xref: /freebsd-src/contrib/bearssl/src/ssl/ssl_keyexport.c (revision 2aaf9152a852aba9eb2036b95f4948ee77988826)
1*0957b409SSimon J. Gerraty /*
2*0957b409SSimon J. Gerraty  * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
3*0957b409SSimon J. Gerraty  *
4*0957b409SSimon J. Gerraty  * Permission is hereby granted, free of charge, to any person obtaining
5*0957b409SSimon J. Gerraty  * a copy of this software and associated documentation files (the
6*0957b409SSimon J. Gerraty  * "Software"), to deal in the Software without restriction, including
7*0957b409SSimon J. Gerraty  * without limitation the rights to use, copy, modify, merge, publish,
8*0957b409SSimon J. Gerraty  * distribute, sublicense, and/or sell copies of the Software, and to
9*0957b409SSimon J. Gerraty  * permit persons to whom the Software is furnished to do so, subject to
10*0957b409SSimon J. Gerraty  * the following conditions:
11*0957b409SSimon J. Gerraty  *
12*0957b409SSimon J. Gerraty  * The above copyright notice and this permission notice shall be
13*0957b409SSimon J. Gerraty  * included in all copies or substantial portions of the Software.
14*0957b409SSimon J. Gerraty  *
15*0957b409SSimon J. Gerraty  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*0957b409SSimon J. Gerraty  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*0957b409SSimon J. Gerraty  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*0957b409SSimon J. Gerraty  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*0957b409SSimon J. Gerraty  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*0957b409SSimon J. Gerraty  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*0957b409SSimon J. Gerraty  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*0957b409SSimon J. Gerraty  * SOFTWARE.
23*0957b409SSimon J. Gerraty  */
24*0957b409SSimon J. Gerraty 
25*0957b409SSimon J. Gerraty #include "inner.h"
26*0957b409SSimon J. Gerraty 
27*0957b409SSimon J. Gerraty /*
28*0957b409SSimon J. Gerraty  * Supported cipher suites that use SHA-384 for the PRF when selected
29*0957b409SSimon J. Gerraty  * for TLS 1.2. All other cipher suites are deemed to use SHA-256.
30*0957b409SSimon J. Gerraty  */
31*0957b409SSimon J. Gerraty static const uint16_t suites_sha384[] = {
32*0957b409SSimon J. Gerraty 	BR_TLS_RSA_WITH_AES_256_GCM_SHA384,
33*0957b409SSimon J. Gerraty 	BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
34*0957b409SSimon J. Gerraty 	BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384,
35*0957b409SSimon J. Gerraty 	BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
36*0957b409SSimon J. Gerraty 	BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384,
37*0957b409SSimon J. Gerraty 	BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
38*0957b409SSimon J. Gerraty 	BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384,
39*0957b409SSimon J. Gerraty 	BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
40*0957b409SSimon J. Gerraty 	BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
41*0957b409SSimon J. Gerraty };
42*0957b409SSimon J. Gerraty 
43*0957b409SSimon J. Gerraty /* see bearssl_ssl.h */
44*0957b409SSimon J. Gerraty 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*0957b409SSimon J. Gerraty br_ssl_key_export(br_ssl_engine_context *cc,
46*0957b409SSimon J. Gerraty 	void *dst, size_t len, const char *label,
47*0957b409SSimon J. Gerraty 	const void *context, size_t context_len)
48*0957b409SSimon J. Gerraty {
49*0957b409SSimon J. Gerraty 	br_tls_prf_seed_chunk chunks[4];
50*0957b409SSimon J. Gerraty 	br_tls_prf_impl iprf;
51*0957b409SSimon J. Gerraty 	size_t num_chunks, u;
52*0957b409SSimon J. Gerraty 	unsigned char tmp[2];
53*0957b409SSimon J. Gerraty 	int prf_id;
54*0957b409SSimon J. Gerraty 
55*0957b409SSimon J. Gerraty 	if (cc->application_data != 1) {
56*0957b409SSimon J. Gerraty 		return 0;
57*0957b409SSimon J. Gerraty 	}
58*0957b409SSimon J. Gerraty 	chunks[0].data = cc->client_random;
59*0957b409SSimon J. Gerraty 	chunks[0].len = sizeof cc->client_random;
60*0957b409SSimon J. Gerraty 	chunks[1].data = cc->server_random;
61*0957b409SSimon J. Gerraty 	chunks[1].len = sizeof cc->server_random;
62*0957b409SSimon J. Gerraty 	if (context != NULL) {
63*0957b409SSimon J. Gerraty 		br_enc16be(tmp, (unsigned)context_len);
64*0957b409SSimon J. Gerraty 		chunks[2].data = tmp;
65*0957b409SSimon J. Gerraty 		chunks[2].len = 2;
66*0957b409SSimon J. Gerraty 		chunks[3].data = context;
67*0957b409SSimon J. Gerraty 		chunks[3].len = context_len;
68*0957b409SSimon J. Gerraty 		num_chunks = 4;
69*0957b409SSimon J. Gerraty 	} else {
70*0957b409SSimon J. Gerraty 		num_chunks = 2;
71*0957b409SSimon J. Gerraty 	}
72*0957b409SSimon J. Gerraty 	prf_id = BR_SSLPRF_SHA256;
73*0957b409SSimon J. Gerraty 	for (u = 0; u < (sizeof suites_sha384) / sizeof(uint16_t); u ++) {
74*0957b409SSimon J. Gerraty 		if (suites_sha384[u] == cc->session.cipher_suite) {
75*0957b409SSimon J. Gerraty 			prf_id = BR_SSLPRF_SHA384;
76*0957b409SSimon J. Gerraty 		}
77*0957b409SSimon J. Gerraty 	}
78*0957b409SSimon J. Gerraty 	iprf = br_ssl_engine_get_PRF(cc, prf_id);
79*0957b409SSimon J. Gerraty 	iprf(dst, len,
80*0957b409SSimon J. Gerraty 		cc->session.master_secret, sizeof cc->session.master_secret,
81*0957b409SSimon J. Gerraty 		label, num_chunks, chunks);
82*0957b409SSimon J. Gerraty 	return 1;
83*0957b409SSimon J. Gerraty }
84