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|
/*
* Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/* Custom extension utility functions */
#include <openssl/ct.h>
#include "../ssl_locl.h"
#include "internal/cryptlib.h"
#include "statem_locl.h"
typedef struct {
void *add_arg;
custom_ext_add_cb add_cb;
custom_ext_free_cb free_cb;
} custom_ext_add_cb_wrap;
typedef struct {
void *parse_arg;
custom_ext_parse_cb parse_cb;
} custom_ext_parse_cb_wrap;
/*
* Provide thin wrapper callbacks which convert new style arguments to old style
*/
static int custom_ext_add_old_cb_wrap(SSL *s, unsigned int ext_type,
unsigned int context,
const unsigned char **out,
size_t *outlen, X509 *x, size_t chainidx,
int *al, void *add_arg)
{
custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
if (add_cb_wrap->add_cb == NULL)
return 1;
return add_cb_wrap->add_cb(s, ext_type, out, outlen, al,
add_cb_wrap->add_arg);
}
static void custom_ext_free_old_cb_wrap(SSL *s, unsigned int ext_type,
unsigned int context,
const unsigned char *out, void *add_arg)
{
custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
if (add_cb_wrap->free_cb == NULL)
return;
add_cb_wrap->free_cb(s, ext_type, out, add_cb_wrap->add_arg);
}
static int custom_ext_parse_old_cb_wrap(SSL *s, unsigned int ext_type,
unsigned int context,
const unsigned char *in,
size_t inlen, X509 *x, size_t chainidx,
int *al, void *parse_arg)
{
custom_ext_parse_cb_wrap *parse_cb_wrap =
(custom_ext_parse_cb_wrap *)parse_arg;
if (parse_cb_wrap->parse_cb == NULL)
return 1;
return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
parse_cb_wrap->parse_arg);
}
/*
* Find a custom extension from the list. The |role| param is there to
* support the legacy API where custom extensions for client and server could
* be set independently on the same SSL_CTX. It is set to ENDPOINT_SERVER if we
* are trying to find a method relevant to the server, ENDPOINT_CLIENT for the
* client, or ENDPOINT_BOTH for either
*/
custom_ext_method *custom_ext_find(const custom_ext_methods *exts,
ENDPOINT role, unsigned int ext_type,
size_t *idx)
{
size_t i;
custom_ext_method *meth = exts->meths;
for (i = 0; i < exts->meths_count; i++, meth++) {
if (ext_type == meth->ext_type
&& (role == ENDPOINT_BOTH || role == meth->role
|| meth->role == ENDPOINT_BOTH)) {
if (idx != NULL)
*idx = i;
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, unsigned int context, unsigned int ext_type,
const unsigned char *ext_data, size_t ext_size, X509 *x,
size_t chainidx)
{
int al;
custom_ext_methods *exts = &s->cert->custext;
custom_ext_method *meth;
ENDPOINT role = ENDPOINT_BOTH;
if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
role = s->server ? ENDPOINT_SERVER : ENDPOINT_CLIENT;
meth = custom_ext_find(exts, role, ext_type, NULL);
/* If not found return success */
if (!meth)
return 1;
/* Check if extension is defined for our protocol. If not, skip */
if (!extension_is_relevant(s, meth->context, context))
return 1;
if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
| SSL_EXT_TLS1_3_SERVER_HELLO
| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
/*
* If it's ServerHello or EncryptedExtensions we can't have any
* extensions not sent in ClientHello.
*/
if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_F_CUSTOM_EXT_PARSE,
SSL_R_BAD_EXTENSION);
return 0;
}
}
/*
* Extensions received in the ClientHello are marked with the
* SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
* extensions in the ServerHello/EncryptedExtensions message
*/
if ((context & SSL_EXT_CLIENT_HELLO) != 0)
meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
/* If no parse function set return success */
if (!meth->parse_cb)
return 1;
if (meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
&al, meth->parse_arg) <= 0) {
SSLfatal(s, al, SSL_F_CUSTOM_EXT_PARSE, SSL_R_BAD_EXTENSION);
return 0;
}
return 1;
}
/*
* Request custom extension data from the application and add to the return
* buffer.
*/
int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
int maxversion)
{
custom_ext_methods *exts = &s->cert->custext;
custom_ext_method *meth;
size_t i;
int al;
for (i = 0; i < exts->meths_count; i++) {
const unsigned char *out = NULL;
size_t outlen = 0;
meth = exts->meths + i;
if (!should_add_extension(s, meth->context, context, maxversion))
continue;
if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
| SSL_EXT_TLS1_3_SERVER_HELLO
| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
| SSL_EXT_TLS1_3_CERTIFICATE
| SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)) != 0) {
/* Only send extensions present in ClientHello. */
if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
continue;
}
/*
* We skip it if the callback is absent - except for a ClientHello where
* we add an empty extension.
*/
if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
continue;
if (meth->add_cb != NULL) {
int cb_retval = meth->add_cb(s, meth->ext_type, context, &out,
&outlen, x,
|