Annotation of src/usr.bin/ssh/ssh-ecdsa.c, Revision 1.11
1.11 ! djm 1: /* $OpenBSD: ssh-ecdsa.c,v 1.10 2014/02/03 23:28:00 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:
1.11 ! djm 42: /* ARGSUSED */
1.1 djm 43: int
1.11 ! djm 44: ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
! 45: const u_char *data, size_t datalen, u_int compat)
1.1 djm 46: {
1.11 ! djm 47: ECDSA_SIG *sig = NULL;
1.8 djm 48: int hash_alg;
49: u_char digest[SSH_DIGEST_MAX_LENGTH];
1.11 ! djm 50: size_t len, dlen;
! 51: struct sshbuf *b = NULL, *bb = NULL;
! 52: int ret = SSH_ERR_INTERNAL_ERROR;
1.1 djm 53:
1.11 ! djm 54: if (lenp != NULL)
! 55: *lenp = 0;
! 56: if (sigp != NULL)
! 57: *sigp = NULL;
! 58:
! 59: if (key == NULL || key->ecdsa == NULL ||
! 60: sshkey_type_plain(key->type) != KEY_ECDSA)
! 61: return SSH_ERR_INVALID_ARGUMENT;
! 62:
! 63: if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
! 64: (dlen = ssh_digest_bytes(hash_alg)) == 0)
! 65: return SSH_ERR_INTERNAL_ERROR;
! 66: if ((ret = ssh_digest_memory(hash_alg, data, datalen,
! 67: digest, sizeof(digest))) != 0)
! 68: goto out;
! 69:
! 70: if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) {
! 71: ret = SSH_ERR_LIBCRYPTO_ERROR;
! 72: goto out;
! 73: }
! 74:
! 75: if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
! 76: ret = SSH_ERR_ALLOC_FAIL;
! 77: goto out;
! 78: }
! 79: if ((ret = sshbuf_put_bignum2(bb, sig->r)) != 0 ||
! 80: (ret = sshbuf_put_bignum2(bb, sig->s)) != 0)
! 81: goto out;
! 82: if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 ||
! 83: (ret = sshbuf_put_stringb(b, bb)) != 0)
! 84: goto out;
! 85: len = sshbuf_len(b);
! 86: if (sigp != NULL) {
! 87: if ((*sigp = malloc(len)) == NULL) {
! 88: ret = SSH_ERR_ALLOC_FAIL;
! 89: goto out;
! 90: }
! 91: memcpy(*sigp, sshbuf_ptr(b), len);
1.1 djm 92: }
93: if (lenp != NULL)
94: *lenp = len;
1.11 ! djm 95: ret = 0;
! 96: out:
! 97: explicit_bzero(digest, sizeof(digest));
! 98: if (b != NULL)
! 99: sshbuf_free(b);
! 100: if (bb != NULL)
! 101: sshbuf_free(bb);
! 102: if (sig != NULL)
! 103: ECDSA_SIG_free(sig);
! 104: return ret;
! 105: }
1.1 djm 106:
1.11 ! djm 107: /* ARGSUSED */
1.1 djm 108: int
1.11 ! djm 109: ssh_ecdsa_verify(const struct sshkey *key,
! 110: const u_char *signature, size_t signaturelen,
! 111: const u_char *data, size_t datalen, u_int compat)
1.1 djm 112: {
1.11 ! djm 113: ECDSA_SIG *sig = NULL;
1.8 djm 114: int hash_alg;
1.11 ! djm 115: u_char digest[SSH_DIGEST_MAX_LENGTH];
! 116: size_t dlen;
! 117: int ret = SSH_ERR_INTERNAL_ERROR;
! 118: struct sshbuf *b = NULL, *sigbuf = NULL;
! 119: char *ktype = NULL;
! 120:
! 121: if (key == NULL || key->ecdsa == NULL ||
! 122: sshkey_type_plain(key->type) != KEY_ECDSA)
! 123: return SSH_ERR_INVALID_ARGUMENT;
! 124:
! 125: if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
! 126: (dlen = ssh_digest_bytes(hash_alg)) == 0)
! 127: return SSH_ERR_INTERNAL_ERROR;
1.7 djm 128:
1.1 djm 129: /* fetch signature */
1.11 ! djm 130: if ((b = sshbuf_from(signature, signaturelen)) == NULL)
! 131: return SSH_ERR_ALLOC_FAIL;
! 132: if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
! 133: sshbuf_froms(b, &sigbuf) != 0) {
! 134: ret = SSH_ERR_INVALID_FORMAT;
! 135: goto out;
! 136: }
! 137: if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
! 138: ret = SSH_ERR_KEY_TYPE_MISMATCH;
! 139: goto out;
! 140: }
! 141: if (sshbuf_len(b) != 0) {
! 142: ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
! 143: goto out;
1.1 djm 144: }
145:
146: /* parse signature */
1.11 ! djm 147: if ((sig = ECDSA_SIG_new()) == NULL) {
! 148: ret = SSH_ERR_ALLOC_FAIL;
! 149: goto out;
! 150: }
! 151: if (sshbuf_get_bignum2(sigbuf, sig->r) != 0 ||
! 152: sshbuf_get_bignum2(sigbuf, sig->s) != 0) {
! 153: ret = SSH_ERR_INVALID_FORMAT;
! 154: goto out;
! 155: }
! 156: if (sshbuf_len(sigbuf) != 0) {
! 157: ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
! 158: goto out;
! 159: }
! 160: if ((ret = ssh_digest_memory(hash_alg, data, datalen,
! 161: digest, sizeof(digest))) != 0)
! 162: goto out;
! 163:
! 164: switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) {
! 165: case 1:
! 166: ret = 0;
! 167: break;
! 168: case 0:
! 169: ret = SSH_ERR_SIGNATURE_INVALID;
! 170: goto out;
! 171: default:
! 172: ret = SSH_ERR_LIBCRYPTO_ERROR;
! 173: goto out;
1.8 djm 174: }
1.1 djm 175:
1.11 ! djm 176: out:
1.9 djm 177: explicit_bzero(digest, sizeof(digest));
1.11 ! djm 178: if (sigbuf != NULL)
! 179: sshbuf_free(sigbuf);
! 180: if (b != NULL)
! 181: sshbuf_free(b);
! 182: if (sig != NULL)
! 183: ECDSA_SIG_free(sig);
! 184: free(ktype);
1.1 djm 185: return ret;
186: }
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