1/* rsa_pss.c */ 2/* 3 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project 4 * 2005. 5 */ 6/* ==================================================================== 7 * Copyright (c) 2005 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * licensing@OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 60#include <stdio.h> 61#include "cryptlib.h" 62#include <openssl/bn.h> 63#include <openssl/rsa.h> 64#include <openssl/evp.h> 65#include <openssl/rand.h> 66#include <openssl/sha.h> 67 68static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 69 70#if defined(_MSC_VER) && defined(_ARM_) 71# pragma optimize("g", off) 72#endif 73 74int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash, 75 const EVP_MD *Hash, const unsigned char *EM, 76 int sLen) 77{ 78 int i; 79 int ret = 0; 80 int hLen, maskedDBLen, MSBits, emLen; 81 const unsigned char *H; 82 unsigned char *DB = NULL; 83 EVP_MD_CTX ctx; 84 unsigned char H_[EVP_MAX_MD_SIZE]; 85 86 hLen = M_EVP_MD_size(Hash); 87 /*- 88 * Negative sLen has special meanings: 89 * -1 sLen == hLen 90 * -2 salt length is autorecovered from signature 91 * -N reserved 92 */ 93 if (sLen == -1) 94 sLen = hLen; 95 else if (sLen == -2) 96 sLen = -2; 97 else if (sLen < -2) { 98 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED); 99 goto err; 100 } 101 102 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; 103 emLen = RSA_size(rsa); 104 if (EM[0] & (0xFF << MSBits)) { 105 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID); 106 goto err; 107 } 108 if (MSBits == 0) { 109 EM++; 110 emLen--; 111 } 112 if (emLen < (hLen + sLen + 2)) { /* sLen can be small negative */ 113 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE); 114 goto err; 115 } 116 if (EM[emLen - 1] != 0xbc) { 117 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID); 118 goto err; 119 } 120 maskedDBLen = emLen - hLen - 1; 121 H = EM + maskedDBLen; 122 DB = OPENSSL_malloc(maskedDBLen); 123 if (!DB) { 124 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE); 125 goto err; 126 } 127 PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash); 128 for (i = 0; i < maskedDBLen; i++) 129 DB[i] ^= EM[i]; 130 if (MSBits) 131 DB[0] &= 0xFF >> (8 - MSBits); 132 for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ; 133 if (DB[i++] != 0x1) { 134 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED); 135 goto err; 136 } 137 if (sLen >= 0 && (maskedDBLen - i) != sLen) { 138 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED); 139 goto err; 140 } 141 EVP_MD_CTX_init(&ctx); 142 EVP_DigestInit_ex(&ctx, Hash, NULL); 143 EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes); 144 EVP_DigestUpdate(&ctx, mHash, hLen); 145 if (maskedDBLen - i) 146 EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i); 147 EVP_DigestFinal(&ctx, H_, NULL); 148 EVP_MD_CTX_cleanup(&ctx); 149 if (memcmp(H_, H, hLen)) { 150 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE); 151 ret = 0; 152 } else 153 ret = 1; 154 155 err: 156 if (DB) 157 OPENSSL_free(DB); 158 159 return ret; 160 161} 162 163int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM, 164 const unsigned char *mHash, 165 const EVP_MD *Hash, int sLen) 166{ 167 int i; 168 int ret = 0; 169 int hLen, maskedDBLen, MSBits, emLen; 170 unsigned char *H, *salt = NULL, *p; 171 EVP_MD_CTX ctx; 172 173 hLen = M_EVP_MD_size(Hash); 174 /*- 175 * Negative sLen has special meanings: 176 * -1 sLen == hLen 177 * -2 salt length is maximized 178 * -N reserved 179 */ 180 if (sLen == -1) 181 sLen = hLen; 182 else if (sLen == -2) 183 sLen = -2; 184 else if (sLen < -2) { 185 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED); 186 goto err; 187 } 188 189 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; 190 emLen = RSA_size(rsa); 191 if (MSBits == 0) { 192 *EM++ = 0; 193 emLen--; 194 } 195 if (sLen == -2) { 196 sLen = emLen - hLen - 2; 197 } else if (emLen < (hLen + sLen + 2)) { 198 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, 199 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); 200 goto err; 201 } 202 if (sLen > 0) { 203 salt = OPENSSL_malloc(sLen); 204 if (!salt) { 205 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, ERR_R_MALLOC_FAILURE); 206 goto err; 207 } 208 if (RAND_bytes(salt, sLen) <= 0) 209 goto err; 210 } 211 maskedDBLen = emLen - hLen - 1; 212 H = EM + maskedDBLen; 213 EVP_MD_CTX_init(&ctx); 214 EVP_DigestInit_ex(&ctx, Hash, NULL); 215 EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes); 216 EVP_DigestUpdate(&ctx, mHash, hLen); 217 if (sLen) 218 EVP_DigestUpdate(&ctx, salt, sLen); 219 EVP_DigestFinal(&ctx, H, NULL); 220 EVP_MD_CTX_cleanup(&ctx); 221 222 /* Generate dbMask in place then perform XOR on it */ 223 PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash); 224 225 p = EM; 226 227 /* 228 * Initial PS XORs with all zeroes which is a NOP so just update pointer. 229 * Note from a test above this value is guaranteed to be non-negative. 230 */ 231 p += emLen - sLen - hLen - 2; 232 *p++ ^= 0x1; 233 if (sLen > 0) { 234 for (i = 0; i < sLen; i++) 235 *p++ ^= salt[i]; 236 } 237 if (MSBits) 238 EM[0] &= 0xFF >> (8 - MSBits); 239 240 /* H is already in place so just set final 0xbc */ 241 242 EM[emLen - 1] = 0xbc; 243 244 ret = 1; 245 246 err: 247 if (salt) 248 OPENSSL_free(salt); 249 250 return ret; 251 252} 253 254#if defined(_MSC_VER) 255# pragma optimize("",on) 256#endif 257