282 lines
7.4 KiB
C
282 lines
7.4 KiB
C
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/* $OpenBSD: rsa_pss.c,v 1.13 2018/09/05 00:55:33 djm Exp $ */
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/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
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* project 2005.
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*/
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/* ====================================================================
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* Copyright (c) 2005 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* licensing@OpenSSL.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/bn.h>
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#include <openssl/err.h>
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#include <openssl/evp.h>
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#include <openssl/rsa.h>
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#include <openssl/sha.h>
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static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
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int
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RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash, const EVP_MD *Hash,
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const unsigned char *EM, int sLen)
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{
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return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
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}
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int
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RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
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const EVP_MD *Hash, const EVP_MD *mgf1Hash, const unsigned char *EM,
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int sLen)
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{
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int i;
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int ret = 0;
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int hLen, maskedDBLen, MSBits, emLen;
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const unsigned char *H;
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unsigned char *DB = NULL;
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EVP_MD_CTX ctx;
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unsigned char H_[EVP_MAX_MD_SIZE];
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EVP_MD_CTX_init(&ctx);
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if (mgf1Hash == NULL)
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mgf1Hash = Hash;
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hLen = EVP_MD_size(Hash);
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if (hLen < 0)
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goto err;
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/*
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* Negative sLen has special meanings:
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* -1 sLen == hLen
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* -2 salt length is autorecovered from signature
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* -N reserved
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*/
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if (sLen == -1)
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sLen = hLen;
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else if (sLen == -2)
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sLen = -2;
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else if (sLen < -2) {
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RSAerror(RSA_R_SLEN_CHECK_FAILED);
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goto err;
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}
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MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
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emLen = RSA_size(rsa);
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if (EM[0] & (0xFF << MSBits)) {
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RSAerror(RSA_R_FIRST_OCTET_INVALID);
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goto err;
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}
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if (MSBits == 0) {
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EM++;
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emLen--;
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}
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if (emLen < (hLen + sLen + 2)) {
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/* sLen can be small negative */
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RSAerror(RSA_R_DATA_TOO_LARGE);
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goto err;
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}
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if (EM[emLen - 1] != 0xbc) {
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RSAerror(RSA_R_LAST_OCTET_INVALID);
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goto err;
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}
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maskedDBLen = emLen - hLen - 1;
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H = EM + maskedDBLen;
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DB = malloc(maskedDBLen);
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if (!DB) {
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RSAerror(ERR_R_MALLOC_FAILURE);
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goto err;
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}
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if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
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goto err;
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for (i = 0; i < maskedDBLen; i++)
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DB[i] ^= EM[i];
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if (MSBits)
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DB[0] &= 0xFF >> (8 - MSBits);
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for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++)
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;
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if (DB[i++] != 0x1) {
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RSAerror(RSA_R_SLEN_RECOVERY_FAILED);
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goto err;
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}
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if (sLen >= 0 && (maskedDBLen - i) != sLen) {
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RSAerror(RSA_R_SLEN_CHECK_FAILED);
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goto err;
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}
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if (!EVP_DigestInit_ex(&ctx, Hash, NULL) ||
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!EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) ||
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!EVP_DigestUpdate(&ctx, mHash, hLen))
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goto err;
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if (maskedDBLen - i) {
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if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i))
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goto err;
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}
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if (!EVP_DigestFinal_ex(&ctx, H_, NULL))
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goto err;
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if (timingsafe_bcmp(H_, H, hLen)) {
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RSAerror(RSA_R_BAD_SIGNATURE);
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ret = 0;
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} else
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ret = 1;
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err:
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free(DB);
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EVP_MD_CTX_cleanup(&ctx);
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return ret;
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}
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int
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RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
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const unsigned char *mHash, const EVP_MD *Hash, int sLen)
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{
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return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
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}
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int
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RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
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const unsigned char *mHash, const EVP_MD *Hash, const EVP_MD *mgf1Hash,
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int sLen)
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{
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int i;
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int ret = 0;
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int hLen, maskedDBLen, MSBits, emLen;
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unsigned char *H, *salt = NULL, *p;
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EVP_MD_CTX ctx;
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EVP_MD_CTX_init(&ctx);
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if (mgf1Hash == NULL)
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mgf1Hash = Hash;
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hLen = EVP_MD_size(Hash);
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if (hLen < 0)
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goto err;
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/*
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* Negative sLen has special meanings:
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* -1 sLen == hLen
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* -2 salt length is maximized
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* -N reserved
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*/
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if (sLen == -1)
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sLen = hLen;
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else if (sLen == -2)
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sLen = -2;
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else if (sLen < -2) {
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RSAerror(RSA_R_SLEN_CHECK_FAILED);
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goto err;
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}
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MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
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emLen = RSA_size(rsa);
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if (MSBits == 0) {
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*EM++ = 0;
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emLen--;
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}
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if (sLen == -2)
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sLen = emLen - hLen - 2;
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else if (emLen < (hLen + sLen + 2)) {
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RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
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goto err;
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}
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if (sLen > 0) {
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salt = malloc(sLen);
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if (!salt) {
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RSAerror(ERR_R_MALLOC_FAILURE);
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goto err;
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}
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arc4random_buf(salt, sLen);
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}
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maskedDBLen = emLen - hLen - 1;
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H = EM + maskedDBLen;
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if (!EVP_DigestInit_ex(&ctx, Hash, NULL) ||
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!EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) ||
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!EVP_DigestUpdate(&ctx, mHash, hLen))
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goto err;
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if (sLen && !EVP_DigestUpdate(&ctx, salt, sLen))
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goto err;
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if (!EVP_DigestFinal_ex(&ctx, H, NULL))
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goto err;
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/* Generate dbMask in place then perform XOR on it */
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if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
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goto err;
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p = EM;
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/*
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* Initial PS XORs with all zeroes which is a NOP so just update
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* pointer. Note from a test above this value is guaranteed to
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* be non-negative.
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*/
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p += emLen - sLen - hLen - 2;
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*p++ ^= 0x1;
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if (sLen > 0) {
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for (i = 0; i < sLen; i++)
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*p++ ^= salt[i];
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}
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if (MSBits)
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EM[0] &= 0xFF >> (8 - MSBits);
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/* H is already in place so just set final 0xbc */
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EM[emLen - 1] = 0xbc;
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ret = 1;
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err:
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free(salt);
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EVP_MD_CTX_cleanup(&ctx);
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return ret;
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}
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