[openssh.git] / ssh-rsa.c

/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * 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.
 *
 * 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.
 */

#include "includes.h"
RCSID("$OpenBSD: ssh-rsa.c,v 1.6 2001/02/08 19:30:52 itojun Exp $");

#include <openssl/evp.h>
#include <openssl/err.h>

#include "xmalloc.h"
#include "log.h"
#include "buffer.h"
#include "bufaux.h"
#include "key.h"
#include "ssh-rsa.h"

/* 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)
{
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	u_char *digest, *sig, *ret;
	u_int slen, dlen, len;
	int ok;
	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);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, NULL);

	ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
	memset(digest, 'd', dlen);
	xfree(digest);

	if (ok != 1) {
		int ecode = ERR_get_error();
		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);
		memmove(sig + diff, sig, len);
		memset(sig, 0, diff);
	} else if (len > slen) {
		error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
		xfree(sig);
		return -1;
	}
	/* encode signature */
	buffer_init(&b);
	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);
	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)
{
	Buffer b;
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	char *ktype;
	u_char *sigblob, *digest;
	u_int len, dlen;
	int rlen;
	int ret;

	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) < 768) {
		error("ssh_rsa_verify: n too small: %d bits",
		    BN_num_bits(key->rsa->n));
		return -1;
	}
	buffer_init(&b);
	buffer_append(&b, (char *) signature, signaturelen);
	ktype = buffer_get_string(&b, NULL);
	if (strcmp("ssh-rsa", ktype) != 0) {
		error("ssh_rsa_verify: cannot handle type %s", ktype);
		buffer_free(&b);
		xfree(ktype);
		return -1;
	}
	xfree(ktype);
	sigblob = (u_char *)buffer_get_string(&b, &len);
	rlen = buffer_len(&b);
	buffer_free(&b);
	if(rlen != 0) {
		error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
		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);

	ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
	memset(digest, 'd', dlen);
	xfree(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;
}
Commit	Line	Data
fa08c86b	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"
5ca51e19	26	RCSID("$OpenBSD: ssh-rsa.c,v 1.6 2001/02/08 19:30:52 itojun Exp $");
fa08c86b	27
fa08c86b	28	#include <openssl/evp.h>
fa08c86b	29	#include <openssl/err.h>
fa08c86b	30
42f11eb2	31	#include "xmalloc.h"
	32	#include "log.h"
	33	#include "buffer.h"
	34	#include "bufaux.h"
fa08c86b	35	#include "key.h"
5ca51e19	36	#include "ssh-rsa.h"
fa08c86b	37
fa08c86b	38	/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
	39	int
	40	ssh_rsa_sign(
	41	Key *key,
1e3b8b07	42	u_char *sigp, int lenp,
1e3b8b07	43	u_char *data, int datalen)
fa08c86b	44	{
	45	EVP_MD *evp_md = EVP_sha1();
	46	EVP_MD_CTX md;
1e3b8b07	47	u_char digest, sig, *ret;
1e3b8b07	48	u_int slen, dlen, len;
fa08c86b	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,
1e3b8b07	107	u_char *signature, int signaturelen,
1e3b8b07	108	u_char *data, int datalen)
fa08c86b	109	{
	110	Buffer b;
	111	EVP_MD *evp_md = EVP_sha1();
	112	EVP_MD_CTX md;
	113	char *ktype;
1e3b8b07	114	u_char sigblob, digest;
1e3b8b07	115	u_int len, dlen;
fa08c86b	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");
	121	return -1;
	122	}
b5c334cc	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));
	126	return -1;
	127	}
fa08c86b	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);
1e3b8b07	138	sigblob = (u_char *)buffer_get_string(&b, &len);
fa08c86b	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	}