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, MSBits, 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         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
  80         emLen = RSA_size(rsa);
  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 << MSBits))
  93                 {
  94                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
  95                 goto err;
  96                 }
  97         if (!MSBits)
  98                 {
  99                 EM++;
 100                 emLen--;
 101                 }
 102         maskedDBLen = emLen - hLen - 1;
 103         H = EM + maskedDBLen;
 104         DB = OPENSSL_malloc(maskedDBLen);
 105         if (!DB)
 106                 {
 107                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
 108                 goto err;
 109                 }
 110         PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash);
 111         for (i = 0; i < maskedDBLen; i++)
 112                 DB[i] ^= EM[i];
 113         if (MSBits)
 114                 DB[0] &= 0xFF >> (8 - MSBits);
 115         for (i = 0; i < (emLen - hLen - sLen - 2); i++)
 116                 {
 117                 if (DB[i] != 0)
 118                         {
 119                         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS,
 120                                                 RSA_R_ZERO_CHECK_FAILED);
 121                         goto err;
 122                         }
 123                 }
 124         if (DB[i] != 0x1)
 125                 {
 126                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_ONE_CHECK_FAILED);
 127                 goto err;
 128                 }
 129         EVP_MD_CTX_init(&ctx);
 130         EVP_DigestInit_ex(&ctx, Hash, NULL);
 131         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 132         EVP_DigestUpdate(&ctx, mHash, hLen);
 133         if (sLen)
 134                 EVP_DigestUpdate(&ctx, DB + maskedDBLen - sLen, sLen);
 135         EVP_DigestFinal(&ctx, H_, NULL);
 136         EVP_MD_CTX_cleanup(&ctx);
 137         if (memcmp(H_, H, hLen))
 138                 {
 139                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
 140                 ret = 0;
 141                 }
 142         else
 143                 ret = 1;
 144
 145         err:
 146         if (DB)
 147                 OPENSSL_free(DB);
 148
 149         return ret;
 150
 151         }
 152
 153 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 154                         const unsigned char *mHash,
 155                         const EVP_MD *Hash, int sLen)
 156         {
 157         int i;
 158         int ret = 0;
 159         int hLen, maskedDBLen, MSBits, emLen;
 160         unsigned char *H, *salt = NULL, *p;
 161         EVP_MD_CTX ctx;
 162         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 163         emLen = RSA_size(rsa);
 164         hLen = EVP_MD_size(Hash);
 165         if (sLen < 0)
 166                 sLen = 0;
 167         if (emLen < (hLen + sLen + 2))
 168                 {
 169                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 170                    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 171                 goto err;
 172                 }
 173         if (MSBits == 0)
 174                 {
 175                 *EM++ = 0;
 176                 emLen--;
 177                 }
 178         if (sLen > 0)
 179                 {
 180                 salt = OPENSSL_malloc(sLen);
 181                 if (!salt)
 182                         {
 183                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 184                                 ERR_R_MALLOC_FAILURE);
 185                         goto err;
 186                         }
 187                 if (!RAND_bytes(salt, sLen))
 188                         goto err;
 189                 }
 190         maskedDBLen = emLen - hLen - 1;
 191         H = EM + maskedDBLen;
 192         EVP_MD_CTX_init(&ctx);
 193         EVP_DigestInit_ex(&ctx, Hash, NULL);
 194         EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
 195         EVP_DigestUpdate(&ctx, mHash, hLen);
 196         if (sLen)
 197                 EVP_DigestUpdate(&ctx, salt, sLen);
 198         EVP_DigestFinal(&ctx, H, NULL);
 199         EVP_MD_CTX_cleanup(&ctx);
 200
 201         /* Generate dbMask in place then perform XOR on it */
 202         PKCS1_MGF1(EM, maskedDBLen, H, hLen, Hash);
 203
 204         p = EM;
 205
 206         /* Initial PS XORs with all zeroes which is a NOP so just update
 207          * pointer. Note from a test above this value is guaranteed to
 208          * be non-negative.
 209          */
 210         p += emLen - sLen - hLen - 2;
 211         *p++ ^= 0x1;
 212         if (sLen > 0)
 213                 {
 214                 for (i = 0; i < sLen; i++)
 215                         *p++ ^= salt[i];
 216                 }
 217         if (MSBits)
 218                 EM[0] &= 0xFF >> (8 - MSBits);
 219
 220         /* H is already in place so just set final 0xbc */
 221
 222         EM[emLen - 1] = 0xbc;
 223
 224         ret = 1;
 225
 226         err:
 227         if (salt)
 228                 OPENSSL_free(salt);
 229
 230         return ret;
 231
 232         }