/* ssl/t1_ext.c */
/* ====================================================================
* Copyright (c) 2014 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
/* Custom extension utility functions */
#include "ssl_locl.h"
#ifndef OPENSSL_NO_TLSEXT
/* Find a custom extension from the list. */
static custom_ext_method *custom_ext_find(custom_ext_methods *exts,
unsigned int ext_type)
{
size_t i;
custom_ext_method *meth = exts->meths;
for (i = 0; i < exts->meths_count; i++, meth++) {
if (ext_type == meth->ext_type)
return meth;
}
return NULL;
}
/*
* Initialise custom extensions flags to indicate neither sent nor received.
*/
void custom_ext_init(custom_ext_methods *exts)
{
size_t i;
custom_ext_method *meth = exts->meths;
for (i = 0; i < exts->meths_count; i++, meth++)
meth->ext_flags = 0;
}
/* Pass received custom extension data to the application for parsing. */
int custom_ext_parse(SSL *s, int server,
unsigned int ext_type,
const unsigned char *ext_data, size_t ext_size, int *al)
{
custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
custom_ext_method *meth;
meth = custom_ext_find(exts, ext_type);
/* If not found return success */
if (!meth)
return 1;
if (!server) {
/*
* If it's ServerHello we can't have any extensions not sent in
* ClientHello.
*/
if (!(meth->ext_flags & SSL_EXT_FLAG_SENT)) {
*al = TLS1_AD_UNSUPPORTED_EXTENSION;
return 0;
}
}
/* If already present it's a duplicate */
if (meth->ext_flags & SSL_EXT_FLAG_RECEIVED) {
*al = TLS1_AD_DECODE_ERROR;
return 0;
}
meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
/* If no parse function set return success */
if (!meth->parse_cb)
return 1;
return meth->parse_cb(s, ext_type, ext_data, ext_size, al,
meth->parse_arg);
}
/*
* Request custom extension data from the application and add to the return
* buffer.
*/
int custom_ext_add(SSL *s, int server,
unsigned char **pret, unsigned char *limit, int *al)
{
custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
custom_ext_method *meth;
unsigned char *ret = *pret;
size_t i;
for (i = 0; i < exts->meths_count; i++) {
const unsigned char *out = NULL;
size_t outlen = 0;
meth = exts->meths + i;
if (server) {
/*
* For ServerHello only send extensions present in ClientHello.
*/
if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
continue;
/* If callback absent for server skip it */
if (!meth->add_cb)
continue;
}
if (meth->add_cb) {
int cb_retval = 0;
cb_retval = meth->add_cb(s, meth->ext_type,
&out, &outlen, al, meth->add_arg);
if (cb_retval < 0)
return 0; /* error */
if (cb_retval == 0)
continue; /* skip this extension */
}
if (4 > limit - ret || outlen > (size_t)(limit - ret - 4))
return 0;
s2n(meth->ext_type, ret);
s2n(outlen, ret);
if (outlen) {
memcpy(ret, out, outlen);
ret += outlen;
}
/*
* We can't send duplicates: code logic should prevent this.
*/
OPENSSL_assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
/*
* Indicate extension has been sent: this is both a sanity check to
* ensure we don't send duplicate extensions and indicates that it is
* not an error if the extension is present in ServerHello.
*/
meth->ext_flags |= SSL_EXT_FLAG_SENT;
if (meth->free_cb)
meth->free_cb(s, meth->ext_type, out, meth->add_arg);
}
*pret = ret;
return 1;
}
/* Copy table of custom extensions */
int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
{
if (src->meths_count) {
dst->meths =
BUF_memdup(src->meths,
sizeof(custom_ext_method) * src->meths_count);
if (dst->meths == NULL)
return 0;
dst->meths_count = src->meths_count;
}
return 1;
}
void custom_exts_free(custom_ext_methods *exts)
{
if (exts->meths)
OPENSSL_free(exts->meths);
}
/* Set callbacks for a custom extension. */
static int custom_ext_meth_add(custom_ext_methods *exts,
unsigned int ext_type,
custom_ext_add_cb add_cb,
custom_ext_free_cb free_cb,
void *add_arg,
custom_ext_parse_cb parse_cb, void *parse_arg)
{
custom_ext_method *meth;
/*
* Check application error: if add_cb is not set free_cb will never be
* called.
*/
if (!add_cb && free_cb)
return 0;
/* Don't add if extension supported internally. */
if (SSL_extension_supported(ext_type))
return 0;
/* Extension type must fit in 16 bits */
if (ext_type > 0xffff)
return 0;
/* Search for duplicate */
if (custom_ext_find(exts, ext_type))
return 0;
exts->meths = OPENSSL_realloc(exts->meths,
(exts->meths_count +
1) * sizeof(custom_ext_method));
if (!exts->meths) {
exts->meths_count = 0;
return 0;
}
meth = exts->meths + exts->meths_count;
memset(meth, 0, sizeof(custom_ext_method));
meth->parse_cb = parse_cb;
meth->add_cb = add_cb;
meth->free_cb = free_cb;
meth->ext_type = ext_type;
meth->add_arg = add_arg;
meth->parse_arg = parse_arg;
exts->meths_count++;
return 1;
}
/* Application level functions to add custom extension callbacks */
int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
custom_ext_add_cb add_cb,
custom_ext_free_cb free_cb,
void *add_arg,
custom_ext_parse_cb parse_cb,
void *parse_arg)
{
return custom_ext_meth_add(&ctx->cert->cli_ext, ext_type,
add_cb, free_cb, add_arg, parse_cb, parse_arg);
}
int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
custom_ext_add_cb add_cb,
custom_ext_free_cb free_cb,
void *add_arg,
custom_ext_parse_cb parse_cb,
void *parse_arg)
{
return custom_ext_meth_add(&ctx->cert->srv_ext, ext_type,
add_cb, free_cb, add_arg, parse_cb, parse_arg);
}
int SSL_extension_supported(unsigned int ext_type)
{
switch (ext_type) {
/* Internally supported extensions. */
case TLSEXT_TYPE_application_layer_protocol_negotiation:
case TLSEXT_TYPE_ec_point_formats:
case TLSEXT_TYPE_elliptic_curves:
case TLSEXT_TYPE_heartbeat:
# ifndef OPENSSL_NO_NEXTPROTONEG
case TLSEXT_TYPE_next_proto_neg:
# endif
case TLSEXT_TYPE_padding:
case TLSEXT_TYPE_renegotiate:
case TLSEXT_TYPE_server_name:
case TLSEXT_TYPE_session_ticket:
case TLSEXT_TYPE_signature_algorithms:
case TLSEXT_TYPE_srp:
case TLSEXT_TYPE_status_request:
case TLSEXT_TYPE_use_srtp:
# ifdef TLSEXT_TYPE_opaque_prf_input
case TLSEXT_TYPE_opaque_prf_input:
# endif
# ifdef TLSEXT_TYPE_encrypt_then_mac
case TLSEXT_TYPE_encrypt_then_mac:
# endif
return 1;
default:
return 0;
}
}
#endif
