crypto/rsa/rsa_pss.c

   1 /*
   2  * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/bn.h>
  13 #include <openssl/rsa.h>
  14 #include <openssl/evp.h>
  15 #include <openssl/rand.h>
  16 #include <openssl/sha.h>
  17 #include "rsa_locl.h"
  18
  19 static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  20
  21 #if defined(_MSC_VER) && defined(_ARM_)
  22 # pragma optimize("g", off)
  23 #endif
  24
  25 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
  26                          const EVP_MD *Hash, const unsigned char *EM,
  27                          int sLen)
  28 {
  29     return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
  30 }
  31
  32 int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
  33                               const EVP_MD *Hash, const EVP_MD *mgf1Hash,
  34                               const unsigned char *EM, int sLen)
  35 {
  36     int i;
  37     int ret = 0;
  38     int hLen, maskedDBLen, MSBits, emLen;
  39     const unsigned char *H;
  40     unsigned char *DB = NULL;
  41     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
  42     unsigned char H_[EVP_MAX_MD_SIZE];
  43
  44
  45     if (ctx == NULL)
  46         goto err;
  47
  48     if (mgf1Hash == NULL)
  49         mgf1Hash = Hash;
  50
  51     hLen = EVP_MD_size(Hash);
  52     if (hLen < 0)
  53         goto err;
  54     /*-
  55      * Negative sLen has special meanings:
  56      *      -1      sLen == hLen
  57      *      -2      salt length is autorecovered from signature
  58      *      -N      reserved
  59      */
  60     if (sLen == -1)
  61         sLen = hLen;
  62     else if (sLen == -2)
  63         sLen = -2;
  64     else if (sLen < -2) {
  65         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
  66         goto err;
  67     }
  68
  69     MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
  70     emLen = RSA_size(rsa);
  71     if (EM[0] & (0xFF << MSBits)) {
  72         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID);
  73         goto err;
  74     }
  75     if (MSBits == 0) {
  76         EM++;
  77         emLen--;
  78     }
  79     if (emLen < hLen + 2) {
  80         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
  81         goto err;
  82     }
  83     if (sLen > emLen - hLen - 2) { /* sLen can be small negative */
  84         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
  85         goto err;
  86     }
  87     if (EM[emLen - 1] != 0xbc) {
  88         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID);
  89         goto err;
  90     }
  91     maskedDBLen = emLen - hLen - 1;
  92     H = EM + maskedDBLen;
  93     DB = OPENSSL_malloc(maskedDBLen);
  94     if (DB == NULL) {
  95         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE);
  96         goto err;
  97     }
  98     if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
  99         goto err;
 100     for (i = 0; i < maskedDBLen; i++)
 101         DB[i] ^= EM[i];
 102     if (MSBits)
 103         DB[0] &= 0xFF >> (8 - MSBits);
 104     for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ;
 105     if (DB[i++] != 0x1) {
 106         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED);
 107         goto err;
 108     }
 109     if (sLen >= 0 && (maskedDBLen - i) != sLen) {
 110         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
 111         goto err;
 112     }
 113     if (!EVP_DigestInit_ex(ctx, Hash, NULL)
 114         || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
 115         || !EVP_DigestUpdate(ctx, mHash, hLen))
 116         goto err;
 117     if (maskedDBLen - i) {
 118         if (!EVP_DigestUpdate(ctx, DB + i, maskedDBLen - i))
 119             goto err;
 120     }
 121     if (!EVP_DigestFinal_ex(ctx, H_, NULL))
 122         goto err;
 123     if (memcmp(H_, H, hLen)) {
 124         RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE);
 125         ret = 0;
 126     } else
 127         ret = 1;
 128
 129  err:
 130     OPENSSL_free(DB);
 131     EVP_MD_CTX_free(ctx);
 132
 133     return ret;
 134
 135 }
 136
 137 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
 138                               const unsigned char *mHash,
 139                               const EVP_MD *Hash, int sLen)
 140 {
 141     return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
 142 }
 143
 144 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
 145                                    const unsigned char *mHash,
 146                                    const EVP_MD *Hash, const EVP_MD *mgf1Hash,
 147                                    int sLen)
 148 {
 149     int i;
 150     int ret = 0;
 151     int hLen, maskedDBLen, MSBits, emLen;
 152     unsigned char *H, *salt = NULL, *p;
 153     EVP_MD_CTX *ctx = NULL;
 154
 155     if (mgf1Hash == NULL)
 156         mgf1Hash = Hash;
 157
 158     hLen = EVP_MD_size(Hash);
 159     if (hLen < 0)
 160         goto err;
 161     /*-
 162      * Negative sLen has special meanings:
 163      *      -1      sLen == hLen
 164      *      -2      salt length is maximized
 165      *      -N      reserved
 166      */
 167     if (sLen == -1)
 168         sLen = hLen;
 169     else if (sLen == -2)
 170         sLen = -2;
 171     else if (sLen < -2) {
 172         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
 173         goto err;
 174     }
 175
 176     MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
 177     emLen = RSA_size(rsa);
 178     if (MSBits == 0) {
 179         *EM++ = 0;
 180         emLen--;
 181     }
 182     if (emLen < hLen + 2) {
 183         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
 184                RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 185         goto err;
 186     }
 187     if (sLen == -2) {
 188         sLen = emLen - hLen - 2;
 189     } else if (sLen > emLen - hLen - 2) {
 190         RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
 191                RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 192         goto err;
 193     }
 194     if (sLen > 0) {
 195         salt = OPENSSL_malloc(sLen);
 196         if (salt == NULL) {
 197             RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
 198                    ERR_R_MALLOC_FAILURE);
 199             goto err;
 200         }
 201         if (RAND_bytes(salt, sLen) <= 0)
 202             goto err;
 203     }
 204     maskedDBLen = emLen - hLen - 1;
 205     H = EM + maskedDBLen;
 206     ctx = EVP_MD_CTX_new();
 207     if (ctx == NULL)
 208         goto err;
 209     if (!EVP_DigestInit_ex(ctx, Hash, NULL)
 210         || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
 211         || !EVP_DigestUpdate(ctx, mHash, hLen))
 212         goto err;
 213     if (sLen && !EVP_DigestUpdate(ctx, salt, sLen))
 214         goto err;
 215     if (!EVP_DigestFinal_ex(ctx, H, NULL))
 216         goto err;
 217
 218     /* Generate dbMask in place then perform XOR on it */
 219     if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
 220         goto err;
 221
 222     p = EM;
 223
 224     /*
 225      * Initial PS XORs with all zeroes which is a NOP so just update pointer.
 226      * Note from a test above this value is guaranteed to be non-negative.
 227      */
 228     p += emLen - sLen - hLen - 2;
 229     *p++ ^= 0x1;
 230     if (sLen > 0) {
 231         for (i = 0; i < sLen; i++)
 232             *p++ ^= salt[i];
 233     }
 234     if (MSBits)
 235         EM[0] &= 0xFF >> (8 - MSBits);
 236
 237     /* H is already in place so just set final 0xbc */
 238
 239     EM[emLen - 1] = 0xbc;
 240
 241     ret = 1;
 242
 243  err:
 244     EVP_MD_CTX_free(ctx);
 245     OPENSSL_clear_free(salt, sLen);
 246
 247     return ret;
 248
 249 }
 250
 251 #if defined(_MSC_VER)
 252 # pragma optimize("",on)
 253 #endif