├── NEWS ├── ChangeLog ├── AUTHORS ├── autogen.sh ├── TODO ├── data ├── tallow.service.in ├── dovecot.json └── sshd.json ├── tallow.conf ├── .gitignore ├── src ├── json.h ├── data.h ├── data.c ├── json.c └── tallow.c ├── .travis.yml ├── .github └── workflows │ └── ccpp.yml ├── Makefile.am ├── configure.ac ├── man ├── tallow.1.md ├── tallow.conf.5.md └── tallow.patterns.5.md ├── README.md ├── INSTALL └── COPYING /NEWS: -------------------------------------------------------------------------------- 1 | -------------------------------------------------------------------------------- /ChangeLog: -------------------------------------------------------------------------------- 1 | -------------------------------------------------------------------------------- /AUTHORS: -------------------------------------------------------------------------------- 1 | Auke Kok 2 | -------------------------------------------------------------------------------- /autogen.sh: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | autoreconf -vif 4 | -------------------------------------------------------------------------------- /TODO: -------------------------------------------------------------------------------- 1 | - Add IPV6 support 2 | - Print usable log messages 3 | -------------------------------------------------------------------------------- /data/tallow.service.in: -------------------------------------------------------------------------------- 1 | 2 | [Unit] 3 | Description=Tallow Service 4 | 5 | [Service] 6 | ExecStart=@prefix@/sbin/tallow 7 | Restart=always 8 | RestartSec=3 9 | Nice=10 10 | 11 | [Install] 12 | WantedBy=network.target 13 | 14 | -------------------------------------------------------------------------------- /tallow.conf: -------------------------------------------------------------------------------- 1 | 2 | # tallow.conf - see `man tallow.conf` for more information 3 | 4 | #fwcmd_path=/usr/sbin 5 | #ipt_path=/usr/sbin 6 | #expires=3600 7 | #whitelist=127.0.0.1 8 | #whitelist=192.168. 9 | #whitelist=10. 10 | #ipv6=0 11 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | .deps/ 2 | Makefile 3 | Makefile.in 4 | aclocal.m4 5 | autom4te.cache/ 6 | compile 7 | config.* 8 | configure 9 | depcomp 10 | install-sh 11 | missing 12 | tallow 13 | tallow-*.tar.* 14 | tallow-*/ 15 | *.o 16 | tallow.service 17 | *~ 18 | DEADJOE 19 | man/*.[0-9] 20 | -------------------------------------------------------------------------------- /data/dovecot.json: -------------------------------------------------------------------------------- 1 | [ 2 | { 3 | "filter": "SYSLOG_IDENTIFIER=auth", 4 | "items": [ 5 | { 6 | "ban": 50, 7 | "score": 0.6, 8 | "pattern": "MESSAGE=pam_unix[(]dovecot:auth[)]: authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=.*@.* rhost=([0-9a-z:.]+)" 9 | } 10 | ] 11 | } 12 | ] 13 | -------------------------------------------------------------------------------- /src/json.h: -------------------------------------------------------------------------------- 1 | /* 2 | * json.h - IP block sshd login abuse 3 | * 4 | * (C) Copyright 2019 Intel Corporation 5 | * Authors: 6 | * Auke Kok 7 | * 8 | * This program is free software; you can redistribute it and/or 9 | * modify it under the terms of the GNU General Public License 10 | * as published by the Free Software Foundation; version 3 11 | * of the License. 12 | */ 13 | 14 | #pragma once 15 | 16 | void json_load_patterns(void); 17 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | sudo: required 2 | dist: trusty 3 | language: c 4 | compiler: gcc 5 | os: linux 6 | 7 | before_script: 8 | - ./autogen.sh 9 | 10 | addons: 11 | apt: 12 | sources: 13 | - ubuntu-toolchain-r-test 14 | packages: 15 | - libsystemd-journal-dev 16 | - valgrind 17 | - autoconf 18 | - automake 19 | - libjson-c-dev 20 | 21 | script: 22 | - ./configure && make && make distcheck 23 | -------------------------------------------------------------------------------- /.github/workflows/ccpp.yml: -------------------------------------------------------------------------------- 1 | name: C/C++ CI 2 | 3 | on: [push] 4 | 5 | jobs: 6 | build: 7 | 8 | runs-on: ubuntu-latest 9 | 10 | steps: 11 | - uses: actions/checkout@v1 12 | - name: install dependencies 13 | run: sudo apt-get install check libjson-c-dev libpcre2-dev libsystemd-dev 14 | - name: autogen 15 | run: sh autogen.sh 16 | - name: configure 17 | run: ./configure 18 | - name: make 19 | run: make 20 | - name: make check 21 | run: make check 22 | - name: make distcheck 23 | run: make distcheck 24 | -------------------------------------------------------------------------------- /Makefile.am: -------------------------------------------------------------------------------- 1 | 2 | AM_CFLAGS = -g \ 3 | $(JSON_C_CFLAGS) $(PCRE_CFLAGS) $(LIBSYSTEMD_CFLAGS) \ 4 | -Wall -Wno-uninitialized -W -D_FORTIFY_SOURCE=2 5 | 6 | AM_CPPFLAGS = \ 7 | -DDATADIR='"$(datadir)"' -DSYSCONFDIR='"$(sysconfdir)"' 8 | 9 | systemdsystemunitdir = @SYSTEMD_SYSTEMUNITDIR@ 10 | systemdsystemunit_DATA = data/tallow.service 11 | 12 | sbin_PROGRAMS = tallow 13 | tallow_SOURCES = \ 14 | src/tallow.c \ 15 | src/json.c \ 16 | src/json.h \ 17 | src/data.c \ 18 | src/data.h 19 | tallow_LDADD = $(JSON_C_LIBS) $(PCRE_LIBS) $(LIBSYSTEMD_LIBS) 20 | 21 | pkgdata_DATA = data/sshd.json 22 | 23 | EXTRA_DIST = \ 24 | AUTHORS COPYING INSTALL README.md \ 25 | data/tallow.service.in \ 26 | data/sshd.json \ 27 | man/tallow.conf.5.md \ 28 | man/tallow.patterns.5.md \ 29 | man/tallow.1.md 30 | 31 | dist_doc_DATA = tallow.conf 32 | 33 | DISTCHECK_CONFIGURE_FLAGS = \ 34 | --with-systemdsystemunitdir=$(DESTDIR)$(SYSTEMDSYSTEMUNITDIR) 35 | 36 | man_MANS = man/tallow.1 man/tallow.conf.5 man/tallow.patterns.5 37 | clean-local: 38 | rm -f $(man_MANS) 39 | 40 | man/%.5: man/%.5.md 41 | @mkdir -p $$(dirname $@) 42 | pandoc -s -f markdown -t man $< --output $@ 43 | 44 | man/%.1: man/%.1.md 45 | @mkdir -p $$(dirname $@) 46 | pandoc -s -f markdown -t man $< --output $@ 47 | 48 | -------------------------------------------------------------------------------- /configure.ac: -------------------------------------------------------------------------------- 1 | # -*- Autoconf -*- 2 | # Process this file with autoconf to produce a configure script. 3 | 4 | AC_PREREQ([2.64]) 5 | AC_INIT([tallow], [21], [auke-jan.h.kok@intel.com]) 6 | AM_INIT_AUTOMAKE([foreign -Wall -Werror -Wno-portability silent-rules subdir-objects color-tests 7 | no-dist-gzip dist-xz]) 8 | AC_CONFIG_FILES([Makefile]) 9 | 10 | # Checks for programs. 11 | AC_PROG_CC 12 | AC_PROG_INSTALL 13 | 14 | AC_CHECK_PROG([PANDOC],[pandoc],yes) 15 | if test x"${PANDOC}" != x"yes" ; then 16 | AC_MSG_ERROR([Pandoc is required to create manual pages.]) 17 | fi 18 | 19 | PKG_CHECK_MODULES(PCRE, libpcre) 20 | PKG_CHECK_MODULES(JSON_C, json-c) 21 | PKG_CHECK_MODULES(LIBSYSTEMD, libsystemd,, [PKG_CHECK_MODULES(LIBSYSTEMD, libsystemd-journal)]) 22 | AC_SUBST(LIBSYSTEMD_CFLAGS) 23 | AC_SUBST(LIBSYSTEMD_LIBS) 24 | AC_SUBST(LIBSYSTEMD_JOURNAL_CFLAGS) 25 | AC_SUBST(LIBSYSTEMD_JOURNAL_LIBS) 26 | 27 | AC_ARG_WITH([systemdsystemunitdir], AC_HELP_STRING([--with-systemdsystemunitdir=DIR], 28 | [path to systemd system service directory]), [path_systemdsystemunit=${withval}], 29 | [path_systemdsystemunit="`$PKG_CONFIG --variable=systemdsystemunitdir systemd`"]) 30 | if (test -n "${path_systemdsystemunit}"); then 31 | SYSTEMD_SYSTEMUNITDIR="${path_systemdsystemunit}" 32 | AC_SUBST(SYSTEMD_SYSTEMUNITDIR) 33 | fi 34 | 35 | AC_CHECK_HEADERS([stdlib.h stdio.h string.h stdarg.h limits.h sys/time.h]) 36 | 37 | AC_OUTPUT([ 38 | data/tallow.service 39 | ]) 40 | -------------------------------------------------------------------------------- /src/data.h: -------------------------------------------------------------------------------- 1 | /* 2 | * data.h - IP block sshd login abuse 3 | * 4 | * (C) Copyright 2019 Intel Corporation 5 | * Authors: 6 | * Auke Kok 7 | * 8 | * This program is free software; you can redistribute it and/or 9 | * modify it under the terms of the GNU General Public License 10 | * as published by the Free Software Foundation; version 3 11 | * of the License. 12 | */ 13 | 14 | #pragma once 15 | 16 | #include 17 | 18 | #ifdef DEBUG 19 | #define dbg(args...) fprintf(stderr, ##args) 20 | #else 21 | #define dbg(args...) do {} while (0) 22 | #endif 23 | 24 | struct block_struct { 25 | char *ip; 26 | float score; 27 | struct timeval time; 28 | struct block_struct *next; 29 | bool blocked; 30 | }; 31 | 32 | struct whitelist_struct { 33 | char *ip; 34 | size_t len; 35 | struct whitelist_struct *next; 36 | }; 37 | 38 | struct pattern_struct { 39 | int instant_block; 40 | float weight; 41 | char *pattern; 42 | pcre *re; 43 | struct pattern_struct *next; 44 | }; 45 | 46 | struct filter_struct { 47 | char *filter; 48 | struct filter_struct *next; 49 | }; 50 | 51 | extern struct block_struct *blocks; 52 | extern struct pattern_struct *patterns; 53 | extern struct filter_struct *filters; 54 | extern struct whitelist_struct *whitelist; 55 | 56 | void filter_add(const char *filter); 57 | void pattern_add(const char *pattern, int ban, double score); 58 | void whitelist_add(const char *ip); 59 | bool whitelist_find(const char *ip); 60 | void prune(int expires); 61 | -------------------------------------------------------------------------------- /data/sshd.json: -------------------------------------------------------------------------------- 1 | [ 2 | { 3 | "filter": "SYSLOG_IDENTIFIER=sshd", 4 | "items": [ 5 | { 6 | "ban": 0, 7 | "score": 0.2, 8 | "pattern": "MESSAGE=Failed .* for .* from ([0-9a-z:.]+) port \\d+ ssh2" 9 | }, 10 | { 11 | "ban": 0, 12 | "score": 0.2, 13 | "pattern": "MESSAGE=error: PAM: Authentication failure for .* from ([0-9a-z:.]+)" 14 | }, 15 | { 16 | "ban": 10, 17 | "score": 0.2, 18 | "pattern": "MESSAGE=Invalid user .* from ([0-9a-z:.]+) port \\d+" 19 | }, 20 | { 21 | "ban": 10, 22 | "score": 0.3, 23 | "pattern": "MESSAGE=Did not receive identification string from ([0-9a-z:.]+) port \\d+" 24 | }, 25 | { 26 | "ban": 15, 27 | "score": 0.4, 28 | "pattern": "MESSAGE=Bad protocol version identification .* from ([0-9a-z:.]+)" 29 | }, 30 | { 31 | "ban": 15, 32 | "score": 0.4, 33 | "pattern": "MESSAGE=Connection closed by authenticating user .* ([0-9a-z:.]+) port \\d+" 34 | }, 35 | { 36 | "ban": 10, 37 | "score": 0.3, 38 | "pattern": "MESSAGE=Received disconnect from ([0-9a-z:.]+) port .*\\[preauth\\]" 39 | }, 40 | { 41 | "ban": 10, 42 | "score": 0.3, 43 | "pattern": "MESSAGE=Connection closed by ([0-9a-z:.]+) port .*\\[preauth\\]" 44 | }, 45 | { 46 | "ban": 30, 47 | "score": 0.5, 48 | "pattern": "MESSAGE=Failed .* for root from ([0-9a-z:.]+) port \\d+ ssh2" 49 | }, 50 | { 51 | "ban": 60, 52 | "score": 0.6, 53 | "pattern": "MESSAGE=Unable to negotiate with ([0-9a-z:.]+) port \\d+: no matching key exchange method found." 54 | } 55 | ] 56 | } 57 | ] 58 | -------------------------------------------------------------------------------- /man/tallow.1.md: -------------------------------------------------------------------------------- 1 | % TALLOW(1) 2 | % Auke Kok `` 3 | 4 | # tallow 5 | 6 | Reduce log clutter due to ssh login attempts. 7 | 8 | # SYNOPSIS 9 | 10 | `/usr/sbin/tallow` 11 | 12 | # DESCRIPTION 13 | 14 | `tallow` is a daemon that watches the systemd journal for messages 15 | from the `sshd` service. It parses the messages and looks for 16 | attempted random logins such as failed logins to the root account and 17 | failed logins to invalid user accounts, and various other obviously 18 | malicious login attempts that try things as forcing old protocols, 19 | or weak key systems. 20 | 21 | If such logins were detected, the offending IP address is stored in 22 | a list. Items from this list are regularly purged, but if the amount 23 | of times that a specific IP address is seen exceeds a threshold, 24 | an ipset(1) entry is inserted in the `tallow` or `tallow6` 25 | ipset, and further packets from that ip address will be blocked 26 | by an `iptables(1)` or `ip6tables(1)` rule that tallow creates at 27 | startup. Additionally, certain types of login failure will trigger 28 | a short term ban of further packets from the offending IP address 29 | immediately. 30 | 31 | The system administrator needs to assure that the tallow and tallow6 32 | ipsets are left alone and that the inserted iptables rules are properly 33 | matching on packets. 34 | 35 | Care should be taken to assure that legitimate users are not 36 | blocked inadvertently. You may wish to list any valid IP address 37 | with the whitelist option in tallow.conf(5). Multiple addresses can 38 | be whitelisted. 39 | 40 | # OPTIONS 41 | 42 | The `tallow` daemon itself has no runtime configuration. All 43 | configuration is done through the tallow.conf(5) config file. 44 | 45 | # SIGNALS 46 | 47 | The `USR1` signal causes `tallow` to print out it's internal tracking 48 | table of IP addresses. This requires that tallow is compiled with 49 | the `-DDEBUG=1` symbol passed to the compiler. 50 | 51 | # SEE ALSO 52 | 53 | systemd-journald(1), iptables(1), ipset(1), tallow.conf(5), tallow.patterns(5) 54 | 55 | # BUGS 56 | 57 | `tallow` is `NOT A SECURITY SOLUTION`, nor does it protect against 58 | random password logins. A attacker may still be able to logon to your 59 | systems if you allow password logins. 60 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | ## DISCONTINUATION OF PROJECT. 2 | 3 | This project will no longer be maintained by Intel. 4 | 5 | Intel will not provide or guarantee development of or support for this project, including but not limited to, maintenance, bug fixes, new releases or updates. Patches to this project are no longer accepted by Intel. If you have an ongoing need to use this project, are interested in independently developing it, or would like to maintain patches for the community, please create your own fork of the project. 6 | 7 | Contact: webadmin@linux.intel.com 8 | 9 | tallow 10 | ====== 11 | 12 | Tallow is a fail2ban/lard replacement that uses systemd's native 13 | journal API to scan for attempted ssh logins, and issues temporary 14 | IP bans for clients that violate certain login patterns. 15 | 16 | Author: Auke Kok 17 | 18 | 19 | How it works 20 | ============ 21 | 22 | Tallow attaches to the journal and subscribes to messages from 23 | /usr/sbin/sshd. The messages are matched against rules and the IP 24 | address is extracted from the message. For each IP address that is 25 | extracted, the last timestamp and count is kept. Once the count exceeds 26 | a threshold, the offending IP address is added to an ipset and blocked 27 | with a corresponding firewall rule. It will use firewalld or 28 | iptables / ip6tables. 29 | 30 | The timestamp is kept for pruning. Records are pruned from the list 31 | if the IP address hasn't been seen by tallow for longer than the 32 | threshold. If the IP was blocked and the threshold was exceeded, 33 | the IP is unblocked. If the threshold was never reached, the record 34 | is removed as well. 35 | 36 | Pruning is done automatically after incoming messages are processed, 37 | so there is a chance that if no messages arrive, that IP addresses 38 | remain blocked for longer than the default blocking period. 39 | 40 | 41 | 42 | Motivation 43 | ========== 44 | 45 | This program was originally written to demonstrate the journal API. One 46 | of the typical use cases for journal (or syslog) readers was to act 47 | dynamically on certain syslog messages, and many types of actions 48 | can be imagined. This is trivial to implement on systems that use 49 | the journal API, and often doesn't take much code at all. 50 | 51 | The journal is attached to and forwarder to the end. We place a 52 | simple message filter, and then process each incoming message. For 53 | more information check out the sd-journal manual pages, which contain 54 | example code that demonstrates almost the exact same code flow. 55 | 56 | 57 | 58 | Security 59 | ======== 60 | 61 | DISCLAIMER: THIS IS NOT A SECURITY APPLICATION !!! 62 | 63 | Tallow is meant to reduce log clutter and system resource usage at 64 | the cost of denying access to potentially valid users. 65 | 66 | Even if you reduce the threshold at which clients are blocked to 1, 67 | an attacker may still gain access to your server if the attacker uses 68 | the correct credentials. 69 | 70 | By itself, tallow is an application that creates a Denial 71 | of Service. It's sole purpose and function is to block IP 72 | addresses. Therefore, with tallow running on a service, you could 73 | potentially deny valid users access to your systems if you deploy 74 | tallow. 75 | 76 | Be very careful if you deploy tallow on systems that expect valid 77 | users to log on from many random source addresses. If your user 78 | mistypes their username, they could find themselves denied access. -------------------------------------------------------------------------------- /man/tallow.conf.5.md: -------------------------------------------------------------------------------- 1 | % TALLOW.CONF(5) 2 | % Auke Kok `` 3 | 4 | # tallow.conf 5 | 6 | The tallow configuration file 7 | 8 | # NAME 9 | 10 | tallow.conf - Tallow daemon configuration file 11 | 12 | # SYNOPSIS 13 | 14 | `/etc/tallow.conf` 15 | 16 | # DESCRIPTION 17 | 18 | This file is read on startup by the tallow(1) daemon, and can 19 | be used to provide options to the tallow daemon. If not present, 20 | tallow will operate with built-in defaults. 21 | 22 | # OPTIONS 23 | 24 | `fwcmd_path`=`` 25 | Specifies the location of the ipset(1) firewall-cmd(1) programs. By 26 | default, tallow will look in "/usr/sbin" for them. 27 | 28 | `ipt_path`=`` 29 | Specifies the location of the ipset(1) program and iptables(1) or 30 | ip6tables(1) programs. By default, tallow will look in "/usr/sbin" 31 | for them. 32 | 33 | `expires`=`` 34 | The number of seconds that IP addresses are blocked for. Note that 35 | due to the implementation, IP addresses may be blocked for much 36 | longer than this period. If IP addresses are seen, but not 37 | blocked within this period, they are also removed from the 38 | watch list. Defaults to 3600s. 39 | 40 | `whitelist`=`` 41 | Specify an IP address or `pattern` that should never be 42 | blocked. Multiple IP addresses can be included by repeating the 43 | `whitelist` option several times. By default, 127.0.0.1, 192.168., and 44 | 10. are whitelisted. If you create a manual whitelist, you must include 45 | these entries if you want to continue them to be whitelisted as 46 | well, otherwise they will be omitted from the whitelist. 47 | 48 | If the last character of the listed ip adress is a `.` or a `:`, then 49 | the matching is only performed on the leftmost characters of an IP 50 | address against the whitelist entry. For instance, if you whitelist 51 | `10.` then all IP addresses in the `10/8` subnet mask will match this 52 | whitelist entry and never be blocked. 53 | 54 | `ipv6`=`<0|1>` 55 | Enable or disable ipv6 (ip6tables) support. Ipv6 is disabled 56 | automatically on systems that do not appear to have ipv6 support 57 | and enabled when ipv6 is present. Use this option to explicitly 58 | disable ipv6 support if your system does not have ipv6 or is 59 | missing ip6tables. Even with ipv6 disabled, tallow will track 60 | and log ipv6 addresses. 61 | 62 | `nocreate`=`<0|1>` Disable the creation of firewall rules and ipset sets. By 63 | default, tallow will create new firewall-cmd(1) or iptables(1) and ip6tables(1) 64 | rules when needed automatically. If set to `1`, `tallow(1)` will not create any 65 | new firewall DROP rules or ipset sets that are needed work. You should create 66 | them manually before tallow starts up and remove them afterwards using the sets 67 | of commands below. 68 | 69 | Use the following commands if you're using iptables(1): 70 | 71 | ``` 72 | ipset create tallow hash:ip family inet timeout 3600 73 | iptables -t filter -I INPUT 1 -m set --match-set tallow src -j DROP 74 | 75 | ipset create tallow6 hash:ip family inet6 timeout 3600 76 | ip6tables -t filter -I INPUT 1 -m set --match-set tallow6 src -j DROP 77 | ``` 78 | 79 | Use the following commands if you're using firewalld(1): 80 | 81 | ``` 82 | firewall-cmd --permanent --new-ipset=tallow --type=hash:ip --family=inet --option=timeout=3600 83 | firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 1 -m set --match-set tallow src -j DROP 84 | 85 | firewall-cmd --permanent --new-ipset=tallow6 --type=hash:ip --family=inet6 --option=timeout=3600 86 | firewall-cmd --permanent --direct --add-rule ipv6 filter INPUT 1 -m set --match-set tallow6 src -j DROP 87 | 88 | ``` 89 | 90 | # SEE ALSO 91 | 92 | tallow(1), tallow.patterns(5) 93 | -------------------------------------------------------------------------------- /src/data.c: -------------------------------------------------------------------------------- 1 | /* 2 | * data.h - IP block sshd login abuse 3 | * 4 | * (C) Copyright 2019 Intel Corporation 5 | * Authors: 6 | * Auke Kok 7 | * 8 | * This program is free software; you can redistribute it and/or 9 | * modify it under the terms of the GNU General Public License 10 | * as published by the Free Software Foundation; version 3 11 | * of the License. 12 | */ 13 | 14 | #include 15 | #include 16 | #include 17 | #include 18 | #include 19 | #include 20 | 21 | #include 22 | 23 | #include "data.h" 24 | 25 | struct block_struct *blocks; 26 | struct pattern_struct *patterns; 27 | struct filter_struct *filters; 28 | struct whitelist_struct *whitelist; 29 | 30 | void filter_add(const char *filter) 31 | { 32 | struct filter_struct *h = filters; 33 | 34 | /* filter duplicates */ 35 | while (h) { 36 | if (strcmp(h->filter, filter) == 0) 37 | return; 38 | 39 | h = h->next; 40 | } 41 | 42 | struct filter_struct *f = calloc(1, sizeof(struct filter_struct)); 43 | if (!f) { 44 | perror("calloc()"); 45 | exit(EXIT_FAILURE); 46 | } 47 | 48 | f->filter = strdup(filter); 49 | 50 | h = filters; 51 | if (!h) { 52 | filters = f; 53 | } else { 54 | while (h->next) 55 | h = h->next; 56 | h->next = f; 57 | } 58 | } 59 | 60 | void pattern_add(const char *pattern, int ban, double score) 61 | { 62 | struct pattern_struct *p = calloc(1, sizeof(struct pattern_struct)); 63 | if (!p) { 64 | perror("calloc()"); 65 | exit(EXIT_FAILURE); 66 | } 67 | 68 | p->pattern = strdup(pattern); 69 | p->instant_block = ban; 70 | p->weight = score; 71 | 72 | const char *pcre_err; 73 | int err; 74 | p->re = pcre_compile(pattern, 0, &pcre_err, &err, NULL); 75 | if (!p->re) { 76 | fprintf(stderr, "PCRE compilation failed. Offset %d: %s\n", 77 | err, pcre_err); 78 | exit(EXIT_FAILURE); 79 | } 80 | 81 | struct pattern_struct *h = patterns; 82 | if (!h) { 83 | patterns = p; 84 | } else { 85 | while (h->next) 86 | h = h->next; 87 | h->next = p; 88 | } 89 | } 90 | 91 | void whitelist_add(const char *ip) 92 | { 93 | struct whitelist_struct *w = calloc(1, sizeof(struct whitelist_struct)); 94 | 95 | if (!w) { 96 | perror("calloc()"); 97 | exit(EXIT_FAILURE); 98 | } 99 | 100 | w->ip = strdup(ip); 101 | 102 | size_t l = strlen(ip); 103 | if ((ip[l-1] == '.') || (ip[l-1] == ':')) 104 | w->len = l; 105 | else 106 | w->len = -1; 107 | 108 | struct whitelist_struct *h = whitelist; 109 | if (!h) { 110 | whitelist = w; 111 | } else { 112 | while (h->next) 113 | h = h->next; 114 | h->next = w; 115 | } 116 | } 117 | 118 | bool whitelist_find(const char *ip) 119 | { 120 | struct whitelist_struct *w = whitelist; 121 | while (w) { 122 | if (w->len > 0) { 123 | if (!strncmp(w->ip, ip, w->len)) 124 | return (true); 125 | } else { 126 | if (!strcmp(w->ip, ip)) 127 | return (true); 128 | } 129 | w = w->next; 130 | } 131 | 132 | return (false); 133 | } 134 | 135 | void prune(int expires) 136 | { 137 | struct block_struct *s = blocks; 138 | struct block_struct *p; 139 | struct timeval tv; 140 | 141 | (void) gettimeofday(&tv, NULL); 142 | p = NULL; 143 | 144 | while (s) { 145 | /* 146 | * Expire all records, but if they are blocked, make sure to 147 | * expire them *before* the ipset rule expires, otherwise 148 | * you might get an IP to bypass checks. 149 | */ 150 | time_t age = tv.tv_sec - s->time.tv_sec; 151 | if ((age > expires) || 152 | ((s->blocked) && (age > expires / 2))) { 153 | dbg("Expired record for %s\n", s->ip); 154 | if (p) { 155 | p->next = s->next; 156 | free(s->ip); 157 | free(s); 158 | s = p->next; 159 | continue; 160 | } else { 161 | blocks = s->next; 162 | free(s->ip); 163 | free(s); 164 | s = blocks; 165 | p = NULL; 166 | continue; 167 | } 168 | } 169 | p = s; 170 | s = s->next; 171 | } 172 | 173 | /* return some memory */ 174 | malloc_trim(0); 175 | } 176 | -------------------------------------------------------------------------------- /man/tallow.patterns.5.md: -------------------------------------------------------------------------------- 1 | % TALLOW.PATTERNS(5) 2 | % Auke Kok `` 3 | 4 | # tallow.patterns 5 | 6 | Tallow pattern matching configuration files. 7 | 8 | 9 | # SYNOPSIS 10 | 11 | tallow(1) uses regular expressions to match journal entries and extract an IP 12 | address from them. JSON files are used to configure the patterns and banning 13 | thresholds used by tallow(1). 14 | 15 | `/etc/tallow/*.json` 16 | `/usr/share/tallow/*.json` 17 | 18 | 19 | # DESCRIPTION 20 | 21 | tallow(1) uses regular expressions to match journal entries and extract an IP 22 | address from them. JSON files are used to configure the patterns and banning 23 | thresholds used by tallow(1). This adds the ability to extend the patterns 24 | tallow(1) will recognize. Many JSON files can exist for logical grouping. The 25 | tallow(1) daemon will read all JSON files in the configuration directories at 26 | startup. 27 | 28 | tallow(1) operates with default pattern definitions 29 | in`/usr/share/tallow/*.json`. Users can add more patterns with their own JSON 30 | files under `/etc/tallow`. The default JSON files can be overridden by creating 31 | the same file under `/etc/tallow`. 32 | 33 | 34 | # FILE FORMAT 35 | 36 | Pattern configuration files use the JavaScript Object Notation (JSON) format. 37 | 38 | The JSON must be two levels deep and all properties are required. The root 39 | object is an array containing objects with a `filter` key and an `items` key. 40 | 41 | * `filter` is a string that defines a field for filtering the journal file. 42 | This helps make sure patterns are only matched to a subset of journal 43 | entries. See systemd.journal-fields(7) for valid journal fields. 44 | 45 | * `items` is an array of objects that contains three elements: `ban`, `score`, 46 | and `pattern`. 47 | 48 | * `ban` is an integer that defines the number of seconds to ban originating 49 | IP for. If this value is > 0, the IP address get banned immediately when a 50 | journal entry matches `pattern`. 51 | 52 | * `score` is a double that defines a value to add to the accumulated "score" 53 | of an originating IP address each time a journal entry matches 54 | the `pattern`. If the combined score is > 1.0, tallow bans the originating 55 | IP for the default time of 1 hour. The `ban` element value above is not 56 | used for bans made due to `score`. 57 | 58 | * `pattern` is a string that defines a Perl Compatible Regular Expressions 59 | (PCRE) to match against the filtered journal entries. The PCRE should 60 | extract exactly one substring: the originating IP address for tallow(1). 61 | See systemd.journal-fields(7) for valid journal fields. 62 | 63 | 64 | # EXAMPLES 65 | 66 | 1. The JSON below is a snippet from one of the default pattern configuration 67 | files for blocking certain failed `sshd` connections. 68 | 69 | The first pattern will ban an IP address after it fails to login 6 times 70 | causing it to reach a total score > 1.0. 71 | 72 | The second pattern will ban an IP address for 10 seconds every time a login is 73 | attempted with an invalid user. Additionally, it will ban the IP address for 74 | 1 hour if it attempts to login with an invalid user 6 times causing it to 75 | reach a total score > 1.0. 76 | 77 | See the `/usr/share/tallow/sshd.json` file for more `sshd` examples. 78 | 79 | ``` 80 | [ 81 | { 82 | "filter": "SYSLOG_IDENTIFIER=sshd", 83 | "items": [ 84 | { 85 | "ban": 0, 86 | "score": 0.2, 87 | "pattern": "MESSAGE=Failed .* for .* from ([0-9a-z:.]+) port \\d+ ssh2" 88 | }, 89 | { 90 | "ban": 10, 91 | "score": 0.2, 92 | "pattern": "MESSAGE=Invalid user .* from ([0-9a-z:.]+) port \\d+" 93 | } 94 | ] 95 | } 96 | ] 97 | ``` 98 | 99 | 100 | 101 | 2. The JSON below defines a pattern for blocking connections based on error logs 102 | from `nginx-mainline` if placed in a `/etc/tallow/nginx-mainline.json` file. 103 | 104 | The pattern will ban an IP address for 15 seconds every time it attempts to 105 | access a script that does not exist. Additionally, it will ban the IP 106 | address for 1 hour if it attempts to access invalid scripts 4 times causing 107 | it to reach a total score > 1.0. 108 | 109 | ``` 110 | [ 111 | { 112 | "filter": "SYSLOG_IDENTIFIER=nginx-mainline", 113 | "items": [ 114 | { 115 | "ban": 15, 116 | "score": 0.3, 117 | "pattern": ".Primary script unknown. while reading response header from upstream, client: ([0-9a-z:.]+)," 118 | } 119 | ] 120 | } 121 | ] 122 | ``` 123 | 124 | 125 | # SEE ALSO 126 | 127 | tallow(1), tallow.conf(5) 128 | 129 | 130 | # BUGS 131 | 132 | `tallow` is `NOT A SECURITY SOLUTION`, nor does it protect against random 133 | password logins. An attacker may still be able to logon to your systems if you 134 | allow password logins. 135 | -------------------------------------------------------------------------------- /src/json.c: -------------------------------------------------------------------------------- 1 | /* 2 | * json.c - IP block sshd login abuse 3 | * 4 | * (C) Copyright 2019 Intel Corporation 5 | * Authors: 6 | * Auke Kok 7 | * 8 | * This program is free software; you can redistribute it and/or 9 | * modify it under the terms of the GNU General Public License 10 | * as published by the Free Software Foundation; version 3 11 | * of the License. 12 | */ 13 | 14 | #define _GNU_SOURCE 15 | 16 | #include 17 | #include 18 | #include 19 | #include 20 | #include 21 | #include 22 | #include 23 | #include 24 | #include 25 | #include 26 | 27 | #include 28 | 29 | #include "data.h" 30 | 31 | static const char *s_pattern; 32 | static const char *s_filter; 33 | static int s_ban; 34 | static double s_score; 35 | static bool g_filter, g_ban, g_score, g_pattern = false; 36 | 37 | static int json_parse(json_object *ob) 38 | { 39 | int i, count = 0; 40 | bool l_filter, l_ban, l_score, l_pattern = false; 41 | 42 | json_object_object_foreach(ob, key, val) { 43 | enum json_type type; 44 | type = json_object_get_type(val); 45 | switch (type) { 46 | case json_type_null: 47 | break; 48 | case json_type_boolean: 49 | break; 50 | case json_type_double: 51 | if (strcmp(key, "score") == 0) { 52 | l_score = g_score = true; 53 | s_score = json_object_get_double(val); 54 | } else { 55 | fprintf(stderr, "Invalid JSON key \"%s\"\n", key); 56 | return (0); 57 | } 58 | break; 59 | case json_type_int: 60 | if (strcmp(key, "ban") == 0) { 61 | l_ban = g_ban = true; 62 | s_ban = json_object_get_int(val); 63 | } else { 64 | fprintf(stderr, "Invalid JSON key \"%s\"\n", key); 65 | return (0); 66 | } 67 | break; 68 | case json_type_string: 69 | if (strcmp(key, "filter") == 0) { 70 | l_filter = g_filter = true; 71 | s_filter = json_object_get_string(val); 72 | } else if (strcmp(key, "pattern") == 0) { 73 | l_pattern = g_pattern = true; 74 | s_pattern = json_object_get_string(val); 75 | } else { 76 | fprintf(stderr, "Invalid JSON key \"%s\"\n", key); 77 | return (0); 78 | } 79 | break; 80 | case json_type_array: 81 | ob = json_object_object_get(ob, key); 82 | int len = json_object_array_length(ob); 83 | json_object *val; 84 | for (i = 0; i < len; i++) { 85 | val = json_object_array_get_idx(ob, i); 86 | count += json_parse(val); 87 | } 88 | break; 89 | case json_type_object: 90 | ob = json_object_object_get(ob, key); 91 | count += json_parse(ob); 92 | break; 93 | } 94 | } 95 | 96 | /* check and finish if can */ 97 | if (g_score && g_ban && g_pattern && g_filter) { 98 | #ifdef DEBUG 99 | fprintf(stderr, "Adding: %s %s %d %lf\n", s_filter, s_pattern, s_ban, s_score); 100 | #endif 101 | filter_add(s_filter); 102 | pattern_add(s_pattern, s_ban, s_score); 103 | count++; 104 | } 105 | 106 | /* cleanup */ 107 | if (l_score) { 108 | l_score = g_score = false; 109 | } else if (l_ban) { 110 | l_ban = g_ban = false; 111 | } else if (l_pattern) { 112 | l_pattern = g_pattern = false; 113 | } else if (l_filter) { 114 | l_filter = g_filter = false; 115 | } 116 | 117 | return (count); 118 | } 119 | 120 | static int json_load_file(const char* file) 121 | { 122 | int i, count = 0; 123 | char *json; 124 | int fd; 125 | struct stat st; 126 | fd = open(file, O_RDONLY); 127 | fstat(fd, &st); 128 | json = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); 129 | close(fd); 130 | 131 | struct json_object *obj; 132 | 133 | obj = json_tokener_parse(json); 134 | if (json_object_is_type(obj,json_type_array)) { 135 | int len = json_object_array_length(obj); 136 | json_object *val; 137 | for (i = 0; i < len; i++) { 138 | val = json_object_array_get_idx(obj, i); 139 | count += json_parse(val); 140 | } 141 | } else if (json_object_is_type(obj, json_type_object)) { 142 | count += json_parse(obj); 143 | } else { 144 | fprintf(stderr, "This does not look like JSON: %s\n", file); 145 | return (0); 146 | } 147 | 148 | json_object_put(obj); 149 | 150 | munmap(json, st.st_size); 151 | return (count); 152 | } 153 | 154 | static int json_load_dir(const char *dir) 155 | { 156 | int count = 0; 157 | 158 | DIR *d = opendir(dir); 159 | if (!d) { 160 | fprintf(stderr, "Skipped reading %s: %s\n", dir, strerror(errno)); 161 | return (count); 162 | } 163 | struct dirent *entry; 164 | for (;;) { 165 | entry = readdir(d); 166 | if (!entry) 167 | break; 168 | size_t l = strlen(entry->d_name); 169 | if (l < strlen(".json")) 170 | continue; 171 | if (strcmp(entry->d_name + l - strlen(".json"), ".json") == 0) { 172 | char *p; 173 | if (!asprintf(&p, "%s/%s", dir, entry->d_name)) { 174 | fprintf(stderr, "asprintf: %s\n", strerror(errno)); 175 | exit(EXIT_FAILURE); 176 | } 177 | 178 | /* allow /etc/tallow files to override /usr/share/tallow files */ 179 | if (strcmp(dir, DATADIR "/" PACKAGE_NAME) == 0) { 180 | char *sp; 181 | if (!asprintf(&sp, SYSCONFDIR "/" PACKAGE_NAME "/%s", entry->d_name)) { 182 | fprintf(stderr, "asprintf: %s\n", strerror(errno)); 183 | exit(EXIT_FAILURE); 184 | } 185 | 186 | struct stat st; 187 | if (stat(sp, &st) == 0) { 188 | dbg("Skipped " SYSCONFDIR "/" PACKAGE_NAME "/%s\n", entry->d_name); 189 | free(sp); 190 | continue; 191 | } 192 | free(sp); 193 | } 194 | 195 | int c = json_load_file(p); 196 | fprintf(stderr, "%s: %d patterns\n", p, c); 197 | count += c; 198 | free(p); 199 | } 200 | 201 | } 202 | closedir(d); 203 | 204 | return (count); 205 | } 206 | 207 | void json_load_patterns(void) 208 | { 209 | int count = 0; 210 | count += json_load_dir(DATADIR "/" PACKAGE_NAME); 211 | count += json_load_dir(SYSCONFDIR "/" PACKAGE_NAME); 212 | fprintf(stderr, "Loaded %d patterns total\n", count); 213 | if (count < 1) { 214 | /* consider sending a special exit code here */ 215 | fprintf(stderr, "No patterns loaded, nothing to do!\n"); 216 | exit(EXIT_SUCCESS); 217 | } 218 | } 219 | -------------------------------------------------------------------------------- /src/tallow.c: -------------------------------------------------------------------------------- 1 | /* 2 | * tallow.c - IP block sshd login abuse 3 | * 4 | * (C) Copyright 2015-2019 Intel Corporation 5 | * Authors: 6 | * Auke Kok 7 | * 8 | * This program is free software; you can redistribute it and/or 9 | * modify it under the terms of the GNU General Public License 10 | * as published by the Free Software Foundation; version 3 11 | * of the License. 12 | */ 13 | 14 | #define _GNU_SOURCE 15 | 16 | #include 17 | #include 18 | #include 19 | #include 20 | #include 21 | #include 22 | #include 23 | #include 24 | #include 25 | #include 26 | #include 27 | #include 28 | 29 | #include 30 | #include 31 | 32 | #include "json.h" 33 | #include "data.h" 34 | 35 | #define MAX_OFFSETS 30 36 | 37 | static char ipt_path[PATH_MAX]; 38 | static char fwcmd_path[PATH_MAX]; 39 | static int expires = 3600; 40 | static int has_ipv6 = 0; 41 | static bool nocreate = false; 42 | static sd_journal *j; 43 | 44 | static int ext(char *fmt, ...) 45 | { 46 | va_list args; 47 | char cmd[1024]; 48 | int ret = 0; 49 | 50 | va_start(args, fmt); 51 | vsnprintf(cmd, sizeof(cmd), fmt, args); 52 | va_end(args); 53 | 54 | ret = system(cmd); 55 | if (ret) 56 | fprintf(stderr, "Error executing \"%s\": returned %d\n", cmd, ret); 57 | return (ret); 58 | } 59 | 60 | static void ext_ignore(char *fmt, ...) 61 | { 62 | va_list args; 63 | char cmd[1024]; 64 | 65 | va_start(args, fmt); 66 | vsnprintf(cmd, sizeof(cmd), fmt, args); 67 | va_end(args); 68 | 69 | __attribute__((unused)) int ret = system(cmd); 70 | } 71 | 72 | static void reset_rules(void) 73 | { 74 | /* reset all rules in case the running fw changes */ 75 | ext_ignore("%s/firewall-cmd --permanent --direct --remove-rule ipv4 filter INPUT 1 -m set --match-set tallow src -j DROP 2> /dev/null", fwcmd_path); 76 | ext_ignore("%s/firewall-cmd --permanent --delete-ipset=tallow 2> /dev/null", fwcmd_path); 77 | 78 | /* delete iptables ref to set before the ipset! */ 79 | ext_ignore("%s/iptables -t filter -D INPUT -m set --match-set tallow src -j DROP 2> /dev/null", ipt_path); 80 | ext_ignore("%s/ipset destroy tallow 2> /dev/null", ipt_path); 81 | 82 | if (has_ipv6) { 83 | ext_ignore("%s/firewall-cmd --permanent --direct --remove-rule ipv6 filter INPUT 1 -m set --match-set tallow6 src -j DROP 2> /dev/null", fwcmd_path); 84 | ext_ignore("%s/firewall-cmd --permanent --delete-ipset=tallow6 2> /dev/null", fwcmd_path); 85 | 86 | /* delete iptables ref to set before the ipset! */ 87 | ext_ignore("%s/ip6tables -t filter -D INPUT -m set --match-set tallow6 src -j DROP 2> /dev/null", ipt_path); 88 | ext_ignore("%s/ipset destroy tallow6 2> /dev/null", ipt_path); 89 | } 90 | } 91 | 92 | static void setup(void) 93 | { 94 | static bool done = false; 95 | if (done) 96 | return; 97 | done = true; 98 | 99 | if (nocreate) 100 | return; 101 | 102 | /* firewalld */ 103 | char *fwd_path; 104 | if (asprintf(&fwd_path, "%s/firewall-cmd", fwcmd_path) < 0) { 105 | exit(EXIT_FAILURE); 106 | } 107 | 108 | if ((access(fwd_path, X_OK) == 0) && ext("%s/firewall-cmd --state --quiet", fwcmd_path) == 0) { 109 | fprintf(stdout, "firewalld is running and will be used by tallow.\n"); 110 | 111 | reset_rules(); 112 | 113 | /* create ipv4 rule and ipset */ 114 | if (ext("%s/firewall-cmd --permanent --quiet --new-ipset=tallow --type=hash:ip --family=inet --option=timeout=%d", fwcmd_path, expires)) { 115 | fprintf(stderr, "Unable to create ipv4 ipset with firewall-cmd.\n"); 116 | exit(EXIT_FAILURE); 117 | } 118 | if (ext("%s/firewall-cmd --permanent --direct --quiet --add-rule ipv4 filter INPUT 1 -m set --match-set tallow src -j DROP", fwcmd_path)) { 119 | fprintf(stderr, "Unable to create ipv4 firewalld rule.\n"); 120 | exit(EXIT_FAILURE); 121 | } 122 | 123 | /* create ipv6 rule and ipset */ 124 | if (has_ipv6) { 125 | if (ext("%s/firewall-cmd --permanent --quiet --new-ipset=tallow6 --type=hash:ip --family=inet6 --option=timeout=%d", fwcmd_path, expires)) { 126 | fprintf(stderr, "Unable to create ipv6 ipset with firewall-cmd.\n"); 127 | exit(EXIT_FAILURE); 128 | } 129 | if (ext("%s/firewall-cmd --permanent --direct --quiet --add-rule ipv6 filter INPUT 1 -m set --match-set tallow6 src -j DROP ", fwcmd_path)) { 130 | fprintf(stderr, "Unable to create ipv6 firewalld rule.\n"); 131 | exit(EXIT_FAILURE); 132 | } 133 | } 134 | 135 | /* reload firewalld for ipsets to load */ 136 | if (ext("%s/firewall-cmd --reload --quiet", fwcmd_path, expires)) { 137 | fprintf(stderr, "Unable to reload firewalld rules.\n"); 138 | exit(EXIT_FAILURE); 139 | } 140 | } else { 141 | /* iptables */ 142 | reset_rules(); 143 | 144 | /* create ipv4 rule and ipset */ 145 | if (ext("%s/ipset create tallow hash:ip family inet timeout %d", ipt_path, expires)) { 146 | fprintf(stderr, "Unable to create ipv4 ipset.\n"); 147 | exit(EXIT_FAILURE); 148 | } 149 | if (ext("%s/iptables -t filter -A INPUT -m set --match-set tallow src -j DROP", ipt_path)) { 150 | fprintf(stderr, "Unable to create iptables rule.\n"); 151 | exit(EXIT_FAILURE); 152 | } 153 | 154 | /* create ipv6 rule and ipset */ 155 | if (has_ipv6) { 156 | if (ext("%s/ipset create tallow6 hash:ip family inet6 timeout %d", ipt_path, expires)) { 157 | fprintf(stderr, "Unable to create ipv6 ipset.\n"); 158 | exit(EXIT_FAILURE); 159 | } 160 | if (ext("%s/ip6tables -t filter -A INPUT -m set --match-set tallow6 src -j DROP", ipt_path)) { 161 | fprintf(stderr, "Unable to create ipt6ables rule.\n"); 162 | exit(EXIT_FAILURE); 163 | } 164 | } 165 | } 166 | 167 | free(fwd_path); 168 | } 169 | 170 | static void block(struct block_struct *s, int instant_block) 171 | { 172 | setup(); 173 | 174 | if (strchr(s->ip, ':')) { 175 | if (has_ipv6) { 176 | if (instant_block > 0) { 177 | (void) ext("%s/ipset -! add tallow6 %s timeout %d", 178 | ipt_path, s->ip, instant_block); 179 | } else { 180 | (void) ext("%s/ipset -! add tallow6 %s", ipt_path, s->ip); 181 | s->blocked = true; 182 | } 183 | } 184 | } else { 185 | if (instant_block > 0) { 186 | (void) ext("%s/ipset -! add tallow %s timeout %d", 187 | ipt_path, s->ip, instant_block); 188 | } else { 189 | (void) ext("%s/ipset -! add tallow %s", ipt_path, s->ip); 190 | s->blocked = true; 191 | } 192 | } 193 | 194 | if (s->blocked) { 195 | fprintf(stderr, "Blocked %s\n", s->ip); 196 | } else { 197 | dbg("Throttled %s\n", s->ip); 198 | } 199 | } 200 | 201 | void find(const char *ip, float weight, int instant_block) 202 | { 203 | struct block_struct *s = blocks; 204 | struct block_struct *n; 205 | 206 | if (!ip) 207 | return; 208 | 209 | /* 210 | * not validating the IP address format here, just 211 | * making sure we're not passing special characters 212 | * to system(). 213 | */ 214 | if (strspn(ip, "0123456789abcdef:.") != strlen(ip)) 215 | return; 216 | 217 | if (whitelist_find(ip)) 218 | return; 219 | 220 | /* walk and update entry */ 221 | while (s) { 222 | if (!strcmp(s->ip, ip)) { 223 | s->score += weight; 224 | dbg("%s: %1.3f\n", s->ip, s->score); 225 | (void) gettimeofday(&s->time, NULL); 226 | 227 | if (s->blocked) { 228 | return; 229 | } 230 | 231 | if (s->score >= 1.0) { 232 | block(s, 0); 233 | } else if (instant_block > 0) { 234 | block(s, instant_block); 235 | } 236 | 237 | return; 238 | } 239 | 240 | if (s->next) 241 | s = s->next; 242 | else 243 | break; 244 | } 245 | 246 | /* append */ 247 | n = calloc(1, sizeof(struct block_struct)); 248 | if (!n) { 249 | fprintf(stderr, "Out of memory.\n"); 250 | exit(EXIT_FAILURE); 251 | } 252 | 253 | if (!blocks) 254 | blocks = n; 255 | else 256 | s->next = n; 257 | 258 | n->ip = strdup(ip); 259 | n->score = weight; 260 | n->next = NULL; 261 | n->blocked = false; 262 | (void) gettimeofday(&n->time, NULL); 263 | dbg("%s: %1.3f\n", n->ip, n->score); 264 | 265 | if (weight >= 1.0) { 266 | block(n, 0); 267 | } else if (instant_block > 0) { 268 | block(n, instant_block); 269 | } 270 | return; 271 | } 272 | 273 | #ifdef DEBUG 274 | static void sigusr1(int u __attribute__ ((unused))) 275 | { 276 | fprintf(stderr, "Dumping score list on request:\n"); 277 | struct block_struct *s = blocks; 278 | while (s) { 279 | fprintf(stderr, "%ld %s %1.3f\n", s->time.tv_sec, s->ip, s->score); 280 | s = s->next; 281 | } 282 | } 283 | #endif 284 | 285 | 286 | int main(void) 287 | { 288 | int r; 289 | FILE *f; 290 | int timeout = 60; 291 | long long unsigned int last_timestamp = 0; 292 | 293 | json_load_patterns(); 294 | 295 | strcpy(ipt_path, "/usr/sbin"); 296 | strcpy(fwcmd_path, "/usr/sbin"); 297 | 298 | #ifdef DEBUG 299 | fprintf(stderr, "Debug output enabled. Send SIGUSR1 to dump internal state table\n"); 300 | 301 | struct sigaction s; 302 | 303 | memset(&s, 0, sizeof(struct sigaction)); 304 | s.sa_handler = sigusr1; 305 | sigaction(SIGUSR1, &s, NULL); 306 | #endif 307 | 308 | if (access("/proc/sys/net/ipv6", R_OK | X_OK) == 0) 309 | has_ipv6 = 1; 310 | 311 | f = fopen(SYSCONFDIR "/tallow.conf", "r"); 312 | if (f) { 313 | char buf[256]; 314 | char *key; 315 | char *val; 316 | 317 | while (fgets(buf, 80, f) != NULL) { 318 | char *c; 319 | 320 | c = strchr(buf, '\n'); 321 | if (c) *c = 0; /* remove trailing \n */ 322 | 323 | if (buf[0] == '#') 324 | continue; /* comment line */ 325 | 326 | key = strtok(buf, "="); 327 | if (!key) 328 | continue; 329 | val = strtok(NULL, "="); 330 | if (!val) 331 | continue; 332 | 333 | // todo: filter leading/trailing whitespace 334 | if (!strcmp(key, "ipt_path")) 335 | strncpy(ipt_path, val, PATH_MAX - 1); 336 | if (!strcmp(key, "fwcmd_path")) 337 | strncpy(fwcmd_path, val, PATH_MAX - 1); 338 | if (!strcmp(key, "expires")) 339 | expires = atoi(val); 340 | if (!strcmp(key, "whitelist")) 341 | whitelist_add(val); 342 | if (!strcmp(key, "ipv6")) 343 | has_ipv6 = atoi(val); 344 | if (!strcmp(key, "nocreate")) 345 | nocreate = (atoi(val) == 1); 346 | } 347 | fclose(f); 348 | } 349 | 350 | if (!has_ipv6) 351 | fprintf(stdout, "ipv6 support disabled.\n"); 352 | 353 | if (!whitelist) { 354 | whitelist_add("127.0.0.1"); 355 | whitelist_add("192.168."); 356 | whitelist_add("10."); 357 | } 358 | 359 | r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY); 360 | if (r < 0) { 361 | fprintf(stderr, "Failed to open journal: %s\n", strerror(-r)); 362 | exit(EXIT_FAILURE); 363 | } 364 | 365 | /* add all filters */ 366 | struct filter_struct *flt = filters; 367 | while (flt) { 368 | sd_journal_add_match(j, flt->filter, 0); 369 | flt = flt->next; 370 | } 371 | 372 | /* go to the tail and wait */ 373 | r = sd_journal_seek_tail(j); 374 | sd_journal_wait(j, (uint64_t) 0); 375 | dbg("sd_journal_seek_tail() returned %d\n", r); 376 | while (sd_journal_next(j) != 0) 377 | r++; 378 | dbg("Forwarded through %d items in the journal to reach the end\n", r); 379 | 380 | fprintf(stderr, PACKAGE_STRING " Started\n"); 381 | 382 | for (;;) { 383 | const void *d, *dt; 384 | size_t l, dl; 385 | 386 | r = sd_journal_wait(j, (uint64_t) timeout * 1000000); 387 | if (r == SD_JOURNAL_INVALIDATE) { 388 | fprintf(stderr, "Journal was rotated, resetting\n"); 389 | sd_journal_seek_tail(j); 390 | } else if (r == SD_JOURNAL_NOP) { 391 | dbg("Timeout reached, waiting again\n"); 392 | continue; 393 | } 394 | 395 | while (sd_journal_next(j) != 0) { 396 | char *m; 397 | 398 | /* 399 | * discard messages older than ones we've already seen before 400 | * this happens when the journal rotates - we get replayed events 401 | */ 402 | if (sd_journal_get_data(j, "_SOURCE_REALTIME_TIMESTAMP", &dt, &dl) == 0) { 403 | long long unsigned int lt = atoll(dt + strlen("_SOURCE_REALTIME_TIMESTAMP=")); 404 | if (lt > last_timestamp) 405 | last_timestamp = lt; 406 | else if (lt < last_timestamp) { 407 | dbg("Discarding old entry: %llu - %llu\n", lt, last_timestamp); 408 | continue; 409 | } 410 | } 411 | 412 | if (sd_journal_get_data(j, "MESSAGE", &d, &l) < 0) { 413 | fprintf(stderr, "Failed to read message field: %s\n", strerror(-r)); 414 | break; 415 | } 416 | 417 | m = strndup(d, l+1); 418 | m[l] = '\0'; 419 | 420 | struct pattern_struct *pat = patterns; 421 | while (pat) { 422 | int off[MAX_OFFSETS]; 423 | int ret = pcre_exec(pat->re, NULL, m, l, 0, 0, off, MAX_OFFSETS); 424 | if (ret == 2) { 425 | const char *s; 426 | ret = pcre_get_substring(m, off, 2, 1, &s); 427 | if (ret > 0) { 428 | dbg("%s == %s\n", s, pat->pattern); 429 | find(s, pat->weight, pat->instant_block); 430 | pcre_free_substring(s); 431 | } 432 | } 433 | 434 | pat = pat->next; 435 | } 436 | 437 | free(m); 438 | 439 | } 440 | 441 | prune(expires); 442 | } 443 | 444 | sd_journal_close(j); 445 | 446 | exit(EXIT_SUCCESS); 447 | } 448 | -------------------------------------------------------------------------------- /INSTALL: -------------------------------------------------------------------------------- 1 | Installation Instructions 2 | ************************* 3 | 4 | Copyright (C) 1994-1996, 1999-2002, 2004-2013 Free Software Foundation, 5 | Inc. 6 | 7 | Copying and distribution of this file, with or without modification, 8 | are permitted in any medium without royalty provided the copyright 9 | notice and this notice are preserved. This file is offered as-is, 10 | without warranty of any kind. 11 | 12 | Basic Installation 13 | ================== 14 | 15 | Briefly, the shell command `./configure && make && make install' 16 | should configure, build, and install this package. The following 17 | more-detailed instructions are generic; see the `README' file for 18 | instructions specific to this package. Some packages provide this 19 | `INSTALL' file but do not implement all of the features documented 20 | below. The lack of an optional feature in a given package is not 21 | necessarily a bug. More recommendations for GNU packages can be found 22 | in *note Makefile Conventions: (standards)Makefile Conventions. 23 | 24 | The `configure' shell script attempts to guess correct values for 25 | various system-dependent variables used during compilation. It uses 26 | those values to create a `Makefile' in each directory of the package. 27 | It may also create one or more `.h' files containing system-dependent 28 | definitions. Finally, it creates a shell script `config.status' that 29 | you can run in the future to recreate the current configuration, and a 30 | file `config.log' containing compiler output (useful mainly for 31 | debugging `configure'). 32 | 33 | It can also use an optional file (typically called `config.cache' 34 | and enabled with `--cache-file=config.cache' or simply `-C') that saves 35 | the results of its tests to speed up reconfiguring. Caching is 36 | disabled by default to prevent problems with accidental use of stale 37 | cache files. 38 | 39 | If you need to do unusual things to compile the package, please try 40 | to figure out how `configure' could check whether to do them, and mail 41 | diffs or instructions to the address given in the `README' so they can 42 | be considered for the next release. If you are using the cache, and at 43 | some point `config.cache' contains results you don't want to keep, you 44 | may remove or edit it. 45 | 46 | The file `configure.ac' (or `configure.in') is used to create 47 | `configure' by a program called `autoconf'. You need `configure.ac' if 48 | you want to change it or regenerate `configure' using a newer version 49 | of `autoconf'. 50 | 51 | The simplest way to compile this package is: 52 | 53 | 1. `cd' to the directory containing the package's source code and type 54 | `./configure' to configure the package for your system. 55 | 56 | Running `configure' might take a while. While running, it prints 57 | some messages telling which features it is checking for. 58 | 59 | 2. Type `make' to compile the package. 60 | 61 | 3. Optionally, type `make check' to run any self-tests that come with 62 | the package, generally using the just-built uninstalled binaries. 63 | 64 | 4. Type `make install' to install the programs and any data files and 65 | documentation. When installing into a prefix owned by root, it is 66 | recommended that the package be configured and built as a regular 67 | user, and only the `make install' phase executed with root 68 | privileges. 69 | 70 | 5. Optionally, type `make installcheck' to repeat any self-tests, but 71 | this time using the binaries in their final installed location. 72 | This target does not install anything. Running this target as a 73 | regular user, particularly if the prior `make install' required 74 | root privileges, verifies that the installation completed 75 | correctly. 76 | 77 | 6. You can remove the program binaries and object files from the 78 | source code directory by typing `make clean'. To also remove the 79 | files that `configure' created (so you can compile the package for 80 | a different kind of computer), type `make distclean'. There is 81 | also a `make maintainer-clean' target, but that is intended mainly 82 | for the package's developers. If you use it, you may have to get 83 | all sorts of other programs in order to regenerate files that came 84 | with the distribution. 85 | 86 | 7. Often, you can also type `make uninstall' to remove the installed 87 | files again. In practice, not all packages have tested that 88 | uninstallation works correctly, even though it is required by the 89 | GNU Coding Standards. 90 | 91 | 8. Some packages, particularly those that use Automake, provide `make 92 | distcheck', which can by used by developers to test that all other 93 | targets like `make install' and `make uninstall' work correctly. 94 | This target is generally not run by end users. 95 | 96 | Compilers and Options 97 | ===================== 98 | 99 | Some systems require unusual options for compilation or linking that 100 | the `configure' script does not know about. Run `./configure --help' 101 | for details on some of the pertinent environment variables. 102 | 103 | You can give `configure' initial values for configuration parameters 104 | by setting variables in the command line or in the environment. Here 105 | is an example: 106 | 107 | ./configure CC=c99 CFLAGS=-g LIBS=-lposix 108 | 109 | *Note Defining Variables::, for more details. 110 | 111 | Compiling For Multiple Architectures 112 | ==================================== 113 | 114 | You can compile the package for more than one kind of computer at the 115 | same time, by placing the object files for each architecture in their 116 | own directory. To do this, you can use GNU `make'. `cd' to the 117 | directory where you want the object files and executables to go and run 118 | the `configure' script. `configure' automatically checks for the 119 | source code in the directory that `configure' is in and in `..'. This 120 | is known as a "VPATH" build. 121 | 122 | With a non-GNU `make', it is safer to compile the package for one 123 | architecture at a time in the source code directory. After you have 124 | installed the package for one architecture, use `make distclean' before 125 | reconfiguring for another architecture. 126 | 127 | On MacOS X 10.5 and later systems, you can create libraries and 128 | executables that work on multiple system types--known as "fat" or 129 | "universal" binaries--by specifying multiple `-arch' options to the 130 | compiler but only a single `-arch' option to the preprocessor. Like 131 | this: 132 | 133 | ./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \ 134 | CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \ 135 | CPP="gcc -E" CXXCPP="g++ -E" 136 | 137 | This is not guaranteed to produce working output in all cases, you 138 | may have to build one architecture at a time and combine the results 139 | using the `lipo' tool if you have problems. 140 | 141 | Installation Names 142 | ================== 143 | 144 | By default, `make install' installs the package's commands under 145 | `/usr/local/bin', include files under `/usr/local/include', etc. You 146 | can specify an installation prefix other than `/usr/local' by giving 147 | `configure' the option `--prefix=PREFIX', where PREFIX must be an 148 | absolute file name. 149 | 150 | You can specify separate installation prefixes for 151 | architecture-specific files and architecture-independent files. If you 152 | pass the option `--exec-prefix=PREFIX' to `configure', the package uses 153 | PREFIX as the prefix for installing programs and libraries. 154 | Documentation and other data files still use the regular prefix. 155 | 156 | In addition, if you use an unusual directory layout you can give 157 | options like `--bindir=DIR' to specify different values for particular 158 | kinds of files. Run `configure --help' for a list of the directories 159 | you can set and what kinds of files go in them. In general, the 160 | default for these options is expressed in terms of `${prefix}', so that 161 | specifying just `--prefix' will affect all of the other directory 162 | specifications that were not explicitly provided. 163 | 164 | The most portable way to affect installation locations is to pass the 165 | correct locations to `configure'; however, many packages provide one or 166 | both of the following shortcuts of passing variable assignments to the 167 | `make install' command line to change installation locations without 168 | having to reconfigure or recompile. 169 | 170 | The first method involves providing an override variable for each 171 | affected directory. For example, `make install 172 | prefix=/alternate/directory' will choose an alternate location for all 173 | directory configuration variables that were expressed in terms of 174 | `${prefix}'. Any directories that were specified during `configure', 175 | but not in terms of `${prefix}', must each be overridden at install 176 | time for the entire installation to be relocated. The approach of 177 | makefile variable overrides for each directory variable is required by 178 | the GNU Coding Standards, and ideally causes no recompilation. 179 | However, some platforms have known limitations with the semantics of 180 | shared libraries that end up requiring recompilation when using this 181 | method, particularly noticeable in packages that use GNU Libtool. 182 | 183 | The second method involves providing the `DESTDIR' variable. For 184 | example, `make install DESTDIR=/alternate/directory' will prepend 185 | `/alternate/directory' before all installation names. The approach of 186 | `DESTDIR' overrides is not required by the GNU Coding Standards, and 187 | does not work on platforms that have drive letters. On the other hand, 188 | it does better at avoiding recompilation issues, and works well even 189 | when some directory options were not specified in terms of `${prefix}' 190 | at `configure' time. 191 | 192 | Optional Features 193 | ================= 194 | 195 | If the package supports it, you can cause programs to be installed 196 | with an extra prefix or suffix on their names by giving `configure' the 197 | option `--program-prefix=PREFIX' or `--program-suffix=SUFFIX'. 198 | 199 | Some packages pay attention to `--enable-FEATURE' options to 200 | `configure', where FEATURE indicates an optional part of the package. 201 | They may also pay attention to `--with-PACKAGE' options, where PACKAGE 202 | is something like `gnu-as' or `x' (for the X Window System). The 203 | `README' should mention any `--enable-' and `--with-' options that the 204 | package recognizes. 205 | 206 | For packages that use the X Window System, `configure' can usually 207 | find the X include and library files automatically, but if it doesn't, 208 | you can use the `configure' options `--x-includes=DIR' and 209 | `--x-libraries=DIR' to specify their locations. 210 | 211 | Some packages offer the ability to configure how verbose the 212 | execution of `make' will be. For these packages, running `./configure 213 | --enable-silent-rules' sets the default to minimal output, which can be 214 | overridden with `make V=1'; while running `./configure 215 | --disable-silent-rules' sets the default to verbose, which can be 216 | overridden with `make V=0'. 217 | 218 | Particular systems 219 | ================== 220 | 221 | On HP-UX, the default C compiler is not ANSI C compatible. If GNU 222 | CC is not installed, it is recommended to use the following options in 223 | order to use an ANSI C compiler: 224 | 225 | ./configure CC="cc -Ae -D_XOPEN_SOURCE=500" 226 | 227 | and if that doesn't work, install pre-built binaries of GCC for HP-UX. 228 | 229 | HP-UX `make' updates targets which have the same time stamps as 230 | their prerequisites, which makes it generally unusable when shipped 231 | generated files such as `configure' are involved. Use GNU `make' 232 | instead. 233 | 234 | On OSF/1 a.k.a. Tru64, some versions of the default C compiler cannot 235 | parse its `' header file. The option `-nodtk' can be used as 236 | a workaround. If GNU CC is not installed, it is therefore recommended 237 | to try 238 | 239 | ./configure CC="cc" 240 | 241 | and if that doesn't work, try 242 | 243 | ./configure CC="cc -nodtk" 244 | 245 | On Solaris, don't put `/usr/ucb' early in your `PATH'. This 246 | directory contains several dysfunctional programs; working variants of 247 | these programs are available in `/usr/bin'. So, if you need `/usr/ucb' 248 | in your `PATH', put it _after_ `/usr/bin'. 249 | 250 | On Haiku, software installed for all users goes in `/boot/common', 251 | not `/usr/local'. It is recommended to use the following options: 252 | 253 | ./configure --prefix=/boot/common 254 | 255 | Specifying the System Type 256 | ========================== 257 | 258 | There may be some features `configure' cannot figure out 259 | automatically, but needs to determine by the type of machine the package 260 | will run on. Usually, assuming the package is built to be run on the 261 | _same_ architectures, `configure' can figure that out, but if it prints 262 | a message saying it cannot guess the machine type, give it the 263 | `--build=TYPE' option. TYPE can either be a short name for the system 264 | type, such as `sun4', or a canonical name which has the form: 265 | 266 | CPU-COMPANY-SYSTEM 267 | 268 | where SYSTEM can have one of these forms: 269 | 270 | OS 271 | KERNEL-OS 272 | 273 | See the file `config.sub' for the possible values of each field. If 274 | `config.sub' isn't included in this package, then this package doesn't 275 | need to know the machine type. 276 | 277 | If you are _building_ compiler tools for cross-compiling, you should 278 | use the option `--target=TYPE' to select the type of system they will 279 | produce code for. 280 | 281 | If you want to _use_ a cross compiler, that generates code for a 282 | platform different from the build platform, you should specify the 283 | "host" platform (i.e., that on which the generated programs will 284 | eventually be run) with `--host=TYPE'. 285 | 286 | Sharing Defaults 287 | ================ 288 | 289 | If you want to set default values for `configure' scripts to share, 290 | you can create a site shell script called `config.site' that gives 291 | default values for variables like `CC', `cache_file', and `prefix'. 292 | `configure' looks for `PREFIX/share/config.site' if it exists, then 293 | `PREFIX/etc/config.site' if it exists. Or, you can set the 294 | `CONFIG_SITE' environment variable to the location of the site script. 295 | A warning: not all `configure' scripts look for a site script. 296 | 297 | Defining Variables 298 | ================== 299 | 300 | Variables not defined in a site shell script can be set in the 301 | environment passed to `configure'. However, some packages may run 302 | configure again during the build, and the customized values of these 303 | variables may be lost. In order to avoid this problem, you should set 304 | them in the `configure' command line, using `VAR=value'. For example: 305 | 306 | ./configure CC=/usr/local2/bin/gcc 307 | 308 | causes the specified `gcc' to be used as the C compiler (unless it is 309 | overridden in the site shell script). 310 | 311 | Unfortunately, this technique does not work for `CONFIG_SHELL' due to 312 | an Autoconf limitation. Until the limitation is lifted, you can use 313 | this workaround: 314 | 315 | CONFIG_SHELL=/bin/bash ./configure CONFIG_SHELL=/bin/bash 316 | 317 | `configure' Invocation 318 | ====================== 319 | 320 | `configure' recognizes the following options to control how it 321 | operates. 322 | 323 | `--help' 324 | `-h' 325 | Print a summary of all of the options to `configure', and exit. 326 | 327 | `--help=short' 328 | `--help=recursive' 329 | Print a summary of the options unique to this package's 330 | `configure', and exit. The `short' variant lists options used 331 | only in the top level, while the `recursive' variant lists options 332 | also present in any nested packages. 333 | 334 | `--version' 335 | `-V' 336 | Print the version of Autoconf used to generate the `configure' 337 | script, and exit. 338 | 339 | `--cache-file=FILE' 340 | Enable the cache: use and save the results of the tests in FILE, 341 | traditionally `config.cache'. FILE defaults to `/dev/null' to 342 | disable caching. 343 | 344 | `--config-cache' 345 | `-C' 346 | Alias for `--cache-file=config.cache'. 347 | 348 | `--quiet' 349 | `--silent' 350 | `-q' 351 | Do not print messages saying which checks are being made. To 352 | suppress all normal output, redirect it to `/dev/null' (any error 353 | messages will still be shown). 354 | 355 | `--srcdir=DIR' 356 | Look for the package's source code in directory DIR. Usually 357 | `configure' can determine that directory automatically. 358 | 359 | `--prefix=DIR' 360 | Use DIR as the installation prefix. *note Installation Names:: 361 | for more details, including other options available for fine-tuning 362 | the installation locations. 363 | 364 | `--no-create' 365 | `-n' 366 | Run the configure checks, but stop before creating any output 367 | files. 368 | 369 | `configure' also accepts some other, not widely useful, options. Run 370 | `configure --help' for more details. 371 | -------------------------------------------------------------------------------- /COPYING: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. 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No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------