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
LLVMFuzzerTestOneInput(const uint8_t * Data,size_t Size)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 /* number of generated parameters is limited by the timeout for the first run */
14 #define NUM_PARAMS 80
15 static struct kex_ecdh_param *ecdh_params[NUM_PARAMS];
16
17 if (!once) {
18 fuzz_common_setup();
19 fuzz_svr_setup();
20
21 /* ses gets zeroed by fuzz_set_input */
22 keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
23 ecdh[0] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp256");
24 ecdh[1] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp384");
25 ecdh[2] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp521");
26 assert(ecdh[0]);
27 assert(ecdh[1]);
28 assert(ecdh[2]);
29 keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
30 ses.newkeys = keep_newkeys;
31
32 /* Pre-generate parameters */
33 int i;
34 for (i = 0; i < NUM_PARAMS; i++) {
35 ses.newkeys->algo_kex = ecdh[i % 3];
36 ecdh_params[i] = gen_kexecdh_param();
37 }
38
39 once = 1;
40 }
41
42 if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
43 return 0;
44 }
45
46 m_malloc_set_epoch(1);
47
48 if (setjmp(fuzz.jmp) == 0) {
49 /* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply()
50 with DROPBEAR_KEX_ECDH */
51 ses.newkeys = keep_newkeys;
52
53 /* random choice of ecdh 256, 384, 521 */
54 unsigned char b = buf_getbyte(fuzz.input);
55 ses.newkeys->algo_kex = ecdh[b % 3];
56
57 /* Choose from the collection of ecdh params */
58 unsigned int e = buf_getint(fuzz.input);
59 struct kex_ecdh_param *ecdh_param = ecdh_params[e % NUM_PARAMS];
60
61 buffer * ecdh_qs = buf_getstringbuf(fuzz.input);
62
63 ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS);
64 kexecdh_comb_key(ecdh_param, ecdh_qs, svr_opts.hostkey);
65
66 mp_clear(ses.dh_K);
67 m_free(ses.dh_K);
68 buf_free(ecdh_qs);
69
70 buf_free(ses.hash);
71 buf_free(ses.session_id);
72 /* kexhashbuf is freed in kexdh_comb_key */
73
74 m_malloc_free_epoch(1, 0);
75 } else {
76 m_malloc_free_epoch(1, 1);
77 TRACE(("dropbear_exit longjmped"))
78 /* dropbear_exit jumped here */
79 }
80
81 return 0;
82 }
83