sl@0: /* rsa_pss.c */
sl@0: /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
sl@0:  * project 2005.
sl@0:  */
sl@0: /* ====================================================================
sl@0:  * Copyright (c) 2005 The OpenSSL Project.  All rights reserved.
sl@0:  *
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  *
sl@0:  * 1. Redistributions of source code must retain the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer. 
sl@0:  *
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in
sl@0:  *    the documentation and/or other materials provided with the
sl@0:  *    distribution.
sl@0:  *
sl@0:  * 3. All advertising materials mentioning features or use of this
sl@0:  *    software must display the following acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
sl@0:  *
sl@0:  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
sl@0:  *    endorse or promote products derived from this software without
sl@0:  *    prior written permission. For written permission, please contact
sl@0:  *    licensing@OpenSSL.org.
sl@0:  *
sl@0:  * 5. Products derived from this software may not be called "OpenSSL"
sl@0:  *    nor may "OpenSSL" appear in their names without prior written
sl@0:  *    permission of the OpenSSL Project.
sl@0:  *
sl@0:  * 6. Redistributions of any form whatsoever must retain the following
sl@0:  *    acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
sl@0:  *
sl@0:  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
sl@0:  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sl@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
sl@0:  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
sl@0:  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
sl@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
sl@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
sl@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
sl@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
sl@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
sl@0:  * ====================================================================
sl@0:  *
sl@0:  * This product includes cryptographic software written by Eric Young
sl@0:  * (eay@cryptsoft.com).  This product includes software written by Tim
sl@0:  * Hudson (tjh@cryptsoft.com).
sl@0:  *
sl@0:  */
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include "cryptlib.h"
sl@0: #include <openssl/bn.h>
sl@0: #include <openssl/rsa.h>
sl@0: #include <openssl/evp.h>
sl@0: #include <openssl/rand.h>
sl@0: #include <openssl/sha.h>
sl@0: 
sl@0: static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
sl@0: 
sl@0: #if defined(_MSC_VER) && defined(_ARM_)
sl@0: #pragma optimize("g", off)
sl@0: #endif
sl@0: 
sl@0: EXPORT_C int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
sl@0: 			const EVP_MD *Hash, const unsigned char *EM, int sLen)
sl@0: 	{
sl@0: 	int i;
sl@0: 	int ret = 0;
sl@0: 	int hLen, maskedDBLen, MSBits, emLen;
sl@0: 	const unsigned char *H;
sl@0: 	unsigned char *DB = NULL;
sl@0: 	EVP_MD_CTX ctx;
sl@0: 	unsigned char H_[EVP_MAX_MD_SIZE];
sl@0: 
sl@0: 	hLen = EVP_MD_size(Hash);
sl@0: 	/*
sl@0: 	 * Negative sLen has special meanings:
sl@0: 	 *	-1	sLen == hLen
sl@0: 	 *	-2	salt length is autorecovered from signature
sl@0: 	 *	-N	reserved
sl@0: 	 */
sl@0: 	if      (sLen == -1)	sLen = hLen;
sl@0: 	else if (sLen == -2)	sLen = -2;
sl@0: 	else if (sLen < -2)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
sl@0: 	emLen = RSA_size(rsa);
sl@0: 	if (EM[0] & (0xFF << MSBits))
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	if (MSBits == 0)
sl@0: 		{
sl@0: 		EM++;
sl@0: 		emLen--;
sl@0: 		}
sl@0: 	if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	if (EM[emLen - 1] != 0xbc)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	maskedDBLen = emLen - hLen - 1;
sl@0: 	H = EM + maskedDBLen;
sl@0: 	DB = OPENSSL_malloc(maskedDBLen);
sl@0: 	if (!DB)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash);
sl@0: 	for (i = 0; i < maskedDBLen; i++)
sl@0: 		DB[i] ^= EM[i];
sl@0: 	if (MSBits)
sl@0: 		DB[0] &= 0xFF >> (8 - MSBits);
sl@0: 	for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
sl@0: 	if (DB[i++] != 0x1)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	if (sLen >= 0 && (maskedDBLen - i) != sLen)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	EVP_MD_CTX_init(&ctx);
sl@0: 	EVP_DigestInit_ex(&ctx, Hash, NULL);
sl@0: 	EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
sl@0: 	EVP_DigestUpdate(&ctx, mHash, hLen);
sl@0: 	if (maskedDBLen - i)
sl@0: 		EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i);
sl@0: 	EVP_DigestFinal(&ctx, H_, NULL);
sl@0: 	EVP_MD_CTX_cleanup(&ctx);
sl@0: 	if (memcmp(H_, H, hLen))
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
sl@0: 		ret = 0;
sl@0: 		}
sl@0: 	else 
sl@0: 		ret = 1;
sl@0: 
sl@0: 	err:
sl@0: 	if (DB)
sl@0: 		OPENSSL_free(DB);
sl@0: 
sl@0: 	return ret;
sl@0: 
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
sl@0: 			const unsigned char *mHash,
sl@0: 			const EVP_MD *Hash, int sLen)
sl@0: 	{
sl@0: 	int i;
sl@0: 	int ret = 0;
sl@0: 	int hLen, maskedDBLen, MSBits, emLen;
sl@0: 	unsigned char *H, *salt = NULL, *p;
sl@0: 	EVP_MD_CTX ctx;
sl@0: 
sl@0: 	hLen = EVP_MD_size(Hash);
sl@0: 	/*
sl@0: 	 * Negative sLen has special meanings:
sl@0: 	 *	-1	sLen == hLen
sl@0: 	 *	-2	salt length is maximized
sl@0: 	 *	-N	reserved
sl@0: 	 */
sl@0: 	if      (sLen == -1)	sLen = hLen;
sl@0: 	else if (sLen == -2)	sLen = -2;
sl@0: 	else if (sLen < -2)
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
sl@0: 	emLen = RSA_size(rsa);
sl@0: 	if (MSBits == 0)
sl@0: 		{
sl@0: 		*EM++ = 0;
sl@0: 		emLen--;
sl@0: 		}
sl@0: 	if (sLen == -2)
sl@0: 		{
sl@0: 		sLen = emLen - hLen - 2;
sl@0: 		}
sl@0: 	else if (emLen < (hLen + sLen + 2))
sl@0: 		{
sl@0: 		RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
sl@0: 		   RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	if (sLen > 0)
sl@0: 		{
sl@0: 		salt = OPENSSL_malloc(sLen);
sl@0: 		if (!salt)
sl@0: 			{
sl@0: 			RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
sl@0: 		   		ERR_R_MALLOC_FAILURE);
sl@0: 			goto err;
sl@0: 			}
sl@0: 		if (!RAND_bytes(salt, sLen))
sl@0: 			goto err;
sl@0: 		}
sl@0: 	maskedDBLen = emLen - hLen - 1;
sl@0: 	H = EM + maskedDBLen;
sl@0: 	EVP_MD_CTX_init(&ctx);
sl@0: 	EVP_DigestInit_ex(&ctx, Hash, NULL);
sl@0: 	EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
sl@0: 	EVP_DigestUpdate(&ctx, mHash, hLen);
sl@0: 	if (sLen)
sl@0: 		EVP_DigestUpdate(&ctx, salt, sLen);
sl@0: 	EVP_DigestFinal(&ctx, H, NULL);
sl@0: 	EVP_MD_CTX_cleanup(&ctx);
sl@0: 
sl@0: 	/* Generate dbMask in place then perform XOR on it */
sl@0: 	PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash);
sl@0: 
sl@0: 	p = EM;
sl@0: 
sl@0: 	/* Initial PS XORs with all zeroes which is a NOP so just update
sl@0: 	 * pointer. Note from a test above this value is guaranteed to
sl@0: 	 * be non-negative.
sl@0: 	 */
sl@0: 	p += emLen - sLen - hLen - 2;
sl@0: 	*p++ ^= 0x1;
sl@0: 	if (sLen > 0)
sl@0: 		{
sl@0: 		for (i = 0; i < sLen; i++)
sl@0: 			*p++ ^= salt[i];
sl@0: 		}
sl@0: 	if (MSBits)
sl@0: 		EM[0] &= 0xFF >> (8 - MSBits);
sl@0: 
sl@0: 	/* H is already in place so just set final 0xbc */
sl@0: 
sl@0: 	EM[emLen - 1] = 0xbc;
sl@0: 
sl@0: 	ret = 1;
sl@0: 
sl@0: 	err:
sl@0: 	if (salt)
sl@0: 		OPENSSL_free(salt);
sl@0: 
sl@0: 	return ret;
sl@0: 
sl@0: 	}
sl@0: 
sl@0: #if defined(_MSC_VER)
sl@0: #pragma optimize("",on)
sl@0: #endif