0800
665 | +++ openssh-8.9p1/ssh.c	2023-12-25 12:09:32.000000000 +0800
666 | @@ -179,13 +179,14 @@
667 |  usage(void)
668 |  {
669 |  	fprintf(stderr,
670 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
671 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface]\n"
672 |  "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
673 |  "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
674 |  "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
675 |  "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
676 |  "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
677 |  "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
678 | +"           [-Z obfuscate_keyword]\n"
679 |  	);
680 |  	exit(255);
681 |  }
682 | @@ -696,7 +697,7 @@
683 |  
684 |   again:
685 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
686 | -	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
687 | +	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYyzZ:")) != -1) {
688 |  		switch (opt) {
689 |  		case '1':
690 |  			fatal("SSH protocol v.1 is no longer supported");
691 | @@ -1044,6 +1045,13 @@
692 |  		case 'F':
693 |  			config = optarg;
694 |  			break;
695 | +		case 'z':
696 | +			options.obfuscate_handshake = 1;
697 | +			break;
698 | +		case 'Z':
699 | +			options.obfuscate_handshake = 1;
700 | +			options.obfuscate_keyword = optarg;
701 | +			break;
702 |  		default:
703 |  			usage();
704 |  		}
705 | Index: openssh-8.9p1/sshconnect.c
706 | ===================================================================
707 | --- openssh-8.9p1.orig/sshconnect.c	2023-12-25 12:09:32.000000000 +0800
708 | +++ openssh-8.9p1/sshconnect.c	2023-12-25 12:09:32.000000000 +0800
709 | @@ -65,6 +65,7 @@
710 |  #include "monitor_fdpass.h"
711 |  #include "ssh2.h"
712 |  #include "version.h"
713 | +#include "obfuscate.h"
714 |  #include "authfile.h"
715 |  #include "ssherr.h"
716 |  #include "authfd.h"
717 | @@ -269,6 +270,12 @@
718 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
719 |  		return -1; /* ssh_packet_set_connection logs error */
720 |  
721 | +	if(options.obfuscate_handshake) {
722 | +		if(options.obfuscate_keyword)
723 | +			obfuscate_set_keyword(options.obfuscate_keyword);
724 | +		sshpkt_enable_obfuscation(ssh);
725 | +	}
726 | +
727 |  	return 0;
728 |  }
729 |  
730 | @@ -530,6 +537,11 @@
731 |  	/* Set the connection. */
732 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
733 |  		return -1; /* ssh_packet_set_connection logs error */
734 | +	if(options.obfuscate_handshake) {
735 | +		if(options.obfuscate_keyword)
736 | +			obfuscate_set_keyword(options.obfuscate_keyword);
737 | +		sshpkt_enable_obfuscation(ssh);
738 | +	}
739 |  
740 |  	return 0;
741 |  }
742 | @@ -1559,6 +1571,9 @@
743 |  	host = xstrdup(orighost);
744 |  	lowercase(host);
745 |  
746 | +	if(options.obfuscate_handshake)
747 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
748 | +
749 |  	/* Exchange protocol version identification strings with the server. */
750 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, 1, NULL)) != 0)
751 |  		sshpkt_fatal(ssh, r, "banner exchange");
752 | Index: openssh-8.9p1/sshd.c
753 | ===================================================================
754 | --- openssh-8.9p1.orig/sshd.c	2023-12-25 12:09:32.000000000 +0800
755 | +++ openssh-8.9p1/sshd.c	2023-12-25 12:09:32.000000000 +0800
756 | @@ -125,6 +125,7 @@
757 |  #include "ssh-gss.h"
758 |  #endif
759 |  #include "monitor_wrap.h"
760 | +#include "obfuscate.h"
761 |  #include "ssh-sandbox.h"
762 |  #include "auth-options.h"
763 |  #include "version.h"
764 | @@ -266,6 +267,9 @@
765 |  /* message to be displayed after login */
766 |  struct sshbuf *loginmsg;
767 |  
768 | +/* Enable handshake obfuscation */
769 | +int use_obfuscation = 0;
770 | +
771 |  /* Unprivileged user */
772 |  struct passwd *privsep_pw = NULL;
773 |  
774 | @@ -1539,7 +1543,7 @@
775 |  	struct ssh *ssh = NULL;
776 |  	extern char *optarg;
777 |  	extern int optind;
778 | -	int r, opt, on = 1, already_daemon, remote_port;
779 | +	int r, opt, on = 1, already_daemon, remote_port, local_port;
780 |  	int sock_in = -1, sock_out = -1, newsock = -1;
781 |  	const char *remote_ip, *rdomain;
782 |  	char *fp, *line, *laddr, *logfile = NULL;
783 | @@ -2162,6 +2166,14 @@
784 |  	channel_set_af(ssh, options.address_family);
785 |  	process_permitopen(ssh, &options);
786 |  
787 | +	local_port = ssh_local_port(ssh);
788 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
789 | +		if(options.obfuscated_ports[i] == local_port) {
790 | +			use_obfuscation = 1;
791 | +			break;
792 | +		}
793 | +	}
794 | +
795 |  	/* Set SO_KEEPALIVE if requested. */
796 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
797 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
798 | @@ -2227,6 +2239,13 @@
799 |  	if (!debug_flag)
800 |  		alarm(options.login_grace_time);
801 |  
802 | +	if(use_obfuscation) {
803 | +		if(options.obfuscate_keyword)
804 | +			obfuscate_set_keyword(options.obfuscate_keyword);
805 | +		sshpkt_enable_obfuscation(ssh);
806 | +		obfuscate_receive_seed(ssh, sock_in);
807 | +	}
808 | +
809 |  	if ((r = kex_exchange_identification(ssh, -1, options.debian_banner,
810 |  	    options.version_addendum)) != 0)
811 |  		sshpkt_fatal(ssh, r, "banner exchange");
812 | @@ -2252,8 +2271,12 @@
813 |  	auth_debug_reset();
814 |  
815 |  	if (use_privsep) {
816 | -		if (privsep_preauth(ssh) == 1)
817 | +
818 | +		if (privsep_preauth(ssh) == 1) {
819 | +			if(use_obfuscation)
820 | +				sshpkt_disable_obfuscation(ssh);
821 |  			goto authenticated;
822 | +		}
823 |  	} else if (have_agent) {
824 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
825 |  			error_r(r, "Unable to get agent socket");
826 | Index: openssh-8.9p1/sshd_config
827 | ===================================================================
828 | --- openssh-8.9p1.orig/sshd_config	2023-12-25 12:09:32.000000000 +0800
829 | +++ openssh-8.9p1/sshd_config	2023-12-25 12:09:32.000000000 +0800
830 | @@ -13,6 +13,8 @@
831 |  Include /etc/ssh/sshd_config.d/*.conf
832 |  
833 |  #Port 22
834 | +#ObfuscatedPort 222
835 | +#ObfuscateKeyword key
836 |  #AddressFamily any
837 |  #ListenAddress 0.0.0.0
838 |  #ListenAddress ::
839 | 


--------------------------------------------------------------------------------
/ubuntu/9.6p1.patch:
--------------------------------------------------------------------------------
  1 | debian/patches/obfuscated-handshake.patch
  2 | 
  3 | Description: Add handshake obfuscation
  4 | Author: zinglau <zinglau2015@gmail.com>
  5 | Index: openssh-9.6p1/Makefile.in
  6 | ===================================================================
  7 | --- openssh-9.6p1.orig/Makefile.in	2024-11-14 14:11:16.000000000 +0800
  8 | +++ openssh-9.6p1/Makefile.in	2024-11-14 14:11:16.990633260 +0800
  9 | @@ -113,7 +113,7 @@
 10 |  	kexsntrup761x25519.o sntrup761.o kexgen.o \
 11 |  	kexgssc.o \
 12 |  	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
 13 | -	sshbuf-io.o
 14 | +	sshbuf-io.o obfuscate.o
 15 |  
 16 |  SKOBJS=	ssh-sk-client.o
 17 |  
 18 | Index: openssh-9.6p1/kex.c
 19 | ===================================================================
 20 | --- openssh-9.6p1.orig/kex.c	2024-11-14 14:11:16.000000000 +0800
 21 | +++ openssh-9.6p1/kex.c	2024-11-14 14:11:16.990633260 +0800
 22 | @@ -60,6 +60,7 @@
 23 |  #include "myproposal.h"
 24 |  #include "xmalloc.h"
 25 |  
 26 | +#include "obfuscate.h"
 27 |  #include "ssherr.h"
 28 |  #include "sshbuf.h"
 29 |  #include "digest.h"
 30 | @@ -705,8 +706,10 @@
 31 |  		return r;
 32 |  	debug("SSH2_MSG_NEWKEYS sent");
 33 |  	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
 34 | +	sshpkt_disable_obfuscation(ssh);
 35 |  	if ((r = kex_maybe_send_ext_info(ssh)) != 0)
 36 |  		return r;
 37 | +	sshpkt_enable_obfuscation(ssh);
 38 |  	debug("expecting SSH2_MSG_NEWKEYS");
 39 |  	return 0;
 40 |  }
 41 | @@ -847,6 +850,7 @@
 42 |  	kex->flags &= ~KEX_INIT_SENT;
 43 |  	free(kex->name);
 44 |  	kex->name = NULL;
 45 | +	sshpkt_disable_obfuscation(ssh);
 46 |  	return 0;
 47 |  }
 48 |  
 49 | @@ -1549,14 +1553,42 @@
 50 |  		goto out;
 51 |  	}
 52 |  
 53 | +	/* Make copy and obfuscate the original */
 54 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 55 | +		if ((cp = sshbuf_dup_string(our_version)) == NULL) {
 56 | +			error("%s: sshbuf_dup_string failed for obfuscation", __func__);
 57 | +			r = SSH_ERR_ALLOC_FAIL;
 58 | +			goto out;
 59 | +		}
 60 | +		obfuscate_output(sshbuf_mutable_ptr(our_version), sshbuf_len(our_version));
 61 | +	}
 62 | +
 63 |  	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
 64 |  	    sshbuf_mutable_ptr(our_version),
 65 |  	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
 66 |  		oerrno = errno;
 67 |  		debug_f("write: %.100s", strerror(errno));
 68 |  		r = SSH_ERR_SYSTEM_ERROR;
 69 | +		if (sshpkt_get_obfuscation(ssh) == 1) {
 70 | +			free(cp);
 71 | +		}
 72 |  		goto out;
 73 |  	}
 74 | +
 75 | +	/* Restore the original */
 76 | +	if (sshpkt_get_obfuscation(ssh) == 1) {
 77 | +		if ((r = sshbuf_consume(our_version, sshbuf_len(our_version))) != 0) {
 78 | +			error("%s: sshbuf_consume failed for obfuscation", __func__);
 79 | +			free(cp);
 80 | +			goto out;
 81 | +		}
 82 | +		if ((r = sshbuf_put(our_version, cp, strlen(cp))) != 0) {
 83 | +			error("%s: sshbuf_put failed for obfuscation", __func__);
 84 | +			free(cp);
 85 | +			goto out;
 86 | +		}
 87 | +	}
 88 | +
 89 |  	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
 90 |  		oerrno = errno;
 91 |  		error_fr(r, "sshbuf_consume_end");
 92 | @@ -1613,6 +1645,8 @@
 93 |  				r = SSH_ERR_SYSTEM_ERROR;
 94 |  				goto out;
 95 |  			}
 96 | +			if(sshpkt_get_obfuscation(ssh) == 1)
 97 | +			  obfuscate_input(&c, 1);
 98 |  			if (c == '\r') {
 99 |  				expect_nl = 1;
100 |  				continue;
101 | Index: openssh-9.6p1/obfuscate.c
102 | ===================================================================
103 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
104 | +++ openssh-9.6p1/obfuscate.c	2024-11-14 14:11:16.990633260 +0800
105 | @@ -0,0 +1,220 @@
106 | +#include "includes.h"
107 | +#include <openssl/evp.h>
108 | +#include <openssl/rc4.h>
109 | +#include "openbsd-compat/openssl-compat.h"
110 | +#include <unistd.h>
111 | +#include <string.h>
112 | +#include "atomicio.h"
113 | +#include "canohost.h"
114 | +#include "xmalloc.h"
115 | +#include "log.h"
116 | +#include "packet.h"
117 | +#include "obfuscate.h"
118 | +
119 | +static RC4_KEY rc4_input;
120 | +static RC4_KEY rc4_output;
121 | +
122 | +static const char *obfuscate_keyword = NULL;
123 | +
124 | +#define OBFUSCATE_KEY_LENGTH 	16
125 | +#define OBFUSCATE_SEED_LENGTH	16
126 | +#define OBFUSCATE_HASH_ITERATIONS 6000
127 | +#define OBFUSCATE_MAX_PADDING	8192
128 | +#define OBFUSCATE_MAGIC_VALUE	0x0BF5CA7E
129 | +
130 | +struct seed_msg {
131 | +	u_char seed_buffer[OBFUSCATE_SEED_LENGTH];
132 | +	u_int32_t magic;
133 | +	u_int32_t padding_length;
134 | +	u_char padding[];
135 | +};
136 | +
137 | +static void generate_key_pair(const u_char *, u_char *, u_char *);
138 | +static void generate_key(const u_char *, const u_char *, u_int, u_char *);
139 | +static void set_keys(const u_char *, const u_char *);
140 | +static void initialize(const u_char *, int);
141 | +static void read_forever(int);
142 | +
143 | +
144 | +/*
145 | + * Server calls this
146 | + */
147 | +void
148 | +obfuscate_receive_seed(struct ssh *ssh, int sock_in)
149 | +{
150 | +	struct seed_msg seed;
151 | +
152 | +	u_char padding_drain[OBFUSCATE_MAX_PADDING];
153 | +	u_int len;
154 | +	u_int32_t padding_length;
155 | +
156 | +	len = atomicio(read, sock_in, &seed, sizeof(struct seed_msg));
157 | +
158 | +	debug2("obfuscate_receive_seed: read %d byte seed message from client", len);
159 | +	if(len != sizeof(struct seed_msg))
160 | +		fatal("obfuscate_receive_seed: read failed");
161 | +
162 | +	initialize(seed.seed_buffer, 1);
163 | +	obfuscate_input((u_char *)&seed.magic, 8);
164 | +
165 | +	if(OBFUSCATE_MAGIC_VALUE != ntohl(seed.magic)) {
166 | +		logit("Magic value check failed (%u) on obfuscated handshake "
167 | + 			"from %.200s port %d", ntohl(seed.magic),
168 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
169 | +		read_forever(sock_in);
170 | +	}
171 | +	padding_length = ntohl(seed.padding_length);
172 | +	if(padding_length > OBFUSCATE_MAX_PADDING) {
173 | +		logit("Illegal padding length %d for obfuscated handshake "
174 | + 			"from %.200s port %d", ntohl(seed.padding_length),
175 | +			ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
176 | +		read_forever(sock_in);
177 | +	}
178 | +	len = atomicio(read, sock_in, padding_drain, padding_length);
179 | +	if(len != padding_length)
180 | +		fatal("obfuscate_receive_seed: read failed");
181 | +	debug2("obfuscate_receive_seed: read %d bytes of padding from client.", len);
182 | +	obfuscate_input(padding_drain, padding_length);
183 | +}
184 | +
185 | +/*
186 | + * Client calls this
187 | + */
188 | +void
189 | +obfuscate_send_seed(int sock_out)
190 | +{
191 | +	struct seed_msg *seed;
192 | +	int i;
193 | +	u_int32_t rnd = 0;
194 | +	u_int message_length;
195 | +	u_int padding_length;
196 | +
197 | +	padding_length = arc4random() % OBFUSCATE_MAX_PADDING;
198 | +	message_length = padding_length + sizeof(struct seed_msg);
199 | +	seed = xmalloc(message_length);
200 | +
201 | +	for(i = 0; i < OBFUSCATE_SEED_LENGTH; i++) {
202 | +		if(i % 4 == 0)
203 | +			rnd = arc4random();
204 | +		seed->seed_buffer[i] = rnd & 0xff;
205 | +		rnd >>= 8;
206 | +	}
207 | +	seed->magic = htonl(OBFUSCATE_MAGIC_VALUE);
208 | +	seed->padding_length = htonl(padding_length);
209 | +	for(i = 0; i < (int)padding_length; i++) {
210 | +		if(i % 4 == 0)
211 | +			rnd = arc4random();
212 | +		seed->padding[i] = rnd & 0xff;
213 | +	}
214 | +	initialize(seed->seed_buffer, 0);
215 | +	obfuscate_output(((u_char *)seed) + OBFUSCATE_SEED_LENGTH,
216 | +		message_length - OBFUSCATE_SEED_LENGTH);
217 | +	debug2("obfuscate_send_seed: Sending seed message with %d bytes of padding", padding_length);
218 | +	atomicio(vwrite, sock_out, seed, message_length);
219 | +	free(seed);
220 | +
221 | +}
222 | +
223 | +void
224 | +obfuscate_set_keyword(const char *keyword)
225 | +{
226 | +	debug2("obfuscate_set_keyword: Setting obfuscation keyword to '%s'", keyword);
227 | +	obfuscate_keyword = keyword;
228 | +}
229 | +
230 | +void
231 | +obfuscate_input(u_char *buffer, u_int buffer_len)
232 | +{
233 | +	RC4(&rc4_input, buffer_len, buffer, buffer);
234 | +}
235 | +
236 | +void
237 | +obfuscate_output(u_char *buffer, u_int buffer_len)
238 | +{
239 | +	RC4(&rc4_output, buffer_len, buffer, buffer);
240 | +}
241 | +
242 | +static void
243 | +initialize(const u_char *seed, int server)
244 | +{
245 | +	u_char client_to_server_key[OBFUSCATE_KEY_LENGTH];
246 | +	u_char server_to_client_key[OBFUSCATE_KEY_LENGTH];
247 | +
248 | +	generate_key_pair(seed, client_to_server_key, server_to_client_key);
249 | +
250 | +	if(server)
251 | +		set_keys(client_to_server_key, server_to_client_key);
252 | +	else
253 | +		set_keys(server_to_client_key, client_to_server_key);
254 | +}
255 | +
256 | +static void
257 | +generate_key_pair(const u_char *seed, u_char *client_to_server_key, u_char *server_to_client_key)
258 | +{
259 | +	generate_key(seed, "client_to_server", strlen("client_to_server"), client_to_server_key);
260 | +	generate_key(seed, "server_to_client", strlen("server_to_client"), server_to_client_key);
261 | +}
262 | +
263 | +static void
264 | +generate_key(const u_char *seed, const u_char *iv, u_int iv_len, u_char *key_data)
265 | +{
266 | +	EVP_MD_CTX *ctx;
267 | +	u_char md_output[EVP_MAX_MD_SIZE];
268 | +	int md_len;
269 | +	int i;
270 | +	u_char *buffer;
271 | +	u_char *p;
272 | +	u_int buffer_length;
273 | +
274 | +	if ((ctx = EVP_MD_CTX_new()) == NULL)
275 | +		fatal("Cannot create new digest context");
276 | +
277 | +	buffer_length = OBFUSCATE_SEED_LENGTH + iv_len;
278 | +	if(obfuscate_keyword)
279 | +		buffer_length += strlen(obfuscate_keyword);
280 | +
281 | +	p = buffer = xmalloc(buffer_length);
282 | +
283 | +	memcpy(p, seed, OBFUSCATE_SEED_LENGTH);
284 | +	p += OBFUSCATE_SEED_LENGTH;
285 | +
286 | +	if(obfuscate_keyword) {
287 | +		memcpy(p, obfuscate_keyword, strlen(obfuscate_keyword));
288 | +		p += strlen(obfuscate_keyword);
289 | +	}
290 | +	memcpy(p, iv, iv_len);
291 | +
292 | +	EVP_DigestInit(ctx, EVP_sha1());
293 | +	EVP_DigestUpdate(ctx, buffer, OBFUSCATE_SEED_LENGTH + iv_len);
294 | +	EVP_DigestFinal(ctx, md_output, &md_len);
295 | +
296 | +	free(buffer);
297 | +
298 | +	for(i = 0; i < OBFUSCATE_HASH_ITERATIONS; i++) {
299 | +		EVP_DigestInit(ctx, EVP_sha1());
300 | +		EVP_DigestUpdate(ctx, md_output, md_len);
301 | +		EVP_DigestFinal(ctx, md_output, &md_len);
302 | +	}
303 | +
304 | +	if(md_len < OBFUSCATE_KEY_LENGTH)
305 | +		fatal("Cannot derive obfuscation keys from hash length of %d", md_len);
306 | +
307 | +	memcpy(key_data, md_output, OBFUSCATE_KEY_LENGTH);
308 | +}
309 | +
310 | +static void
311 | +set_keys(const u_char *input_key, const u_char *output_key)
312 | +{
313 | +	RC4_set_key(&rc4_input, OBFUSCATE_KEY_LENGTH, input_key);
314 | +	RC4_set_key(&rc4_output, OBFUSCATE_KEY_LENGTH, output_key);
315 | +}
316 | +
317 | +static void
318 | +read_forever(int sock_in)
319 | +{
320 | +	u_char discard_buffer[1024];
321 | +
322 | +	while(atomicio(read, sock_in, discard_buffer, sizeof(discard_buffer)) > 0)
323 | +		;
324 | +	cleanup_exit(255);
325 | +}
326 | Index: openssh-9.6p1/obfuscate.h
327 | ===================================================================
328 | --- /dev/null	1970-01-01 00:00:00.000000000 +0000
329 | +++ openssh-9.6p1/obfuscate.h	2024-11-14 14:11:16.990633260 +0800
330 | @@ -0,0 +1,10 @@
331 | +#ifndef _OBFUSCATE_H
332 | +#define _OBFUSCATE_H
333 | +
334 | +void obfuscate_receive_seed(struct ssh *, int);
335 | +void obfuscate_send_seed(int);
336 | +void obfuscate_set_keyword(const char *);
337 | +void obfuscate_input(u_char *, u_int);
338 | +void obfuscate_output(u_char *, u_int);
339 | +
340 | +#endif
341 | Index: openssh-9.6p1/packet.c
342 | ===================================================================
343 | --- openssh-9.6p1.orig/packet.c	2023-12-18 22:59:50.000000000 +0800
344 | +++ openssh-9.6p1/packet.c	2024-11-14 14:11:16.990633260 +0800
345 | @@ -94,6 +94,7 @@
346 |  #include "channels.h"
347 |  #include "ssh.h"
348 |  #include "packet.h"
349 | +#include "obfuscate.h"
350 |  #include "ssherr.h"
351 |  #include "sshbuf.h"
352 |  
353 | @@ -177,6 +178,8 @@
354 |  	/* Set to true if we are authenticated. */
355 |  	int after_authentication;
356 |  
357 | +	int obfuscation;
358 | +
359 |  	int keep_alive_timeouts;
360 |  
361 |  	/* The maximum time that we will wait to send or receive a packet */
362 | @@ -1202,6 +1205,8 @@
363 |  		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
364 |  			goto out;
365 |  	}
366 | +	if(state->obfuscation)
367 | +		obfuscate_output(cp, sshbuf_len(state->outgoing_packet));
368 |  #ifdef PACKET_DEBUG
369 |  	fprintf(stderr, "encrypted: ");
370 |  	sshbuf_dump(state->output, stderr);
371 | @@ -1522,6 +1527,8 @@
372 |  		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
373 |  		    &cp)) != 0)
374 |  			goto out;
375 | +		if(state->obfuscation)
376 | +			obfuscate_input(sshbuf_mutable_ptr(state->input), block_size);
377 |  		if ((r = cipher_crypt(state->receive_context,
378 |  		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
379 |  		    block_size, 0, 0)) != 0)
380 | @@ -1587,6 +1594,8 @@
381 |  			goto out;
382 |  		}
383 |  	}
384 | +	if(state->obfuscation)
385 | +		obfuscate_input(sshbuf_mutable_ptr(state->input), need);
386 |  	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
387 |  	    &cp)) != 0)
388 |  		goto out;
389 | @@ -2763,3 +2772,25 @@
390 |  	ssh->state->extra_pad = pad;
391 |  	return 0;
392 |  }
393 | +
394 | +void
395 | +sshpkt_enable_obfuscation(struct ssh *ssh)
396 | +{
397 | +	debug("Obfuscation enabled");
398 | +	ssh->state->obfuscation = 1;
399 | +}
400 | +
401 | +void
402 | +sshpkt_disable_obfuscation(struct ssh *ssh)
403 | +{
404 | +	if(ssh->state->obfuscation) {
405 | +		debug("Obfuscation disabled");
406 | +		ssh->state->obfuscation = 0;
407 | +	}
408 | +}
409 | +
410 | +int
411 | +sshpkt_get_obfuscation(struct ssh *ssh)
412 | +{
413 | +	return ssh->state->obfuscation;
414 | +}
415 | Index: openssh-9.6p1/packet.h
416 | ===================================================================
417 | --- openssh-9.6p1.orig/packet.h	2023-12-18 22:59:50.000000000 +0800
418 | +++ openssh-9.6p1/packet.h	2024-11-14 14:11:16.990633260 +0800
419 | @@ -182,6 +182,9 @@
420 |  	    __attribute__((format(printf, 3, 4)))
421 |  	    __attribute__((noreturn));
422 |  int	sshpkt_msg_ignore(struct ssh *, u_int);
423 | +void	sshpkt_enable_obfuscation(struct ssh *);
424 | +void	sshpkt_disable_obfuscation(struct ssh *);
425 | +int sshpkt_get_obfuscation(struct ssh *);
426 |  
427 |  int	sshpkt_put(struct ssh *ssh, const void *v, size_t len);
428 |  int	sshpkt_putb(struct ssh *ssh, const struct sshbuf *b);
429 | Index: openssh-9.6p1/readconf.c
430 | ===================================================================
431 | --- openssh-9.6p1.orig/readconf.c	2024-11-14 14:11:16.000000000 +0800
432 | +++ openssh-9.6p1/readconf.c	2024-11-14 14:11:16.990633260 +0800
433 | @@ -147,7 +147,7 @@
434 |  	oBadOption,
435 |  	oHost, oMatch, oInclude, oTag,
436 |  	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
437 | -	oGatewayPorts, oExitOnForwardFailure,
438 | +	oGatewayPorts, oExitOnForwardFailure, oObfuscateHandshake, oObfuscateKeyword,
439 |  	oPasswordAuthentication,
440 |  	oXAuthLocation,
441 |  	oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward,
442 | @@ -348,6 +348,8 @@
443 |  	{ "channeltimeout", oChannelTimeout },
444 |  	{ "protocolkeepalives", oProtocolKeepAlives },
445 |  	{ "setuptimeout", oSetupTimeOut },
446 | +	{ "obfuscatehandshake", oObfuscateHandshake },
447 | +	{ "obfuscatekeyword", oObfuscateKeyword },
448 |  
449 |  	{ NULL, oBadOption }
450 |  };
451 | @@ -2410,6 +2412,16 @@
452 |  		}
453 |  		break;
454 |  
455 | +	case oObfuscateHandshake:
456 | +		intptr = &options->obfuscate_handshake;
457 | +		goto parse_flag;
458 | +
459 | +	case oObfuscateKeyword:
460 | +		if (*activep)
461 | +			options->obfuscate_handshake = 1;
462 | +		charptr = &options->obfuscate_keyword;
463 | +		goto parse_string;
464 | +
465 |  	case oDeprecated:
466 |  		debug("%s line %d: Deprecated option \"%s\"",
467 |  		    filename, linenum, keyword);
468 | @@ -2644,6 +2656,8 @@
469 |  	options->add_keys_to_agent_lifespan = -1;
470 |  	options->identity_agent = NULL;
471 |  	options->visual_host_key = -1;
472 | +	options->obfuscate_handshake = 0;
473 | +	options->obfuscate_keyword = NULL;
474 |  	options->ip_qos_interactive = -1;
475 |  	options->ip_qos_bulk = -1;
476 |  	options->request_tty = -1;
477 | Index: openssh-9.6p1/readconf.h
478 | ===================================================================
479 | --- openssh-9.6p1.orig/readconf.h	2024-11-14 14:11:16.000000000 +0800
480 | +++ openssh-9.6p1/readconf.h	2024-11-14 14:11:16.994633258 +0800
481 | @@ -152,6 +152,8 @@
482 |  	int	permit_local_command;
483 |  	char	*remote_command;
484 |  	int	visual_host_key;
485 | +	int obfuscate_handshake;
486 | +	char *obfuscate_keyword;
487 |  
488 |  	int	request_tty;
489 |  	int	session_type;
490 | Index: openssh-9.6p1/scp.c
491 | ===================================================================
492 | --- openssh-9.6p1.orig/scp.c	2024-11-14 14:11:16.000000000 +0800
493 | +++ openssh-9.6p1/scp.c	2024-11-14 14:11:16.994633258 +0800
494 | @@ -514,7 +514,7 @@
495 |  
496 |  	fflag = Tflag = tflag = 0;
497 |  	while ((ch = getopt(argc, argv,
498 | -	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:")) != -1) {
499 | +	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:zZ:")) != -1) {
500 |  		switch (ch) {
501 |  		/* User-visible flags. */
502 |  		case '1':
503 | @@ -527,6 +527,7 @@
504 |  		case '4':
505 |  		case '6':
506 |  		case 'C':
507 | +		case 'z':
508 |  			addargs(&args, "-%c", ch);
509 |  			addargs(&remote_remote_args, "-%c", ch);
510 |  			break;
511 | @@ -544,6 +545,7 @@
512 |  		case 'i':
513 |  		case 'F':
514 |  		case 'J':
515 | +		case 'Z':
516 |  			addargs(&remote_remote_args, "-%c", ch);
517 |  			addargs(&remote_remote_args, "%s", optarg);
518 |  			addargs(&args, "-%c", ch);
519 | Index: openssh-9.6p1/servconf.c
520 | ===================================================================
521 | --- openssh-9.6p1.orig/servconf.c	2024-11-14 14:11:16.000000000 +0800
522 | +++ openssh-9.6p1/servconf.c	2024-11-14 14:11:16.994633258 +0800
523 | @@ -94,6 +94,7 @@
524 |  
525 |  	/* Standard Options */
526 |  	options->num_ports = 0;
527 | +	options->num_obfuscated_ports = 0;
528 |  	options->ports_from_cmdline = 0;
529 |  	options->queued_listen_addrs = NULL;
530 |  	options->num_queued_listens = 0;
531 | @@ -183,6 +184,7 @@
532 |  	options->permitted_listens = NULL;
533 |  	options->adm_forced_command = NULL;
534 |  	options->chroot_directory = NULL;
535 | +	options->obfuscate_keyword = NULL;
536 |  	options->authorized_keys_command = NULL;
537 |  	options->authorized_keys_command_user = NULL;
538 |  	options->revoked_keys_file = NULL;
539 | @@ -303,7 +305,7 @@
540 |  #endif /* WITH_XMSS */
541 |  	}
542 |  	/* No certificates by default */
543 | -	if (options->num_ports == 0)
544 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
545 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
546 |  	if (options->address_family == -1)
547 |  		options->address_family = AF_UNSPEC;
548 | @@ -515,7 +517,7 @@
549 |  	/* Portable-specific options */
550 |  	sUsePAM,
551 |  	/* Standard Options */
552 | -	sPort, sHostKeyFile, sLoginGraceTime,
553 | +	sPort, sObfuscatedPort, sObfuscateKeyword, sHostKeyFile, sLoginGraceTime,
554 |  	sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
555 |  	sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
556 |  	sKerberosGetAFSToken, sPasswordAuthentication,
557 | @@ -572,6 +574,8 @@
558 |  	{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
559 |  	/* Standard Options */
560 |  	{ "port", sPort, SSHCFG_GLOBAL },
561 | +	{ "obfuscatedport", sObfuscatedPort, SSHCFG_GLOBAL },
562 | +	{ "obfuscatekeyword", sObfuscateKeyword, SSHCFG_GLOBAL },
563 |  	{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
564 |  	{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL },		/* alias */
565 |  	{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
566 | @@ -801,6 +805,10 @@
567 |  			add_one_listen_addr(options, addr, rdomain,
568 |  			    options->ports[i]);
569 |  		}
570 | +		for (i = 0; i < options->num_obfuscated_ports; i++) {
571 | +			add_one_listen_addr(options, addr, rdomain,
572 | +				options->obfuscated_ports[i]);
573 | +		}
574 |  	}
575 |  }
576 |  
577 | @@ -915,7 +923,7 @@
578 |  	u_int i;
579 |  	struct queued_listenaddr *qla;
580 |  
581 | -	if (options->num_ports == 0)
582 | +	if (options->num_ports == 0 && options->num_obfuscated_ports == 0)
583 |  		options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
584 |  	if (options->address_family == -1)
585 |  		options->address_family = AF_UNSPEC;
586 | @@ -1420,6 +1428,30 @@
587 |  			    filename, linenum);
588 |  		break;
589 |  
590 | +	case sObfuscatedPort:
591 | +		if(options->ports_from_cmdline)
592 | +			return 0;
593 | +		if(options->listen_addrs != NULL)
594 | +			fatal("%s line %d: ports must be specified before ListenAddress.", filename, linenum);
595 | +		if(options->num_obfuscated_ports >= MAX_PORTS)
596 | +			fatal("%s line %d: too many ports.", filename, linenum);
597 | +		arg = argv_next(&ac, &av);
598 | +		if(!arg || *arg == '\0')
599 | +			fatal("%s line %d: missing port number.", filename, linenum);
600 | +		options->obfuscated_ports[options->num_obfuscated_ports++] = a2port(arg);
601 | +		if(options->obfuscated_ports[options->num_obfuscated_ports - 1] <= 0)
602 | +			fatal("%s line %d: badly formatted port number.", filename, linenum);
603 | +		break;
604 | +	case sObfuscateKeyword:
605 | +		charptr = &options->obfuscate_keyword;
606 | +		arg = argv_next(&ac, &av);
607 | +		if(!arg || *arg == '\0')
608 | +			fatal("%s line %d: missing keyword argument.",
609 | +					filename, linenum);
610 | +		if(*activep && *charptr == NULL)
611 | +			*charptr = xstrdup(arg);
612 | +		break;
613 | +
614 |  	case sLoginGraceTime:
615 |  		intptr = &options->login_grace_time;
616 |   parse_time:
617 | Index: openssh-9.6p1/servconf.h
618 | ===================================================================
619 | --- openssh-9.6p1.orig/servconf.h	2024-11-14 14:11:16.000000000 +0800
620 | +++ openssh-9.6p1/servconf.h	2024-11-14 14:11:16.994633258 +0800
621 | @@ -210,6 +210,11 @@
622 |  	u_int   num_permitted_listens;
623 |  
624 |  	char   *chroot_directory;
625 | +
626 | +	int obfuscated_ports[MAX_PORTS];
627 | +	u_int num_obfuscated_ports;
628 | +	char *obfuscate_keyword;
629 | +
630 |  	char   *revoked_keys_file;
631 |  	char   *trusted_user_ca_keys;
632 |  	char   *authorized_keys_command;
633 | Index: openssh-9.6p1/sftp.c
634 | ===================================================================
635 | --- openssh-9.6p1.orig/sftp.c	2023-12-18 22:59:50.000000000 +0800
636 | +++ openssh-9.6p1/sftp.c	2024-11-14 14:11:16.994633258 +0800
637 | @@ -2464,13 +2464,14 @@
638 |  	infile = stdin;
639 |  
640 |  	while ((ch = getopt(argc, argv,
641 | -	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:")) != -1) {
642 | +	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:zZ:")) != -1) {
643 |  		switch (ch) {
644 |  		/* Passed through to ssh(1) */
645 |  		case 'A':
646 |  		case '4':
647 |  		case '6':
648 |  		case 'C':
649 | +		case 'z':
650 |  			addargs(&args, "-%c", ch);
651 |  			break;
652 |  		/* Passed through to ssh(1) with argument */
653 | @@ -2479,6 +2480,7 @@
654 |  		case 'c':
655 |  		case 'i':
656 |  		case 'o':
657 | +		case 'Z':
658 |  			addargs(&args, "-%c", ch);
659 |  			addargs(&args, "%s", optarg);
660 |  			break;
661 | Index: openssh-9.6p1/ssh.c
662 | ===================================================================
663 | --- openssh-9.6p1.orig/ssh.c	2024-11-14 14:11:16.000000000 +0800
664 | +++ openssh-9.6p1/ssh.c	2024-11-14 14:11:16.998633255 +0800
665 | @@ -180,12 +180,13 @@
666 |  usage(void)
667 |  {
668 |  	fprintf(stderr,
669 | -"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] [-b bind_address]\n"
670 | +"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYyz] [-B bind_interface] [-b bind_address]\n"
671 |  "           [-c cipher_spec] [-D [bind_address:]port] [-E log_file]\n"
672 |  "           [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file]\n"
673 |  "           [-J destination] [-L address] [-l login_name] [-m mac_spec]\n"
674 |  "           [-O ctl_cmd] [-o option] [-P tag] [-p port] [-R address]\n"
675 |  "           [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
676 | +"           [-Z obfuscate_keyword]\n"
677 |  "           destination [command [argument ...]]\n"
678 |  "       ssh [-Q query_option]\n"
679 |  	);
680 | @@ -746,7 +747,7 @@
681 |  
682 |   again:
683 |  	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
684 | -	    "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
685 | +	    "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYyzZ:")) != -1) { /* HUZdhjruz */
686 |  		switch (opt) {
687 |  		case '1':
688 |  			fatal("SSH protocol v.1 is no longer supported");
689 | @@ -1100,6 +1101,13 @@
690 |  		case 'F':
691 |  			config = optarg;
692 |  			break;
693 | +		case 'z':
694 | +			options.obfuscate_handshake = 1;
695 | +			break;
696 | +		case 'Z':
697 | +			options.obfuscate_handshake = 1;
698 | +			options.obfuscate_keyword = optarg;
699 | +			break;
700 |  		default:
701 |  			usage();
702 |  		}
703 | Index: openssh-9.6p1/sshconnect.c
704 | ===================================================================
705 | --- openssh-9.6p1.orig/sshconnect.c	2024-11-14 14:11:16.000000000 +0800
706 | +++ openssh-9.6p1/sshconnect.c	2024-11-14 14:11:16.998633255 +0800
707 | @@ -64,6 +64,7 @@
708 |  #include "monitor_fdpass.h"
709 |  #include "ssh2.h"
710 |  #include "version.h"
711 | +#include "obfuscate.h"
712 |  #include "authfile.h"
713 |  #include "ssherr.h"
714 |  #include "authfd.h"
715 | @@ -268,6 +269,12 @@
716 |  	if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
717 |  		return -1; /* ssh_packet_set_connection logs error */
718 |  
719 | +	if(options.obfuscate_handshake) {
720 | +		if(options.obfuscate_keyword)
721 | +			obfuscate_set_keyword(options.obfuscate_keyword);
722 | +		sshpkt_enable_obfuscation(ssh);
723 | +	}
724 | +
725 |  	return 0;
726 |  }
727 |  
728 | @@ -537,6 +544,11 @@
729 |  	/* Set the connection. */
730 |  	if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
731 |  		return -1; /* ssh_packet_set_connection logs error */
732 | +	if(options.obfuscate_handshake) {
733 | +		if(options.obfuscate_keyword)
734 | +			obfuscate_set_keyword(options.obfuscate_keyword);
735 | +		sshpkt_enable_obfuscation(ssh);
736 | +	}
737 |  
738 |  	return 0;
739 |  }
740 | @@ -1580,6 +1592,9 @@
741 |  	host = xstrdup(orighost);
742 |  	lowercase(host);
743 |  
744 | +	if(options.obfuscate_handshake)
745 | +		obfuscate_send_seed(ssh_packet_get_connection_out(ssh));
746 | +
747 |  	/* Exchange protocol version identification strings with the server. */
748 |  	if ((r = kex_exchange_identification(ssh, timeout_ms, 1, NULL)) != 0)
749 |  		sshpkt_fatal(ssh, r, "banner exchange");
750 | Index: openssh-9.6p1/sshd.c
751 | ===================================================================
752 | --- openssh-9.6p1.orig/sshd.c	2024-11-14 14:11:16.000000000 +0800
753 | +++ openssh-9.6p1/sshd.c	2024-11-14 14:11:16.998633255 +0800
754 | @@ -120,6 +120,7 @@
755 |  #include "ssh-gss.h"
756 |  #endif
757 |  #include "monitor_wrap.h"
758 | +#include "obfuscate.h"
759 |  #include "ssh-sandbox.h"
760 |  #include "auth-options.h"
761 |  #include "version.h"
762 | @@ -269,6 +270,9 @@
763 |  /* message to be displayed after login */
764 |  struct sshbuf *loginmsg;
765 |  
766 | +/* Enable handshake obfuscation */
767 | +int use_obfuscation = 0;
768 | +
769 |  /* Unprivileged user */
770 |  struct passwd *privsep_pw = NULL;
771 |  
772 | @@ -1668,7 +1672,7 @@
773 |  	struct ssh *ssh = NULL;
774 |  	extern char *optarg;
775 |  	extern int optind;
776 | -	int r, opt, on = 1, do_dump_cfg = 0, already_daemon, remote_port;
777 | +	int r, opt, on = 1, do_dump_cfg = 0, already_daemon, remote_port, local_port;
778 |  	int sock_in = -1, sock_out = -1, newsock = -1;
779 |  	const char *remote_ip, *rdomain;
780 |  	char *fp, *line, *laddr, *logfile = NULL;
781 | @@ -2321,6 +2325,14 @@
782 |  	process_channel_timeouts(ssh, &options);
783 |  	process_permitopen(ssh, &options);
784 |  
785 | +	local_port = ssh_local_port(ssh);
786 | +	for(i = 0; i < options.num_obfuscated_ports; i++) {
787 | +		if(options.obfuscated_ports[i] == local_port) {
788 | +			use_obfuscation = 1;
789 | +			break;
790 | +		}
791 | +	}
792 | +
793 |  	/* Set SO_KEEPALIVE if requested. */
794 |  	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
795 |  	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
796 | @@ -2386,6 +2398,13 @@
797 |  	if (!debug_flag)
798 |  		alarm(options.login_grace_time);
799 |  
800 | +	if(use_obfuscation) {
801 | +		if(options.obfuscate_keyword)
802 | +			obfuscate_set_keyword(options.obfuscate_keyword);
803 | +		sshpkt_enable_obfuscation(ssh);
804 | +		obfuscate_receive_seed(ssh, sock_in);
805 | +	}
806 | +
807 |  	if ((r = kex_exchange_identification(ssh, -1, options.debian_banner,
808 |  	    options.version_addendum)) != 0)
809 |  		sshpkt_fatal(ssh, r, "banner exchange");
810 | @@ -2411,8 +2430,12 @@
811 |  	auth_debug_reset();
812 |  
813 |  	if (use_privsep) {
814 | -		if (privsep_preauth(ssh) == 1)
815 | +
816 | +		if (privsep_preauth(ssh) == 1) {
817 | +			if(use_obfuscation)
818 | +				sshpkt_disable_obfuscation(ssh);
819 |  			goto authenticated;
820 | +		}
821 |  	} else if (have_agent) {
822 |  		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
823 |  			error_r(r, "Unable to get agent socket");
824 | Index: openssh-9.6p1/sshd_config
825 | ===================================================================
826 | --- openssh-9.6p1.orig/sshd_config	2024-11-14 14:11:16.000000000 +0800
827 | +++ openssh-9.6p1/sshd_config	2024-11-14 14:11:16.998633255 +0800
828 | @@ -22,6 +22,8 @@
829 |  #   systemctl restart ssh.socket
830 |  #
831 |  #Port 22
832 | +#ObfuscatedPort 222
833 | +#ObfuscateKeyword key
834 |  #AddressFamily any
835 |  #ListenAddress 0.0.0.0
836 |  #ListenAddress ::
837 | 


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