+/* $OpenBSD: ssh-rsa.c,v 1.39 2006/08/03 03:34:42 deraadt Exp $ */
/*
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
*
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
*
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
-RCSID("$OpenBSD: ssh-rsa.c,v 1.2 2000/12/19 23:17:58 markus Exp $");
-#include "ssh.h"
-#include "xmalloc.h"
-#include "buffer.h"
-#include "bufaux.h"
+#include <sys/types.h>
#include <openssl/evp.h>
-#include <openssl/dsa.h>
-#include <openssl/rsa.h>
#include <openssl/err.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "log.h"
+#include "buffer.h"
#include "key.h"
+#include "compat.h"
+#include "ssh.h"
-#define INTBLOB_LEN 20
-#define SIGBLOB_LEN (2*INTBLOB_LEN)
+static int openssh_RSA_verify(int, u_char *, u_int, u_char *, u_int, RSA *);
/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
int
-ssh_rsa_sign(
- Key *key,
- u_char **sigp, int *lenp,
- u_char *data, int datalen)
+ssh_rsa_sign(const Key *key, u_char **sigp, u_int *lenp,
+ const u_char *data, u_int datalen)
{
- EVP_MD *evp_md = EVP_sha1();
+ const EVP_MD *evp_md;
EVP_MD_CTX md;
- u_char *digest, *sig, *ret;
+ u_char digest[EVP_MAX_MD_SIZE], *sig;
u_int slen, dlen, len;
- int ok;
+ int ok, nid;
Buffer b;
if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
error("ssh_rsa_sign: no RSA key");
return -1;
}
- slen = RSA_size(key->rsa);
- sig = xmalloc(slen);
-
- dlen = evp_md->md_size;
- digest = xmalloc(dlen);
+ nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
+ if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
+ error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
+ return -1;
+ }
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, data, datalen);
- EVP_DigestFinal(&md, digest, NULL);
+ EVP_DigestFinal(&md, digest, &dlen);
- ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
- memset(digest, 'd', dlen);
- xfree(digest);
+ slen = RSA_size(key->rsa);
+ sig = xmalloc(slen);
+
+ ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
+ memset(digest, 'd', sizeof(digest));
if (ok != 1) {
int ecode = ERR_get_error();
- error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
+
+ error("ssh_rsa_sign: RSA_sign failed: %s",
+ ERR_error_string(ecode, NULL));
xfree(sig);
return -1;
}
if (len < slen) {
- int diff = slen - len;
- debug("slen %d > len %d", slen, len);
+ u_int diff = slen - len;
+ debug("slen %u > len %u", slen, len);
memmove(sig + diff, sig, len);
memset(sig, 0, diff);
} else if (len > slen) {
- error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
+ error("ssh_rsa_sign: slen %u slen2 %u", slen, len);
xfree(sig);
return -1;
}
buffer_put_cstring(&b, "ssh-rsa");
buffer_put_string(&b, sig, slen);
len = buffer_len(&b);
- ret = xmalloc(len);
- memcpy(ret, buffer_ptr(&b), len);
+ if (lenp != NULL)
+ *lenp = len;
+ if (sigp != NULL) {
+ *sigp = xmalloc(len);
+ memcpy(*sigp, buffer_ptr(&b), len);
+ }
buffer_free(&b);
memset(sig, 's', slen);
xfree(sig);
- if (lenp != NULL)
- *lenp = len;
- if (sigp != NULL)
- *sigp = ret;
- debug2("ssh_rsa_sign: done");
return 0;
}
int
-ssh_rsa_verify(
- Key *key,
- u_char *signature, int signaturelen,
- u_char *data, int datalen)
+ssh_rsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
+ const u_char *data, u_int datalen)
{
Buffer b;
- EVP_MD *evp_md = EVP_sha1();
+ const EVP_MD *evp_md;
EVP_MD_CTX md;
char *ktype;
- u_char *sigblob, *digest;
- u_int len, dlen;
- int rlen;
- int ret;
+ u_char digest[EVP_MAX_MD_SIZE], *sigblob;
+ u_int len, dlen, modlen;
+ int rlen, ret, nid;
if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
error("ssh_rsa_verify: no RSA key");
return -1;
}
+ if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+ error("ssh_rsa_verify: RSA modulus too small: %d < minimum %d bits",
+ BN_num_bits(key->rsa->n), SSH_RSA_MINIMUM_MODULUS_SIZE);
+ return -1;
+ }
buffer_init(&b);
- buffer_append(&b, (char *) signature, signaturelen);
+ buffer_append(&b, signature, signaturelen);
ktype = buffer_get_string(&b, NULL);
if (strcmp("ssh-rsa", ktype) != 0) {
error("ssh_rsa_verify: cannot handle type %s", ktype);
return -1;
}
xfree(ktype);
- sigblob = (u_char *)buffer_get_string(&b, &len);
+ sigblob = buffer_get_string(&b, &len);
rlen = buffer_len(&b);
buffer_free(&b);
- if(rlen != 0) {
+ if (rlen != 0) {
error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
+ xfree(sigblob);
+ return -1;
+ }
+ /* RSA_verify expects a signature of RSA_size */
+ modlen = RSA_size(key->rsa);
+ if (len > modlen) {
+ error("ssh_rsa_verify: len %u > modlen %u", len, modlen);
+ xfree(sigblob);
+ return -1;
+ } else if (len < modlen) {
+ u_int diff = modlen - len;
+ debug("ssh_rsa_verify: add padding: modlen %u > len %u",
+ modlen, len);
+ sigblob = xrealloc(sigblob, 1, modlen);
+ memmove(sigblob + diff, sigblob, len);
+ memset(sigblob, 0, diff);
+ len = modlen;
+ }
+ nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
+ if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
+ error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
+ xfree(sigblob);
return -1;
}
-
- dlen = evp_md->md_size;
- digest = xmalloc(dlen);
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, data, datalen);
- EVP_DigestFinal(&md, digest, NULL);
+ EVP_DigestFinal(&md, digest, &dlen);
- ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
- memset(digest, 'd', dlen);
- xfree(digest);
+ ret = openssh_RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
+ memset(digest, 'd', sizeof(digest));
memset(sigblob, 's', len);
xfree(sigblob);
- if (ret == 0) {
- int ecode = ERR_get_error();
- error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
- }
debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
return ret;
}
+
+/*
+ * See:
+ * http://www.rsasecurity.com/rsalabs/pkcs/pkcs-1/
+ * ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.asn
+ */
+/*
+ * id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
+ * oiw(14) secsig(3) algorithms(2) 26 }
+ */
+static const u_char id_sha1[] = {
+ 0x30, 0x21, /* type Sequence, length 0x21 (33) */
+ 0x30, 0x09, /* type Sequence, length 0x09 */
+ 0x06, 0x05, /* type OID, length 0x05 */
+ 0x2b, 0x0e, 0x03, 0x02, 0x1a, /* id-sha1 OID */
+ 0x05, 0x00, /* NULL */
+ 0x04, 0x14 /* Octet string, length 0x14 (20), followed by sha1 hash */
+};
+/*
+ * id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
+ * rsadsi(113549) digestAlgorithm(2) 5 }
+ */
+static const u_char id_md5[] = {
+ 0x30, 0x20, /* type Sequence, length 0x20 (32) */
+ 0x30, 0x0c, /* type Sequence, length 0x09 */
+ 0x06, 0x08, /* type OID, length 0x05 */
+ 0x2a, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* id-md5 */
+ 0x05, 0x00, /* NULL */
+ 0x04, 0x10 /* Octet string, length 0x10 (16), followed by md5 hash */
+};
+
+static int
+openssh_RSA_verify(int type, u_char *hash, u_int hashlen,
+ u_char *sigbuf, u_int siglen, RSA *rsa)
+{
+ u_int ret, rsasize, oidlen = 0, hlen = 0;
+ int len;
+ const u_char *oid = NULL;
+ u_char *decrypted = NULL;
+
+ ret = 0;
+ switch (type) {
+ case NID_sha1:
+ oid = id_sha1;
+ oidlen = sizeof(id_sha1);
+ hlen = 20;
+ break;
+ case NID_md5:
+ oid = id_md5;
+ oidlen = sizeof(id_md5);
+ hlen = 16;
+ break;
+ default:
+ goto done;
+ }
+ if (hashlen != hlen) {
+ error("bad hashlen");
+ goto done;
+ }
+ rsasize = RSA_size(rsa);
+ if (siglen == 0 || siglen > rsasize) {
+ error("bad siglen");
+ goto done;
+ }
+ decrypted = xmalloc(rsasize);
+ if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa,
+ RSA_PKCS1_PADDING)) < 0) {
+ error("RSA_public_decrypt failed: %s",
+ ERR_error_string(ERR_get_error(), NULL));
+ goto done;
+ }
+ if (len < 0 || (u_int)len != hlen + oidlen) {
+ error("bad decrypted len: %d != %d + %d", len, hlen, oidlen);
+ goto done;
+ }
+ if (memcmp(decrypted, oid, oidlen) != 0) {
+ error("oid mismatch");
+ goto done;
+ }
+ if (memcmp(decrypted + oidlen, hash, hlen) != 0) {
+ error("hash mismatch");
+ goto done;
+ }
+ ret = 1;
+done:
+ if (decrypted)
+ xfree(decrypted);
+ return ret;
+}
andersk / openssh.git / blobdiff