Annotation of src/usr.bin/ssh/ssh-rsa.c, Revision 1.3
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"
1.3 ! markus 26: RCSID("$OpenBSD: ssh-rsa.c,v 1.2 2000/12/19 23:17:58 markus Exp $");
1.1 markus 27:
28: #include "ssh.h"
29: #include "xmalloc.h"
30: #include "buffer.h"
31: #include "bufaux.h"
32:
33: #include <openssl/evp.h>
34: #include <openssl/dsa.h>
35: #include <openssl/rsa.h>
36: #include <openssl/err.h>
37:
38: #include "key.h"
39:
40: /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
41: int
42: ssh_rsa_sign(
43: Key *key,
1.2 markus 44: u_char **sigp, int *lenp,
45: u_char *data, int datalen)
1.1 markus 46: {
47: EVP_MD *evp_md = EVP_sha1();
48: EVP_MD_CTX md;
1.2 markus 49: u_char *digest, *sig, *ret;
50: u_int slen, dlen, len;
1.1 markus 51: int ok;
52: Buffer b;
53:
54: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
55: error("ssh_rsa_sign: no RSA key");
56: return -1;
57: }
58: slen = RSA_size(key->rsa);
59: sig = xmalloc(slen);
60:
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:
67: ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
68: memset(digest, 'd', dlen);
69: xfree(digest);
70:
71: if (ok != 1) {
72: int ecode = ERR_get_error();
73: error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
74: xfree(sig);
75: return -1;
76: }
77: if (len < slen) {
78: int diff = slen - len;
79: debug("slen %d > len %d", slen, len);
80: memmove(sig + diff, sig, len);
81: memset(sig, 0, diff);
82: } else if (len > slen) {
83: error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
84: xfree(sig);
85: return -1;
86: }
87: /* encode signature */
88: buffer_init(&b);
89: buffer_put_cstring(&b, "ssh-rsa");
90: buffer_put_string(&b, sig, slen);
91: len = buffer_len(&b);
92: ret = xmalloc(len);
93: memcpy(ret, buffer_ptr(&b), len);
94: buffer_free(&b);
95: memset(sig, 's', slen);
96: xfree(sig);
97:
98: if (lenp != NULL)
99: *lenp = len;
100: if (sigp != NULL)
101: *sigp = ret;
102: debug2("ssh_rsa_sign: done");
103: return 0;
104: }
105:
106: int
107: ssh_rsa_verify(
108: Key *key,
1.2 markus 109: u_char *signature, int signaturelen,
110: u_char *data, int datalen)
1.1 markus 111: {
112: Buffer b;
113: EVP_MD *evp_md = EVP_sha1();
114: EVP_MD_CTX md;
115: char *ktype;
1.2 markus 116: u_char *sigblob, *digest;
117: u_int len, dlen;
1.1 markus 118: int rlen;
119: int ret;
120:
121: if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
122: error("ssh_rsa_verify: no RSA key");
123: return -1;
124: }
125: buffer_init(&b);
126: buffer_append(&b, (char *) signature, signaturelen);
127: ktype = buffer_get_string(&b, NULL);
128: if (strcmp("ssh-rsa", ktype) != 0) {
129: error("ssh_rsa_verify: cannot handle type %s", ktype);
130: buffer_free(&b);
131: xfree(ktype);
132: return -1;
133: }
134: xfree(ktype);
1.2 markus 135: sigblob = (u_char *)buffer_get_string(&b, &len);
1.1 markus 136: rlen = buffer_len(&b);
137: buffer_free(&b);
138: if(rlen != 0) {
139: error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
140: return -1;
141: }
142:
143: dlen = evp_md->md_size;
144: digest = xmalloc(dlen);
145: EVP_DigestInit(&md, evp_md);
146: EVP_DigestUpdate(&md, data, datalen);
147: EVP_DigestFinal(&md, digest, NULL);
148:
149: ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
150: memset(digest, 'd', dlen);
151: xfree(digest);
152: memset(sigblob, 's', len);
153: xfree(sigblob);
154: if (ret == 0) {
155: int ecode = ERR_get_error();
156: error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
157: }
158: debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
159: return ret;
160: }
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