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 68 static 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 74 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash, 75 const EVP_MD *Hash, const unsigned char *EM, 76 int sLen) 77 { 78 return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen); 79 } 80 81 int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash, 82 const EVP_MD *Hash, const EVP_MD *mgf1Hash, 83 const unsigned char *EM, int sLen) 84 { 85 int i; 86 int ret = 0; 87 int hLen, maskedDBLen, MSBits, emLen; 88 const unsigned char *H; 89 unsigned char *DB = NULL; 90 EVP_MD_CTX ctx; 91 unsigned char H_[EVP_MAX_MD_SIZE]; 92 EVP_MD_CTX_init(&ctx); 93 94 if (mgf1Hash == NULL) 95 mgf1Hash = Hash; 96 97 hLen = EVP_MD_size(Hash); 98 if (hLen < 0) 99 goto err; 100 /*- 101 * Negative sLen has special meanings: 102 * -1 sLen == hLen 103 * -2 salt length is autorecovered from signature 104 * -N reserved 105 */ 106 if (sLen == -1) 107 sLen = hLen; 108 else if (sLen == -2) 109 sLen = -2; 110 else if (sLen < -2) { 111 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED); 112 goto err; 113 } 114 115 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; 116 emLen = RSA_size(rsa); 117 if (EM[0] & (0xFF << MSBits)) { 118 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID); 119 goto err; 120 } 121 if (MSBits == 0) { 122 EM++; 123 emLen--; 124 } 125 if (emLen < hLen + 2) { 126 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE); 127 goto err; 128 } 129 if (sLen > emLen - hLen - 2) { /* sLen can be small negative */ 130 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE); 131 goto err; 132 } 133 if (EM[emLen - 1] != 0xbc) { 134 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID); 135 goto err; 136 } 137 maskedDBLen = emLen - hLen - 1; 138 H = EM + maskedDBLen; 139 DB = OPENSSL_malloc(maskedDBLen); 140 if (!DB) { 141 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE); 142 goto err; 143 } 144 if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0) 145 goto err; 146 for (i = 0; i < maskedDBLen; i++) 147 DB[i] ^= EM[i]; 148 if (MSBits) 149 DB[0] &= 0xFF >> (8 - MSBits); 150 for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ; 151 if (DB[i++] != 0x1) { 152 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED); 153 goto err; 154 } 155 if (sLen >= 0 && (maskedDBLen - i) != sLen) { 156 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED); 157 goto err; 158 } 159 if (!EVP_DigestInit_ex(&ctx, Hash, NULL) 160 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) 161 || !EVP_DigestUpdate(&ctx, mHash, hLen)) 162 goto err; 163 if (maskedDBLen - i) { 164 if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i)) 165 goto err; 166 } 167 if (!EVP_DigestFinal_ex(&ctx, H_, NULL)) 168 goto err; 169 if (memcmp(H_, H, hLen)) { 170 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE); 171 ret = 0; 172 } else 173 ret = 1; 174 175 err: 176 if (DB) 177 OPENSSL_free(DB); 178 EVP_MD_CTX_cleanup(&ctx); 179 180 return ret; 181 182 } 183 184 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM, 185 const unsigned char *mHash, 186 const EVP_MD *Hash, int sLen) 187 { 188 return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen); 189 } 190 191 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM, 192 const unsigned char *mHash, 193 const EVP_MD *Hash, const EVP_MD *mgf1Hash, 194 int sLen) 195 { 196 int i; 197 int ret = 0; 198 int hLen, maskedDBLen, MSBits, emLen; 199 unsigned char *H, *salt = NULL, *p; 200 EVP_MD_CTX ctx; 201 202 if (mgf1Hash == NULL) 203 mgf1Hash = Hash; 204 205 hLen = EVP_MD_size(Hash); 206 if (hLen < 0) 207 goto err; 208 /*- 209 * Negative sLen has special meanings: 210 * -1 sLen == hLen 211 * -2 salt length is maximized 212 * -N reserved 213 */ 214 if (sLen == -1) 215 sLen = hLen; 216 else if (sLen == -2) 217 sLen = -2; 218 else if (sLen < -2) { 219 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED); 220 goto err; 221 } 222 223 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; 224 emLen = RSA_size(rsa); 225 if (MSBits == 0) { 226 *EM++ = 0; 227 emLen--; 228 } 229 if (emLen < hLen + 2) { 230 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, 231 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); 232 goto err; 233 } 234 if (sLen == -2) { 235 sLen = emLen - hLen - 2; 236 } else if (sLen > emLen - hLen - 2) { 237 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, 238 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); 239 goto err; 240 } 241 if (sLen > 0) { 242 salt = OPENSSL_malloc(sLen); 243 if (!salt) { 244 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, 245 ERR_R_MALLOC_FAILURE); 246 goto err; 247 } 248 if (RAND_bytes(salt, sLen) <= 0) 249 goto err; 250 } 251 maskedDBLen = emLen - hLen - 1; 252 H = EM + maskedDBLen; 253 EVP_MD_CTX_init(&ctx); 254 if (!EVP_DigestInit_ex(&ctx, Hash, NULL) 255 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) 256 || !EVP_DigestUpdate(&ctx, mHash, hLen)) 257 goto err; 258 if (sLen && !EVP_DigestUpdate(&ctx, salt, sLen)) 259 goto err; 260 if (!EVP_DigestFinal_ex(&ctx, H, NULL)) 261 goto err; 262 EVP_MD_CTX_cleanup(&ctx); 263 264 /* Generate dbMask in place then perform XOR on it */ 265 if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash)) 266 goto err; 267 268 p = EM; 269 270 /* 271 * Initial PS XORs with all zeroes which is a NOP so just update pointer. 272 * Note from a test above this value is guaranteed to be non-negative. 273 */ 274 p += emLen - sLen - hLen - 2; 275 *p++ ^= 0x1; 276 if (sLen > 0) { 277 for (i = 0; i < sLen; i++) 278 *p++ ^= salt[i]; 279 } 280 if (MSBits) 281 EM[0] &= 0xFF >> (8 - MSBits); 282 283 /* H is already in place so just set final 0xbc */ 284 285 EM[emLen - 1] = 0xbc; 286 287 ret = 1; 288 289 err: 290 if (salt) 291 OPENSSL_free(salt); 292 293 return ret; 294 295 } 296 297 #if defined(_MSC_VER) 298 # pragma optimize("",on) 299 #endif 300