Annotation of src/usr.bin/ssh/ssh-rsa.c, Revision 1.6.4.1
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"
1.6.4.1 ! jason 26: RCSID("$OpenBSD: ssh-rsa.c,v 1.6 2001/02/08 19:30:52 itojun 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"
1.1 markus 37:
38: /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
39: int
40: ssh_rsa_sign(
41: Key *key,
1.2 markus 42: u_char **sigp, int *lenp,
43: u_char *data, int datalen)
1.1 markus 44: {
45: EVP_MD *evp_md = EVP_sha1();
46: EVP_MD_CTX md;
1.2 markus 47: u_char *digest, *sig, *ret;
48: u_int slen, dlen, len;
1.1 markus 49: int ok;
50: Buffer b;
51:
52: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
53: error("ssh_rsa_sign: no RSA key");
54: return -1;
55: }
56: slen = RSA_size(key->rsa);
57: sig = xmalloc(slen);
58:
59: dlen = evp_md->md_size;
60: digest = xmalloc(dlen);
61: EVP_DigestInit(&md, evp_md);
62: EVP_DigestUpdate(&md, data, datalen);
63: EVP_DigestFinal(&md, digest, NULL);
64:
65: ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
66: memset(digest, 'd', dlen);
67: xfree(digest);
68:
69: if (ok != 1) {
70: int ecode = ERR_get_error();
71: error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
72: xfree(sig);
73: return -1;
74: }
75: if (len < slen) {
76: int diff = slen - len;
77: debug("slen %d > len %d", slen, len);
78: memmove(sig + diff, sig, len);
79: memset(sig, 0, diff);
80: } else if (len > slen) {
81: error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
82: xfree(sig);
83: return -1;
84: }
85: /* encode signature */
86: buffer_init(&b);
87: buffer_put_cstring(&b, "ssh-rsa");
88: buffer_put_string(&b, sig, slen);
89: len = buffer_len(&b);
90: ret = xmalloc(len);
91: memcpy(ret, buffer_ptr(&b), len);
92: buffer_free(&b);
93: memset(sig, 's', slen);
94: xfree(sig);
95:
96: if (lenp != NULL)
97: *lenp = len;
98: if (sigp != NULL)
99: *sigp = ret;
100: debug2("ssh_rsa_sign: done");
101: return 0;
102: }
103:
104: int
105: ssh_rsa_verify(
106: Key *key,
1.2 markus 107: u_char *signature, int signaturelen,
108: u_char *data, int datalen)
1.1 markus 109: {
110: Buffer b;
111: EVP_MD *evp_md = EVP_sha1();
112: EVP_MD_CTX md;
113: char *ktype;
1.2 markus 114: u_char *sigblob, *digest;
115: u_int len, dlen;
1.1 markus 116: int rlen;
117: int ret;
118:
119: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
120: error("ssh_rsa_verify: no RSA key");
1.4 markus 121: return -1;
122: }
123: if (BN_num_bits(key->rsa->n) < 768) {
124: error("ssh_rsa_verify: n too small: %d bits",
125: BN_num_bits(key->rsa->n));
1.1 markus 126: return -1;
127: }
128: buffer_init(&b);
129: buffer_append(&b, (char *) signature, signaturelen);
130: ktype = buffer_get_string(&b, NULL);
131: if (strcmp("ssh-rsa", ktype) != 0) {
132: error("ssh_rsa_verify: cannot handle type %s", ktype);
133: buffer_free(&b);
134: xfree(ktype);
135: return -1;
136: }
137: xfree(ktype);
1.2 markus 138: sigblob = (u_char *)buffer_get_string(&b, &len);
1.1 markus 139: rlen = buffer_len(&b);
140: buffer_free(&b);
141: if(rlen != 0) {
142: error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
143: return -1;
144: }
145:
146: dlen = evp_md->md_size;
147: digest = xmalloc(dlen);
148: EVP_DigestInit(&md, evp_md);
149: EVP_DigestUpdate(&md, data, datalen);
150: EVP_DigestFinal(&md, digest, NULL);
151:
152: ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
153: memset(digest, 'd', dlen);
154: xfree(digest);
155: memset(sigblob, 's', len);
156: xfree(sigblob);
157: if (ret == 0) {
158: int ecode = ERR_get_error();
159: error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
160: }
161: debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
162: return ret;
163: }
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