Made client stricter in cipher suite selection (better consistency with server behavi...
[BearSSL] / src / ec / ecdsa_i31_vrfy_asn1.c
1 /*
2 * Copyright (c) 2016 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 #define FIELD_LEN ((BR_MAX_EC_SIZE + 7) >> 3)
28
29 /* see bearssl_ec.h */
30 uint32_t
31 br_ecdsa_i31_vrfy_asn1(const br_ec_impl *impl,
32 const void *hash, size_t hash_len,
33 const br_ec_public_key *pk,
34 const void *sig, size_t sig_len)
35 {
36 /*
37 * We use a double-sized buffer because a malformed ASN.1 signature
38 * may trigger a size expansion when converting to "raw" format.
39 */
40 unsigned char rsig[(FIELD_LEN << 2) + 24];
41
42 if (sig_len > ((sizeof rsig) >> 1)) {
43 return 0;
44 }
45 memcpy(rsig, sig, sig_len);
46 sig_len = br_ecdsa_asn1_to_raw(rsig, sig_len);
47 return br_ecdsa_i31_vrfy_raw(impl, hash, hash_len, pk, rsig, sig_len);
48 }