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
  64 static custom_ext_method *custom_ext_find(custom_ext_methods *exts,
  65                                                 unsigned short ext_type)
  66         {
  67         size_t i;
  68         custom_ext_method *meth = exts->meths;
  69         for (i = 0; i < exts->meths_count; i++, meth++)
  70                 {
  71                 if (ext_type == meth->ext_type)
  72                         return meth;
  73                 }
  74         return NULL;
  75         }
  76 /* Initialise custom extensions flags to indicate neither sent nor
  77  * received.
  78  */
  79 void custom_ext_init(custom_ext_methods *exts)
  80         {
  81         size_t i;
  82         custom_ext_method *meth = exts->meths;
  83         for (i = 0; i < exts->meths_count; i++, meth++)
  84                 meth->ext_flags = 0;
  85         }
  86
  87 /* pass received custom extension data to the application for parsing */
  88
  89 int custom_ext_parse(SSL *s, int server,
  90                         unsigned int ext_type,
  91                         const unsigned char *ext_data,
  92                         size_t ext_size,
  93                         int *al)
  94         {
  95         custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
  96         custom_ext_method *meth;
  97         meth = custom_ext_find(exts, ext_type);
  98         /* If not found or no parse function set, return success */
  99         /* If not found return success */
 100         if (!meth)
 101                 return 1;
 102         if (!server)
 103                 {
 104                 /* If it's ServerHello we can't have any extensions not
 105                  * sent in ClientHello.
 106                  */
 107                 if (!(meth->ext_flags & SSL_EXT_FLAG_SENT))
 108                         {
 109                         *al = TLS1_AD_UNSUPPORTED_EXTENSION;
 110                         return 0;
 111                         }
 112                 }
 113         /* If already present it's a duplicate */
 114         if (meth->ext_flags & SSL_EXT_FLAG_RECEIVED)
 115                 {
 116                 *al = TLS1_AD_DECODE_ERROR;
 117                 return 0;
 118                 }
 119         meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
 120         if (!meth->parse_cb)
 121                 return 1;
 122
 123         return meth->parse_cb(s, ext_type, ext_data, ext_size, al, meth->arg);
 124         }
 125
 126 /* request custom extension data from the application and add to the
 127  * return buffer
 128  */
 129
 130 int custom_ext_add(SSL *s, int server,
 131                         unsigned char **pret,
 132                         unsigned char *limit,
 133                         int *al)
 134         {
 135         custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
 136         custom_ext_method *meth;
 137         unsigned char *ret = *pret;
 138         size_t i;
 139
 140         for (i = 0; i < exts->meths_count; i++)
 141                 {
 142                 const unsigned char *out = NULL;
 143                 size_t outlen = 0;
 144                 meth = exts->meths + i;
 145
 146                 if (server)
 147                         {
 148                         /* For ServerHello only send extensions present
 149                          * in ClientHello.
 150                          */
 151                         if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
 152                                 continue;
 153                         /* If callback absent for server skip it */
 154                         if (!meth->add_cb)
 155                                 continue;
 156                         }
 157                 if (meth->add_cb)
 158                         {
 159                         int cb_retval = 0;
 160                         cb_retval = meth->add_cb(s, meth->ext_type,
 161                                                         &out, &outlen, al,
 162                                                         meth->arg);
 163                         if (cb_retval == 0)
 164                                 return 0; /* error */
 165                         if (cb_retval == -1)
 166                                         continue; /* skip this extension */
 167                         }
 168                 if (4 > limit - ret || outlen > (size_t)(limit - ret - 4))
 169                         return 0;
 170                 s2n(meth->ext_type, ret);
 171                 s2n(outlen, ret);
 172                 if (outlen)
 173                         {
 174                         memcpy(ret, out, outlen);
 175                         ret += outlen;
 176                         }
 177                 /* We can't send duplicates: code logic should prevent this */
 178                 OPENSSL_assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
 179                 /* Indicate extension has been sent: this is both a sanity
 180                  * check to ensure we don't send duplicate extensions
 181                  * and indicates to servers that an extension can be
 182                  * sent in ServerHello.
 183                  */
 184                 meth->ext_flags |= SSL_EXT_FLAG_SENT;
 185                 }
 186         *pret = ret;
 187         return 1;
 188         }
 189
 190 /* Copy table of custom extensions */
 191
 192 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
 193         {
 194         if (src->meths_count)
 195                 {
 196                 dst->meths = BUF_memdup(src->meths, sizeof(custom_ext_method) * src->meths_count);
 197                 if (dst->meths == NULL)
 198                         return 0;
 199                 dst->meths_count = src->meths_count;
 200                 }
 201         return 1;
 202         }
 203
 204 void custom_exts_free(custom_ext_methods *exts)
 205         {
 206         if (exts->meths)
 207                 OPENSSL_free(exts->meths);
 208         }
 209
 210 /* Set callbacks for a custom extension */
 211 static int custom_ext_set(custom_ext_methods *exts,
 212                         unsigned int ext_type,
 213                         custom_ext_parse_cb parse_cb,
 214                         custom_ext_add_cb add_cb,
 215                         void *arg)
 216         {
 217         custom_ext_method *meth;
 218         /* See if it is a supported internally */
 219         switch(ext_type)
 220                 {
 221         case TLSEXT_TYPE_application_layer_protocol_negotiation:
 222         case TLSEXT_TYPE_ec_point_formats:
 223         case TLSEXT_TYPE_elliptic_curves:
 224         case TLSEXT_TYPE_heartbeat:
 225         case TLSEXT_TYPE_next_proto_neg:
 226         case TLSEXT_TYPE_padding:
 227         case TLSEXT_TYPE_renegotiate:
 228         case TLSEXT_TYPE_server_name:
 229         case TLSEXT_TYPE_session_ticket:
 230         case TLSEXT_TYPE_signature_algorithms:
 231         case TLSEXT_TYPE_srp:
 232         case TLSEXT_TYPE_status_request:
 233         case TLSEXT_TYPE_use_srtp:
 234 #ifdef TLSEXT_TYPE_opaque_prf_input
 235         case TLSEXT_TYPE_opaque_prf_input:
 236 #endif
 237 #ifdef TLSEXT_TYPE_encrypt_then_mac
 238         case TLSEXT_TYPE_encrypt_then_mac:
 239 #endif
 240                 return 0;
 241                 }
 242         /* Extension type must fit in 16 bits */
 243         if (ext_type > 0xffff)
 244                 return 0;
 245         /* Search for duplicate */
 246         if (custom_ext_find(exts, ext_type))
 247                 return 0;
 248         exts->meths = OPENSSL_realloc(exts->meths,
 249                                         (exts->meths_count + 1) * sizeof(custom_ext_method));
 250
 251         if (!exts->meths)
 252                 {
 253                 exts->meths_count = 0;
 254                 return 0;
 255                 }
 256
 257         meth = exts->meths + exts->meths_count;
 258         memset(meth, 0, sizeof(custom_ext_method));
 259         meth->parse_cb = parse_cb;
 260         meth->add_cb = add_cb;
 261         meth->ext_type = ext_type;
 262         meth->arg = arg;
 263         exts->meths_count++;
 264         return 1;
 265         }
 266
 267 /* Application level functions to add custom extension callbacks */
 268
 269 int SSL_CTX_set_custom_cli_ext(SSL_CTX *ctx, unsigned int ext_type,
 270                                custom_ext_add_cb add_cb,
 271                                custom_ext_parse_cb parse_cb, void *arg)
 272
 273         {
 274         return custom_ext_set(&ctx->cert->cli_ext, ext_type, parse_cb, add_cb,
 275                                                                         arg);
 276         }
 277
 278 int SSL_CTX_set_custom_srv_ext(SSL_CTX *ctx, unsigned int ext_type,
 279                                custom_ext_parse_cb parse_cb,
 280                                custom_ext_add_cb add_cb, void *arg)
 281         {
 282         return custom_ext_set(&ctx->cert->srv_ext, ext_type, parse_cb, add_cb,
 283                                                                         arg);
 284         }
 285 #endif