1 /* rsa_pss.c */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project 2005.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2005 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58 
  59 #include <stdio.h>
  60 #include "cryptlib.h"
  61 #include <openssl/bn.h>
  62 #include <openssl/rsa.h>
  63 #include <openssl/evp.h>
  64 #include <openssl/rand.h>
  65 #include <openssl/sha.h>
  66 
  67 static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
  68 
  69 #if defined(_MSC_VER) && defined(_ARM_)
  70 #pragma optimize("g", off)
  71 #endif
  72 
  73 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
  74                         const EVP_MD *Hash, const unsigned char *EM, int sLen)
  75         {
  76         return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
  77         }
  78 
  79 int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
  80                         const EVP_MD *Hash, const EVP_MD *mgf1Hash,
  81                         const unsigned char *EM, int sLen)
  82         {
  83         int i;
  84         int ret = 0;
  85         int hLen, maskedDBLen, MSBits, emLen;
  86         const unsigned char *H;
  87         unsigned char *DB = NULL;
  88         EVP_MD_CTX ctx;
  89         unsigned char H_[EVP_MAX_MD_SIZE];
  90         EVP_MD_CTX_init(&ctx);
  91 
  92         if (mgf1Hash == NULL)
  93                 mgf1Hash = Hash;
  94 
  95         hLen = EVP_MD_size(Hash);
  96         if (hLen < 0)
  97                 goto err;
  98         /*
  99          * Negative sLen has special meanings:
 100          *      -1      sLen == hLen
 101          *      -2      salt length is autorecovered from signature
 102          *      -N      reserved
 103          */
 104         if      (sLen == -1)    sLen = hLen;
 105         else if (sLen == -2)    sLen = -2;
 106         else if (sLen < -2)
 107                 {
 108                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
 109                 goto err;
 110                 }
 111 
 112         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 113         emLen = RSA_size(rsa);
 114         if (EM[0] & (0xFF << MSBits))
 115                 {
 116                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID);
 117                 goto err;
 118                 }
 119         if (MSBits == 0)
 120                 {
 121                 EM++;
 122                 emLen--;
 123                 }
 124         if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
 125                 {
 126                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
 127                 goto err;
 128                 }
 129         if (EM[emLen - 1] != 0xbc)
 130                 {
 131                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID);
 132                 goto err;
 133                 }
 134         maskedDBLen = emLen - hLen - 1;
 135         H = EM + maskedDBLen;
 136         DB = OPENSSL_malloc(maskedDBLen);
 137         if (!DB)
 138                 {
 139                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE);
 140                 goto err;
 141                 }
 142         if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
 143                 goto err;
 144         for (i = 0; i < maskedDBLen; i++)
 145                 DB[i] ^= EM[i];
 146         if (MSBits)
 147                 DB[0] &= 0xFF >> (8 - MSBits);
 148         for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
 149         if (DB[i++] != 0x1)
 150                 {
 151                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED);
 152                 goto err;
 153                 }
 154         if (sLen >= 0 && (maskedDBLen - i) != sLen)
 155                 {
 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                 {
 165                 if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i))
 166                         goto err;
 167                 }
 168         if (!EVP_DigestFinal_ex(&ctx, H_, NULL))
 169                 goto err;
 170         if (memcmp(H_, H, hLen))
 171                 {
 172                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE);
 173                 ret = 0;
 174                 }
 175         else
 176                 ret = 1;
 177 
 178         err:
 179         if (DB)
 180                 OPENSSL_free(DB);
 181         EVP_MD_CTX_cleanup(&ctx);
 182 
 183         return ret;
 184 
 185         }
 186 
 187 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 188                         const unsigned char *mHash,
 189                         const EVP_MD *Hash, int sLen)
 190         {
 191         return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
 192         }
 193 
 194 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
 195                         const unsigned char *mHash,
 196                         const EVP_MD *Hash, const EVP_MD *mgf1Hash, int sLen)
 197         {
 198         int i;
 199         int ret = 0;
 200         int hLen, maskedDBLen, MSBits, emLen;
 201         unsigned char *H, *salt = NULL, *p;
 202         EVP_MD_CTX ctx;
 203 
 204         if (mgf1Hash == NULL)
 205                 mgf1Hash = Hash;
 206 
 207         hLen = EVP_MD_size(Hash);
 208         if (hLen < 0)
 209                 goto err;
 210         /*
 211          * Negative sLen has special meanings:
 212          *      -1      sLen == hLen
 213          *      -2      salt length is maximized
 214          *      -N      reserved
 215          */
 216         if      (sLen == -1)    sLen = hLen;
 217         else if (sLen == -2)    sLen = -2;
 218         else if (sLen < -2)
 219                 {
 220                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
 221                 goto err;
 222                 }
 223 
 224         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 225         emLen = RSA_size(rsa);
 226         if (MSBits == 0)
 227                 {
 228                 *EM++ = 0;
 229                 emLen--;
 230                 }
 231         if (sLen == -2)
 232                 {
 233                 sLen = emLen - hLen - 2;
 234                 }
 235         else if (emLen < (hLen + sLen + 2))
 236                 {
 237                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 238                 goto err;
 239                 }
 240         if (sLen > 0)
 241                 {
 242                 salt = OPENSSL_malloc(sLen);
 243                 if (!salt)
 244                         {
 245                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,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         /* Initial PS XORs with all zeroes which is a NOP so just update
 271          * pointer. Note from a test above this value is guaranteed to
 272          * be non-negative.
 273          */
 274         p += emLen - sLen - hLen - 2;
 275         *p++ ^= 0x1;
 276         if (sLen > 0)
 277                 {
 278                 for (i = 0; i < sLen; i++)
 279                         *p++ ^= salt[i];
 280                 }
 281         if (MSBits)
 282                 EM[0] &= 0xFF >> (8 - MSBits);
 283 
 284         /* H is already in place so just set final 0xbc */
 285 
 286         EM[emLen - 1] = 0xbc;
 287 
 288         ret = 1;
 289 
 290         err:
 291         if (salt)
 292                 OPENSSL_free(salt);
 293 
 294         return ret;
 295 
 296         }
 297 
 298 #if defined(_MSC_VER)
 299 #pragma optimize("",on)
 300 #endif