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/*
* Copyright (C) 2001 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* Functions that relate to the TLS hello extension parsing.
* Hello extensions are packets appended in the TLS hello packet, and
* allow for extra functionality.
*/
#include "gnutls_int.h"
#include "gnutls_extensions.h"
#include "gnutls_errors.h"
#include "ext_max_record.h"
#include <ext_cert_type.h>
#include "gnutls_num.h"
/* Key Exchange Section */
#define GNUTLS_EXTENSION_ENTRY(type, ext_func_recv, ext_func_send) \
{ #type, type, ext_func_recv, ext_func_send }
#define MAX_EXT_SIZE 10
const int _gnutls_extensions_size = MAX_EXT_SIZE;
gnutls_extension_entry _gnutls_extensions[MAX_EXT_SIZE] = {
GNUTLS_EXTENSION_ENTRY( GNUTLS_EXTENSION_MAX_RECORD_SIZE, _gnutls_max_record_recv_params, _gnutls_max_record_send_params),
GNUTLS_EXTENSION_ENTRY( GNUTLS_EXTENSION_CERT_TYPE, _gnutls_cert_type_recv_params, _gnutls_cert_type_send_params),
{0}
};
#define GNUTLS_EXTENSION_LOOP2(b) \
gnutls_extension_entry *p; \
for(p = _gnutls_extensions; p->name != NULL; p++) { b ; }
#define GNUTLS_EXTENSION_LOOP(a) \
GNUTLS_EXTENSION_LOOP2( if(p->type == type) { a; break; } )
/* EXTENSION functions */
void* _gnutls_ext_func_recv(uint16 type)
{
void* ret=NULL;
GNUTLS_EXTENSION_LOOP(ret = p->gnutls_ext_func_recv);
return ret;
}
void* _gnutls_ext_func_send(uint16 type)
{
void* ret=NULL;
GNUTLS_EXTENSION_LOOP(ret = p->gnutls_ext_func_send);
return ret;
}
const char *_gnutls_extension_get_name(uint16 type)
{
const char *ret = NULL;
/* avoid prefix */
GNUTLS_EXTENSION_LOOP(ret = p->name + sizeof("EXTENSION_") - 1);
return ret;
}
/* Checks if the extension we just received is one of the
* requested ones. Otherwise it's a fatal error.
*/
static int _gnutls_extension_list_check( gnutls_session session, uint16 type) {
int i;
if (session->security_parameters.entity==GNUTLS_CLIENT) {
for(i=0;i<session->internals.extensions_sent_size;i++) {
if (type==session->internals.extensions_sent[i])
return 0; /* ok found */
}
return GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION;
}
return 0;
}
int _gnutls_parse_extensions( gnutls_session session, const opaque* data, int data_size) {
int next, ret;
int pos=0;
uint16 type;
const opaque* sdata;
int (*ext_func_recv)( gnutls_session, const opaque*, int);
uint16 size;
#ifdef DEBUG
int i;
if (session->security_parameters.entity==GNUTLS_CLIENT)
for (i=0;i<session->internals.extensions_sent_size;i++) {
_gnutls_log("EXT: expecting extension %d\n", session->internals.extensions_sent[i]);
}
#endif
DECR_LENGTH_RET( data_size, 2, 0);
next = _gnutls_read_uint16( data);
pos+=2;
DECR_LENGTH_RET( data_size, next, 0);
do {
DECR_LENGTH_RET( next, 1, 0);
type = _gnutls_read_uint16( &data[pos]);
pos+=2;
if ( (ret=_gnutls_extension_list_check( session, type)) < 0) {
gnutls_assert();
return ret;
}
DECR_LENGTH_RET( next, 2, 0);
size = _gnutls_read_uint16(&data[pos]);
pos+=2;
DECR_LENGTH_RET( next, size, 0);
sdata = &data[pos];
pos+=size;
ext_func_recv = _gnutls_ext_func_recv(type);
if (ext_func_recv == NULL) continue;
if ( (ret=ext_func_recv( session, sdata, size)) < 0) {
gnutls_assert();
return ret;
}
} while(next > 2);
return 0;
}
/* Adds the extension we want to send in the extensions list.
* This list is used to check whether the (later) received
* extensions are the ones we requested.
*/
static void _gnutls_extension_list_add( gnutls_session session, uint16 type) {
if (session->security_parameters.entity==GNUTLS_CLIENT) {
if (session->internals.extensions_sent_size < MAX_EXT_TYPES) {
session->internals.extensions_sent[session->internals.extensions_sent_size] = type;
session->internals.extensions_sent_size++;
} else {
#ifdef DEBUG
_gnutls_log("EXT: Increase MAX_EXT_TYPES\n");
#endif
}
}
return;
}
int _gnutls_gen_extensions( gnutls_session session, opaque** data) {
int next, size;
uint16 pos=0;
opaque sdata[1024];
int sdata_size = sizeof(sdata);
int (*ext_func_send)( gnutls_session, opaque*, int);
(*data) = gnutls_malloc(2); /* allocate size for size */
pos+=2;
if ((*data)==NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
next = MAX_EXT_TYPES; /* maximum supported extensions */
do {
next--;
ext_func_send = _gnutls_ext_func_send(next);
if (ext_func_send == NULL) continue;
size = ext_func_send( session, sdata, sdata_size);
if (size > 0) {
(*data) = gnutls_realloc_fast( (*data), pos+size+4);
if ((*data)==NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
/* write extension type */
_gnutls_write_uint16( next, &(*data)[pos]);
pos+=2;
/* write size */
_gnutls_write_uint16( size, &(*data)[pos]);
pos+=2;
memcpy( &(*data)[pos], sdata, size);
pos+=size;
/* add this extension to the extension list
*/
_gnutls_extension_list_add( session, next);
}
} while(next >= 0);
size = pos;
pos-=2; /* remove the size of the size header! */
_gnutls_write_uint16( pos, (*data));
if (size==2) { /* empty */
size = 0;
gnutls_free(*data);
(*data) = NULL;
}
return size;
}
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