| /* |
| * Copyright 2014-2021 The OpenSSL Project Authors. All Rights Reserved. |
| * |
| * Licensed under the Apache License 2.0 (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_local.h" |
| #include "internal/cryptlib.h" |
| #include "statem_local.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_R_BAD_EXTENSION); |
| return 0; |
| } |
| } |
| |
| /* |
| * Extensions received in the ClientHello or CertificateRequest are marked |
| * with the SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent |
| * extensions in the response messages |
| */ |
| if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST)) |
| != 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_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/CertificateRequest */ |
| 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, chainidx, &al, |
| meth->add_arg); |
| |
| if (cb_retval < 0) { |
| SSLfatal(s, al, SSL_R_CALLBACK_FAILED); |
| 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)) { |
| SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); |
| return 0; |
| } |
| if ((context & SSL_EXT_CLIENT_HELLO) != 0) { |
| /* |
| * We can't send duplicates: code logic should prevent this. |
| */ |
| if (!ossl_assert((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0)) { |
| SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); |
| return 0; |
| } |
| /* |
| * 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 != NULL) |
| meth->free_cb(s, meth->ext_type, context, out, meth->add_arg); |
| } |
| return 1; |
| } |
| |
| /* Copy the flags from src to dst for any extensions that exist in both */ |
| int custom_exts_copy_flags(custom_ext_methods *dst, |
| const custom_ext_methods *src) |
| { |
| size_t i; |
| custom_ext_method *methsrc = src->meths; |
| |
| for (i = 0; i < src->meths_count; i++, methsrc++) { |
| custom_ext_method *methdst = custom_ext_find(dst, methsrc->role, |
| methsrc->ext_type, NULL); |
| |
| if (methdst == NULL) |
| continue; |
| |
| methdst->ext_flags = methsrc->ext_flags; |
| } |
| |
| return 1; |
| } |
| |
| /* Copy table of custom extensions */ |
| int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src) |
| { |
| size_t i; |
| int err = 0; |
| |
| if (src->meths_count > 0) { |
| dst->meths = |
| OPENSSL_memdup(src->meths, |
| sizeof(*src->meths) * src->meths_count); |
| if (dst->meths == NULL) |
| return 0; |
| dst->meths_count = src->meths_count; |
| |
| for (i = 0; i < src->meths_count; i++) { |
| custom_ext_method *methsrc = src->meths + i; |
| custom_ext_method *methdst = dst->meths + i; |
| |
| if (methsrc->add_cb != custom_ext_add_old_cb_wrap) |
| continue; |
| |
| /* |
| * We have found an old style API wrapper. We need to copy the |
| * arguments too. |
| */ |
| |
| if (err) { |
| methdst->add_arg = NULL; |
| methdst->parse_arg = NULL; |
| continue; |
| } |
| |
| methdst->add_arg = OPENSSL_memdup(methsrc->add_arg, |
| sizeof(custom_ext_add_cb_wrap)); |
| methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg, |
| sizeof(custom_ext_parse_cb_wrap)); |
| |
| if (methdst->add_arg == NULL || methdst->parse_arg == NULL) |
| err = 1; |
| } |
| } |
| |
| if (err) { |
| custom_exts_free(dst); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| void custom_exts_free(custom_ext_methods *exts) |
| { |
| size_t i; |
| custom_ext_method *meth; |
| |
| for (i = 0, meth = exts->meths; i < exts->meths_count; i++, meth++) { |
| if (meth->add_cb != custom_ext_add_old_cb_wrap) |
| continue; |
| |
| /* Old style API wrapper. Need to free the arguments too */ |
| OPENSSL_free(meth->add_arg); |
| OPENSSL_free(meth->parse_arg); |
| } |
| OPENSSL_free(exts->meths); |
| } |
| |
| /* 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->custext, ENDPOINT_CLIENT, ext_type, |
| NULL) != NULL; |
| } |
| |
| static int add_custom_ext_intern(SSL_CTX *ctx, ENDPOINT role, |
| unsigned int ext_type, |
| unsigned int context, |
| SSL_custom_ext_add_cb_ex add_cb, |
| SSL_custom_ext_free_cb_ex free_cb, |
| void *add_arg, |
| SSL_custom_ext_parse_cb_ex parse_cb, |
| void *parse_arg) |
| { |
| custom_ext_methods *exts = &ctx->cert->custext; |
| custom_ext_method *meth, *tmp; |
| |
| /* |
| * Check application error: if add_cb is not set free_cb will never be |
| * called. |
| */ |
| if (add_cb == NULL && free_cb != NULL) |
| return 0; |
| |
| #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 |
| && (context & SSL_EXT_CLIENT_HELLO) != 0 |
| && SSL_CTX_ct_is_enabled(ctx)) |
| return 0; |
| #endif |
| |
| /* |
| * 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, role, ext_type, NULL)) |
| return 0; |
| tmp = OPENSSL_realloc(exts->meths, |
| (exts->meths_count + 1) * sizeof(custom_ext_method)); |
| if (tmp == NULL) |
| return 0; |
| |
| exts->meths = tmp; |
| meth = exts->meths + exts->meths_count; |
| memset(meth, 0, sizeof(*meth)); |
| meth->role = role; |
| meth->context = context; |
| 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; |
| } |
| |
| static int add_old_custom_ext(SSL_CTX *ctx, ENDPOINT role, |
| unsigned int ext_type, |
| unsigned int context, |
| 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_add_cb_wrap *add_cb_wrap |
| = OPENSSL_malloc(sizeof(*add_cb_wrap)); |
| custom_ext_parse_cb_wrap *parse_cb_wrap |
| = OPENSSL_malloc(sizeof(*parse_cb_wrap)); |
| int ret; |
| |
| if (add_cb_wrap == NULL || parse_cb_wrap == NULL) { |
| OPENSSL_free(add_cb_wrap); |
| OPENSSL_free(parse_cb_wrap); |
| return 0; |
| } |
| |
| add_cb_wrap->add_arg = add_arg; |
| add_cb_wrap->add_cb = add_cb; |
| add_cb_wrap->free_cb = free_cb; |
| parse_cb_wrap->parse_arg = parse_arg; |
| parse_cb_wrap->parse_cb = parse_cb; |
| |
| ret = add_custom_ext_intern(ctx, role, ext_type, |
| context, |
| custom_ext_add_old_cb_wrap, |
| custom_ext_free_old_cb_wrap, |
| add_cb_wrap, |
| custom_ext_parse_old_cb_wrap, |
| parse_cb_wrap); |
| |
| if (!ret) { |
| OPENSSL_free(add_cb_wrap); |
| OPENSSL_free(parse_cb_wrap); |
| } |
| |
| return ret; |
| } |
| |
| /* Application level functions to add the old 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) |
| { |
| return add_old_custom_ext(ctx, ENDPOINT_CLIENT, ext_type, |
| SSL_EXT_TLS1_2_AND_BELOW_ONLY |
| | SSL_EXT_CLIENT_HELLO |
| | SSL_EXT_TLS1_2_SERVER_HELLO |
| | SSL_EXT_IGNORE_ON_RESUMPTION, |
| 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 add_old_custom_ext(ctx, ENDPOINT_SERVER, ext_type, |
| SSL_EXT_TLS1_2_AND_BELOW_ONLY |
| | SSL_EXT_CLIENT_HELLO |
| | SSL_EXT_TLS1_2_SERVER_HELLO |
| | SSL_EXT_IGNORE_ON_RESUMPTION, |
| add_cb, free_cb, add_arg, parse_cb, parse_arg); |
| } |
| |
| int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type, |
| unsigned int context, |
| SSL_custom_ext_add_cb_ex add_cb, |
| SSL_custom_ext_free_cb_ex free_cb, |
| void *add_arg, |
| SSL_custom_ext_parse_cb_ex parse_cb, void *parse_arg) |
| { |
| return add_custom_ext_intern(ctx, ENDPOINT_BOTH, ext_type, context, 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: |
| case TLSEXT_TYPE_key_share: |
| #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; |
| } |
| } |
