1 /* $OpenBSD: ssh-ecdsa.c,v 1.12 2015/12/11 04:21:12 mmcc Exp $ */
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Copyright (c) 2010 Damien Miller. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
31 #include <sys/types.h>
33 #include <openssl/bn.h>
34 #include <openssl/ec.h>
35 #include <openssl/ecdsa.h>
36 #include <openssl/evp.h>
43 #define SSHKEY_INTERNAL
48 ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
49 const u_char *data, size_t datalen, u_int compat)
51 ECDSA_SIG *sig = NULL;
53 u_char digest[SSH_DIGEST_MAX_LENGTH];
55 struct sshbuf *b = NULL, *bb = NULL;
56 int ret = SSH_ERR_INTERNAL_ERROR;
63 if (key == NULL || key->ecdsa == NULL ||
64 sshkey_type_plain(key->type) != KEY_ECDSA)
65 return SSH_ERR_INVALID_ARGUMENT;
67 if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
68 (dlen = ssh_digest_bytes(hash_alg)) == 0)
69 return SSH_ERR_INTERNAL_ERROR;
70 if ((ret = ssh_digest_memory(hash_alg, data, datalen,
71 digest, sizeof(digest))) != 0)
74 if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) {
75 ret = SSH_ERR_LIBCRYPTO_ERROR;
79 if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
80 ret = SSH_ERR_ALLOC_FAIL;
83 if ((ret = sshbuf_put_bignum2(bb, sig->r)) != 0 ||
84 (ret = sshbuf_put_bignum2(bb, sig->s)) != 0)
86 if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 ||
87 (ret = sshbuf_put_stringb(b, bb)) != 0)
91 if ((*sigp = malloc(len)) == NULL) {
92 ret = SSH_ERR_ALLOC_FAIL;
95 memcpy(*sigp, sshbuf_ptr(b), len);
101 explicit_bzero(digest, sizeof(digest));
111 ssh_ecdsa_verify(const struct sshkey *key,
112 const u_char *signature, size_t signaturelen,
113 const u_char *data, size_t datalen, u_int compat)
115 ECDSA_SIG *sig = NULL;
117 u_char digest[SSH_DIGEST_MAX_LENGTH];
119 int ret = SSH_ERR_INTERNAL_ERROR;
120 struct sshbuf *b = NULL, *sigbuf = NULL;
123 if (key == NULL || key->ecdsa == NULL ||
124 sshkey_type_plain(key->type) != KEY_ECDSA)
125 return SSH_ERR_INVALID_ARGUMENT;
127 if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
128 (dlen = ssh_digest_bytes(hash_alg)) == 0)
129 return SSH_ERR_INTERNAL_ERROR;
131 /* fetch signature */
132 if ((b = sshbuf_from(signature, signaturelen)) == NULL)
133 return SSH_ERR_ALLOC_FAIL;
134 if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
135 sshbuf_froms(b, &sigbuf) != 0) {
136 ret = SSH_ERR_INVALID_FORMAT;
139 if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
140 ret = SSH_ERR_KEY_TYPE_MISMATCH;
143 if (sshbuf_len(b) != 0) {
144 ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
148 /* parse signature */
149 if ((sig = ECDSA_SIG_new()) == NULL) {
150 ret = SSH_ERR_ALLOC_FAIL;
153 if (sshbuf_get_bignum2(sigbuf, sig->r) != 0 ||
154 sshbuf_get_bignum2(sigbuf, sig->s) != 0) {
155 ret = SSH_ERR_INVALID_FORMAT;
158 if (sshbuf_len(sigbuf) != 0) {
159 ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
162 if ((ret = ssh_digest_memory(hash_alg, data, datalen,
163 digest, sizeof(digest))) != 0)
166 switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) {
171 ret = SSH_ERR_SIGNATURE_INVALID;
174 ret = SSH_ERR_LIBCRYPTO_ERROR;
179 explicit_bzero(digest, sizeof(digest));
188 #endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */