lib/libcrypto/rsa/rsa_pk1.c

   1 /* $OpenBSD: rsa_pk1.c,v 1.15 2017/01/29 17:49:23 beck Exp $ */
   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 <stdio.h>
  60 #include <stdlib.h>
  61 #include <string.h>
  62
  63 #include <openssl/bn.h>
  64 #include <openssl/err.h>
  65 #include <openssl/rsa.h>
  66
  67 int
  68 RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
  69     const unsigned char *from, int flen)
  70 {
  71         int j;
  72         unsigned char *p;
  73
  74         if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {
  75                 RSAerror(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, flen);
  90
  91         return 1;
  92 }
  93
  94 int
  95 RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
  96     const unsigned char *from, int flen, int num)
  97 {
  98         int i, j;
  99         const unsigned char *p;
 100
 101         p = from;
 102         if (num != flen + 1 || *(p++) != 01) {
 103                 RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_01);
 104                 return -1;
 105         }
 106
 107         /* scan over padding data */
 108         j = flen - 1; /* one for type. */
 109         for (i = 0; i < j; i++) {
 110                 if (*p != 0xff) {
 111                         /* should decrypt to 0xff */
 112                         if (*p == 0) {
 113                                 p++;
 114                                 break;
 115                         } else {
 116                                 RSAerror(RSA_R_BAD_FIXED_HEADER_DECRYPT);
 117                                 return -1;
 118                         }
 119                 }
 120                 p++;
 121         }
 122
 123         if (i == j) {
 124                 RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING);
 125                 return -1;
 126         }
 127
 128         if (i < 8) {
 129                 RSAerror(RSA_R_BAD_PAD_BYTE_COUNT);
 130                 return -1;
 131         }
 132         i++; /* Skip over the '\0' */
 133         j -= i;
 134         if (j > tlen) {
 135                 RSAerror(RSA_R_DATA_TOO_LARGE);
 136                 return -1;
 137         }
 138         memcpy(to, p, j);
 139
 140         return j;
 141 }
 142
 143 int
 144 RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
 145     const unsigned char *from, int flen)
 146 {
 147         int i, j;
 148         unsigned char *p;
 149
 150         if (flen > tlen - 11) {
 151                 RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
 152                 return 0;
 153         }
 154
 155         p = (unsigned char *)to;
 156
 157         *(p++) = 0;
 158         *(p++) = 2; /* Public Key BT (Block Type) */
 159
 160         /* pad out with non-zero random data */
 161         j = tlen - 3 - flen;
 162
 163         arc4random_buf(p, j);
 164         for (i = 0; i < j; i++) {
 165                 while (*p == '\0')
 166                         arc4random_buf(p, 1);
 167                 p++;
 168         }
 169
 170         *(p++) = '\0';
 171
 172         memcpy(p, from, flen);
 173         return 1;
 174 }
 175
 176 int
 177 RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
 178     const unsigned char *from, int flen, int num)
 179 {
 180         int i, j;
 181         const unsigned char *p;
 182
 183         p = from;
 184         if (num != flen + 1 || *(p++) != 02) {
 185                 RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_02);
 186                 return -1;
 187         }
 188
 189         /* scan over padding data */
 190         j = flen - 1; /* one for type. */
 191         for (i = 0; i < j; i++)
 192                 if (*(p++) == 0)
 193                         break;
 194
 195         if (i == j) {
 196                 RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING);
 197                 return -1;
 198         }
 199
 200         if (i < 8) {
 201                 RSAerror(RSA_R_BAD_PAD_BYTE_COUNT);
 202                 return -1;
 203         }
 204         i++; /* Skip over the '\0' */
 205         j -= i;
 206         if (j > tlen) {
 207                 RSAerror(RSA_R_DATA_TOO_LARGE);
 208                 return -1;
 209         }
 210         memcpy(to, p, j);
 211
 212         return j;
 213 }