crypto/rsa/rsa_pss.c

   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         int i;
  77         int ret = 0;
  78         int hLen, maskedDBLen, MSBits, emLen;
  79         const unsigned char *H;
  80         unsigned char *DB = NULL;
  81         EVP_MD_CTX ctx;
  82         unsigned char H_[EVP_MAX_MD_SIZE];
  83
  84         hLen = EVP_MD_size(Hash);
  85         if (hLen < 0)
  86                 goto err;
  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)    sLen = hLen;
  94         else if (sLen == -2)    sLen = -2;
  95         else if (sLen < -2)
  96                 {
  97                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
  98                 goto err;
  99                 }
 100
 101         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 102         emLen = RSA_size(rsa);
 103         if (EM[0] & (0xFF << MSBits))
 104                 {
 105                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
 106                 goto err;
 107                 }
 108         if (MSBits == 0)
 109                 {
 110                 EM++;
 111                 emLen--;
 112                 }
 113         if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
 114                 {
 115                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
 116                 goto err;
 117                 }
 118         if (EM[emLen - 1] != 0xbc)
 119                 {
 120                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
 121                 goto err;
 122                 }
 123         maskedDBLen = emLen - hLen - 1;
 124         H = EM + maskedDBLen;
 125         DB = OPENSSL_malloc(maskedDBLen);
 126         if (!DB)
 127                 {
 128                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
 129                 goto err;
 130                 }
 131         if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash) < 0)
 132                 goto err;
 133         for (i = 0; i < maskedDBLen; i++)
 134                 DB[i] ^= EM[i];
 135         if (MSBits)
 136                 DB[0] &= 0xFF >> (8 - MSBits);
 137         for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
 138         if (DB[i++] != 0x1)
 139                 {
 140                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED);
 141                 goto err;
 142                 }
 143         if (sLen >= 0 && (maskedDBLen - i) != sLen)
 144                 {
 145                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 146                 goto err;
 147                 }
 148         EVP_MD_CTX_init(&ctx);
 149         EVP_DigestInit_ex(&ctx, Hash, NULL);
 150         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 151         EVP_DigestUpdate(&ctx, mHash, hLen);
 152         if (maskedDBLen - i)
 153                 EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i);
 154         EVP_DigestFinal(&ctx, H_, NULL);
 155         EVP_MD_CTX_cleanup(&ctx);
 156         if (memcmp(H_, H, hLen))
 157                 {
 158                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
 159                 ret = 0;
 160                 }
 161         else
 162                 ret = 1;
 163
 164         err:
 165         if (DB)
 166                 OPENSSL_free(DB);
 167
 168         return ret;
 169
 170         }
 171
 172 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 173                         const unsigned char *mHash,
 174                         const EVP_MD *Hash, int sLen)
 175         {
 176         int i;
 177         int ret = 0;
 178         int hLen, maskedDBLen, MSBits, emLen;
 179         unsigned char *H, *salt = NULL, *p;
 180         EVP_MD_CTX ctx;
 181
 182         hLen = EVP_MD_size(Hash);
 183         if (hLen < 0)
 184                 goto err;
 185         /*
 186          * Negative sLen has special meanings:
 187          *      -1      sLen == hLen
 188          *      -2      salt length is maximized
 189          *      -N      reserved
 190          */
 191         if      (sLen == -1)    sLen = hLen;
 192         else if (sLen == -2)    sLen = -2;
 193         else if (sLen < -2)
 194                 {
 195                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 196                 goto err;
 197                 }
 198
 199         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 200         emLen = RSA_size(rsa);
 201         if (MSBits == 0)
 202                 {
 203                 *EM++ = 0;
 204                 emLen--;
 205                 }
 206         if (sLen == -2)
 207                 {
 208                 sLen = emLen - hLen - 2;
 209                 }
 210         else if (emLen < (hLen + sLen + 2))
 211                 {
 212                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 213                    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 214                 goto err;
 215                 }
 216         if (sLen > 0)
 217                 {
 218                 salt = OPENSSL_malloc(sLen);
 219                 if (!salt)
 220                         {
 221                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 222                                 ERR_R_MALLOC_FAILURE);
 223                         goto err;
 224                         }
 225                 if (!RAND_bytes(salt, sLen))
 226                         goto err;
 227                 }
 228         maskedDBLen = emLen - hLen - 1;
 229         H = EM + maskedDBLen;
 230         EVP_MD_CTX_init(&ctx);
 231         EVP_DigestInit_ex(&ctx, Hash, NULL);
 232         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 233         EVP_DigestUpdate(&ctx, mHash, hLen);
 234         if (sLen)
 235                 EVP_DigestUpdate(&ctx, salt, sLen);
 236         EVP_DigestFinal(&ctx, H, NULL);
 237         EVP_MD_CTX_cleanup(&ctx);
 238
 239         /* Generate dbMask in place then perform XOR on it */
 240         if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash))
 241                 goto err;
 242
 243         p = EM;
 244
 245         /* Initial PS XORs with all zeroes which is a NOP so just update
 246          * pointer. Note from a test above this value is guaranteed to
 247          * be non-negative.
 248          */
 249         p += emLen - sLen - hLen - 2;
 250         *p++ ^= 0x1;
 251         if (sLen > 0)
 252                 {
 253                 for (i = 0; i < sLen; i++)
 254                         *p++ ^= salt[i];
 255                 }
 256         if (MSBits)
 257                 EM[0] &= 0xFF >> (8 - MSBits);
 258
 259         /* H is already in place so just set final 0xbc */
 260
 261         EM[emLen - 1] = 0xbc;
 262
 263         ret = 1;
 264
 265         err:
 266         if (salt)
 267                 OPENSSL_free(salt);
 268
 269         return ret;
 270
 271         }
 272
 273 #if defined(_MSC_VER)
 274 #pragma optimize("",on)
 275 #endif