lib/libcrypto/rsa/rsa_ssl.c

   1 /* $OpenBSD: rsa_ssl.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_SSLv23(unsigned char *to, int tlen, const unsigned char *from,
  69     int flen)
  70 {
  71         int i, j;
  72         unsigned char *p;
  73
  74         if (flen > tlen - 11) {
  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++) = 2; /* Public Key BT (Block Type) */
  83
  84         /* pad out with non-zero random data */
  85         j = tlen - 3 - 8 - flen;
  86
  87         arc4random_buf(p, j);
  88         for (i = 0; i < j; i++) {
  89                 while (*p == '\0')
  90                         arc4random_buf(p, 1);
  91                 p++;
  92         }
  93
  94         memset(p, 3, 8);
  95         p += 8;
  96         *(p++) = '\0';
  97
  98         memcpy(p, from, flen);
  99         return 1;
 100 }
 101
 102 int
 103 RSA_padding_check_SSLv23(unsigned char *to, int tlen, const unsigned char *from,
 104     int flen, int num)
 105 {
 106         int i, j, k;
 107         const unsigned char *p;
 108
 109         p = from;
 110         if (flen < 10) {
 111                 RSAerror(RSA_R_DATA_TOO_SMALL);
 112                 return -1;
 113         }
 114         if (num != flen + 1 || *(p++) != 02) {
 115                 RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_02);
 116                 return -1;
 117         }
 118
 119         /* scan over padding data */
 120         j = flen - 1; /* one for type */
 121         for (i = 0; i < j; i++)
 122                 if (*(p++) == 0)
 123                         break;
 124
 125         if (i == j || i < 8) {
 126                 RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING);
 127                 return -1;
 128         }
 129         for (k = -9; k < -1; k++) {
 130                 if (p[k] !=  0x03)
 131                         break;
 132         }
 133         if (k == -1) {
 134                 RSAerror(RSA_R_SSLV3_ROLLBACK_ATTACK);
 135                 return -1;
 136         }
 137
 138         i++; /* Skip over the '\0' */
 139         j -= i;
 140         if (j > tlen) {
 141                 RSAerror(RSA_R_DATA_TOO_LARGE);
 142                 return -1;
 143         }
 144         memcpy(to, p, j);
 145
 146         return j;
 147 }