Mercurial > dropbear

comparison fuzz/fuzzer-verify.c @ 1756:d5680e12ac33

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Move fuzzing code to fuzz/ subdirectory, improve Makefile.in
author Matt Johnston <matt@ucc.asn.au>
date Fri, 23 Oct 2020 23:10:20 +0800
parents fuzzer-verify.c@e01f9ec6d177
children
comparison
equal deleted inserted replaced
1753:7c0fcd19e492 1756:d5680e12ac33
1 #include "fuzz.h"
2 #include "session.h"
3 #include "fuzz-wrapfd.h"
4 #include "debug.h"
5 #include "dss.h"
6
7 static void setup_fuzzer(void) {
8 fuzz_common_setup();
9 }
10
11 static buffer *verifydata;
12
13 /* Tests reading a public key and verifying a signature */
14 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
15 static int once = 0;
16 if (!once) {
17 setup_fuzzer();
18 verifydata = buf_new(30);
19 buf_putstring(verifydata, "x", 1);
20 once = 1;
21 }
22
23 if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
24 return 0;
25 }
26
27 m_malloc_set_epoch(1);
28
29 if (setjmp(fuzz.jmp) == 0) {
30 sign_key *key = new_sign_key();
31 enum signkey_type keytype = DROPBEAR_SIGNKEY_ANY;
32 if (buf_get_pub_key(fuzz.input, key, &keytype) == DROPBEAR_SUCCESS) {
33 enum signature_type sigtype;
34 if (keytype == DROPBEAR_SIGNKEY_RSA) {
35 /* Flip a coin to decide rsa signature type */
36 int flag = buf_getbyte(fuzz.input);
37 if (flag & 0x01) {
38 sigtype = DROPBEAR_SIGNATURE_RSA_SHA256;
39 } else {
40 sigtype = DROPBEAR_SIGNATURE_RSA_SHA1;
41 }
42 } else {
43 sigtype = signature_type_from_signkey(keytype);
44 }
45 if (buf_verify(fuzz.input, key, sigtype, verifydata) == DROPBEAR_SUCCESS) {
46 /* The fuzzer is capable of generating keys with a signature to match.
47 We don't want false positives if the key is bogus, since a client/server
48 wouldn't be trusting a bogus key anyway */
49 int boguskey = 0;
50
51 if (keytype == DROPBEAR_SIGNKEY_DSS) {
52 /* So far have seen dss keys with bad p/q/g domain parameters */
53 int pprime, qprime, trials;
54 trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->p));
55 assert(mp_prime_is_prime(key->dsskey->p, trials, &pprime) == MP_OKAY);
56 trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->q));
57 assert(mp_prime_is_prime(key->dsskey->q, trials, &qprime) == MP_OKAY);
58 boguskey = !(pprime && qprime);
59 /* Could also check g**q mod p == 1 */
60 }
61
62 if (!boguskey) {
63 printf("Random key/signature managed to verify!\n");
64 abort();
65 }
66
67
68 }
69 }
70 sign_key_free(key);
71 m_malloc_free_epoch(1, 0);
72 } else {
73 m_malloc_free_epoch(1, 1);
74 TRACE(("dropbear_exit longjmped"))
75 /* dropbear_exit jumped here */
76 }
77
78 return 0;
79 }