Annotation of src/usr.bin/ssh/ssh-ecdsa.c, Revision 1.17
1.17 ! djm 1: /* $OpenBSD: ssh-ecdsa.c,v 1.16 2019/01/21 09:54:11 djm Exp $ */
1.1 djm 2: /*
3: * Copyright (c) 2000 Markus Friedl. All rights reserved.
4: * Copyright (c) 2010 Damien Miller. All rights reserved.
5: *
6: * Redistribution and use in source and binary forms, with or without
7: * modification, are permitted provided that the following conditions
8: * are met:
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.
14: *
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.
25: */
26:
27: #include <sys/types.h>
28:
29: #include <openssl/bn.h>
30: #include <openssl/ec.h>
31: #include <openssl/ecdsa.h>
32: #include <openssl/evp.h>
33:
34: #include <string.h>
35:
1.11 djm 36: #include "sshbuf.h"
37: #include "ssherr.h"
1.8 djm 38: #include "digest.h"
1.11 djm 39: #define SSHKEY_INTERNAL
40: #include "sshkey.h"
1.1 djm 41:
1.17 ! djm 42: static u_int
! 43: ssh_ecdsa_size(const struct sshkey *key)
! 44: {
! 45: switch (key->ecdsa_nid) {
! 46: case NID_X9_62_prime256v1:
! 47: return 256;
! 48: case NID_secp384r1:
! 49: return 384;
! 50: case NID_secp521r1:
! 51: return 521;
! 52: default:
! 53: return 0;
! 54: }
! 55: }
! 56:
! 57: static void
! 58: ssh_ecdsa_cleanup(struct sshkey *k)
! 59: {
! 60: EC_KEY_free(k->ecdsa);
! 61: k->ecdsa = NULL;
! 62: }
! 63:
1.11 djm 64: /* ARGSUSED */
1.1 djm 65: int
1.11 djm 66: ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
67: const u_char *data, size_t datalen, u_int compat)
1.1 djm 68: {
1.11 djm 69: ECDSA_SIG *sig = NULL;
1.15 djm 70: const BIGNUM *sig_r, *sig_s;
1.8 djm 71: int hash_alg;
72: u_char digest[SSH_DIGEST_MAX_LENGTH];
1.11 djm 73: size_t len, dlen;
74: struct sshbuf *b = NULL, *bb = NULL;
75: int ret = SSH_ERR_INTERNAL_ERROR;
1.1 djm 76:
1.11 djm 77: if (lenp != NULL)
78: *lenp = 0;
79: if (sigp != NULL)
80: *sigp = NULL;
81:
82: if (key == NULL || key->ecdsa == NULL ||
83: sshkey_type_plain(key->type) != KEY_ECDSA)
84: return SSH_ERR_INVALID_ARGUMENT;
85:
86: if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
87: (dlen = ssh_digest_bytes(hash_alg)) == 0)
88: return SSH_ERR_INTERNAL_ERROR;
89: if ((ret = ssh_digest_memory(hash_alg, data, datalen,
90: digest, sizeof(digest))) != 0)
91: goto out;
92:
93: if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) {
94: ret = SSH_ERR_LIBCRYPTO_ERROR;
95: goto out;
96: }
97:
98: if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
99: ret = SSH_ERR_ALLOC_FAIL;
100: goto out;
101: }
1.15 djm 102: ECDSA_SIG_get0(sig, &sig_r, &sig_s);
103: if ((ret = sshbuf_put_bignum2(bb, sig_r)) != 0 ||
104: (ret = sshbuf_put_bignum2(bb, sig_s)) != 0)
1.11 djm 105: goto out;
106: if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 ||
107: (ret = sshbuf_put_stringb(b, bb)) != 0)
108: goto out;
109: len = sshbuf_len(b);
110: if (sigp != NULL) {
111: if ((*sigp = malloc(len)) == NULL) {
112: ret = SSH_ERR_ALLOC_FAIL;
113: goto out;
114: }
115: memcpy(*sigp, sshbuf_ptr(b), len);
1.1 djm 116: }
117: if (lenp != NULL)
118: *lenp = len;
1.11 djm 119: ret = 0;
120: out:
121: explicit_bzero(digest, sizeof(digest));
1.12 mmcc 122: sshbuf_free(b);
123: sshbuf_free(bb);
1.14 jsing 124: ECDSA_SIG_free(sig);
1.11 djm 125: return ret;
126: }
1.1 djm 127:
1.11 djm 128: /* ARGSUSED */
1.1 djm 129: int
1.11 djm 130: ssh_ecdsa_verify(const struct sshkey *key,
131: const u_char *signature, size_t signaturelen,
132: const u_char *data, size_t datalen, u_int compat)
1.1 djm 133: {
1.11 djm 134: ECDSA_SIG *sig = NULL;
1.15 djm 135: BIGNUM *sig_r = NULL, *sig_s = NULL;
1.8 djm 136: int hash_alg;
1.11 djm 137: u_char digest[SSH_DIGEST_MAX_LENGTH];
138: size_t dlen;
139: int ret = SSH_ERR_INTERNAL_ERROR;
140: struct sshbuf *b = NULL, *sigbuf = NULL;
141: char *ktype = NULL;
142:
143: if (key == NULL || key->ecdsa == NULL ||
1.13 djm 144: sshkey_type_plain(key->type) != KEY_ECDSA ||
145: signature == NULL || signaturelen == 0)
1.11 djm 146: return SSH_ERR_INVALID_ARGUMENT;
147:
148: if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
149: (dlen = ssh_digest_bytes(hash_alg)) == 0)
150: return SSH_ERR_INTERNAL_ERROR;
1.7 djm 151:
1.1 djm 152: /* fetch signature */
1.11 djm 153: if ((b = sshbuf_from(signature, signaturelen)) == NULL)
154: return SSH_ERR_ALLOC_FAIL;
155: if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
156: sshbuf_froms(b, &sigbuf) != 0) {
157: ret = SSH_ERR_INVALID_FORMAT;
158: goto out;
159: }
160: if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
161: ret = SSH_ERR_KEY_TYPE_MISMATCH;
162: goto out;
163: }
164: if (sshbuf_len(b) != 0) {
165: ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
166: goto out;
1.1 djm 167: }
168:
169: /* parse signature */
1.16 djm 170: if (sshbuf_get_bignum2(sigbuf, &sig_r) != 0 ||
171: sshbuf_get_bignum2(sigbuf, &sig_s) != 0) {
172: ret = SSH_ERR_INVALID_FORMAT;
1.11 djm 173: goto out;
174: }
1.16 djm 175: if ((sig = ECDSA_SIG_new()) == NULL) {
176: ret = SSH_ERR_ALLOC_FAIL;
1.11 djm 177: goto out;
178: }
1.15 djm 179: if (!ECDSA_SIG_set0(sig, sig_r, sig_s)) {
180: ret = SSH_ERR_LIBCRYPTO_ERROR;
181: goto out;
182: }
183: sig_r = sig_s = NULL; /* transferred */
184:
1.11 djm 185: if (sshbuf_len(sigbuf) != 0) {
186: ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
187: goto out;
188: }
189: if ((ret = ssh_digest_memory(hash_alg, data, datalen,
190: digest, sizeof(digest))) != 0)
191: goto out;
192:
193: switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) {
194: case 1:
195: ret = 0;
196: break;
197: case 0:
198: ret = SSH_ERR_SIGNATURE_INVALID;
199: goto out;
200: default:
201: ret = SSH_ERR_LIBCRYPTO_ERROR;
202: goto out;
1.8 djm 203: }
1.1 djm 204:
1.11 djm 205: out:
1.9 djm 206: explicit_bzero(digest, sizeof(digest));
1.12 mmcc 207: sshbuf_free(sigbuf);
208: sshbuf_free(b);
1.14 jsing 209: ECDSA_SIG_free(sig);
1.15 djm 210: BN_clear_free(sig_r);
211: BN_clear_free(sig_s);
1.11 djm 212: free(ktype);
1.1 djm 213: return ret;
214: }
1.17 ! djm 215:
! 216: static const struct sshkey_impl_funcs sshkey_ecdsa_funcs = {
! 217: /* .size = */ ssh_ecdsa_size,
! 218: /* .alloc = */ NULL,
! 219: /* .cleanup = */ ssh_ecdsa_cleanup,
! 220: };
! 221:
! 222: const struct sshkey_impl sshkey_ecdsa_nistp256_impl = {
! 223: /* .name = */ "ecdsa-sha2-nistp256",
! 224: /* .shortname = */ "ECDSA",
! 225: /* .sigalg = */ NULL,
! 226: /* .type = */ KEY_ECDSA,
! 227: /* .nid = */ NID_X9_62_prime256v1,
! 228: /* .cert = */ 0,
! 229: /* .sigonly = */ 0,
! 230: /* .keybits = */ 0,
! 231: /* .funcs = */ &sshkey_ecdsa_funcs,
! 232: };
! 233:
! 234: const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl = {
! 235: /* .name = */ "ecdsa-sha2-nistp256-cert-v01@openssh.com",
! 236: /* .shortname = */ "ECDSA-CERT",
! 237: /* .sigalg = */ NULL,
! 238: /* .type = */ KEY_ECDSA_CERT,
! 239: /* .nid = */ NID_X9_62_prime256v1,
! 240: /* .cert = */ 1,
! 241: /* .sigonly = */ 0,
! 242: /* .keybits = */ 0,
! 243: /* .funcs = */ &sshkey_ecdsa_funcs,
! 244: };
! 245:
! 246: const struct sshkey_impl sshkey_ecdsa_nistp384_impl = {
! 247: /* .name = */ "ecdsa-sha2-nistp384",
! 248: /* .shortname = */ "ECDSA",
! 249: /* .sigalg = */ NULL,
! 250: /* .type = */ KEY_ECDSA,
! 251: /* .nid = */ NID_secp384r1,
! 252: /* .cert = */ 0,
! 253: /* .sigonly = */ 0,
! 254: /* .keybits = */ 0,
! 255: /* .funcs = */ &sshkey_ecdsa_funcs,
! 256: };
! 257:
! 258: const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl = {
! 259: /* .name = */ "ecdsa-sha2-nistp384-cert-v01@openssh.com",
! 260: /* .shortname = */ "ECDSA-CERT",
! 261: /* .sigalg = */ NULL,
! 262: /* .type = */ KEY_ECDSA_CERT,
! 263: /* .nid = */ NID_secp384r1,
! 264: /* .cert = */ 1,
! 265: /* .sigonly = */ 0,
! 266: /* .keybits = */ 0,
! 267: /* .funcs = */ &sshkey_ecdsa_funcs,
! 268: };
! 269:
! 270: const struct sshkey_impl sshkey_ecdsa_nistp521_impl = {
! 271: /* .name = */ "ecdsa-sha2-nistp521",
! 272: /* .shortname = */ "ECDSA",
! 273: /* .sigalg = */ NULL,
! 274: /* .type = */ KEY_ECDSA,
! 275: /* .nid = */ NID_secp521r1,
! 276: /* .cert = */ 0,
! 277: /* .sigonly = */ 0,
! 278: /* .keybits = */ 0,
! 279: /* .funcs = */ &sshkey_ecdsa_funcs,
! 280: };
! 281:
! 282: const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl = {
! 283: /* .name = */ "ecdsa-sha2-nistp521-cert-v01@openssh.com",
! 284: /* .shortname = */ "ECDSA-CERT",
! 285: /* .sigalg = */ NULL,
! 286: /* .type = */ KEY_ECDSA_CERT,
! 287: /* .nid = */ NID_secp521r1,
! 288: /* .cert = */ 1,
! 289: /* .sigonly = */ 0,
! 290: /* .keybits = */ 0,
! 291: /* .funcs = */ &sshkey_ecdsa_funcs,
! 292: };
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