lib/libssl/d1_enc.c

   1 /* $OpenBSD: d1_enc.c,v 1.14 2017/01/23 08:08:06 beck Exp $ */
   2 /*
   3  * DTLS implementation written by Nagendra Modadugu
   4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. All advertising materials mentioning features or use of this
  22  *    software must display the following acknowledgment:
  23  *    "This product includes software developed by the OpenSSL Project
  24  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  25  *
  26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  27  *    endorse or promote products derived from this software without
  28  *    prior written permission. For written permission, please contact
  29  *    openssl-core@openssl.org.
  30  *
  31  * 5. Products derived from this software may not be called "OpenSSL"
  32  *    nor may "OpenSSL" appear in their names without prior written
  33  *    permission of the OpenSSL Project.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  51  * OF THE POSSIBILITY OF SUCH DAMAGE.
  52  * ====================================================================
  53  *
  54  * This product includes cryptographic software written by Eric Young
  55  * (eay@cryptsoft.com).  This product includes software written by Tim
  56  * Hudson (tjh@cryptsoft.com).
  57  *
  58  */
  59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  60  * All rights reserved.
  61  *
  62  * This package is an SSL implementation written
  63  * by Eric Young (eay@cryptsoft.com).
  64  * The implementation was written so as to conform with Netscapes SSL.
  65  *
  66  * This library is free for commercial and non-commercial use as long as
  67  * the following conditions are aheared to.  The following conditions
  68  * apply to all code found in this distribution, be it the RC4, RSA,
  69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  70  * included with this distribution is covered by the same copyright terms
  71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  72  *
  73  * Copyright remains Eric Young's, and as such any Copyright notices in
  74  * the code are not to be removed.
  75  * If this package is used in a product, Eric Young should be given attribution
  76  * as the author of the parts of the library used.
  77  * This can be in the form of a textual message at program startup or
  78  * in documentation (online or textual) provided with the package.
  79  *
  80  * Redistribution and use in source and binary forms, with or without
  81  * modification, are permitted provided that the following conditions
  82  * are met:
  83  * 1. Redistributions of source code must retain the copyright
  84  *    notice, this list of conditions and the following disclaimer.
  85  * 2. Redistributions in binary form must reproduce the above copyright
  86  *    notice, this list of conditions and the following disclaimer in the
  87  *    documentation and/or other materials provided with the distribution.
  88  * 3. All advertising materials mentioning features or use of this software
  89  *    must display the following acknowledgement:
  90  *    "This product includes cryptographic software written by
  91  *     Eric Young (eay@cryptsoft.com)"
  92  *    The word 'cryptographic' can be left out if the rouines from the library
  93  *    being used are not cryptographic related :-).
  94  * 4. If you include any Windows specific code (or a derivative thereof) from
  95  *    the apps directory (application code) you must include an acknowledgement:
  96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  97  *
  98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 108  * SUCH DAMAGE.
 109  *
 110  * The licence and distribution terms for any publically available version or
 111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
 112  * copied and put under another distribution licence
 113  * [including the GNU Public Licence.]
 114  */
 115
 116 #include <stdio.h>
 117
 118 #include "ssl_locl.h"
 119
 120 #include <openssl/evp.h>
 121 #include <openssl/hmac.h>
 122 #include <openssl/md5.h>
 123
 124 /* dtls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
 125  *
 126  * Returns:
 127  *   0: (in non-constant time) if the record is publically invalid (i.e. too
 128  *       short etc).
 129  *   1: if the record's padding is valid / the encryption was successful.
 130  *   -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
 131  *       an internal error occured. */
 132 int
 133 dtls1_enc(SSL *s, int send)
 134 {
 135         SSL3_RECORD *rec;
 136         EVP_CIPHER_CTX *ds;
 137         unsigned long l;
 138         int bs, i, j, k, mac_size = 0;
 139         const EVP_CIPHER *enc;
 140
 141         if (send) {
 142                 if (EVP_MD_CTX_md(s->internal->write_hash)) {
 143                         mac_size = EVP_MD_CTX_size(s->internal->write_hash);
 144                         if (mac_size < 0)
 145                                 return -1;
 146                 }
 147                 ds = s->internal->enc_write_ctx;
 148                 rec = &(S3I(s)->wrec);
 149                 if (s->internal->enc_write_ctx == NULL)
 150                         enc = NULL;
 151                 else {
 152                         enc = EVP_CIPHER_CTX_cipher(s->internal->enc_write_ctx);
 153                         if (rec->data != rec->input) {
 154 #ifdef DEBUG
 155                                 /* we can't write into the input stream */
 156                                 fprintf(stderr, "%s:%d: rec->data != rec->input\n",
 157                                     __FILE__, __LINE__);
 158 #endif
 159                         } else if (EVP_CIPHER_block_size(ds->cipher) > 1) {
 160                                 arc4random_buf(rec->input,
 161                                     EVP_CIPHER_block_size(ds->cipher));
 162                         }
 163                 }
 164         } else {
 165                 if (EVP_MD_CTX_md(s->read_hash)) {
 166                         mac_size = EVP_MD_CTX_size(s->read_hash);
 167                         OPENSSL_assert(mac_size >= 0);
 168                 }
 169                 ds = s->enc_read_ctx;
 170                 rec = &(S3I(s)->rrec);
 171                 if (s->enc_read_ctx == NULL)
 172                         enc = NULL;
 173                 else
 174                         enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
 175         }
 176
 177
 178         if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) {
 179                 memmove(rec->data, rec->input, rec->length);
 180                 rec->input = rec->data;
 181         } else {
 182                 l = rec->length;
 183                 bs = EVP_CIPHER_block_size(ds->cipher);
 184
 185                 if ((bs != 1) && send) {
 186                         i = bs - ((int)l % bs);
 187
 188                         /* Add weird padding of upto 256 bytes */
 189
 190                         /* we need to add 'i' padding bytes of value j */
 191                         j = i - 1;
 192                         for (k = (int)l; k < (int)(l + i); k++)
 193                                 rec->input[k] = j;
 194                         l += i;
 195                         rec->length += i;
 196                 }
 197
 198
 199                 if (!send) {
 200                         if (l == 0 || l % bs != 0)
 201                                 return 0;
 202                 }
 203
 204                 EVP_Cipher(ds, rec->data, rec->input, l);
 205
 206
 207                 if ((bs != 1) && !send)
 208                         return tls1_cbc_remove_padding(s, rec, bs, mac_size);
 209         }
 210         return (1);
 211 }
 212