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 #include "rsa_locl.h"
  67
  68 static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
  69
  70 #if defined(_MSC_VER) && defined(_ARM_)
  71 #pragma optimize("g", off)
  72 #endif
  73
  74 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
  75                         const EVP_MD *Hash, const unsigned char *EM, int sLen)
  76         {
  77         return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
  78         }
  79
  80 int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
  81                         const EVP_MD *Hash, const EVP_MD *mgf1Hash,
  82                         const unsigned char *EM, int sLen)
  83         {
  84         int i;
  85         int ret = 0;
  86         int hLen, maskedDBLen, MSBits, emLen;
  87         const unsigned char *H;
  88         unsigned char *DB = NULL;
  89         EVP_MD_CTX ctx;
  90         unsigned char H_[EVP_MAX_MD_SIZE];
  91         EVP_MD_CTX_init(&ctx);
  92
  93         if (mgf1Hash == NULL)
  94                 mgf1Hash = Hash;
  95
  96         hLen = EVP_MD_size(Hash);
  97         if (hLen < 0)
  98                 goto err;
  99         /*
 100          * Negative sLen has special meanings:
 101          *      -1      sLen == hLen
 102          *      -2      salt length is autorecovered from signature
 103          *      -N      reserved
 104          */
 105         if      (sLen == -1)    sLen = hLen;
 106         else if (sLen == -2)    sLen = -2;
 107         else if (sLen < -2)
 108                 {
 109                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 110                 goto err;
 111                 }
 112
 113         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 114         emLen = RSA_size(rsa);
 115         if (EM[0] & (0xFF << MSBits))
 116                 {
 117                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
 118                 goto err;
 119                 }
 120         if (MSBits == 0)
 121                 {
 122                 EM++;
 123                 emLen--;
 124                 }
 125         if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
 126                 {
 127                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
 128                 goto err;
 129                 }
 130         if (EM[emLen - 1] != 0xbc)
 131                 {
 132                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
 133                 goto err;
 134                 }
 135         maskedDBLen = emLen - hLen - 1;
 136         H = EM + maskedDBLen;
 137         DB = OPENSSL_malloc(maskedDBLen);
 138         if (!DB)
 139                 {
 140                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, ERR_R_MALLOC_FAILURE);
 141                 goto err;
 142                 }
 143         if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
 144                 goto err;
 145         for (i = 0; i < maskedDBLen; i++)
 146                 DB[i] ^= EM[i];
 147         if (MSBits)
 148                 DB[0] &= 0xFF >> (8 - MSBits);
 149         for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
 150         if (DB[i++] != 0x1)
 151                 {
 152                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED);
 153                 goto err;
 154                 }
 155         if (sLen >= 0 && (maskedDBLen - i) != sLen)
 156                 {
 157                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 158                 goto err;
 159                 }
 160         if (!EVP_DigestInit_ex(&ctx, Hash, NULL)
 161                 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes)
 162                 || !EVP_DigestUpdate(&ctx, mHash, hLen))
 163                 goto err;
 164         if (maskedDBLen - i)
 165                 {
 166                 if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i))
 167                         goto err;
 168                 }
 169         if (!EVP_DigestFinal(&ctx, H_, NULL))
 170                 goto err;
 171         if (memcmp(H_, H, hLen))
 172                 {
 173                 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_BAD_SIGNATURE);
 174                 ret = 0;
 175                 }
 176         else
 177                 ret = 1;
 178
 179         err:
 180         if (DB)
 181                 OPENSSL_free(DB);
 182         EVP_MD_CTX_cleanup(&ctx);
 183
 184         return ret;
 185
 186         }
 187
 188 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 189                         const unsigned char *mHash,
 190                         const EVP_MD *Hash, int sLen)
 191         {
 192         return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
 193         }
 194
 195 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
 196                         const unsigned char *mHash,
 197                         const EVP_MD *Hash, const EVP_MD *mgf1Hash, int sLen)
 198         {
 199         int i;
 200         int ret = 0;
 201         int hLen, maskedDBLen, MSBits, emLen;
 202         unsigned char *H, *salt = NULL, *p;
 203         EVP_MD_CTX ctx;
 204
 205         if (mgf1Hash == NULL)
 206                 mgf1Hash = Hash;
 207
 208         hLen = EVP_MD_size(Hash);
 209         if (hLen < 0)
 210                 goto err;
 211         /*
 212          * Negative sLen has special meanings:
 213          *      -1      sLen == hLen
 214          *      -2      salt length is maximized
 215          *      -N      reserved
 216          */
 217         if      (sLen == -1)    sLen = hLen;
 218         else if (sLen == -2)    sLen = -2;
 219         else if (sLen < -2)
 220                 {
 221                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
 222                 goto err;
 223                 }
 224
 225         MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 226         emLen = RSA_size(rsa);
 227         if (MSBits == 0)
 228                 {
 229                 *EM++ = 0;
 230                 emLen--;
 231                 }
 232         if (sLen == -2)
 233                 {
 234                 sLen = emLen - hLen - 2;
 235                 }
 236         else if (emLen < (hLen + sLen + 2))
 237                 {
 238                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 239                    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 240                 goto err;
 241                 }
 242         if (sLen > 0)
 243                 {
 244                 salt = OPENSSL_malloc(sLen);
 245                 if (!salt)
 246                         {
 247                         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
 248                                 ERR_R_MALLOC_FAILURE);
 249                         goto err;
 250                         }
 251                 if (RAND_bytes(salt, sLen) <= 0)
 252                         goto err;
 253                 }
 254         maskedDBLen = emLen - hLen - 1;
 255         H = EM + maskedDBLen;
 256         EVP_MD_CTX_init(&ctx);
 257         if (!EVP_DigestInit_ex(&ctx, Hash, NULL)
 258                 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes)
 259                 || !EVP_DigestUpdate(&ctx, mHash, hLen))
 260                 goto err;
 261         if (sLen && !EVP_DigestUpdate(&ctx, salt, sLen))
 262                 goto err;
 263         if (!EVP_DigestFinal(&ctx, H, NULL))
 264                 goto err;
 265         EVP_MD_CTX_cleanup(&ctx);
 266
 267         /* Generate dbMask in place then perform XOR on it */
 268         if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
 269                 goto err;
 270
 271         p = EM;
 272
 273         /* Initial PS XORs with all zeroes which is a NOP so just update
 274          * pointer. Note from a test above this value is guaranteed to
 275          * be non-negative.
 276          */
 277         p += emLen - sLen - hLen - 2;
 278         *p++ ^= 0x1;
 279         if (sLen > 0)
 280                 {
 281                 for (i = 0; i < sLen; i++)
 282                         *p++ ^= salt[i];
 283                 }
 284         if (MSBits)
 285                 EM[0] &= 0xFF >> (8 - MSBits);
 286
 287         /* H is already in place so just set final 0xbc */
 288
 289         EM[emLen - 1] = 0xbc;
 290
 291         ret = 1;
 292
 293         err:
 294         if (salt)
 295                 OPENSSL_free(salt);
 296
 297         return ret;
 298
 299         }
 300
 301 #if defined(_MSC_VER)
 302 #pragma optimize("",on)
 303 #endif