[openssh.git] / dsa.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: dsa.c,v 1.11 2000/09/07 20:27:51 deraadt Exp $");

#include "ssh.h"
#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"
#include "compat.h"

#include <openssl/bn.h>
#include <openssl/dh.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/pem.h>

#include <openssl/hmac.h>
#include "kex.h"
#include "key.h"
#include "uuencode.h"

#define INTBLOB_LEN	20
#define SIGBLOB_LEN	(2*INTBLOB_LEN)

Key *
dsa_key_from_blob(char *blob, int blen)
{
	Buffer b;
	char *ktype;
	int rlen;
	DSA *dsa;
	Key *key;

#ifdef DEBUG_DSS
	dump_base64(stderr, blob, blen);
#endif
	/* fetch & parse DSA/DSS pubkey */
	buffer_init(&b);
	buffer_append(&b, blob, blen);
	ktype = buffer_get_string(&b, NULL);
	if (strcmp(KEX_DSS, ktype) != 0) {
		error("dsa_key_from_blob: cannot handle type %s", ktype);
		buffer_free(&b);
		xfree(ktype);
		return NULL;
	}
	key = key_new(KEY_DSA);
	dsa = key->dsa;
	buffer_get_bignum2(&b, dsa->p);
	buffer_get_bignum2(&b, dsa->q);
	buffer_get_bignum2(&b, dsa->g);
	buffer_get_bignum2(&b, dsa->pub_key);
	rlen = buffer_len(&b);
	if(rlen != 0)
		error("dsa_key_from_blob: remaining bytes in key blob %d", rlen);
	buffer_free(&b);
	xfree(ktype);

#ifdef DEBUG_DSS
	DSA_print_fp(stderr, dsa, 8);
#endif
	return key;
}
int
dsa_make_key_blob(Key *key, unsigned char **blobp, unsigned int *lenp)
{
	Buffer b;
	int len;
	unsigned char *buf;

	if (key == NULL || key->type != KEY_DSA)
		return 0;
	buffer_init(&b);
	buffer_put_cstring(&b, KEX_DSS);
	buffer_put_bignum2(&b, key->dsa->p);
	buffer_put_bignum2(&b, key->dsa->q);
	buffer_put_bignum2(&b, key->dsa->g);
	buffer_put_bignum2(&b, key->dsa->pub_key);
	len = buffer_len(&b);
	buf = xmalloc(len);
	memcpy(buf, buffer_ptr(&b), len);
	memset(buffer_ptr(&b), 0, len);
	buffer_free(&b);
	if (lenp != NULL)
		*lenp = len;
	if (blobp != NULL)
		*blobp = buf;
	return len;
}
int
dsa_sign(
    Key *key,
    unsigned char **sigp, int *lenp,
    unsigned char *data, int datalen)
{
	unsigned char *digest;
	unsigned char *ret;
	DSA_SIG *sig;
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	unsigned int rlen;
	unsigned int slen;
	unsigned int len;
	unsigned char sigblob[SIGBLOB_LEN];
	Buffer b;

	if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
		error("dsa_sign: no DSA key");
		return -1;
	}
	digest = xmalloc(evp_md->md_size);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, NULL);

	sig = DSA_do_sign(digest, evp_md->md_size, key->dsa);
	if (sig == NULL) {
		fatal("dsa_sign: cannot sign");
	}

	rlen = BN_num_bytes(sig->r);
	slen = BN_num_bytes(sig->s);
	if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
		error("bad sig size %d %d", rlen, slen);
		DSA_SIG_free(sig);
		return -1;
	}
	debug("sig size %d %d", rlen, slen);

	memset(sigblob, 0, SIGBLOB_LEN);
	BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen);
	BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen);
	DSA_SIG_free(sig);

	if (datafellows & SSH_BUG_SIGBLOB) {
		debug("datafellows");
		ret = xmalloc(SIGBLOB_LEN);
		memcpy(ret, sigblob, SIGBLOB_LEN);
		if (lenp != NULL)
			*lenp = SIGBLOB_LEN;
		if (sigp != NULL)
			*sigp = ret;
	} else {
		/* ietf-drafts */
		buffer_init(&b);
		buffer_put_cstring(&b, KEX_DSS);
		buffer_put_string(&b, sigblob, SIGBLOB_LEN);
		len = buffer_len(&b);
		ret = xmalloc(len);
		memcpy(ret, buffer_ptr(&b), len);
		buffer_free(&b);
		if (lenp != NULL)
			*lenp = len;
		if (sigp != NULL)
			*sigp = ret;
	}
	return 0;
}
int
dsa_verify(
    Key *key,
    unsigned char *signature, int signaturelen,
    unsigned char *data, int datalen)
{
	Buffer b;
	unsigned char *digest;
	DSA_SIG *sig;
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	unsigned char *sigblob;
	char *txt;
	unsigned int len;
	int rlen;
	int ret;

	if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
		error("dsa_verify: no DSA key");
		return -1;
	}

	if (!(datafellows & SSH_BUG_SIGBLOB) &&
	    signaturelen == SIGBLOB_LEN) {
		datafellows |= ~SSH_BUG_SIGBLOB;
		log("autodetect SSH_BUG_SIGBLOB");
	} else if ((datafellows & SSH_BUG_SIGBLOB) &&
	    signaturelen != SIGBLOB_LEN) {
		log("autoremove SSH_BUG_SIGBLOB");
		datafellows &= ~SSH_BUG_SIGBLOB;
	}

	debug("len %d datafellows %d", signaturelen, datafellows);

	/* fetch signature */
	if (datafellows & SSH_BUG_SIGBLOB) {
		sigblob = signature;
		len = signaturelen;
	} else {
		/* ietf-drafts */
		char *ktype;
		buffer_init(&b);
		buffer_append(&b, (char *) signature, signaturelen);
		ktype = buffer_get_string(&b, NULL);
		if (strcmp(KEX_DSS, ktype) != 0) {
			error("dsa_verify: cannot handle type %s", ktype);
			buffer_free(&b);
			return -1;
		}
		sigblob = (unsigned char *)buffer_get_string(&b, &len);
		rlen = buffer_len(&b);
		if(rlen != 0) {
			error("remaining bytes in signature %d", rlen);
			buffer_free(&b);
			return -1;
		}
		buffer_free(&b);
		xfree(ktype);
	}

	if (len != SIGBLOB_LEN) {
		fatal("bad sigbloblen %d != SIGBLOB_LEN", len);
	}

	/* parse signature */
	sig = DSA_SIG_new();
	sig->r = BN_new();
	sig->s = BN_new();
	BN_bin2bn(sigblob, INTBLOB_LEN, sig->r);
	BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s);

	if (!(datafellows & SSH_BUG_SIGBLOB)) {
		memset(sigblob, 0, len);
		xfree(sigblob);
	}
	
	/* sha1 the data */
	digest = xmalloc(evp_md->md_size);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, NULL);

	ret = DSA_do_verify(digest, evp_md->md_size, sig, key->dsa);

	memset(digest, 0, evp_md->md_size);
	xfree(digest);
	DSA_SIG_free(sig);

	switch (ret) {
	case 1:
		txt = "correct";
		break;
	case 0:
		txt = "incorrect";
		break;
	case -1:
	default:
		txt = "error";
		break;
	}
	debug("dsa_verify: signature %s", txt);
	return ret;
}

Key *
dsa_generate_key(unsigned int bits)
{
	DSA *dsa = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
	Key *k;
	if (dsa == NULL) {
		fatal("DSA_generate_parameters failed");
	}
	if (!DSA_generate_key(dsa)) {
		fatal("DSA_generate_keys failed");
	}

	k = key_new(KEY_EMPTY);
	k->type = KEY_DSA;
	k->dsa = dsa;
	return k;
}
Commit	Line	Data
4f8c6159	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.
4f8c6159	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"
bcbf86ec	26	RCSID("$OpenBSD: dsa.c,v 1.11 2000/09/07 20:27:51 deraadt Exp $");
4f8c6159	27
	28	#include "ssh.h"
	29	#include "xmalloc.h"
	30	#include "buffer.h"
	31	#include "bufaux.h"
	32	#include "compat.h"
	33
	34	#include <openssl/bn.h>
	35	#include <openssl/dh.h>
	36	#include <openssl/rsa.h>
	37	#include <openssl/dsa.h>
	38	#include <openssl/evp.h>
	39	#include <openssl/bio.h>
	40	#include <openssl/pem.h>
	41
	42	#include <openssl/hmac.h>
	43	#include "kex.h"
	44	#include "key.h"
a306f2dd	45	#include "uuencode.h"
4f8c6159	46
	47	#define INTBLOB_LEN 20
	48	#define SIGBLOB_LEN (2*INTBLOB_LEN)
	49
	50	Key *
4c8722d9	51	dsa_key_from_blob(char *blob, int blen)
4f8c6159	52	{
	53	Buffer b;
	54	char *ktype;
	55	int rlen;
	56	DSA *dsa;
	57	Key *key;
	58
a306f2dd	59	#ifdef DEBUG_DSS
1d1ffb87	60	dump_base64(stderr, blob, blen);
a306f2dd	61	#endif
4f8c6159	62	/* fetch & parse DSA/DSS pubkey */
4f8c6159	63	buffer_init(&b);
a306f2dd	64	buffer_append(&b, blob, blen);
4f8c6159	65	ktype = buffer_get_string(&b, NULL);
4f8c6159	66	if (strcmp(KEX_DSS, ktype) != 0) {
74fc9186	67	error("dsa_key_from_blob: cannot handle type %s", ktype);
4c8722d9	68	buffer_free(&b);
4c8722d9	69	xfree(ktype);
4f8c6159	70	return NULL;
4f8c6159	71	}
4c8722d9	72	key = key_new(KEY_DSA);
4c8722d9	73	dsa = key->dsa;
4f8c6159	74	buffer_get_bignum2(&b, dsa->p);
	75	buffer_get_bignum2(&b, dsa->q);
	76	buffer_get_bignum2(&b, dsa->g);
	77	buffer_get_bignum2(&b, dsa->pub_key);
	78	rlen = buffer_len(&b);
	79	if(rlen != 0)
a306f2dd	80	error("dsa_key_from_blob: remaining bytes in key blob %d", rlen);
4f8c6159	81	buffer_free(&b);
4c8722d9	82	xfree(ktype);
4f8c6159	83
4f8c6159	84	#ifdef DEBUG_DSS
	85	DSA_print_fp(stderr, dsa, 8);
	86	#endif
	87	return key;
	88	}
4f8c6159	89	int
a306f2dd	90	dsa_make_key_blob(Key key, unsigned char blobp, unsigned int lenp)
4f8c6159	91	{
	92	Buffer b;
	93	int len;
	94	unsigned char *buf;
	95
	96	if (key == NULL \|\| key->type != KEY_DSA)
	97	return 0;
	98	buffer_init(&b);
	99	buffer_put_cstring(&b, KEX_DSS);
	100	buffer_put_bignum2(&b, key->dsa->p);
	101	buffer_put_bignum2(&b, key->dsa->q);
	102	buffer_put_bignum2(&b, key->dsa->g);
	103	buffer_put_bignum2(&b, key->dsa->pub_key);
	104	len = buffer_len(&b);
	105	buf = xmalloc(len);
	106	memcpy(buf, buffer_ptr(&b), len);
	107	memset(buffer_ptr(&b), 0, len);
	108	buffer_free(&b);
	109	if (lenp != NULL)
	110	*lenp = len;
	111	if (blobp != NULL)
	112	*blobp = buf;
	113	return len;
	114	}
	115	int
	116	dsa_sign(
	117	Key *key,
	118	unsigned char *sigp, int lenp,
a306f2dd	119	unsigned char *data, int datalen)
4f8c6159	120	{
	121	unsigned char *digest;
	122	unsigned char *ret;
	123	DSA_SIG *sig;
	124	EVP_MD *evp_md = EVP_sha1();
	125	EVP_MD_CTX md;
	126	unsigned int rlen;
	127	unsigned int slen;
	128	unsigned int len;
	129	unsigned char sigblob[SIGBLOB_LEN];
	130	Buffer b;
	131
	132	if (key == NULL \|\| key->type != KEY_DSA \|\| key->dsa == NULL) {
	133	error("dsa_sign: no DSA key");
	134	return -1;
	135	}
	136	digest = xmalloc(evp_md->md_size);
	137	EVP_DigestInit(&md, evp_md);
a306f2dd	138	EVP_DigestUpdate(&md, data, datalen);
4f8c6159	139	EVP_DigestFinal(&md, digest, NULL);
	140
	141	sig = DSA_do_sign(digest, evp_md->md_size, key->dsa);
a306f2dd	142	if (sig == NULL) {
	143	fatal("dsa_sign: cannot sign");
	144	}
4f8c6159	145
	146	rlen = BN_num_bytes(sig->r);
	147	slen = BN_num_bytes(sig->s);
	148	if (rlen > INTBLOB_LEN \|\| slen > INTBLOB_LEN) {
	149	error("bad sig size %d %d", rlen, slen);
	150	DSA_SIG_free(sig);
	151	return -1;
	152	}
	153	debug("sig size %d %d", rlen, slen);
	154
	155	memset(sigblob, 0, SIGBLOB_LEN);
	156	BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen);
	157	BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen);
	158	DSA_SIG_free(sig);
	159
d0c832f3	160	if (datafellows & SSH_BUG_SIGBLOB) {
4f8c6159	161	debug("datafellows");
	162	ret = xmalloc(SIGBLOB_LEN);
	163	memcpy(ret, sigblob, SIGBLOB_LEN);
	164	if (lenp != NULL)
	165	*lenp = SIGBLOB_LEN;
	166	if (sigp != NULL)
	167	*sigp = ret;
	168	} else {
	169	/* ietf-drafts */
	170	buffer_init(&b);
	171	buffer_put_cstring(&b, KEX_DSS);
	172	buffer_put_string(&b, sigblob, SIGBLOB_LEN);
	173	len = buffer_len(&b);
	174	ret = xmalloc(len);
	175	memcpy(ret, buffer_ptr(&b), len);
	176	buffer_free(&b);
	177	if (lenp != NULL)
	178	*lenp = len;
	179	if (sigp != NULL)
	180	*sigp = ret;
	181	}
	182	return 0;
	183	}
	184	int
	185	dsa_verify(
	186	Key *key,
	187	unsigned char *signature, int signaturelen,
a306f2dd	188	unsigned char *data, int datalen)
4f8c6159	189	{
	190	Buffer b;
	191	unsigned char *digest;
	192	DSA_SIG *sig;
	193	EVP_MD *evp_md = EVP_sha1();
	194	EVP_MD_CTX md;
4f8c6159	195	unsigned char *sigblob;
	196	char *txt;
	197	unsigned int len;
	198	int rlen;
	199	int ret;
	200
	201	if (key == NULL \|\| key->type != KEY_DSA \|\| key->dsa == NULL) {
	202	error("dsa_verify: no DSA key");
	203	return -1;
	204	}
	205
d0c832f3	206	if (!(datafellows & SSH_BUG_SIGBLOB) &&
	207	signaturelen == SIGBLOB_LEN) {
	208	datafellows \|= ~SSH_BUG_SIGBLOB;
	209	log("autodetect SSH_BUG_SIGBLOB");
	210	} else if ((datafellows & SSH_BUG_SIGBLOB) &&
	211	signaturelen != SIGBLOB_LEN) {
	212	log("autoremove SSH_BUG_SIGBLOB");
	213	datafellows &= ~SSH_BUG_SIGBLOB;
4f8c6159	214	}
	215
	216	debug("len %d datafellows %d", signaturelen, datafellows);
	217
	218	/* fetch signature */
d0c832f3	219	if (datafellows & SSH_BUG_SIGBLOB) {
4f8c6159	220	sigblob = signature;
	221	len = signaturelen;
	222	} else {
	223	/* ietf-drafts */
74fc9186	224	char *ktype;
4f8c6159	225	buffer_init(&b);
	226	buffer_append(&b, (char *) signature, signaturelen);
	227	ktype = buffer_get_string(&b, NULL);
74fc9186	228	if (strcmp(KEX_DSS, ktype) != 0) {
	229	error("dsa_verify: cannot handle type %s", ktype);
	230	buffer_free(&b);
	231	return -1;
	232	}
4f8c6159	233	sigblob = (unsigned char *)buffer_get_string(&b, &len);
4f8c6159	234	rlen = buffer_len(&b);
74fc9186	235	if(rlen != 0) {
4f8c6159	236	error("remaining bytes in signature %d", rlen);
74fc9186	237	buffer_free(&b);
	238	return -1;
	239	}
4f8c6159	240	buffer_free(&b);
74fc9186	241	xfree(ktype);
4f8c6159	242	}
	243
	244	if (len != SIGBLOB_LEN) {
	245	fatal("bad sigbloblen %d != SIGBLOB_LEN", len);
	246	}
	247
	248	/* parse signature */
	249	sig = DSA_SIG_new();
	250	sig->r = BN_new();
	251	sig->s = BN_new();
	252	BN_bin2bn(sigblob, INTBLOB_LEN, sig->r);
	253	BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s);
d0c832f3	254
d0c832f3	255	if (!(datafellows & SSH_BUG_SIGBLOB)) {
4f8c6159	256	memset(sigblob, 0, len);
	257	xfree(sigblob);
	258	}
	259
a306f2dd	260	/* sha1 the data */
4f8c6159	261	digest = xmalloc(evp_md->md_size);
4f8c6159	262	EVP_DigestInit(&md, evp_md);
a306f2dd	263	EVP_DigestUpdate(&md, data, datalen);
4f8c6159	264	EVP_DigestFinal(&md, digest, NULL);
	265
	266	ret = DSA_do_verify(digest, evp_md->md_size, sig, key->dsa);
	267
	268	memset(digest, 0, evp_md->md_size);
	269	xfree(digest);
	270	DSA_SIG_free(sig);
	271
	272	switch (ret) {
	273	case 1:
	274	txt = "correct";
	275	break;
	276	case 0:
	277	txt = "incorrect";
	278	break;
	279	case -1:
	280	default:
	281	txt = "error";
	282	break;
	283	}
	284	debug("dsa_verify: signature %s", txt);
	285	return ret;
	286	}
a306f2dd	287
	288	Key *
	289	dsa_generate_key(unsigned int bits)
	290	{
	291	DSA *dsa = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
	292	Key *k;
	293	if (dsa == NULL) {
	294	fatal("DSA_generate_parameters failed");
	295	}
	296	if (!DSA_generate_key(dsa)) {
	297	fatal("DSA_generate_keys failed");
	298	}
	299
	300	k = key_new(KEY_EMPTY);
	301	k->type = KEY_DSA;
	302	k->dsa = dsa;
	303	return k;
	304	}