Annotation of src/usr.bin/ssh/ssh-rsa.c, Revision 1.7
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"
1.7 ! markus 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: {
1.7 ! markus 45: const EVP_MD *evp_md;
1.1 markus 46: EVP_MD_CTX md;
1.2 markus 47: u_char *digest, *sig, *ret;
48: u_int slen, dlen, len;
1.7 ! markus 49: int ok, nid;
1.1 markus 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: }
1.7 ! markus 56: nid = NID_sha1;
! 57: if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
! 58: error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
! 59: return -1;
! 60: }
1.1 markus 61: dlen = evp_md->md_size;
62: digest = xmalloc(dlen);
63: EVP_DigestInit(&md, evp_md);
64: EVP_DigestUpdate(&md, data, datalen);
65: EVP_DigestFinal(&md, digest, NULL);
66:
1.7 ! markus 67: slen = RSA_size(key->rsa);
! 68: sig = xmalloc(slen);
! 69:
! 70: ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
1.1 markus 71: memset(digest, 'd', dlen);
72: xfree(digest);
73:
74: if (ok != 1) {
75: int ecode = ERR_get_error();
76: error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
77: xfree(sig);
78: return -1;
79: }
80: if (len < slen) {
81: int diff = slen - len;
82: debug("slen %d > len %d", slen, len);
83: memmove(sig + diff, sig, len);
84: memset(sig, 0, diff);
85: } else if (len > slen) {
86: error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
87: xfree(sig);
88: return -1;
89: }
90: /* encode signature */
91: buffer_init(&b);
92: buffer_put_cstring(&b, "ssh-rsa");
93: buffer_put_string(&b, sig, slen);
94: len = buffer_len(&b);
95: ret = xmalloc(len);
96: memcpy(ret, buffer_ptr(&b), len);
97: buffer_free(&b);
98: memset(sig, 's', slen);
99: xfree(sig);
100:
101: if (lenp != NULL)
102: *lenp = len;
103: if (sigp != NULL)
104: *sigp = ret;
105: debug2("ssh_rsa_sign: done");
106: return 0;
107: }
108:
109: int
110: ssh_rsa_verify(
111: Key *key,
1.2 markus 112: u_char *signature, int signaturelen,
113: u_char *data, int datalen)
1.1 markus 114: {
115: Buffer b;
1.7 ! markus 116: const EVP_MD *evp_md;
1.1 markus 117: EVP_MD_CTX md;
118: char *ktype;
1.2 markus 119: u_char *sigblob, *digest;
120: u_int len, dlen;
1.7 ! markus 121: int rlen, ret, nid;
1.1 markus 122:
123: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
124: error("ssh_rsa_verify: no RSA key");
1.4 markus 125: return -1;
126: }
127: if (BN_num_bits(key->rsa->n) < 768) {
128: error("ssh_rsa_verify: n too small: %d bits",
129: BN_num_bits(key->rsa->n));
1.1 markus 130: return -1;
131: }
132: buffer_init(&b);
133: buffer_append(&b, (char *) signature, signaturelen);
134: ktype = buffer_get_string(&b, NULL);
135: if (strcmp("ssh-rsa", ktype) != 0) {
136: error("ssh_rsa_verify: cannot handle type %s", ktype);
137: buffer_free(&b);
138: xfree(ktype);
139: return -1;
140: }
141: xfree(ktype);
1.2 markus 142: sigblob = (u_char *)buffer_get_string(&b, &len);
1.1 markus 143: rlen = buffer_len(&b);
144: buffer_free(&b);
145: if(rlen != 0) {
1.7 ! markus 146: xfree(sigblob);
1.1 markus 147: error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
148: return -1;
149: }
1.7 ! markus 150: nid = NID_sha1;
! 151: if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
! 152: xfree(sigblob);
! 153: error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
! 154: return -1;
! 155: }
1.1 markus 156: dlen = evp_md->md_size;
157: digest = xmalloc(dlen);
158: EVP_DigestInit(&md, evp_md);
159: EVP_DigestUpdate(&md, data, datalen);
160: EVP_DigestFinal(&md, digest, NULL);
161:
1.7 ! markus 162: ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
1.1 markus 163: memset(digest, 'd', dlen);
164: xfree(digest);
165: memset(sigblob, 's', len);
166: xfree(sigblob);
167: if (ret == 0) {
168: int ecode = ERR_get_error();
169: error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
170: }
171: debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
172: return ret;
173: }