crypto/rsa/rsa_pss.c

   1 /* rsa_pss.c */
   2 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) 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         /*
  86          * Negative sLen has special meanings:
  87          *      -1      sLen == hLen
  88          *      -2      salt length is autorecovered from signature
  89          *      -N      reserved
  90          */
  91         if      (sLen == -1)    sLen = hLen;
  92         else if (sLen == -2)    sLen = -2;
  93         else if (sLen < -2)
  94                 {
  95                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
  96                 goto err;
  97                 }
  98
  99         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 100         emLen = RSA_size(rsa);
 101         if (EM[0] & (0xFF << MSBits))
 102                 {
 103                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
 104                 goto err;
 105                 }
 106         if (MSBits == 0)
 107                 {
 108                 EM++;
 109                 emLen--;
 110                 }
 111         if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
 112                 {
 113                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
 114                 goto err;
 115                 }
 116         if (EM[emLen - 1] != 0xbc)
 117                 {
 118                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
 119                 goto err;
 120                 }
 121         maskedDBLen = emLen - hLen - 1;
 122         H = EM + maskedDBLen;
 123         DB = OPENSSL_malloc(maskedDBLen);
 124         if (!DB)
 125                 {
 126                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
 127                 goto err;
 128                 }
 129         PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash);
 130         for (i = 0; i < maskedDBLen; i++)
 131                 DB[i] ^= EM[i];
 132         if (MSBits)
 133                 DB[0] &= 0xFF >> (8 - MSBits);
 134         for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
 135         if (DB[i++] != 0x1)
 136                 {
 137                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED);
 138                 goto err;
 139                 }
 140         if (sLen >= 0 && (maskedDBLen - i) != sLen)
 141                 {
 142                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 143                 goto err;
 144                 }
 145         EVP_MD_CTX_init(&ctx);
 146         EVP_DigestInit_ex(&ctx, Hash, NULL);
 147         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 148         EVP_DigestUpdate(&ctx, mHash, hLen);
 149         if (maskedDBLen - i)
 150                 EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i);
 151         EVP_DigestFinal(&ctx, H_, NULL);
 152         EVP_MD_CTX_cleanup(&ctx);
 153         if (memcmp(H_, H, hLen))
 154                 {
 155                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
 156                 ret = 0;
 157                 }
 158         else
 159                 ret = 1;
 160
 161         err:
 162         if (DB)
 163                 OPENSSL_free(DB);
 164
 165         return ret;
 166
 167         }
 168
 169 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 170                         const unsigned char *mHash,
 171                         const EVP_MD *Hash, int sLen)
 172         {
 173         int i;
 174         int ret = 0;
 175         int hLen, maskedDBLen, MSBits, emLen;
 176         unsigned char *H, *salt = NULL, *p;
 177         EVP_MD_CTX ctx;
 178
 179         hLen = EVP_MD_size(Hash);
 180         /*
 181          * Negative sLen has special meanings:
 182          *      -1      sLen == hLen
 183          *      -2      salt length is maximized
 184          *      -N      reserved
 185          */
 186         if      (sLen == -1)    sLen = hLen;
 187         else if (sLen == -2)    sLen = -2;
 188         else if (sLen < -2)
 189                 {
 190                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 191                 goto err;
 192                 }
 193
 194         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 195         emLen = RSA_size(rsa);
 196         if (MSBits == 0)
 197                 {
 198                 *EM++ = 0;
 199                 emLen--;
 200                 }
 201         if (sLen == -2)
 202                 {
 203                 sLen = emLen - hLen - 2;
 204                 }
 205         else if (emLen < (hLen + sLen + 2))
 206                 {
 207                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 208                    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 209                 goto err;
 210                 }
 211         if (sLen > 0)
 212                 {
 213                 salt = OPENSSL_malloc(sLen);
 214                 if (!salt)
 215                         {
 216                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 217                                 ERR_R_MALLOC_FAILURE);
 218                         goto err;
 219                         }
 220                 if (!RAND_bytes(salt, sLen))
 221                         goto err;
 222                 }
 223         maskedDBLen = emLen - hLen - 1;
 224         H = EM + maskedDBLen;
 225         EVP_MD_CTX_init(&ctx);
 226         EVP_DigestInit_ex(&ctx, Hash, NULL);
 227         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 228         EVP_DigestUpdate(&ctx, mHash, hLen);
 229         if (sLen)
 230                 EVP_DigestUpdate(&ctx, salt, sLen);
 231         EVP_DigestFinal(&ctx, H, NULL);
 232         EVP_MD_CTX_cleanup(&ctx);
 233
 234         /* Generate dbMask in place then perform XOR on it */
 235         PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash);
 236
 237         p = EM;
 238
 239         /* Initial PS XORs with all zeroes which is a NOP so just update
 240          * pointer. Note from a test above this value is guaranteed to
 241          * be non-negative.
 242          */
 243         p += emLen - sLen - hLen - 2;
 244         *p++ ^= 0x1;
 245         if (sLen > 0)
 246                 {
 247                 for (i = 0; i < sLen; i++)
 248                         *p++ ^= salt[i];
 249                 }
 250         if (MSBits)
 251                 EM[0] &= 0xFF >> (8 - MSBits);
 252
 253         /* H is already in place so just set final 0xbc */
 254
 255         EM[emLen - 1] = 0xbc;
 256
 257         ret = 1;
 258
 259         err:
 260         if (salt)
 261                 OPENSSL_free(salt);
 262
 263         return ret;
 264
 265         }
 266
 267 #if defined(_MSC_VER)
 268 #pragma optimize("",on)
 269 #endif