Annotation of src/usr.bin/ssh/ssh-dss.c, Revision 1.14
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"
1.14 ! markus 26: RCSID("$OpenBSD: ssh-dss.c,v 1.13 2002/02/24 19:14:59 markus Exp $");
1.4 markus 27:
28: #include <openssl/bn.h>
29: #include <openssl/evp.h>
1.1 markus 30:
31: #include "xmalloc.h"
32: #include "buffer.h"
33: #include "bufaux.h"
34: #include "compat.h"
1.4 markus 35: #include "log.h"
1.1 markus 36: #include "key.h"
1.6 itojun 37: #include "ssh-dss.h"
1.1 markus 38:
39: #define INTBLOB_LEN 20
40: #define SIGBLOB_LEN (2*INTBLOB_LEN)
41:
42: int
43: ssh_dss_sign(
44: Key *key,
1.13 markus 45: u_char **sigp, u_int *lenp,
46: u_char *data, u_int datalen)
1.1 markus 47: {
48: DSA_SIG *sig;
1.14 ! markus 49: const EVP_MD *evp_md = EVP_sha1();
1.1 markus 50: EVP_MD_CTX md;
1.12 markus 51: u_char *ret, digest[EVP_MAX_MD_SIZE], sigblob[SIGBLOB_LEN];
1.7 markus 52: u_int rlen, slen, len, dlen;
1.1 markus 53: Buffer b;
54:
55: if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
56: error("ssh_dss_sign: no DSA key");
57: return -1;
58: }
59: EVP_DigestInit(&md, evp_md);
60: EVP_DigestUpdate(&md, data, datalen);
1.12 markus 61: EVP_DigestFinal(&md, digest, &dlen);
1.1 markus 62:
1.3 markus 63: sig = DSA_do_sign(digest, dlen, key->dsa);
1.12 markus 64: memset(digest, 'd', sizeof(digest));
1.7 markus 65:
1.1 markus 66: if (sig == NULL) {
1.7 markus 67: error("ssh_dss_sign: sign failed");
68: return -1;
1.1 markus 69: }
70:
71: rlen = BN_num_bytes(sig->r);
72: slen = BN_num_bytes(sig->s);
73: if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
74: error("bad sig size %d %d", rlen, slen);
75: DSA_SIG_free(sig);
76: return -1;
77: }
78: memset(sigblob, 0, SIGBLOB_LEN);
79: BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen);
80: BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen);
81: DSA_SIG_free(sig);
82:
83: if (datafellows & SSH_BUG_SIGBLOB) {
84: ret = xmalloc(SIGBLOB_LEN);
85: memcpy(ret, sigblob, SIGBLOB_LEN);
86: if (lenp != NULL)
87: *lenp = SIGBLOB_LEN;
88: if (sigp != NULL)
89: *sigp = ret;
90: } else {
91: /* ietf-drafts */
92: buffer_init(&b);
93: buffer_put_cstring(&b, "ssh-dss");
94: buffer_put_string(&b, sigblob, SIGBLOB_LEN);
95: len = buffer_len(&b);
96: ret = xmalloc(len);
97: memcpy(ret, buffer_ptr(&b), len);
98: buffer_free(&b);
99: if (lenp != NULL)
100: *lenp = len;
101: if (sigp != NULL)
102: *sigp = ret;
103: }
104: return 0;
105: }
106: int
107: ssh_dss_verify(
108: Key *key,
1.13 markus 109: u_char *signature, u_int signaturelen,
110: u_char *data, u_int datalen)
1.1 markus 111: {
112: DSA_SIG *sig;
1.14 ! markus 113: const EVP_MD *evp_md = EVP_sha1();
1.1 markus 114: EVP_MD_CTX md;
1.12 markus 115: u_char digest[EVP_MAX_MD_SIZE], *sigblob;
1.2 markus 116: u_int len, dlen;
1.7 markus 117: int rlen, ret;
118: Buffer b;
1.1 markus 119:
120: if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
121: error("ssh_dss_verify: no DSA key");
122: return -1;
123: }
124:
125: /* fetch signature */
126: if (datafellows & SSH_BUG_SIGBLOB) {
127: sigblob = signature;
128: len = signaturelen;
129: } else {
130: /* ietf-drafts */
131: char *ktype;
132: buffer_init(&b);
1.8 stevesk 133: buffer_append(&b, signature, signaturelen);
1.1 markus 134: ktype = buffer_get_string(&b, NULL);
135: if (strcmp("ssh-dss", ktype) != 0) {
136: error("ssh_dss_verify: cannot handle type %s", ktype);
137: buffer_free(&b);
1.9 markus 138: xfree(ktype);
1.1 markus 139: return -1;
140: }
1.9 markus 141: xfree(ktype);
1.8 stevesk 142: sigblob = buffer_get_string(&b, &len);
1.1 markus 143: rlen = buffer_len(&b);
1.9 markus 144: buffer_free(&b);
1.10 deraadt 145: if (rlen != 0) {
1.9 markus 146: error("ssh_dss_verify: "
147: "remaining bytes in signature %d", rlen);
148: xfree(sigblob);
1.1 markus 149: return -1;
150: }
151: }
152:
153: if (len != SIGBLOB_LEN) {
154: fatal("bad sigbloblen %d != SIGBLOB_LEN", len);
155: }
156:
157: /* parse signature */
1.11 markus 158: if ((sig = DSA_SIG_new()) == NULL)
159: fatal("ssh_dss_verify: DSA_SIG_new failed");
160: if ((sig->r = BN_new()) == NULL)
161: fatal("ssh_dss_verify: BN_new failed");
162: if ((sig->s = BN_new()) == NULL)
163: fatal("ssh_dss_verify: BN_new failed");
1.1 markus 164: BN_bin2bn(sigblob, INTBLOB_LEN, sig->r);
165: BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s);
166:
167: if (!(datafellows & SSH_BUG_SIGBLOB)) {
168: memset(sigblob, 0, len);
169: xfree(sigblob);
170: }
1.5 stevesk 171:
1.1 markus 172: /* sha1 the data */
173: EVP_DigestInit(&md, evp_md);
174: EVP_DigestUpdate(&md, data, datalen);
1.12 markus 175: EVP_DigestFinal(&md, digest, &dlen);
1.1 markus 176:
177: ret = DSA_do_verify(digest, dlen, sig, key->dsa);
1.12 markus 178: memset(digest, 'd', sizeof(digest));
1.1 markus 179:
180: DSA_SIG_free(sig);
181:
1.7 markus 182: debug("ssh_dss_verify: signature %s",
183: ret == 1 ? "correct" : ret == 0 ? "incorrect" : "error");
1.1 markus 184: return ret;
185: }
![[BACK]](/icons/back.gif){kind=icon}
Return to ssh-dss.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh