2015-07-31 02:10:13 +01:00
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/* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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2015-09-15 06:48:04 +01:00
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#include <openssl/ssl.h>
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2015-07-31 02:10:13 +01:00
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#include <assert.h>
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#include <string.h>
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2015-09-15 06:48:04 +01:00
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#include <openssl/bytestring.h>
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#include <openssl/err.h>
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#include <openssl/mem.h>
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#include <openssl/stack.h>
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2015-07-31 02:10:13 +01:00
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#include "internal.h"
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void SSL_CUSTOM_EXTENSION_free(SSL_CUSTOM_EXTENSION *custom_extension) {
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OPENSSL_free(custom_extension);
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}
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static const SSL_CUSTOM_EXTENSION *custom_ext_find(
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STACK_OF(SSL_CUSTOM_EXTENSION) *stack,
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unsigned *out_index, uint16_t value) {
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2016-09-05 17:47:25 +01:00
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for (size_t i = 0; i < sk_SSL_CUSTOM_EXTENSION_num(stack); i++) {
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2015-07-31 02:10:13 +01:00
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const SSL_CUSTOM_EXTENSION *ext = sk_SSL_CUSTOM_EXTENSION_value(stack, i);
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if (ext->value == value) {
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if (out_index != NULL) {
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*out_index = i;
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}
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return ext;
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}
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}
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return NULL;
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}
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/* default_add_callback is used as the |add_callback| when the user doesn't
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* provide one. For servers, it does nothing while, for clients, it causes an
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* empty extension to be included. */
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static int default_add_callback(SSL *ssl, unsigned extension_value,
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const uint8_t **out, size_t *out_len,
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int *out_alert_value, void *add_arg) {
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if (ssl->server) {
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return 0;
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}
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*out_len = 0;
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return 1;
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}
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2016-11-17 07:47:15 +00:00
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static int custom_ext_add_hello(SSL_HANDSHAKE *hs, CBB *extensions) {
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SSL *const ssl = hs->ssl;
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2015-07-31 02:10:13 +01:00
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STACK_OF(SSL_CUSTOM_EXTENSION) *stack = ssl->ctx->client_custom_extensions;
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if (ssl->server) {
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stack = ssl->ctx->server_custom_extensions;
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}
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if (stack == NULL) {
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return 1;
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}
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2017-03-26 02:54:16 +01:00
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if (ssl->ctx->enable_early_data) {
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/* TODO(svaldez): Support Custom Extensions with 0-RTT. For now the caller
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* is expected not to configure both together.
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* https://crbug.com/boringssl/173. */
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OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR);
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return 0;
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}
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2016-09-05 17:47:25 +01:00
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for (size_t i = 0; i < sk_SSL_CUSTOM_EXTENSION_num(stack); i++) {
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2015-07-31 02:10:13 +01:00
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const SSL_CUSTOM_EXTENSION *ext = sk_SSL_CUSTOM_EXTENSION_value(stack, i);
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if (ssl->server &&
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2016-11-17 07:47:15 +00:00
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!(hs->custom_extensions.received & (1u << i))) {
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2015-07-31 02:10:13 +01:00
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/* Servers cannot echo extensions that the client didn't send. */
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continue;
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}
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const uint8_t *contents;
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size_t contents_len;
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int alert = SSL_AD_DECODE_ERROR;
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CBB contents_cbb;
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switch (ext->add_callback(ssl, ext->value, &contents, &contents_len, &alert,
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ext->add_arg)) {
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case 1:
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if (!CBB_add_u16(extensions, ext->value) ||
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!CBB_add_u16_length_prefixed(extensions, &contents_cbb) ||
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!CBB_add_bytes(&contents_cbb, contents, contents_len) ||
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!CBB_flush(extensions)) {
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OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
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2016-11-17 20:55:14 +00:00
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ERR_add_error_dataf("extension %u", (unsigned) ext->value);
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2015-07-31 02:10:13 +01:00
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if (ext->free_callback && 0 < contents_len) {
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ext->free_callback(ssl, ext->value, contents, ext->add_arg);
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}
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return 0;
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}
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if (ext->free_callback && 0 < contents_len) {
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ext->free_callback(ssl, ext->value, contents, ext->add_arg);
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}
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if (!ssl->server) {
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2016-11-17 07:47:15 +00:00
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assert((hs->custom_extensions.sent & (1u << i)) == 0);
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hs->custom_extensions.sent |= (1u << i);
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2015-07-31 02:10:13 +01:00
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}
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break;
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case 0:
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break;
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default:
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ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
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OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR);
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2016-11-17 20:55:14 +00:00
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ERR_add_error_dataf("extension %u", (unsigned) ext->value);
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2015-07-31 02:10:13 +01:00
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return 0;
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}
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}
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return 1;
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}
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2016-11-17 07:47:15 +00:00
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int custom_ext_add_clienthello(SSL_HANDSHAKE *hs, CBB *extensions) {
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return custom_ext_add_hello(hs, extensions);
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2015-07-31 02:10:13 +01:00
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}
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2016-11-17 07:47:15 +00:00
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int custom_ext_parse_serverhello(SSL_HANDSHAKE *hs, int *out_alert,
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uint16_t value, const CBS *extension) {
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SSL *const ssl = hs->ssl;
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2015-07-31 02:10:13 +01:00
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unsigned index;
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const SSL_CUSTOM_EXTENSION *ext =
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custom_ext_find(ssl->ctx->client_custom_extensions, &index, value);
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if (/* Unknown extensions are not allowed in a ServerHello. */
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ext == NULL ||
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/* Also, if we didn't send the extension, that's also unacceptable. */
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2016-11-17 07:47:15 +00:00
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!(hs->custom_extensions.sent & (1u << index))) {
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2015-07-31 02:10:13 +01:00
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OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
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2016-11-17 20:55:14 +00:00
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ERR_add_error_dataf("extension %u", (unsigned)value);
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2016-08-01 17:05:50 +01:00
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*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
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2015-07-31 02:10:13 +01:00
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return 0;
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}
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if (ext->parse_callback != NULL &&
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!ext->parse_callback(ssl, value, CBS_data(extension), CBS_len(extension),
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out_alert, ext->parse_arg)) {
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OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR);
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2016-11-17 20:55:14 +00:00
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ERR_add_error_dataf("extension %u", (unsigned)ext->value);
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2015-07-31 02:10:13 +01:00
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return 0;
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}
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return 1;
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}
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2016-11-17 07:47:15 +00:00
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int custom_ext_parse_clienthello(SSL_HANDSHAKE *hs, int *out_alert,
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uint16_t value, const CBS *extension) {
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SSL *const ssl = hs->ssl;
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2015-07-31 02:10:13 +01:00
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unsigned index;
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const SSL_CUSTOM_EXTENSION *ext =
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custom_ext_find(ssl->ctx->server_custom_extensions, &index, value);
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if (ext == NULL) {
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return 1;
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}
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2016-11-17 07:47:15 +00:00
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assert((hs->custom_extensions.received & (1u << index)) == 0);
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hs->custom_extensions.received |= (1u << index);
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2015-07-31 02:10:13 +01:00
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if (ext->parse_callback &&
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!ext->parse_callback(ssl, value, CBS_data(extension), CBS_len(extension),
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out_alert, ext->parse_arg)) {
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OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR);
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2016-11-17 20:55:14 +00:00
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ERR_add_error_dataf("extension %u", (unsigned)ext->value);
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2015-07-31 02:10:13 +01:00
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return 0;
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}
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return 1;
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}
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2016-11-17 07:47:15 +00:00
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int custom_ext_add_serverhello(SSL_HANDSHAKE *hs, CBB *extensions) {
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return custom_ext_add_hello(hs, extensions);
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2015-07-31 02:10:13 +01:00
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}
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/* MAX_NUM_CUSTOM_EXTENSIONS is the maximum number of custom extensions that
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* can be set on an |SSL_CTX|. It's determined by the size of the bitset used
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* to track when an extension has been sent. */
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#define MAX_NUM_CUSTOM_EXTENSIONS \
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2016-10-07 00:39:20 +01:00
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(sizeof(((SSL_HANDSHAKE *)NULL)->custom_extensions.sent) * 8)
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2015-07-31 02:10:13 +01:00
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static int custom_ext_append(STACK_OF(SSL_CUSTOM_EXTENSION) **stack,
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unsigned extension_value,
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SSL_custom_ext_add_cb add_cb,
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SSL_custom_ext_free_cb free_cb, void *add_arg,
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SSL_custom_ext_parse_cb parse_cb,
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void *parse_arg) {
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if (add_cb == NULL ||
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0xffff < extension_value ||
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SSL_extension_supported(extension_value) ||
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/* Specifying a free callback without an add callback is nonsensical
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* and an error. */
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(*stack != NULL &&
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(MAX_NUM_CUSTOM_EXTENSIONS <= sk_SSL_CUSTOM_EXTENSION_num(*stack) ||
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custom_ext_find(*stack, NULL, extension_value) != NULL))) {
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return 0;
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}
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SSL_CUSTOM_EXTENSION *ext = OPENSSL_malloc(sizeof(SSL_CUSTOM_EXTENSION));
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if (ext == NULL) {
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return 0;
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}
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ext->add_callback = add_cb;
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ext->add_arg = add_arg;
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ext->free_callback = free_cb;
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ext->parse_callback = parse_cb;
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ext->parse_arg = parse_arg;
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ext->value = extension_value;
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if (*stack == NULL) {
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*stack = sk_SSL_CUSTOM_EXTENSION_new_null();
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if (*stack == NULL) {
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SSL_CUSTOM_EXTENSION_free(ext);
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return 0;
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}
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}
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if (!sk_SSL_CUSTOM_EXTENSION_push(*stack, ext)) {
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SSL_CUSTOM_EXTENSION_free(ext);
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if (sk_SSL_CUSTOM_EXTENSION_num(*stack) == 0) {
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sk_SSL_CUSTOM_EXTENSION_free(*stack);
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*stack = NULL;
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}
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return 0;
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}
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return 1;
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}
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int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned extension_value,
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SSL_custom_ext_add_cb add_cb,
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SSL_custom_ext_free_cb free_cb, void *add_arg,
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SSL_custom_ext_parse_cb parse_cb,
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void *parse_arg) {
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return custom_ext_append(&ctx->client_custom_extensions, extension_value,
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add_cb ? add_cb : default_add_callback, free_cb,
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add_arg, parse_cb, parse_arg);
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}
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int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned extension_value,
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SSL_custom_ext_add_cb add_cb,
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SSL_custom_ext_free_cb free_cb, void *add_arg,
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SSL_custom_ext_parse_cb parse_cb,
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void *parse_arg) {
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return custom_ext_append(&ctx->server_custom_extensions, extension_value,
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add_cb ? add_cb : default_add_callback, free_cb,
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add_arg, parse_cb, parse_arg);
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}
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