Annotation of src/usr.bin/ssh/ssh-rsa.c, Revision 1.10.2.2
1.1 markus 1: /*
2: * Copyright (c) 2000 Markus Friedl. All rights reserved.
3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
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.
12: *
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.
23: */
24:
25: #include "includes.h"
1.10.2.2! jason 26: RCSID("$OpenBSD: ssh-rsa.c,v 1.16 2002/02/24 19:14:59 markus Exp $");
1.5 markus 27:
28: #include <openssl/evp.h>
29: #include <openssl/err.h>
1.1 markus 30:
31: #include "xmalloc.h"
1.5 markus 32: #include "log.h"
1.1 markus 33: #include "buffer.h"
34: #include "bufaux.h"
35: #include "key.h"
1.6 itojun 36: #include "ssh-rsa.h"
1.8 markus 37: #include "compat.h"
1.1 markus 38:
39: /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
40: int
41: ssh_rsa_sign(
42: Key *key,
1.10.2.2! jason 43: u_char **sigp, u_int *lenp,
! 44: u_char *data, u_int datalen)
1.1 markus 45: {
1.7 markus 46: const EVP_MD *evp_md;
1.1 markus 47: EVP_MD_CTX md;
1.10.2.2! jason 48: u_char digest[EVP_MAX_MD_SIZE], *sig, *ret;
1.2 markus 49: u_int slen, dlen, len;
1.7 markus 50: int ok, nid;
1.1 markus 51: Buffer b;
52:
53: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
54: error("ssh_rsa_sign: no RSA key");
55: return -1;
56: }
1.10.2.1 jason 57: if (datafellows & SSH_BUG_SIGBLOB) {
58: error("ssh_rsa_sign: SSH_BUG_SIGBLOB not supported");
59: return -1;
60: }
1.8 markus 61: nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
1.7 markus 62: if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
63: error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
64: return -1;
65: }
1.1 markus 66: EVP_DigestInit(&md, evp_md);
67: EVP_DigestUpdate(&md, data, datalen);
1.10.2.2! jason 68: EVP_DigestFinal(&md, digest, &dlen);
1.1 markus 69:
1.7 markus 70: slen = RSA_size(key->rsa);
71: sig = xmalloc(slen);
72:
73: ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
1.10.2.2! jason 74: memset(digest, 'd', sizeof(digest));
1.1 markus 75:
76: if (ok != 1) {
77: int ecode = ERR_get_error();
78: error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
79: xfree(sig);
80: return -1;
81: }
82: if (len < slen) {
83: int diff = slen - len;
84: debug("slen %d > len %d", slen, len);
85: memmove(sig + diff, sig, len);
86: memset(sig, 0, diff);
87: } else if (len > slen) {
88: error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
89: xfree(sig);
90: return -1;
91: }
92: /* encode signature */
93: buffer_init(&b);
94: buffer_put_cstring(&b, "ssh-rsa");
95: buffer_put_string(&b, sig, slen);
96: len = buffer_len(&b);
97: ret = xmalloc(len);
98: memcpy(ret, buffer_ptr(&b), len);
99: buffer_free(&b);
100: memset(sig, 's', slen);
101: xfree(sig);
102:
103: if (lenp != NULL)
104: *lenp = len;
105: if (sigp != NULL)
106: *sigp = ret;
107: return 0;
108: }
109:
110: int
111: ssh_rsa_verify(
112: Key *key,
1.10.2.2! jason 113: u_char *signature, u_int signaturelen,
! 114: u_char *data, u_int datalen)
1.1 markus 115: {
116: Buffer b;
1.7 markus 117: const EVP_MD *evp_md;
1.1 markus 118: EVP_MD_CTX md;
119: char *ktype;
1.10.2.2! jason 120: u_char digest[EVP_MAX_MD_SIZE], *sigblob;
1.2 markus 121: u_int len, dlen;
1.7 markus 122: int rlen, ret, nid;
1.1 markus 123:
124: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
125: error("ssh_rsa_verify: no RSA key");
1.4 markus 126: return -1;
127: }
1.10.2.1 jason 128: if (datafellows & SSH_BUG_SIGBLOB) {
129: error("ssh_rsa_verify: SSH_BUG_SIGBLOB not supported");
130: return -1;
131: }
1.4 markus 132: if (BN_num_bits(key->rsa->n) < 768) {
133: error("ssh_rsa_verify: n too small: %d bits",
134: BN_num_bits(key->rsa->n));
1.1 markus 135: return -1;
136: }
137: buffer_init(&b);
1.10 stevesk 138: buffer_append(&b, signature, signaturelen);
1.1 markus 139: ktype = buffer_get_string(&b, NULL);
140: if (strcmp("ssh-rsa", ktype) != 0) {
141: error("ssh_rsa_verify: cannot handle type %s", ktype);
142: buffer_free(&b);
143: xfree(ktype);
144: return -1;
145: }
146: xfree(ktype);
1.10 stevesk 147: sigblob = buffer_get_string(&b, &len);
1.1 markus 148: rlen = buffer_len(&b);
149: buffer_free(&b);
1.10.2.2! jason 150: if (rlen != 0) {
1.1 markus 151: error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
1.10.2.1 jason 152: xfree(sigblob);
1.1 markus 153: return -1;
154: }
1.8 markus 155: nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
1.7 markus 156: if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
157: error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
1.10.2.1 jason 158: xfree(sigblob);
1.7 markus 159: return -1;
160: }
1.1 markus 161: EVP_DigestInit(&md, evp_md);
162: EVP_DigestUpdate(&md, data, datalen);
1.10.2.2! jason 163: EVP_DigestFinal(&md, digest, &dlen);
1.1 markus 164:
1.7 markus 165: ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
1.10.2.2! jason 166: memset(digest, 'd', sizeof(digest));
1.1 markus 167: memset(sigblob, 's', len);
168: xfree(sigblob);
169: if (ret == 0) {
170: int ecode = ERR_get_error();
171: error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
172: }
173: debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
174: return ret;
175: }
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