1 /*
2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /*
28 * Supported cipher suites that use SHA-384 for the PRF when selected
29 * for TLS 1.2. All other cipher suites are deemed to use SHA-256.
30 */
31 static const uint16_t suites_sha384[] = {
32 BR_TLS_RSA_WITH_AES_256_GCM_SHA384,
33 BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
34 BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384,
35 BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
36 BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384,
37 BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
38 BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384,
39 BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
40 BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
41 };
42
43 /* see bearssl_ssl.h */
44 int
br_ssl_key_export(br_ssl_engine_context * cc,void * dst,size_t len,const char * label,const void * context,size_t context_len)45 br_ssl_key_export(br_ssl_engine_context *cc,
46 void *dst, size_t len, const char *label,
47 const void *context, size_t context_len)
48 {
49 br_tls_prf_seed_chunk chunks[4];
50 br_tls_prf_impl iprf;
51 size_t num_chunks, u;
52 unsigned char tmp[2];
53 int prf_id;
54
55 if (cc->application_data != 1) {
56 return 0;
57 }
58 chunks[0].data = cc->client_random;
59 chunks[0].len = sizeof cc->client_random;
60 chunks[1].data = cc->server_random;
61 chunks[1].len = sizeof cc->server_random;
62 if (context != NULL) {
63 br_enc16be(tmp, (unsigned)context_len);
64 chunks[2].data = tmp;
65 chunks[2].len = 2;
66 chunks[3].data = context;
67 chunks[3].len = context_len;
68 num_chunks = 4;
69 } else {
70 num_chunks = 2;
71 }
72 prf_id = BR_SSLPRF_SHA256;
73 for (u = 0; u < (sizeof suites_sha384) / sizeof(uint16_t); u ++) {
74 if (suites_sha384[u] == cc->session.cipher_suite) {
75 prf_id = BR_SSLPRF_SHA384;
76 }
77 }
78 iprf = br_ssl_engine_get_PRF(cc, prf_id);
79 iprf(dst, len,
80 cc->session.master_secret, sizeof cc->session.master_secret,
81 label, num_chunks, chunks);
82 return 1;
83 }
84