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comparison fuzzer-kexecdh.c @ 1589:35af85194268

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Add kexdh and kexecdh fuzzers
author Matt Johnston <matt@ucc.asn.au>
date Mon, 05 Mar 2018 11:50:31 +0800
parents
children 46506b32650a
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1588:149a5329d83a 1589:35af85194268
1 #include "fuzz.h"
2 #include "session.h"
3 #include "fuzz-wrapfd.h"
4 #include "debug.h"
5 #include "runopts.h"
6 #include "algo.h"
7 #include "bignum.h"
8
9 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
10 static int once = 0;
11 static const struct dropbear_kex *ecdh[3]; /* 256, 384, 521 */
12 static struct key_context* keep_newkeys = NULL;
13 #define NUM_PARAMS 800
14 static struct kex_ecdh_param *ecdh_params[NUM_PARAMS];
15
16 if (!once) {
17 fuzz_common_setup();
18 fuzz_svr_setup();
19
20 /* ses gets zeroed by fuzz_set_input */
21 keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
22 ecdh[0] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp256");
23 ecdh[1] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp384");
24 ecdh[2] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp521");
25 assert(ecdh[0]);
26 assert(ecdh[1]);
27 assert(ecdh[2]);
28 keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
29 ses.newkeys = keep_newkeys;
30
31 /* Pre-generate parameters */
32 int i;
33 for (i = 0; i < NUM_PARAMS; i++) {
34 ses.newkeys->algo_kex = ecdh[i % 3];
35 ecdh_params[i] = gen_kexecdh_param();
36 }
37
38 once = 1;
39 }
40
41 if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
42 return 0;
43 }
44
45 m_malloc_set_epoch(1);
46
47 if (setjmp(fuzz.jmp) == 0) {
48 /* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply()
49 with DROPBEAR_KEX_ECDH */
50 ses.newkeys = keep_newkeys;
51
52 /* random choice of ecdh 256, 384, 521 */
53 unsigned char b = buf_getbyte(fuzz.input);
54 ses.newkeys->algo_kex = ecdh[b % 3];
55
56 /* Choose from the collection of ecdh params */
57 unsigned int e = buf_getint(fuzz.input);
58 struct kex_ecdh_param *ecdh_param = ecdh_params[e % NUM_PARAMS];
59
60 buffer * ecdh_qs = buf_getstringbuf(fuzz.input);
61
62 ses.kexhashbuf = buf_new(4);
63 buf_putint(ses.kexhashbuf, 12345);
64 kexecdh_comb_key(ecdh_param, ecdh_qs, svr_opts.hostkey);
65
66 /* kexhashbuf is freed in kexdh_comb_key */
67 m_free(ses.dh_K);
68 buf_free(ecdh_qs);
69
70 m_malloc_free_epoch(1, 0);
71 } else {
72 m_malloc_free_epoch(1, 1);
73 TRACE(("dropbear_exit longjmped"))
74 /* dropbear_exit jumped here */
75 }
76
77 return 0;
78 }