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 const static unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
  68
  69 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
  70                         const EVP_MD *Hash, const unsigned char *EM, int sLen)
  71         {
  72         int i;
  73         int ret = 0;
  74         int hLen, maskedDBLen, emBits, emLen;
  75         const unsigned char *H;
  76         unsigned char *DB = NULL;
  77         EVP_MD_CTX ctx;
  78         unsigned char H_[EVP_MAX_MD_SIZE];
  79         emBits = BN_num_bits(rsa->n) - 1;
  80         emLen = (emBits + 7) >> 3;
  81         hLen = EVP_MD_size(Hash);
  82         if (emLen < (hLen + sLen + 2))
  83                 {
  84                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
  85                 goto err;
  86                 }
  87         if (EM[emLen - 1] != 0xbc)
  88                 {
  89                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
  90                 goto err;
  91                 }
  92         if (EM[0] & (0xFF << (emBits & 0x7)))
  93                 {
  94                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
  95                 goto err;
  96                 }
  97         maskedDBLen = emLen - hLen - 1;
  98         H = EM + maskedDBLen;
  99         DB = OPENSSL_malloc(maskedDBLen);
 100         if (!DB)
 101                 {
 102                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
 103                 goto err;
 104                 }
 105         PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash);
 106         for (i = 0; i < maskedDBLen; i++)
 107                 DB[i] ^= EM[i];
 108         DB[0] &= 0xFF >> (8 - (emBits & 0x7));
 109         for (i = 0; i < (emLen - hLen - sLen - 2); i++)
 110                 {
 111                 if (DB[i] != 0)
 112                         {
 113                         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS,
 114                                                 RSA_R_ZERO_CHECK_FAILED);
 115                         goto err;
 116                         }
 117                 }
 118         if (DB[i] != 0x1)
 119                 {
 120                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_ONE_CHECK_FAILED);
 121                 goto err;
 122                 }
 123         EVP_MD_CTX_init(&ctx);
 124         EVP_DigestInit_ex(&ctx, Hash, NULL);
 125         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 126         EVP_DigestUpdate(&ctx, mHash, hLen);
 127         if (sLen)
 128                 EVP_DigestUpdate(&ctx, DB + maskedDBLen - sLen, sLen);
 129         EVP_DigestFinal(&ctx, H_, NULL);
 130         EVP_MD_CTX_cleanup(&ctx);
 131         if (memcmp(H_, H, hLen))
 132                 {
 133                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
 134                 ret = 0;
 135                 }
 136         else
 137                 ret = 1;
 138
 139         err:
 140         if (DB)
 141                 OPENSSL_free(DB);
 142
 143         return ret;
 144
 145         }
 146
 147 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 148                         const unsigned char *mHash,
 149                         const EVP_MD *Hash, int sLen)
 150         {
 151         int i;
 152         int ret = 0;
 153         int hLen, maskedDBLen, emBits, emLen;
 154         unsigned char *H, *salt = NULL, *p;
 155         EVP_MD_CTX ctx;
 156         emBits = BN_num_bits(rsa->n) - 1;
 157         emLen = (emBits + 7) >> 3;
 158         hLen = EVP_MD_size(Hash);
 159         if (sLen < 0)
 160                 sLen = 0;
 161         if (emLen < (hLen + sLen + 2))
 162                 {
 163                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 164                    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 165                 goto err;
 166                 }
 167         if (sLen > 0)
 168                 {
 169                 salt = OPENSSL_malloc(sLen);
 170                 if (!salt)
 171                         {
 172                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 173                                 ERR_R_MALLOC_FAILURE);
 174                         goto err;
 175                         }
 176                 if (!RAND_bytes(salt, sLen))
 177                         goto err;
 178                 }
 179         maskedDBLen = emLen - hLen - 1;
 180         H = EM + maskedDBLen;
 181         EVP_MD_CTX_init(&ctx);
 182         EVP_DigestInit_ex(&ctx, Hash, NULL);
 183         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 184         EVP_DigestUpdate(&ctx, mHash, hLen);
 185         if (sLen)
 186                 EVP_DigestUpdate(&ctx, salt, sLen);
 187         EVP_DigestFinal(&ctx, H, NULL);
 188         EVP_MD_CTX_cleanup(&ctx);
 189
 190         /* Generate dbMask in place then perform XOR on it */
 191         PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash);
 192
 193         p = EM;
 194
 195         /* Initial PS XORs with all zeroes which is a NOP so just update
 196          * pointer. Note from a test above this value is guaranteed to
 197          * be non-negative.
 198          */
 199         p += emLen - sLen - hLen - 2;
 200         *p++ ^= 0x1;
 201         if (sLen > 0)
 202                 {
 203                 for (i = 0; i < sLen; i++)
 204                         *p++ ^= salt[i];
 205                 }
 206         EM[0] &= 0xFF >> (8 - (emBits & 0x7));
 207
 208         /* H is already in place so just set final 0xbc */
 209
 210         EM[emLen - 1] = 0xbc;
 211
 212         ret = 1;
 213
 214         err:
 215         if (salt)
 216                 OPENSSL_free(salt);
 217
 218         return ret;
 219
 220         }