[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 1.5 2001/01/21 19:05:58 markus Exp $");

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

#include "xmalloc.h"
#include "log.h"
#include "buffer.h"
#include "bufaux.h"
#include "key.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"
42f11eb2	26	RCSID("$OpenBSD: ssh-rsa.c,v 1.5 2001/01/21 19:05:58 markus 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"
fa08c86b	36
fa08c86b	37	/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
	38	int
	39	ssh_rsa_sign(
	40	Key *key,
1e3b8b07	41	u_char *sigp, int lenp,
1e3b8b07	42	u_char *data, int datalen)
fa08c86b	43	{
	44	EVP_MD *evp_md = EVP_sha1();
	45	EVP_MD_CTX md;
1e3b8b07	46	u_char digest, sig, *ret;
1e3b8b07	47	u_int slen, dlen, len;
fa08c86b	48	int ok;
	49	Buffer b;
	50
	51	if (key == NULL \|\| key->type != KEY_RSA \|\| key->rsa == NULL) {
	52	error("ssh_rsa_sign: no RSA key");
	53	return -1;
	54	}
	55	slen = RSA_size(key->rsa);
	56	sig = xmalloc(slen);
	57
	58	dlen = evp_md->md_size;
	59	digest = xmalloc(dlen);
	60	EVP_DigestInit(&md, evp_md);
	61	EVP_DigestUpdate(&md, data, datalen);
	62	EVP_DigestFinal(&md, digest, NULL);
	63
	64	ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
	65	memset(digest, 'd', dlen);
	66	xfree(digest);
	67
	68	if (ok != 1) {
	69	int ecode = ERR_get_error();
	70	error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
	71	xfree(sig);
	72	return -1;
	73	}
	74	if (len < slen) {
	75	int diff = slen - len;
	76	debug("slen %d > len %d", slen, len);
	77	memmove(sig + diff, sig, len);
	78	memset(sig, 0, diff);
	79	} else if (len > slen) {
	80	error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
	81	xfree(sig);
	82	return -1;
	83	}
	84	/* encode signature */
	85	buffer_init(&b);
	86	buffer_put_cstring(&b, "ssh-rsa");
	87	buffer_put_string(&b, sig, slen);
	88	len = buffer_len(&b);
	89	ret = xmalloc(len);
	90	memcpy(ret, buffer_ptr(&b), len);
	91	buffer_free(&b);
	92	memset(sig, 's', slen);
	93	xfree(sig);
	94
	95	if (lenp != NULL)
	96	*lenp = len;
	97	if (sigp != NULL)
	98	*sigp = ret;
	99	debug2("ssh_rsa_sign: done");
	100	return 0;
	101	}
	102
	103	int
	104	ssh_rsa_verify(
	105	Key *key,
1e3b8b07	106	u_char *signature, int signaturelen,
1e3b8b07	107	u_char *data, int datalen)
fa08c86b	108	{
	109	Buffer b;
	110	EVP_MD *evp_md = EVP_sha1();
	111	EVP_MD_CTX md;
	112	char *ktype;
1e3b8b07	113	u_char sigblob, digest;
1e3b8b07	114	u_int len, dlen;
fa08c86b	115	int rlen;
	116	int ret;
	117
	118	if (key == NULL \|\| key->type != KEY_RSA \|\| key->rsa == NULL) {
	119	error("ssh_rsa_verify: no RSA key");
	120	return -1;
	121	}
b5c334cc	122	if (BN_num_bits(key->rsa->n) < 768) {
	123	error("ssh_rsa_verify: n too small: %d bits",
	124	BN_num_bits(key->rsa->n));
	125	return -1;
	126	}
fa08c86b	127	buffer_init(&b);
	128	buffer_append(&b, (char *) signature, signaturelen);
	129	ktype = buffer_get_string(&b, NULL);
	130	if (strcmp("ssh-rsa", ktype) != 0) {
	131	error("ssh_rsa_verify: cannot handle type %s", ktype);
	132	buffer_free(&b);
	133	xfree(ktype);
	134	return -1;
	135	}
	136	xfree(ktype);
1e3b8b07	137	sigblob = (u_char *)buffer_get_string(&b, &len);
fa08c86b	138	rlen = buffer_len(&b);
	139	buffer_free(&b);
	140	if(rlen != 0) {
	141	error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
	142	return -1;
	143	}
	144
	145	dlen = evp_md->md_size;
	146	digest = xmalloc(dlen);
	147	EVP_DigestInit(&md, evp_md);
	148	EVP_DigestUpdate(&md, data, datalen);
	149	EVP_DigestFinal(&md, digest, NULL);
	150
	151	ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
	152	memset(digest, 'd', dlen);
	153	xfree(digest);
	154	memset(sigblob, 's', len);
	155	xfree(sigblob);
	156	if (ret == 0) {
	157	int ecode = ERR_get_error();
	158	error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
	159	}
	160	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
	161	return ret;
	162	}