1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2019 Google LLC
4 */
5
6 /*
7 * Regression test for commit ecaaab564978 ("crypto: salsa20 - fix
8 * blkcipher_walk API usage"), or CVE-2017-17805. This test verifies that an
9 * empty message can be encrypted with Salsa20 without crashing the kernel.
10 *
11 * Fix for kernels < 4.14:
12 * With kernels missing commit 2d97591ef43d ("crypto: af_alg - consolidation
13 * of duplicate code") read() does not return in this situation. The call is
14 * now moved to a child thread in order to cancel it in case read() takes an
15 * unusual long amount of time.
16 */
17
18 #include "tst_test.h"
19 #include "tst_af_alg.h"
20 #include "tst_safe_pthread.h"
21 #include <pthread.h>
22 #include <errno.h>
23
24 #define SALSA20_IV_SIZE 8
25 #define SALSA20_MIN_KEY_SIZE 16
26
verify_encrypt(void * arg)27 static void *verify_encrypt(void *arg)
28 {
29 const uint8_t iv[SALSA20_IV_SIZE] = { 0 };
30 const struct tst_alg_sendmsg_params params = {
31 .encrypt = true,
32 .iv = iv,
33 .ivlen = SALSA20_IV_SIZE,
34 };
35 char buf[16];
36 int reqfd = tst_alg_setup_reqfd("skcipher", "salsa20", NULL,
37 SALSA20_MIN_KEY_SIZE);
38
39 /* Send a zero-length message to encrypt */
40 tst_alg_sendmsg(reqfd, NULL, 0, ¶ms);
41
42 /*
43 * Read the zero-length encrypted data.
44 * With the bug, the kernel crashed here.
45 */
46 TST_CHECKPOINT_WAKE(0);
47 if (read(reqfd, buf, 16) == 0)
48 tst_res(TPASS, "Successfully \"encrypted\" an empty message");
49 else
50 tst_res(TFAIL, "read() didn't return 0");
51 return arg;
52 }
53
run(void)54 static void run(void)
55 {
56 pthread_t thr;
57
58 pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
59 SAFE_PTHREAD_CREATE(&thr, NULL, verify_encrypt, NULL);
60
61 TST_CHECKPOINT_WAIT(0);
62
63 while (pthread_kill(thr, 0) != ESRCH) {
64 if (tst_timeout_remaining() <= 10) {
65 pthread_cancel(thr);
66 tst_brk(TBROK,
67 "Timed out while reading from request socket.");
68 }
69 usleep(1000);
70 }
71 }
72
73 static struct tst_test test = {
74 .test_all = run,
75 .timeout = 20,
76 .needs_checkpoints = 1,
77 .tags = (const struct tst_tag[]) {
78 {"linux-git", "ecaaab564978"},
79 {"CVE", "2017-17805"},
80 {}
81 }
82 };
83