ssl/t1_ext.c

   1 /* ssl/t1_ext.c */
   2 /* ====================================================================
   3  * Copyright (c) 2014 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    openssl-core@openssl.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  * This product includes cryptographic software written by Eric Young
  51  * (eay@cryptsoft.com).  This product includes software written by Tim
  52  * Hudson (tjh@cryptsoft.com).
  53  *
  54  */
  55
  56 /* Custom extension utility functions */
  57
  58 #include "ssl_locl.h"
  59
  60 #ifndef OPENSSL_NO_TLSEXT
  61
  62 /* Find a custom extension from the list. */
  63 static custom_ext_method *custom_ext_find(custom_ext_methods *exts,
  64                                           unsigned int ext_type)
  65         {
  66         size_t i;
  67         custom_ext_method *meth = exts->meths;
  68         for (i = 0; i < exts->meths_count; i++, meth++)
  69                 {
  70                 if (ext_type == meth->ext_type)
  71                         return meth;
  72                 }
  73         return NULL;
  74         }
  75 /* Initialise custom extensions flags to indicate neither sent nor
  76  * received.
  77  */
  78 void custom_ext_init(custom_ext_methods *exts)
  79         {
  80         size_t i;
  81         custom_ext_method *meth = exts->meths;
  82         for (i = 0; i < exts->meths_count; i++, meth++)
  83                 meth->ext_flags = 0;
  84         }
  85
  86 /* Pass received custom extension data to the application for parsing. */
  87 int custom_ext_parse(SSL *s, int server,
  88                      unsigned int ext_type,
  89                      const unsigned char *ext_data,
  90                      size_t ext_size,
  91                      int *al)
  92         {
  93         custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
  94         custom_ext_method *meth;
  95         meth = custom_ext_find(exts, ext_type);
  96         /* If not found return success */
  97         if (!meth)
  98                 return 1;
  99         if (!server)
 100                 {
 101                 /* If it's ServerHello we can't have any extensions not
 102                  * sent in ClientHello.
 103                  */
 104                 if (!(meth->ext_flags & SSL_EXT_FLAG_SENT))
 105                         {
 106                         *al = TLS1_AD_UNSUPPORTED_EXTENSION;
 107                         return 0;
 108                         }
 109                 }
 110         /* If already present it's a duplicate */
 111         if (meth->ext_flags & SSL_EXT_FLAG_RECEIVED)
 112                 {
 113                 *al = TLS1_AD_DECODE_ERROR;
 114                 return 0;
 115                 }
 116         meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
 117         /* If no parse function set return success */
 118         if (!meth->parse_cb)
 119                 return 1;
 120
 121         return meth->parse_cb(s, ext_type, ext_data, ext_size, al, meth->parse_arg);
 122         }
 123
 124 /* Request custom extension data from the application and add to the
 125  * return buffer.
 126  */
 127 int custom_ext_add(SSL *s, int server,
 128                    unsigned char **pret,
 129                    unsigned char *limit,
 130                    int *al)
 131         {
 132         custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
 133         custom_ext_method *meth;
 134         unsigned char *ret = *pret;
 135         size_t i;
 136
 137         for (i = 0; i < exts->meths_count; i++)
 138                 {
 139                 const unsigned char *out = NULL;
 140                 size_t outlen = 0;
 141                 meth = exts->meths + i;
 142
 143                 if (server)
 144                         {
 145                         /* For ServerHello only send extensions present
 146                          * in ClientHello.
 147                          */
 148                         if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
 149                                 continue;
 150                         /* If callback absent for server skip it */
 151                         if (!meth->add_cb)
 152                                 continue;
 153                         }
 154                 if (meth->add_cb)
 155                         {
 156                         int cb_retval = 0;
 157                         cb_retval = meth->add_cb(s, meth->ext_type,
 158                                                         &out, &outlen, al,
 159                                                         meth->add_arg);
 160                         if (cb_retval < 0)
 161                                 return 0; /* error */
 162                         if (cb_retval == 0)
 163                                         continue; /* skip this extension */
 164                         }
 165                 if (4 > limit - ret || outlen > (size_t)(limit - ret - 4))
 166                         return 0;
 167                 s2n(meth->ext_type, ret);
 168                 s2n(outlen, ret);
 169                 if (outlen)
 170                         {
 171                         memcpy(ret, out, outlen);
 172                         ret += outlen;
 173                         }
 174                 /* We can't send duplicates: code logic should prevent this. */
 175                 OPENSSL_assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
 176                 /* Indicate extension has been sent: this is both a sanity
 177                  * check to ensure we don't send duplicate extensions
 178                  * and indicates that it is not an error if the extension
 179                  * is present in ServerHello.
 180                  */
 181                 meth->ext_flags |= SSL_EXT_FLAG_SENT;
 182                 if (meth->free_cb)
 183                         meth->free_cb(s, meth->ext_type, out, meth->add_arg);
 184                 }
 185         *pret = ret;
 186         return 1;
 187         }
 188
 189 /* Copy table of custom extensions */
 190 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
 191         {
 192         if (src->meths_count)
 193                 {
 194                 dst->meths = BUF_memdup(src->meths, sizeof(custom_ext_method) * src->meths_count);
 195                 if (dst->meths == NULL)
 196                         return 0;
 197                 dst->meths_count = src->meths_count;
 198                 }
 199         return 1;
 200         }
 201
 202 void custom_exts_free(custom_ext_methods *exts)
 203         {
 204         if (exts->meths)
 205                 OPENSSL_free(exts->meths);
 206         }
 207
 208 /* Set callbacks for a custom extension. */
 209 static int custom_ext_meth_add(custom_ext_methods *exts,
 210                                unsigned int ext_type,
 211                                custom_ext_add_cb add_cb,
 212                                custom_ext_free_cb free_cb,
 213                                void *add_arg,
 214                                custom_ext_parse_cb parse_cb, void *parse_arg)
 215         {
 216         custom_ext_method *meth;
 217         /* Check application error: if add_cb is not set free_cb will never
 218          * be called.
 219          */
 220         if (!add_cb && free_cb)
 221                 return 0;
 222         /* Don't add if extension supported internally. */
 223         if (SSL_extension_supported(ext_type))
 224                 return 0;
 225         /* Extension type must fit in 16 bits */
 226         if (ext_type > 0xffff)
 227                 return 0;
 228         /* Search for duplicate */
 229         if (custom_ext_find(exts, ext_type))
 230                 return 0;
 231         exts->meths = OPENSSL_realloc(exts->meths,
 232                                       (exts->meths_count + 1) * sizeof(custom_ext_method));
 233
 234         if (!exts->meths)
 235                 {
 236                 exts->meths_count = 0;
 237                 return 0;
 238                 }
 239
 240         meth = exts->meths + exts->meths_count;
 241         memset(meth, 0, sizeof(custom_ext_method));
 242         meth->parse_cb = parse_cb;
 243         meth->add_cb = add_cb;
 244         meth->free_cb = free_cb;
 245         meth->ext_type = ext_type;
 246         meth->add_arg = add_arg;
 247         meth->parse_arg = parse_arg;
 248         exts->meths_count++;
 249         return 1;
 250         }
 251
 252 /* Application level functions to add custom extension callbacks */
 253 int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
 254                                   custom_ext_add_cb add_cb,
 255                                   custom_ext_free_cb free_cb,
 256                                   void *add_arg,
 257                                   custom_ext_parse_cb parse_cb, void *parse_arg)
 258
 259         {
 260         return custom_ext_meth_add(&ctx->cert->cli_ext, ext_type,
 261                                    add_cb, free_cb, add_arg,
 262                                    parse_cb, parse_arg);
 263         }
 264
 265 int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
 266                                   custom_ext_add_cb add_cb,
 267                                   custom_ext_free_cb free_cb,
 268                                   void *add_arg,
 269                                   custom_ext_parse_cb parse_cb, void *parse_arg)
 270         {
 271         return custom_ext_meth_add(&ctx->cert->srv_ext, ext_type,
 272                                    add_cb, free_cb, add_arg,
 273                                    parse_cb, parse_arg);
 274         }
 275
 276 int SSL_extension_supported(unsigned int ext_type)
 277         {
 278         switch(ext_type)
 279                 {
 280         /* Internally supported extensions. */
 281         case TLSEXT_TYPE_application_layer_protocol_negotiation:
 282         case TLSEXT_TYPE_ec_point_formats:
 283         case TLSEXT_TYPE_elliptic_curves:
 284         case TLSEXT_TYPE_heartbeat:
 285         case TLSEXT_TYPE_next_proto_neg:
 286         case TLSEXT_TYPE_padding:
 287         case TLSEXT_TYPE_renegotiate:
 288         case TLSEXT_TYPE_server_name:
 289         case TLSEXT_TYPE_session_ticket:
 290         case TLSEXT_TYPE_signature_algorithms:
 291         case TLSEXT_TYPE_srp:
 292         case TLSEXT_TYPE_status_request:
 293         case TLSEXT_TYPE_use_srtp:
 294 #ifdef TLSEXT_TYPE_opaque_prf_input
 295         case TLSEXT_TYPE_opaque_prf_input:
 296 #endif
 297 #ifdef TLSEXT_TYPE_encrypt_then_mac
 298         case TLSEXT_TYPE_encrypt_then_mac:
 299 #endif
 300                 return 1;
 301         default:
 302                 return 0;
 303                 }
 304         }
 305 #endif