534 lines
18 KiB
C
534 lines
18 KiB
C
/*
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* Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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/* Custom extension utility functions */
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#include <openssl/ct.h>
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#include "../ssl_locl.h"
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#include "internal/cryptlib.h"
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#include "statem_locl.h"
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typedef struct {
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void *add_arg;
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custom_ext_add_cb add_cb;
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custom_ext_free_cb free_cb;
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} custom_ext_add_cb_wrap;
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typedef struct {
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void *parse_arg;
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custom_ext_parse_cb parse_cb;
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} custom_ext_parse_cb_wrap;
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/*
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* Provide thin wrapper callbacks which convert new style arguments to old style
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*/
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static int custom_ext_add_old_cb_wrap(SSL *s, unsigned int ext_type,
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unsigned int context,
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const unsigned char **out,
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size_t *outlen, X509 *x, size_t chainidx,
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int *al, void *add_arg)
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{
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custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
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if (add_cb_wrap->add_cb == NULL)
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return 1;
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return add_cb_wrap->add_cb(s, ext_type, out, outlen, al,
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add_cb_wrap->add_arg);
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}
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static void custom_ext_free_old_cb_wrap(SSL *s, unsigned int ext_type,
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unsigned int context,
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const unsigned char *out, void *add_arg)
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{
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custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
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if (add_cb_wrap->free_cb == NULL)
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return;
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add_cb_wrap->free_cb(s, ext_type, out, add_cb_wrap->add_arg);
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}
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static int custom_ext_parse_old_cb_wrap(SSL *s, unsigned int ext_type,
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unsigned int context,
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const unsigned char *in,
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size_t inlen, X509 *x, size_t chainidx,
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int *al, void *parse_arg)
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{
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custom_ext_parse_cb_wrap *parse_cb_wrap =
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(custom_ext_parse_cb_wrap *)parse_arg;
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if (parse_cb_wrap->parse_cb == NULL)
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return 1;
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return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
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parse_cb_wrap->parse_arg);
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}
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/*
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* Find a custom extension from the list. The |role| param is there to
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* support the legacy API where custom extensions for client and server could
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* be set independently on the same SSL_CTX. It is set to ENDPOINT_SERVER if we
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* are trying to find a method relevant to the server, ENDPOINT_CLIENT for the
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* client, or ENDPOINT_BOTH for either
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*/
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custom_ext_method *custom_ext_find(const custom_ext_methods *exts,
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ENDPOINT role, unsigned int ext_type,
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size_t *idx)
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{
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size_t i;
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custom_ext_method *meth = exts->meths;
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for (i = 0; i < exts->meths_count; i++, meth++) {
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if (ext_type == meth->ext_type
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&& (role == ENDPOINT_BOTH || role == meth->role
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|| meth->role == ENDPOINT_BOTH)) {
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if (idx != NULL)
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*idx = i;
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return meth;
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}
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}
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return NULL;
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}
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/*
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* Initialise custom extensions flags to indicate neither sent nor received.
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*/
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void custom_ext_init(custom_ext_methods *exts)
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{
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size_t i;
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custom_ext_method *meth = exts->meths;
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for (i = 0; i < exts->meths_count; i++, meth++)
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meth->ext_flags = 0;
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}
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/* Pass received custom extension data to the application for parsing. */
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int custom_ext_parse(SSL *s, unsigned int context, unsigned int ext_type,
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const unsigned char *ext_data, size_t ext_size, X509 *x,
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size_t chainidx)
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{
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int al;
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custom_ext_methods *exts = &s->cert->custext;
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custom_ext_method *meth;
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ENDPOINT role = ENDPOINT_BOTH;
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if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
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role = s->server ? ENDPOINT_SERVER : ENDPOINT_CLIENT;
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meth = custom_ext_find(exts, role, ext_type, NULL);
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/* If not found return success */
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if (!meth)
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return 1;
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/* Check if extension is defined for our protocol. If not, skip */
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if (!extension_is_relevant(s, meth->context, context))
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return 1;
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if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
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| SSL_EXT_TLS1_3_SERVER_HELLO
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| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
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/*
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* If it's ServerHello or EncryptedExtensions we can't have any
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* extensions not sent in ClientHello.
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*/
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if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
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SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_F_CUSTOM_EXT_PARSE,
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SSL_R_BAD_EXTENSION);
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return 0;
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}
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}
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/*
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* Extensions received in the ClientHello are marked with the
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* SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
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* extensions in the ServerHello/EncryptedExtensions message
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*/
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if ((context & SSL_EXT_CLIENT_HELLO) != 0)
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meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
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/* If no parse function set return success */
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if (!meth->parse_cb)
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return 1;
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if (meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
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&al, meth->parse_arg) <= 0) {
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SSLfatal(s, al, SSL_F_CUSTOM_EXT_PARSE, SSL_R_BAD_EXTENSION);
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return 0;
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}
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return 1;
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}
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/*
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* Request custom extension data from the application and add to the return
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* buffer.
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*/
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int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
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int maxversion)
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{
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custom_ext_methods *exts = &s->cert->custext;
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custom_ext_method *meth;
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size_t i;
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int al;
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for (i = 0; i < exts->meths_count; i++) {
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const unsigned char *out = NULL;
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size_t outlen = 0;
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meth = exts->meths + i;
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if (!should_add_extension(s, meth->context, context, maxversion))
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continue;
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if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
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| SSL_EXT_TLS1_3_SERVER_HELLO
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| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
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| SSL_EXT_TLS1_3_CERTIFICATE
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| SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)) != 0) {
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/* Only send extensions present in ClientHello. */
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if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
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continue;
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}
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/*
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* We skip it if the callback is absent - except for a ClientHello where
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* we add an empty extension.
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*/
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if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
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continue;
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if (meth->add_cb != NULL) {
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int cb_retval = meth->add_cb(s, meth->ext_type, context, &out,
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&outlen, x, chainidx, &al,
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meth->add_arg);
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if (cb_retval < 0) {
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SSLfatal(s, al, SSL_F_CUSTOM_EXT_ADD, SSL_R_CALLBACK_FAILED);
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return 0; /* error */
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}
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if (cb_retval == 0)
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continue; /* skip this extension */
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}
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if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
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|| !WPACKET_start_sub_packet_u16(pkt)
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|| (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
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|| !WPACKET_close(pkt)) {
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SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CUSTOM_EXT_ADD,
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ERR_R_INTERNAL_ERROR);
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return 0;
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}
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if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
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/*
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* We can't send duplicates: code logic should prevent this.
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*/
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if (!ossl_assert((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0)) {
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SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CUSTOM_EXT_ADD,
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ERR_R_INTERNAL_ERROR);
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return 0;
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}
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/*
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* Indicate extension has been sent: this is both a sanity check to
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* ensure we don't send duplicate extensions and indicates that it
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* is not an error if the extension is present in ServerHello.
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*/
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meth->ext_flags |= SSL_EXT_FLAG_SENT;
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}
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if (meth->free_cb != NULL)
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meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
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}
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return 1;
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}
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/* Copy the flags from src to dst for any extensions that exist in both */
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int custom_exts_copy_flags(custom_ext_methods *dst,
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const custom_ext_methods *src)
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{
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size_t i;
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custom_ext_method *methsrc = src->meths;
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for (i = 0; i < src->meths_count; i++, methsrc++) {
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custom_ext_method *methdst = custom_ext_find(dst, methsrc->role,
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methsrc->ext_type, NULL);
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if (methdst == NULL)
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continue;
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methdst->ext_flags = methsrc->ext_flags;
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}
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return 1;
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}
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/* Copy table of custom extensions */
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int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
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{
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size_t i;
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int err = 0;
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if (src->meths_count > 0) {
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dst->meths =
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OPENSSL_memdup(src->meths,
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sizeof(*src->meths) * src->meths_count);
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if (dst->meths == NULL)
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return 0;
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dst->meths_count = src->meths_count;
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for (i = 0; i < src->meths_count; i++) {
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custom_ext_method *methsrc = src->meths + i;
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custom_ext_method *methdst = dst->meths + i;
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if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
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continue;
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/*
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* We have found an old style API wrapper. We need to copy the
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* arguments too.
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*/
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if (err) {
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methdst->add_arg = NULL;
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methdst->parse_arg = NULL;
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continue;
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}
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methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
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sizeof(custom_ext_add_cb_wrap));
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methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
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sizeof(custom_ext_parse_cb_wrap));
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if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
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err = 1;
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}
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}
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if (err) {
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custom_exts_free(dst);
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return 0;
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}
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return 1;
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}
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void custom_exts_free(custom_ext_methods *exts)
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{
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size_t i;
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custom_ext_method *meth;
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for (i = 0, meth = exts->meths; i < exts->meths_count; i++, meth++) {
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if (meth->add_cb != custom_ext_add_old_cb_wrap)
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continue;
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/* Old style API wrapper. Need to free the arguments too */
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OPENSSL_free(meth->add_arg);
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OPENSSL_free(meth->parse_arg);
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}
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OPENSSL_free(exts->meths);
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}
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/* Return true if a client custom extension exists, false otherwise */
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int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
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{
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return custom_ext_find(&ctx->cert->custext, ENDPOINT_CLIENT, ext_type,
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NULL) != NULL;
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}
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static int add_custom_ext_intern(SSL_CTX *ctx, ENDPOINT role,
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unsigned int ext_type,
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unsigned int context,
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SSL_custom_ext_add_cb_ex add_cb,
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SSL_custom_ext_free_cb_ex free_cb,
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void *add_arg,
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SSL_custom_ext_parse_cb_ex parse_cb,
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void *parse_arg)
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{
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custom_ext_methods *exts = &ctx->cert->custext;
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custom_ext_method *meth, *tmp;
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/*
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* Check application error: if add_cb is not set free_cb will never be
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* called.
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*/
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if (add_cb == NULL && free_cb != NULL)
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return 0;
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#ifndef OPENSSL_NO_CT
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/*
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* We don't want applications registering callbacks for SCT extensions
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* whilst simultaneously using the built-in SCT validation features, as
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* these two things may not play well together.
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*/
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if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
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&& (context & SSL_EXT_CLIENT_HELLO) != 0
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&& SSL_CTX_ct_is_enabled(ctx))
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return 0;
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#endif
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/*
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* Don't add if extension supported internally, but make exception
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* for extension types that previously were not supported, but now are.
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*/
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if (SSL_extension_supported(ext_type)
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&& ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
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return 0;
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/* Extension type must fit in 16 bits */
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if (ext_type > 0xffff)
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return 0;
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/* Search for duplicate */
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if (custom_ext_find(exts, role, ext_type, NULL))
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return 0;
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tmp = OPENSSL_realloc(exts->meths,
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(exts->meths_count + 1) * sizeof(custom_ext_method));
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if (tmp == NULL)
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return 0;
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exts->meths = tmp;
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meth = exts->meths + exts->meths_count;
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memset(meth, 0, sizeof(*meth));
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meth->role = role;
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meth->context = context;
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meth->parse_cb = parse_cb;
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meth->add_cb = add_cb;
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meth->free_cb = free_cb;
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meth->ext_type = ext_type;
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meth->add_arg = add_arg;
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meth->parse_arg = parse_arg;
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exts->meths_count++;
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return 1;
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}
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static int add_old_custom_ext(SSL_CTX *ctx, ENDPOINT role,
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unsigned int ext_type,
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unsigned int context,
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custom_ext_add_cb add_cb,
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custom_ext_free_cb free_cb,
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void *add_arg,
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custom_ext_parse_cb parse_cb, void *parse_arg)
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{
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custom_ext_add_cb_wrap *add_cb_wrap
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= OPENSSL_malloc(sizeof(*add_cb_wrap));
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custom_ext_parse_cb_wrap *parse_cb_wrap
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= OPENSSL_malloc(sizeof(*parse_cb_wrap));
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int ret;
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if (add_cb_wrap == NULL || parse_cb_wrap == NULL) {
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OPENSSL_free(add_cb_wrap);
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OPENSSL_free(parse_cb_wrap);
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return 0;
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}
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add_cb_wrap->add_arg = add_arg;
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add_cb_wrap->add_cb = add_cb;
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add_cb_wrap->free_cb = free_cb;
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parse_cb_wrap->parse_arg = parse_arg;
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parse_cb_wrap->parse_cb = parse_cb;
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ret = add_custom_ext_intern(ctx, role, ext_type,
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context,
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custom_ext_add_old_cb_wrap,
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custom_ext_free_old_cb_wrap,
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add_cb_wrap,
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custom_ext_parse_old_cb_wrap,
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parse_cb_wrap);
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if (!ret) {
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OPENSSL_free(add_cb_wrap);
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OPENSSL_free(parse_cb_wrap);
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}
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return ret;
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}
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/* Application level functions to add the old custom extension callbacks */
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int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
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custom_ext_add_cb add_cb,
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custom_ext_free_cb free_cb,
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void *add_arg,
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custom_ext_parse_cb parse_cb, void *parse_arg)
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{
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return add_old_custom_ext(ctx, ENDPOINT_CLIENT, ext_type,
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SSL_EXT_TLS1_2_AND_BELOW_ONLY
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| SSL_EXT_CLIENT_HELLO
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| SSL_EXT_TLS1_2_SERVER_HELLO
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| SSL_EXT_IGNORE_ON_RESUMPTION,
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add_cb, free_cb, 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 int ext_type,
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custom_ext_add_cb add_cb,
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custom_ext_free_cb free_cb,
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void *add_arg,
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custom_ext_parse_cb parse_cb, void *parse_arg)
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{
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return add_old_custom_ext(ctx, ENDPOINT_SERVER, ext_type,
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SSL_EXT_TLS1_2_AND_BELOW_ONLY
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| SSL_EXT_CLIENT_HELLO
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| SSL_EXT_TLS1_2_SERVER_HELLO
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| SSL_EXT_IGNORE_ON_RESUMPTION,
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add_cb, free_cb, add_arg, parse_cb, parse_arg);
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}
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int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
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unsigned int context,
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SSL_custom_ext_add_cb_ex add_cb,
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SSL_custom_ext_free_cb_ex free_cb,
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void *add_arg,
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SSL_custom_ext_parse_cb_ex parse_cb, void *parse_arg)
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{
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return add_custom_ext_intern(ctx, ENDPOINT_BOTH, ext_type, context, add_cb,
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free_cb, add_arg, parse_cb, parse_arg);
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}
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int SSL_extension_supported(unsigned int ext_type)
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{
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switch (ext_type) {
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/* Internally supported extensions. */
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case TLSEXT_TYPE_application_layer_protocol_negotiation:
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#ifndef OPENSSL_NO_EC
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case TLSEXT_TYPE_ec_point_formats:
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case TLSEXT_TYPE_supported_groups:
|
|
case TLSEXT_TYPE_key_share:
|
|
#endif
|
|
#ifndef OPENSSL_NO_NEXTPROTONEG
|
|
case TLSEXT_TYPE_next_proto_neg:
|
|
#endif
|
|
case TLSEXT_TYPE_padding:
|
|
case TLSEXT_TYPE_renegotiate:
|
|
case TLSEXT_TYPE_max_fragment_length:
|
|
case TLSEXT_TYPE_server_name:
|
|
case TLSEXT_TYPE_session_ticket:
|
|
case TLSEXT_TYPE_signature_algorithms:
|
|
#ifndef OPENSSL_NO_SRP
|
|
case TLSEXT_TYPE_srp:
|
|
#endif
|
|
#ifndef OPENSSL_NO_OCSP
|
|
case TLSEXT_TYPE_status_request:
|
|
#endif
|
|
#ifndef OPENSSL_NO_CT
|
|
case TLSEXT_TYPE_signed_certificate_timestamp:
|
|
#endif
|
|
#ifndef OPENSSL_NO_SRTP
|
|
case TLSEXT_TYPE_use_srtp:
|
|
#endif
|
|
case TLSEXT_TYPE_encrypt_then_mac:
|
|
case TLSEXT_TYPE_supported_versions:
|
|
case TLSEXT_TYPE_extended_master_secret:
|
|
case TLSEXT_TYPE_psk_kex_modes:
|
|
case TLSEXT_TYPE_cookie:
|
|
case TLSEXT_TYPE_early_data:
|
|
case TLSEXT_TYPE_certificate_authorities:
|
|
case TLSEXT_TYPE_psk:
|
|
case TLSEXT_TYPE_post_handshake_auth:
|
|
return 1;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|