release/src/router/openssl/crypto/rsa/rsa_pk1.c

   1 /* crypto/rsa/rsa_pk1.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include "constant_time_locl.h"
  60
  61 #include <stdio.h>
  62 #include "cryptlib.h"
  63 #include <openssl/bn.h>
  64 #include <openssl/rsa.h>
  65 #include <openssl/rand.h>
  66
  67 int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
  68              const unsigned char *from, int flen)
  69         {
  70         int j;
  71         unsigned char *p;
  72
  73         if (flen > (tlen-RSA_PKCS1_PADDING_SIZE))
  74                 {
  75                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_1,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
  76                 return(0);
  77                 }
  78
  79         p=(unsigned char *)to;
  80
  81         *(p++)=0;
  82         *(p++)=1; /* Private Key BT (Block Type) */
  83
  84         /* pad out with 0xff data */
  85         j=tlen-3-flen;
  86         memset(p,0xff,j);
  87         p+=j;
  88         *(p++)='\0';
  89         memcpy(p,from,(unsigned int)flen);
  90         return(1);
  91         }
  92
  93 int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
  94              const unsigned char *from, int flen, int num)
  95         {
  96         int i,j;
  97         const unsigned char *p;
  98
  99         p=from;
 100         if ((num != (flen+1)) || (*(p++) != 01))
 101                 {
 102                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BLOCK_TYPE_IS_NOT_01);
 103                 return(-1);
 104                 }
 105
 106         /* scan over padding data */
 107         j=flen-1; /* one for type. */
 108         for (i=0; i<j; i++)
 109                 {
 110                 if (*p != 0xff) /* should decrypt to 0xff */
 111                         {
 112                         if (*p == 0)
 113                                 { p++; break; }
 114                         else    {
 115                                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_FIXED_HEADER_DECRYPT);
 116                                 return(-1);
 117                                 }
 118                         }
 119                 p++;
 120                 }
 121
 122         if (i == j)
 123                 {
 124                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_NULL_BEFORE_BLOCK_MISSING);
 125                 return(-1);
 126                 }
 127
 128         if (i < 8)
 129                 {
 130                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_PAD_BYTE_COUNT);
 131                 return(-1);
 132                 }
 133         i++; /* Skip over the '\0' */
 134         j-=i;
 135         if (j > tlen)
 136                 {
 137                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_DATA_TOO_LARGE);
 138                 return(-1);
 139                 }
 140         memcpy(to,p,(unsigned int)j);
 141
 142         return(j);
 143         }
 144
 145 int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
 146              const unsigned char *from, int flen)
 147         {
 148         int i,j;
 149         unsigned char *p;
 150
 151         if (flen > (tlen-11))
 152                 {
 153                 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_2,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 154                 return(0);
 155                 }
 156
 157         p=(unsigned char *)to;
 158
 159         *(p++)=0;
 160         *(p++)=2; /* Public Key BT (Block Type) */
 161
 162         /* pad out with non-zero random data */
 163         j=tlen-3-flen;
 164
 165         if (RAND_bytes(p,j) <= 0)
 166                 return(0);
 167         for (i=0; i<j; i++)
 168                 {
 169                 if (*p == '\0')
 170                         do      {
 171                                 if (RAND_bytes(p,1) <= 0)
 172                                         return(0);
 173                                 } while (*p == '\0');
 174                 p++;
 175                 }
 176
 177         *(p++)='\0';
 178
 179         memcpy(p,from,(unsigned int)flen);
 180         return(1);
 181         }
 182
 183 int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
 184              const unsigned char *from, int flen, int num)
 185         {
 186         int i;
 187         /* |em| is the encoded message, zero-padded to exactly |num| bytes */
 188         unsigned char *em = NULL;
 189         unsigned int good, found_zero_byte;
 190         int zero_index = 0, msg_index, mlen = -1;
 191
 192         if (tlen < 0 || flen < 0)
 193                 return -1;
 194
 195         /* PKCS#1 v1.5 decryption. See "PKCS #1 v2.2: RSA Cryptography
 196          * Standard", section 7.2.2. */
 197
 198         if (flen > num)
 199                 goto err;
 200
 201         if (num < 11)
 202                 goto err;
 203
 204         em = OPENSSL_malloc(num);
 205         if (em == NULL)
 206                 {
 207                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2, ERR_R_MALLOC_FAILURE);
 208                 return -1;
 209                 }
 210         memset(em, 0, num);
 211         /*
 212          * Always do this zero-padding copy (even when num == flen) to avoid
 213          * leaking that information. The copy still leaks some side-channel
 214          * information, but it's impossible to have a fixed  memory access
 215          * pattern since we can't read out of the bounds of |from|.
 216          *
 217          * TODO(emilia): Consider porting BN_bn2bin_padded from BoringSSL.
 218          */
 219         memcpy(em + num - flen, from, flen);
 220
 221         good = constant_time_is_zero(em[0]);
 222         good &= constant_time_eq(em[1], 2);
 223
 224         found_zero_byte = 0;
 225         for (i = 2; i < num; i++)
 226                 {
 227                 unsigned int equals0 = constant_time_is_zero(em[i]);
 228                 zero_index = constant_time_select_int(~found_zero_byte & equals0, i, zero_index);
 229                 found_zero_byte |= equals0;
 230                 }
 231
 232         /*
 233          * PS must be at least 8 bytes long, and it starts two bytes into |em|.
 234          * If we never found a 0-byte, then |zero_index| is 0 and the check
 235          * also fails.
 236          */
 237         good &= constant_time_ge((unsigned int)(zero_index), 2 + 8);
 238
 239         /* Skip the zero byte. This is incorrect if we never found a zero-byte
 240          * but in this case we also do not copy the message out. */
 241         msg_index = zero_index + 1;
 242         mlen = num - msg_index;
 243
 244         /* For good measure, do this check in constant time as well; it could
 245          * leak something if |tlen| was assuming valid padding. */
 246         good &= constant_time_ge((unsigned int)(tlen), (unsigned int)(mlen));
 247
 248         /*
 249          * We can't continue in constant-time because we need to copy the result
 250          * and we cannot fake its length. This unavoidably leaks timing
 251          * information at the API boundary.
 252          * TODO(emilia): this could be addressed at the call site,
 253          * see BoringSSL commit 0aa0767340baf925bda4804882aab0cb974b2d26.
 254          */
 255         if (!good)
 256                 {
 257                 mlen = -1;
 258                 goto err;
 259                 }
 260
 261         memcpy(to, em + msg_index, mlen);
 262
 263 err:
 264         if (em != NULL)
 265                 OPENSSL_free(em);
 266         if (mlen == -1)
 267                 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2, RSA_R_PKCS_DECODING_ERROR);
 268         return mlen;
 269         }