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/* $OpenBSD: rsa_pss.c,v 1.12 2017/01/29 17:49:23 beck 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 (memcmp(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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} |