| /* |
| * Copyright 2014-2016 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" |
| |
| /* Find a custom extension from the list. */ |
| static custom_ext_method *custom_ext_find(const 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, WPACKET *pkt, int *al) |
| { |
| custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext; |
| custom_ext_method *meth; |
| 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 (!WPACKET_put_bytes_u16(pkt, meth->ext_type) |
| || !WPACKET_start_sub_packet_u16(pkt) |
| || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen)) |
| || !WPACKET_close(pkt)) { |
| *al = SSL_AD_INTERNAL_ERROR; |
| return 0; |
| } |
| /* |
| * 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); |
| } |
| 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 = |
| OPENSSL_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) |
| { |
| 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, *tmp; |
| /* |
| * 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, but make exception |
| * for extension types that previously were not supported, but now are. |
| */ |
| if (SSL_extension_supported(ext_type) && |
| ext_type != TLSEXT_TYPE_signed_certificate_timestamp) |
| 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; |
| tmp = OPENSSL_realloc(exts->meths, |
| (exts->meths_count + 1) * sizeof(custom_ext_method)); |
| |
| if (tmp == NULL) { |
| OPENSSL_free(exts->meths); |
| exts->meths = NULL; |
| exts->meths_count = 0; |
| return 0; |
| } |
| |
| exts->meths = tmp; |
| meth = exts->meths + exts->meths_count; |
| memset(meth, 0, sizeof(*meth)); |
| 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; |
| } |
| |
| /* Return true if a client custom extension exists, false otherwise */ |
| int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type) |
| { |
| return custom_ext_find(&ctx->cert->cli_ext, ext_type) != NULL; |
| } |
| |
| /* 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) |
| { |
| #ifndef OPENSSL_NO_CT |
| /* |
| * We don't want applications registering callbacks for SCT extensions |
| * whilst simultaneously using the built-in SCT validation features, as |
| * these two things may not play well together. |
| */ |
| if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp && |
| SSL_CTX_ct_is_enabled(ctx)) |
| return 0; |
| #endif |
| 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_supported_groups: |
| #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_signed_certificate_timestamp: |
| case TLSEXT_TYPE_use_srtp: |
| #ifdef TLSEXT_TYPE_encrypt_then_mac |
| case TLSEXT_TYPE_encrypt_then_mac: |
| #endif |
| return 1; |
| default: |
| return 0; |
| } |
| } |
