2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 RCSID("$OpenBSD: ssh-rsa.c,v 1.13 2001/11/10 13:22:42 markus Exp $");
28 #include <openssl/evp.h>
29 #include <openssl/err.h>
39 /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
43 u_char **sigp, int *lenp,
44 u_char *data, int datalen)
48 u_char *digest, *sig, *ret;
49 u_int slen, dlen, len;
53 if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
54 error("ssh_rsa_sign: no RSA key");
57 if (datafellows & SSH_BUG_SIGBLOB) {
58 error("ssh_rsa_sign: SSH_BUG_SIGBLOB not supported");
61 nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
62 if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
63 error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
66 dlen = evp_md->md_size;
67 digest = xmalloc(dlen);
68 EVP_DigestInit(&md, evp_md);
69 EVP_DigestUpdate(&md, data, datalen);
70 EVP_DigestFinal(&md, digest, NULL);
72 slen = RSA_size(key->rsa);
75 ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
76 memset(digest, 'd', dlen);
80 int ecode = ERR_get_error();
81 error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
86 int diff = slen - len;
87 debug("slen %d > len %d", slen, len);
88 memmove(sig + diff, sig, len);
90 } else if (len > slen) {
91 error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
95 /* encode signature */
97 buffer_put_cstring(&b, "ssh-rsa");
98 buffer_put_string(&b, sig, slen);
101 memcpy(ret, buffer_ptr(&b), len);
103 memset(sig, 's', slen);
116 u_char *signature, int signaturelen,
117 u_char *data, int datalen)
120 const EVP_MD *evp_md;
123 u_char *sigblob, *digest;
127 if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
128 error("ssh_rsa_verify: no RSA key");
131 if (datafellows & SSH_BUG_SIGBLOB) {
132 error("ssh_rsa_verify: SSH_BUG_SIGBLOB not supported");
135 if (BN_num_bits(key->rsa->n) < 768) {
136 error("ssh_rsa_verify: n too small: %d bits",
137 BN_num_bits(key->rsa->n));
141 buffer_append(&b, signature, signaturelen);
142 ktype = buffer_get_string(&b, NULL);
143 if (strcmp("ssh-rsa", ktype) != 0) {
144 error("ssh_rsa_verify: cannot handle type %s", ktype);
150 sigblob = buffer_get_string(&b, &len);
151 rlen = buffer_len(&b);
154 error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
158 nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
159 if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
160 error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
164 dlen = evp_md->md_size;
165 digest = xmalloc(dlen);
166 EVP_DigestInit(&md, evp_md);
167 EVP_DigestUpdate(&md, data, datalen);
168 EVP_DigestFinal(&md, digest, NULL);
170 ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
171 memset(digest, 'd', dlen);
173 memset(sigblob, 's', len);
176 int ecode = ERR_get_error();
177 error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
179 debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");