dsa.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * 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.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *      This product includes software developed by Markus Friedl.
  * 4. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * 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("$Id: dsa.c,v 1.4 2000/04/14 10:30:31 markus 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"

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

 Key *
 dsa_serverkey_from_blob(
     char *serverhostkey, int serverhostkeylen)
 {
 	Buffer b;
 	char *ktype;
 	int rlen;
 	DSA *dsa;
 	Key *key;

 	/* fetch & parse DSA/DSS pubkey */
 	key = key_new(KEY_DSA);
 	dsa = key->dsa;
 	buffer_init(&b);
 	buffer_append(&b, serverhostkey, serverhostkeylen);
 	ktype = buffer_get_string(&b, NULL);
 	if (strcmp(KEX_DSS, ktype) != 0) {
 		error("dsa_serverkey_from_blob: cannot handle type  %s", ktype);
 		key_free(key);
 		return NULL;
 	}
 	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_serverkey_from_blob: remaining bytes in serverhostkey %d", rlen);
 	buffer_free(&b);

 	debug("keytype %s", ktype);
 #ifdef DEBUG_DSS
 	DSA_print_fp(stderr, dsa, 8);
 #endif
 	return key;
 }
 DSA *
 dsa_load_private(char *filename)
 {
 	DSA *dsa;
 	BIO *in;

 	in = BIO_new(BIO_s_file());
 	if (in == NULL)
 		fatal("BIO_new failed");
 	if (BIO_read_filename(in, filename) <= 0)
 		fatal("BIO_read failed %s: %s", filename, strerror(errno));
 	fprintf(stderr, "read DSA private key\n");
 	dsa = PEM_read_bio_DSAPrivateKey(in,NULL,NULL,NULL);
 	if (dsa == NULL)
 		fatal("PEM_read_bio_DSAPrivateKey failed %s", filename);
 	BIO_free(in);
 	return dsa;
 }
 Key *
 dsa_get_serverkey(char *filename)
 {
 	Key *k = key_new(KEY_EMPTY);
 	k->type = KEY_DSA;
 	k->dsa = dsa_load_private(filename);
 #ifdef DEBUG_DSS
 	DSA_print_fp(stderr, dsa, 8);
 #endif
 	return k;
 }
 int
 dsa_make_serverkey_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 *hash, int hlen)
 {
 	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, hash, hlen);
 	EVP_DigestFinal(&md, digest, NULL);

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

 	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) {
 		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 *hash, int hlen)
 {
 	Buffer b;
 	unsigned char *digest;
 	DSA_SIG *sig;
 	EVP_MD *evp_md = EVP_sha1();
 	EVP_MD_CTX md;
 	char *ktype;
 	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 && signaturelen != SIGBLOB_LEN) {
 		log("heh? datafellows ssh2 complies with ietf-drafts????");
 		datafellows = 0;
 	}

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

 	/* fetch signature */
 	if (datafellows) {
 		sigblob = signature;
 		len = signaturelen;
 	} else {
 		/* ietf-drafts */
 		buffer_init(&b);
 		buffer_append(&b, (char *) signature, signaturelen);
 		ktype = buffer_get_string(&b, NULL);
 		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);
 	}

 	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) {
 		memset(sigblob, 0, len);
 		xfree(sigblob);
 	}

 	/* sha1 the signed data (== session_id == hash) */
 	digest = xmalloc(evp_md->md_size);
 	EVP_DigestInit(&md, evp_md);
 	EVP_DigestUpdate(&md, hash, hlen);
 	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;
 }
	/*
	* 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.
	* 3. All advertising materials mentioning features or use of this software
	* must display the following acknowledgement:
	* This product includes software developed by Markus Friedl.
	* 4. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* 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("$Id: dsa.c,v 1.4 2000/04/14 10:30:31 markus 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"

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

	Key *
	dsa_serverkey_from_blob(
	char *serverhostkey, int serverhostkeylen)
	{
	Buffer b;
	char *ktype;
	int rlen;
	DSA *dsa;
	Key *key;

	/* fetch & parse DSA/DSS pubkey */
	key = key_new(KEY_DSA);
	dsa = key->dsa;
	buffer_init(&b);
	buffer_append(&b, serverhostkey, serverhostkeylen);
	ktype = buffer_get_string(&b, NULL);
	if (strcmp(KEX_DSS, ktype) != 0) {
	error("dsa_serverkey_from_blob: cannot handle type %s", ktype);
	key_free(key);
	return NULL;
	}
	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_serverkey_from_blob: remaining bytes in serverhostkey %d", rlen);
	buffer_free(&b);

	debug("keytype %s", ktype);
	#ifdef DEBUG_DSS
	DSA_print_fp(stderr, dsa, 8);
	#endif
	return key;
	}
	DSA *
	dsa_load_private(char *filename)
	{
	DSA *dsa;
	BIO *in;

	in = BIO_new(BIO_s_file());
	if (in == NULL)
	fatal("BIO_new failed");
	if (BIO_read_filename(in, filename) <= 0)
	fatal("BIO_read failed %s: %s", filename, strerror(errno));
	fprintf(stderr, "read DSA private key\n");
	dsa = PEM_read_bio_DSAPrivateKey(in,NULL,NULL,NULL);
	if (dsa == NULL)
	fatal("PEM_read_bio_DSAPrivateKey failed %s", filename);
	BIO_free(in);
	return dsa;
	}
	Key *
	dsa_get_serverkey(char *filename)
	{
	Key *k = key_new(KEY_EMPTY);
	k->type = KEY_DSA;
	k->dsa = dsa_load_private(filename);
	#ifdef DEBUG_DSS
	DSA_print_fp(stderr, dsa, 8);
	#endif
	return k;
	}
	int
	dsa_make_serverkey_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 *hash, int hlen)
	{
	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, hash, hlen);
	EVP_DigestFinal(&md, digest, NULL);

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

	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) {
	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 *hash, int hlen)
	{
	Buffer b;
	unsigned char *digest;
	DSA_SIG *sig;
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	char *ktype;
	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 && signaturelen != SIGBLOB_LEN) {
	log("heh? datafellows ssh2 complies with ietf-drafts????");
	datafellows = 0;
	}

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

	/* fetch signature */
	if (datafellows) {
	sigblob = signature;
	len = signaturelen;
	} else {
	/* ietf-drafts */
	buffer_init(&b);
	buffer_append(&b, (char *) signature, signaturelen);
	ktype = buffer_get_string(&b, NULL);
	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);
	}

	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) {
	memset(sigblob, 0, len);
	xfree(sigblob);
	}

	/* sha1 the signed data (== session_id == hash) */
	digest = xmalloc(evp_md->md_size);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, hash, hlen);
	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;
	}