src/mac.c

/* Copyright (c) 2004-2005, Sara Golemon <sarag@libssh2.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided
 * that the following conditions are met:
 *
 *   Redistributions of source code must retain the above
 *   copyright notice, this list of conditions and the
 *   following disclaimer.
 *
 *   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.
 *
 *   Neither the name of the copyright holder nor the names
 *   of any other contributors may be used to endorse or
 *   promote products derived from this software without
 *   specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "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 COPYRIGHT OWNER OR
 * CONTRIBUTORS 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 "libssh2_priv.h"
#include <openssl/hmac.h>

#ifdef LIBSSH2_MAC_NONE
/* {{{ libssh2_mac_none_MAC
 * Minimalist MAC: No MAC
 */
static int libssh2_mac_none_MAC(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno, 
														  const unsigned char *packet, unsigned long packet_len,
														  const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	return 0;
}
/* }}} */


static LIBSSH2_MAC_METHOD libssh2_mac_method_none = {
	"none",
	0,
	0,
	NULL,
	libssh2_mac_none_MAC,
	NULL
};
#endif /* LIBSSH2_MAC_NONE */

/* {{{ libssh2_mac_method_common_init
 * Initialize simple mac methods
 */
static int libssh2_mac_method_common_init(LIBSSH2_SESSION *session, unsigned char *key, int *free_key, void **abstract)
{
	*abstract = key;
	*free_key = 0;

	return 0;
}
/* }}} */

/* {{{ libssh2_mac_method_common_dtor
 * Cleanup simple mac methods
 */
static int libssh2_mac_method_common_dtor(LIBSSH2_SESSION *session, void **abstract)
{
	if (*abstract) {
		LIBSSH2_FREE(session, *abstract);
	}
	*abstract = NULL;

	return 0;
}
/* }}} */

/* {{{ libssh2_mac_method_hmac_sha1_hash
 * Calculate hash using full sha1 value
 */
static int libssh2_mac_method_hmac_sha1_hash(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno,
																	   const unsigned char *packet, unsigned long packet_len, 
																	   const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	HMAC_CTX ctx;
	unsigned char seqno_buf[4];

	libssh2_htonu32(seqno_buf, seqno);

	HMAC_Init(&ctx, *abstract, 20, EVP_sha1());
	HMAC_Update(&ctx, seqno_buf, 4);
	HMAC_Update(&ctx, packet, packet_len);
	if (addtl && addtl_len) {
		HMAC_Update(&ctx, addtl, addtl_len);
	}
	HMAC_Final(&ctx, buf, NULL);
	HMAC_cleanup(&ctx);

	return 0;
}
/* }}} */

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_sha1 = {
	"hmac-sha1",
	20,
	20,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_sha1_hash,
	libssh2_mac_method_common_dtor,
};

/* {{{ libssh2_mac_method_hmac_sha1_96_hash
 * Calculate hash using first 96 bits of sha1 value
 */
static int libssh2_mac_method_hmac_sha1_96_hash(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno,
																		  const unsigned char *packet, unsigned long packet_len, 
																		  const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	char temp[SHA_DIGEST_LENGTH];

	libssh2_mac_method_hmac_sha1_hash(session, temp, seqno, packet, packet_len, addtl, addtl_len, abstract);
	memcpy(buf, temp, 96 / 8);

	return 0;
}
/* }}} */

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_sha1_96 = {
	"hmac-sha1-96",
	12,
	20,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_sha1_96_hash,
	libssh2_mac_method_common_dtor,
};

/* {{{ libssh2_mac_method_hmac_md5_hash
 * Calculate hash using full md5 value
 */
static int libssh2_mac_method_hmac_md5_hash(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno,
																	  const unsigned char *packet, unsigned long packet_len, 
																	  const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	HMAC_CTX ctx;
	unsigned char seqno_buf[4];

	libssh2_htonu32(seqno_buf, seqno);

	HMAC_Init(&ctx, *abstract, 16, EVP_md5());
	HMAC_Update(&ctx, seqno_buf, 4);
	HMAC_Update(&ctx, packet, packet_len);
	if (addtl && addtl_len) {
		HMAC_Update(&ctx, addtl, addtl_len);
	}
	HMAC_Final(&ctx, buf, NULL);
	HMAC_cleanup(&ctx);

	return 0;
}
/* }}} */

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_md5 = {
	"hmac-md5",
	16,
	16,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_md5_hash,
	libssh2_mac_method_common_dtor,
};

/* {{{ libssh2_mac_method_hmac_md5_96_hash
 * Calculate hash using first 96 bits of md5 value
 */
static int libssh2_mac_method_hmac_md5_96_hash(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno,
																		 const unsigned char *packet, unsigned long packet_len,
																		 const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	char temp[MD5_DIGEST_LENGTH];

	libssh2_mac_method_hmac_md5_hash(session, temp, seqno, packet, packet_len, addtl, addtl_len, abstract);
	memcpy(buf, temp, 96 / 8);

	return 0;
}
/* }}} */

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_md5_96 = {
	"hmac-md5-96",
	12,
	16,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_md5_96_hash,
	libssh2_mac_method_common_dtor,
};

#ifndef OPENSSL_NO_RIPEMD
/* {{{ libssh2_mac_method_hmac_ripemd160_hash
 * Calculate hash using ripemd160 value
 */
static int libssh2_mac_method_hmac_ripemd160_hash(LIBSSH2_SESSION *session, unsigned char *buf, unsigned long seqno,
																			const unsigned char *packet, unsigned long packet_len,
																			const unsigned char *addtl, unsigned long addtl_len, void **abstract)
{
	HMAC_CTX ctx;
	unsigned char seqno_buf[4];

	libssh2_htonu32(seqno_buf, seqno);

	HMAC_Init(&ctx, *abstract, 20, EVP_ripemd160());
	HMAC_Update(&ctx, seqno_buf, 4);
	HMAC_Update(&ctx, packet, packet_len);
	if (addtl && addtl_len) {
		HMAC_Update(&ctx, addtl, addtl_len);
	}
	HMAC_Final(&ctx, buf, NULL);
	HMAC_cleanup(&ctx);

	return 0;
}
/* }}} */

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_ripemd160 = {
	"hmac-ripemd160",
	20,
	20,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_ripemd160_hash,
	libssh2_mac_method_common_dtor,
};

static LIBSSH2_MAC_METHOD libssh2_mac_method_hmac_ripemd160_openssh_com = {
	"hmac-ripemd160@openssh.com",
	20,
	20,
	libssh2_mac_method_common_init,
	libssh2_mac_method_hmac_ripemd160_hash,
	libssh2_mac_method_common_dtor,
};
#endif /* ! OPENSSL_NO_RIPEMD */

static LIBSSH2_MAC_METHOD *_libssh2_mac_methods[] = {
	&libssh2_mac_method_hmac_sha1,
	&libssh2_mac_method_hmac_sha1_96,
	&libssh2_mac_method_hmac_md5,
	&libssh2_mac_method_hmac_md5_96,
#ifndef OPENSSL_NO_RIPEMD
	&libssh2_mac_method_hmac_ripemd160,
	&libssh2_mac_method_hmac_ripemd160_openssh_com,
#endif /* ! OPENSSL_NO_RIPEMD */
#ifdef LIBSSH2_MAC_NONE
	&libssh2_mac_method_none,
#endif /* LIBSSH2_MAC_NONE */
	NULL
};

LIBSSH2_MAC_METHOD **libssh2_mac_methods(void) {
	return _libssh2_mac_methods;
}