| /* |
| * TLS 1.3 server-side functions |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3) |
| |
| #include "mbedtls/debug.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/platform.h" |
| |
| #include "ssl_misc.h" |
| #include "ssl_tls13_keys.h" |
| #include "ssl_debug_helpers.h" |
| |
| #if defined(MBEDTLS_ECP_C) |
| #include "mbedtls/ecp.h" |
| #endif /* MBEDTLS_ECP_C */ |
| |
| #if defined(MBEDTLS_PLATFORM_C) |
| #include "mbedtls/platform.h" |
| #else |
| #include <stdlib.h> |
| #define mbedtls_calloc calloc |
| #define mbedtls_free free |
| #endif /* MBEDTLS_PLATFORM_C */ |
| |
| #include "ssl_misc.h" |
| #include "ssl_tls13_keys.h" |
| #include "ssl_debug_helpers.h" |
| |
| /* From RFC 8446: |
| * struct { |
| * ProtocolVersion versions<2..254>; |
| * } SupportedVersions; |
| */ |
| static int ssl_tls13_parse_supported_versions_ext( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end ) |
| { |
| const unsigned char *p = buf; |
| size_t versions_len; |
| const unsigned char *versions_end; |
| uint16_t tls_version; |
| int tls13_supported = 0; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 1 ); |
| versions_len = p[0]; |
| p += 1; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, versions_len ); |
| versions_end = p + versions_len; |
| while( p < versions_end ) |
| { |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, versions_end, 2 ); |
| tls_version = mbedtls_ssl_read_version( p, ssl->conf->transport ); |
| p += 2; |
| |
| /* In this implementation we only support TLS 1.3 and DTLS 1.3. */ |
| if( tls_version == MBEDTLS_SSL_VERSION_TLS1_3 ) |
| { |
| tls13_supported = 1; |
| break; |
| } |
| } |
| |
| if( !tls13_supported ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS 1.3 is not supported by the client" ) ); |
| |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, |
| MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION ); |
| return( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Negotiated version. Supported is [%04x]", |
| (unsigned int)tls_version ) ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_ECDH_C) |
| /* |
| * |
| * From RFC 8446: |
| * enum { |
| * ... (0xFFFF) |
| * } NamedGroup; |
| * struct { |
| * NamedGroup named_group_list<2..2^16-1>; |
| * } NamedGroupList; |
| */ |
| static int ssl_tls13_parse_supported_groups_ext( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end ) |
| { |
| const unsigned char *p = buf; |
| size_t named_group_list_len; |
| const unsigned char *named_group_list_end; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "supported_groups extension", p, end - buf ); |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 ); |
| named_group_list_len = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, named_group_list_len ); |
| named_group_list_end = p + named_group_list_len; |
| ssl->handshake->hrr_selected_group = 0; |
| |
| while( p < named_group_list_end ) |
| { |
| uint16_t named_group; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, named_group_list_end, 2 ); |
| named_group = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| p += 2; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, |
| ( "got named group: %s(%04x)", |
| mbedtls_ssl_named_group_to_str( named_group ), |
| named_group ) ); |
| |
| if( ! mbedtls_ssl_named_group_is_offered( ssl, named_group ) || |
| ! mbedtls_ssl_named_group_is_supported( named_group ) || |
| ssl->handshake->hrr_selected_group != 0 ) |
| { |
| continue; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, |
| ( "add named group %s(%04x) into received list.", |
| mbedtls_ssl_named_group_to_str( named_group ), |
| named_group ) ); |
| |
| ssl->handshake->hrr_selected_group = named_group; |
| } |
| |
| return( 0 ); |
| |
| } |
| #endif /* MBEDTLS_ECDH_C */ |
| |
| #define SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH 1 |
| |
| #if defined(MBEDTLS_ECDH_C) |
| /* |
| * ssl_tls13_parse_key_shares_ext() verifies whether the information in the |
| * extension is correct and stores the first acceptable key share and its associated group. |
| * |
| * Possible return values are: |
| * - 0: Successful processing of the client provided key share extension. |
| * - SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH: The key shares provided by the client |
| * does not match a group supported by the server. A HelloRetryRequest will |
| * be needed. |
| * - A negative value for fatal errors. |
| */ |
| static int ssl_tls13_parse_key_shares_ext( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char const *p = buf; |
| unsigned char const *client_shares_end; |
| size_t client_shares_len; |
| |
| /* From RFC 8446: |
| * |
| * struct { |
| * KeyShareEntry client_shares<0..2^16-1>; |
| * } KeyShareClientHello; |
| * |
| */ |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 ); |
| client_shares_len = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, client_shares_len ); |
| |
| ssl->handshake->offered_group_id = 0; |
| client_shares_end = p + client_shares_len; |
| |
| /* We try to find a suitable key share entry and copy it to the |
| * handshake context. Later, we have to find out whether we can do |
| * something with the provided key share or whether we have to |
| * dismiss it and send a HelloRetryRequest message. |
| */ |
| |
| while( p < client_shares_end ) |
| { |
| uint16_t group; |
| size_t key_exchange_len; |
| const unsigned char *key_exchange; |
| |
| /* |
| * struct { |
| * NamedGroup group; |
| * opaque key_exchange<1..2^16-1>; |
| * } KeyShareEntry; |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, client_shares_end, 4 ); |
| group = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| key_exchange_len = MBEDTLS_GET_UINT16_BE( p, 2 ); |
| p += 4; |
| key_exchange = p; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, client_shares_end, key_exchange_len ); |
| p += key_exchange_len; |
| |
| /* Continue parsing even if we have already found a match, |
| * for input validation purposes. |
| */ |
| if( ! mbedtls_ssl_named_group_is_offered( ssl, group ) || |
| ! mbedtls_ssl_named_group_is_supported( group ) || |
| ssl->handshake->offered_group_id != 0 ) |
| { |
| continue; |
| } |
| |
| /* |
| * For now, we only support ECDHE groups. |
| */ |
| if( mbedtls_ssl_tls13_named_group_is_ecdhe( group ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDH group: %s (%04x)", |
| mbedtls_ssl_named_group_to_str( group ), |
| group ) ); |
| ret = mbedtls_ssl_tls13_read_public_ecdhe_share( |
| ssl, key_exchange - 2, key_exchange_len + 2 ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 4, ( "Unrecognized NamedGroup %u", |
| (unsigned) group ) ); |
| continue; |
| } |
| |
| ssl->handshake->offered_group_id = group; |
| } |
| |
| |
| if( ssl->handshake->offered_group_id == 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching key share" ) ); |
| return( SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH ); |
| } |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_ECDH_C */ |
| |
| #if defined(MBEDTLS_DEBUG_C) |
| static void ssl_tls13_debug_print_client_hello_exts( mbedtls_ssl_context *ssl ) |
| { |
| ((void) ssl); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "Supported Extensions:" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- KEY_SHARE_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_KEY_SHARE ) > 0 ) ? "TRUE" : "FALSE" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- PSK_KEY_EXCHANGE_MODES_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_PSK_KEY_EXCHANGE_MODES ) > 0 ) ? |
| "TRUE" : "FALSE" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- PRE_SHARED_KEY_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_PRE_SHARED_KEY ) > 0 ) ? "TRUE" : "FALSE" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- SIGNATURE_ALGORITHM_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_SIG_ALG ) > 0 ) ? "TRUE" : "FALSE" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- SUPPORTED_GROUPS_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_SUPPORTED_GROUPS ) >0 ) ? |
| "TRUE" : "FALSE" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- SUPPORTED_VERSION_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_SUPPORTED_VERSIONS ) > 0 ) ? |
| "TRUE" : "FALSE" ) ); |
| #if defined ( MBEDTLS_SSL_SERVER_NAME_INDICATION ) |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "- SERVERNAME_EXTENSION ( %s )", |
| ( ( ssl->handshake->extensions_present |
| & MBEDTLS_SSL_EXT_SERVERNAME ) > 0 ) ? |
| "TRUE" : "FALSE" ) ); |
| #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ |
| } |
| #endif /* MBEDTLS_DEBUG_C */ |
| |
| static int ssl_tls13_client_hello_has_exts( mbedtls_ssl_context *ssl, |
| int exts_mask ) |
| { |
| int masked = ssl->handshake->extensions_present & exts_mask; |
| return( masked == exts_mask ); |
| } |
| |
| static int ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange( |
| mbedtls_ssl_context *ssl ) |
| { |
| return( ssl_tls13_client_hello_has_exts( ssl, |
| MBEDTLS_SSL_EXT_SUPPORTED_GROUPS | |
| MBEDTLS_SSL_EXT_KEY_SHARE | |
| MBEDTLS_SSL_EXT_SIG_ALG ) ); |
| } |
| |
| static int ssl_tls13_check_ephemeral_key_exchange( mbedtls_ssl_context *ssl ) |
| { |
| if( !mbedtls_ssl_conf_tls13_ephemeral_enabled( ssl ) ) |
| return( 0 ); |
| |
| if( !ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange( ssl ) ) |
| return( 0 ); |
| |
| ssl->handshake->tls13_kex_modes = |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL; |
| return( 1 ); |
| } |
| |
| /* |
| * |
| * STATE HANDLING: ClientHello |
| * |
| * There are three possible classes of outcomes when parsing the ClientHello: |
| * |
| * 1) The ClientHello was well-formed and matched the server's configuration. |
| * |
| * In this case, the server progresses to sending its ServerHello. |
| * |
| * 2) The ClientHello was well-formed but didn't match the server's |
| * configuration. |
| * |
| * For example, the client might not have offered a key share which |
| * the server supports, or the server might require a cookie. |
| * |
| * In this case, the server sends a HelloRetryRequest. |
| * |
| * 3) The ClientHello was ill-formed |
| * |
| * In this case, we abort the handshake. |
| * |
| */ |
| |
| /* |
| * Structure of this message: |
| * |
| * uint16 ProtocolVersion; |
| * opaque Random[32]; |
| * uint8 CipherSuite[2]; // Cryptographic suite selector |
| * |
| * struct { |
| * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 |
| * Random random; |
| * opaque legacy_session_id<0..32>; |
| * CipherSuite cipher_suites<2..2^16-2>; |
| * opaque legacy_compression_methods<1..2^8-1>; |
| * Extension extensions<8..2^16-1>; |
| * } ClientHello; |
| */ |
| |
| #define SSL_CLIENT_HELLO_OK 0 |
| #define SSL_CLIENT_HELLO_HRR_REQUIRED 1 |
| |
| static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| const unsigned char *p = buf; |
| size_t legacy_session_id_len; |
| const unsigned char *cipher_suites; |
| size_t cipher_suites_len; |
| const unsigned char *cipher_suites_end; |
| size_t extensions_len; |
| const unsigned char *extensions_end; |
| int hrr_required = 0; |
| |
| const mbedtls_ssl_ciphersuite_t* ciphersuite_info; |
| |
| ssl->handshake->extensions_present = MBEDTLS_SSL_EXT_NONE; |
| |
| /* |
| * ClientHello layout: |
| * 0 . 1 protocol version |
| * 2 . 33 random bytes |
| * 34 . 34 session id length ( 1 byte ) |
| * 35 . 34+x session id |
| * .. . .. ciphersuite list length ( 2 bytes ) |
| * .. . .. ciphersuite list |
| * .. . .. compression alg. list length ( 1 byte ) |
| * .. . .. compression alg. list |
| * .. . .. extensions length ( 2 bytes, optional ) |
| * .. . .. extensions ( optional ) |
| */ |
| |
| /* |
| * Minimal length ( with everything empty and extensions omitted ) is |
| * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can |
| * read at least up to session id length without worrying. |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 38 ); |
| |
| /* ... |
| * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 |
| * ... |
| * with ProtocolVersion defined as: |
| * uint16 ProtocolVersion; |
| */ |
| if( mbedtls_ssl_read_version( p, ssl->conf->transport ) != |
| MBEDTLS_SSL_VERSION_TLS1_2 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Unsupported version of TLS." ) ); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, |
| MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION ); |
| return ( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION ); |
| } |
| p += 2; |
| |
| /* |
| * Only support TLS 1.3 currently, temporarily set the version. |
| */ |
| ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_3; |
| |
| /* ... |
| * Random random; |
| * ... |
| * with Random defined as: |
| * opaque Random[32]; |
| */ |
| MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", |
| p, MBEDTLS_CLIENT_HELLO_RANDOM_LEN ); |
| |
| memcpy( &ssl->handshake->randbytes[0], p, MBEDTLS_CLIENT_HELLO_RANDOM_LEN ); |
| p += MBEDTLS_CLIENT_HELLO_RANDOM_LEN; |
| |
| /* ... |
| * opaque legacy_session_id<0..32>; |
| * ... |
| */ |
| legacy_session_id_len = p[0]; |
| p++; |
| |
| if( legacy_session_id_len > sizeof( ssl->session_negotiate->id ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); |
| return( MBEDTLS_ERR_SSL_DECODE_ERROR ); |
| } |
| |
| ssl->session_negotiate->id_len = legacy_session_id_len; |
| MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", |
| p, legacy_session_id_len ); |
| /* |
| * Check we have enough data for the legacy session identifier |
| * and the ciphersuite list length. |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, legacy_session_id_len + 2 ); |
| |
| memcpy( &ssl->session_negotiate->id[0], p, legacy_session_id_len ); |
| p += legacy_session_id_len; |
| |
| cipher_suites_len = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| p += 2; |
| |
| /* Check we have enough data for the ciphersuite list, the legacy |
| * compression methods and the length of the extensions. |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, cipher_suites_len + 2 + 2 ); |
| |
| /* ... |
| * CipherSuite cipher_suites<2..2^16-2>; |
| * ... |
| * with CipherSuite defined as: |
| * uint8 CipherSuite[2]; |
| */ |
| cipher_suites = p; |
| cipher_suites_end = p + cipher_suites_len; |
| MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", |
| p, cipher_suites_len ); |
| /* |
| * Search for a matching ciphersuite |
| */ |
| int ciphersuite_match = 0; |
| for ( ; p < cipher_suites_end; p += 2 ) |
| { |
| uint16_t cipher_suite; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, cipher_suites_end, 2 ); |
| cipher_suite = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( cipher_suite ); |
| /* |
| * Check whether this ciphersuite is valid and offered. |
| */ |
| if( ( mbedtls_ssl_validate_ciphersuite( |
| ssl, ciphersuite_info, ssl->tls_version, |
| ssl->tls_version ) != 0 ) || |
| ! mbedtls_ssl_tls13_cipher_suite_is_offered( ssl, cipher_suite ) ) |
| { |
| continue; |
| } |
| |
| ssl->session_negotiate->ciphersuite = cipher_suite; |
| ssl->handshake->ciphersuite_info = ciphersuite_info; |
| ciphersuite_match = 1; |
| |
| break; |
| |
| } |
| |
| if( ! ciphersuite_match ) |
| { |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| return ( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", |
| ciphersuite_info->name ) ); |
| |
| p = cipher_suites + cipher_suites_len; |
| |
| /* ... |
| * opaque legacy_compression_methods<1..2^8-1>; |
| * ... |
| */ |
| if( p[0] != 1 || p[1] != MBEDTLS_SSL_COMPRESS_NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad legacy compression method" ) ); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER ); |
| return ( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER ); |
| } |
| p += 2; |
| |
| /* ... |
| * Extension extensions<8..2^16-1>; |
| * ... |
| * with Extension defined as: |
| * struct { |
| * ExtensionType extension_type; |
| * opaque extension_data<0..2^16-1>; |
| * } Extension; |
| */ |
| extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extensions_len ); |
| extensions_end = p + extensions_len; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", p, extensions_len ); |
| |
| while( p < extensions_end ) |
| { |
| unsigned int extension_type; |
| size_t extension_data_len; |
| const unsigned char *extension_data_end; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, 4 ); |
| extension_type = MBEDTLS_GET_UINT16_BE( p, 0 ); |
| extension_data_len = MBEDTLS_GET_UINT16_BE( p, 2 ); |
| p += 4; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, extension_data_len ); |
| extension_data_end = p + extension_data_len; |
| |
| switch( extension_type ) |
| { |
| #if defined(MBEDTLS_ECDH_C) |
| case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS: |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported group extension" ) ); |
| |
| /* Supported Groups Extension |
| * |
| * When sent by the client, the "supported_groups" extension |
| * indicates the named groups which the client supports, |
| * ordered from most preferred to least preferred. |
| */ |
| ret = ssl_tls13_parse_supported_groups_ext( |
| ssl, p, extension_data_end ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, |
| "mbedtls_ssl_parse_supported_groups_ext", ret ); |
| return( ret ); |
| } |
| |
| ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS; |
| break; |
| #endif /* MBEDTLS_ECDH_C */ |
| |
| #if defined(MBEDTLS_ECDH_C) |
| case MBEDTLS_TLS_EXT_KEY_SHARE: |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "found key share extension" ) ); |
| |
| /* |
| * Key Share Extension |
| * |
| * When sent by the client, the "key_share" extension |
| * contains the endpoint's cryptographic parameters for |
| * ECDHE/DHE key establishment methods. |
| */ |
| ret = ssl_tls13_parse_key_shares_ext( |
| ssl, p, extension_data_end ); |
| if( ret == SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "HRR needed " ) ); |
| hrr_required = 1; |
| } |
| |
| if( ret < 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_parse_key_shares_ext", ret ); |
| return( ret ); |
| } |
| |
| ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE; |
| break; |
| #endif /* MBEDTLS_ECDH_C */ |
| |
| case MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS: |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported versions extension" ) ); |
| |
| ret = ssl_tls13_parse_supported_versions_ext( |
| ssl, p, extension_data_end ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, |
| ( "ssl_tls13_parse_supported_versions_ext" ), ret ); |
| return( ret ); |
| } |
| ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_VERSIONS; |
| break; |
| |
| #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) |
| case MBEDTLS_TLS_EXT_SIG_ALG: |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) ); |
| |
| ret = mbedtls_ssl_parse_sig_alg_ext( |
| ssl, p, extension_data_end ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, |
| ( "ssl_parse_supported_signature_algorithms_server_ext ( %d )", |
| ret ) ); |
| return( ret ); |
| } |
| ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SIG_ALG; |
| break; |
| #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ |
| |
| default: |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "unknown extension found: %ud ( ignoring )", |
| extension_type ) ); |
| } |
| |
| p += extension_data_len; |
| } |
| |
| /* Update checksum with either |
| * - The entire content of the CH message, if no PSK extension is present |
| * - The content up to but excluding the PSK extension, if present. |
| */ |
| mbedtls_ssl_add_hs_msg_to_checksum( ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, |
| buf, p - buf ); |
| |
| /* List all the extensions we have received */ |
| #if defined(MBEDTLS_DEBUG_C) |
| ssl_tls13_debug_print_client_hello_exts( ssl ); |
| #endif /* MBEDTLS_DEBUG_C */ |
| |
| /* |
| * Here we only support the ephemeral or (EC)DHE key echange mode |
| */ |
| |
| if( !ssl_tls13_check_ephemeral_key_exchange( ssl ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, |
| ( "ClientHello message misses mandatory extensions." ) ); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION , |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER ); |
| return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER ); |
| } |
| |
| return( hrr_required ? SSL_CLIENT_HELLO_HRR_REQUIRED : SSL_CLIENT_HELLO_OK ); |
| } |
| |
| /* Update the handshake state machine */ |
| |
| static int ssl_tls13_postprocess_client_hello( mbedtls_ssl_context* ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ret = mbedtls_ssl_tls13_key_schedule_stage_early( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, |
| "mbedtls_ssl_tls1_3_key_schedule_stage_early", ret ); |
| return( ret ); |
| } |
| |
| return( 0 ); |
| |
| } |
| |
| /* |
| * Main entry point from the state machine; orchestrates the otherfunctions. |
| */ |
| |
| static int ssl_tls13_process_client_hello( mbedtls_ssl_context *ssl ) |
| { |
| |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char* buf = NULL; |
| size_t buflen = 0; |
| int parse_client_hello_ret; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, |
| &buf, &buflen ) ); |
| |
| MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_parse_client_hello( ssl, buf, |
| buf + buflen ) ); |
| parse_client_hello_ret = ret; /* Store return value of parse_client_hello, |
| * only SSL_CLIENT_HELLO_OK or |
| * SSL_CLIENT_HELLO_HRR_REQUIRED at this |
| * stage as negative error codes are handled |
| * by MBEDTLS_SSL_PROC_CHK_NEG. */ |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_postprocess_client_hello( ssl ) ); |
| |
| if( parse_client_hello_ret == SSL_CLIENT_HELLO_OK ) |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO ); |
| else |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HELLO_RETRY_REQUEST ); |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) ); |
| return( ret ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_HELLO |
| */ |
| static int ssl_tls13_prepare_server_hello( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *server_randbytes = |
| ssl->handshake->randbytes + MBEDTLS_CLIENT_HELLO_RANDOM_LEN; |
| if( ssl->conf->f_rng == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided" ) ); |
| return( MBEDTLS_ERR_SSL_NO_RNG ); |
| } |
| |
| if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, server_randbytes, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret ); |
| return( ret ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", server_randbytes, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN ); |
| |
| #if defined(MBEDTLS_HAVE_TIME) |
| ssl->session_negotiate->start = time( NULL ); |
| #endif /* MBEDTLS_HAVE_TIME */ |
| |
| return( ret ); |
| } |
| |
| /* |
| * ssl_tls13_write_server_hello_supported_versions_ext (): |
| * |
| * struct { |
| * ProtocolVersion selected_version; |
| * } SupportedVersions; |
| */ |
| static int ssl_tls13_write_server_hello_supported_versions_ext( |
| mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len ) |
| { |
| *out_len = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, write selected version" ) ); |
| |
| /* Check if we have space to write the extension: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - selected_version (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 6 ); |
| |
| MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, buf, 0 ); |
| |
| MBEDTLS_PUT_UINT16_BE( 2, buf, 2 ); |
| |
| mbedtls_ssl_write_version( buf + 4, |
| ssl->conf->transport, |
| ssl->tls_version ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "supported version: [%04x]", |
| ssl->tls_version ) ); |
| |
| *out_len = 6; |
| |
| return( 0 ); |
| } |
| |
| |
| |
| /* Generate and export a single key share. For hybrid KEMs, this can |
| * be called multiple times with the different components of the hybrid. */ |
| static int ssl_tls13_generate_and_write_key_share( mbedtls_ssl_context *ssl, |
| uint16_t named_group, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| *out_len = 0; |
| |
| #if defined(MBEDTLS_ECDH_C) |
| if( mbedtls_ssl_tls13_named_group_is_ecdhe( named_group ) ) |
| { |
| ret = mbedtls_ssl_tls13_generate_and_write_ecdh_key_exchange( |
| ssl, named_group, buf, end, out_len ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_tls13_generate_and_write_ecdh_key_exchange", |
| ret ); |
| return( ret ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_ECDH_C */ |
| if( 0 /* Other kinds of KEMs */ ) |
| { |
| } |
| else |
| { |
| ((void) ssl); |
| ((void) named_group); |
| ((void) buf); |
| ((void) end); |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| |
| return( ret ); |
| } |
| |
| /* |
| * ssl_tls13_write_key_share_ext |
| * |
| * Structure of key_share extension in ServerHello: |
| * |
| * struct { |
| * NamedGroup group; |
| * opaque key_exchange<1..2^16-1>; |
| * } KeyShareEntry; |
| * struct { |
| * KeyShareEntry server_share; |
| * } KeyShareServerHello; |
| */ |
| static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| uint16_t group = ssl->handshake->offered_group_id; |
| unsigned char *server_share = buf + 4; |
| size_t key_exchange_length; |
| |
| *out_len = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding key share extension" ) ); |
| |
| /* Check if we have space for header and length fields: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - group (2 bytes) |
| * - key_exchange_length (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 8 ); |
| MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, p, 0 ); |
| MBEDTLS_PUT_UINT16_BE( group, server_share, 0 ); |
| p += 8; |
| |
| /* When we introduce PQC-ECDHE hybrids, we'll want to call this |
| * function multiple times. */ |
| ret = ssl_tls13_generate_and_write_key_share( |
| ssl, group, server_share + 4, end, &key_exchange_length ); |
| if( ret != 0 ) |
| return( ret ); |
| p += key_exchange_length; |
| |
| MBEDTLS_PUT_UINT16_BE( key_exchange_length, server_share + 2, 0 ); |
| |
| MBEDTLS_PUT_UINT16_BE( p - server_share, buf, 2 ); |
| |
| *out_len = p - buf; |
| |
| return( 0 ); |
| } |
| |
| static int ssl_tls13_write_hrr_key_share_ext( mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len ) |
| { |
| uint16_t selected_group = ssl->handshake->hrr_selected_group; |
| /* key_share Extension |
| * |
| * struct { |
| * select (Handshake.msg_type) { |
| * ... |
| * case hello_retry_request: |
| * NamedGroup selected_group; |
| * ... |
| * }; |
| * } KeyShare; |
| */ |
| |
| *out_len = 0; |
| |
| /* |
| * For a pure PSK key exchange, there is no group to agree upon. The purpose |
| * of the HRR is then to transmit a cookie to force the client to demonstrate |
| * reachability at their apparent network address (primarily useful for DTLS). |
| */ |
| if( ! mbedtls_ssl_tls13_some_ephemeral_enabled( ssl ) ) |
| return( 0 ); |
| |
| /* We should only send the key_share extension if the client's initial |
| * key share was not acceptable. */ |
| if( ssl->handshake->offered_group_id != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 4, ( "Skip key_share extension in HRR" ) ); |
| return( 0 ); |
| } |
| |
| if( selected_group == 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching named group found" ) ); |
| return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| } |
| |
| /* Check if we have enough space: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - selected_group (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR( buf, end, 6 ); |
| |
| MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 ); |
| MBEDTLS_PUT_UINT16_BE( 2, buf, 2 ); |
| MBEDTLS_PUT_UINT16_BE( selected_group, buf, 4 ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "HRR selected_group: %s (%x)", |
| mbedtls_ssl_named_group_to_str( selected_group ), |
| selected_group ) ); |
| |
| *out_len = 6; |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Structure of ServerHello message: |
| * |
| * struct { |
| * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 |
| * Random random; |
| * opaque legacy_session_id_echo<0..32>; |
| * CipherSuite cipher_suite; |
| * uint8 legacy_compression_method = 0; |
| * Extension extensions<6..2^16-1>; |
| * } ServerHello; |
| */ |
| static int ssl_tls13_write_server_hello_body( mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len, |
| int is_hrr ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| unsigned char *p_extensions_len; |
| size_t output_len; |
| |
| *out_len = 0; |
| |
| /* ... |
| * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 |
| * ... |
| * with ProtocolVersion defined as: |
| * uint16 ProtocolVersion; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 ); |
| MBEDTLS_PUT_UINT16_BE( 0x0303, p, 0 ); |
| p += 2; |
| |
| /* ... |
| * Random random; |
| * ... |
| * with Random defined as: |
| * opaque Random[MBEDTLS_SERVER_HELLO_RANDOM_LEN]; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, MBEDTLS_SERVER_HELLO_RANDOM_LEN ); |
| if( is_hrr ) |
| { |
| memcpy( p, mbedtls_ssl_tls13_hello_retry_request_magic, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN ); |
| } |
| else |
| { |
| memcpy( p, &ssl->handshake->randbytes[MBEDTLS_CLIENT_HELLO_RANDOM_LEN], |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN ); |
| } |
| MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", |
| p, MBEDTLS_SERVER_HELLO_RANDOM_LEN ); |
| p += MBEDTLS_SERVER_HELLO_RANDOM_LEN; |
| |
| /* ... |
| * opaque legacy_session_id_echo<0..32>; |
| * ... |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 + ssl->session_negotiate->id_len ); |
| *p++ = (unsigned char)ssl->session_negotiate->id_len; |
| if( ssl->session_negotiate->id_len > 0 ) |
| { |
| memcpy( p, &ssl->session_negotiate->id[0], |
| ssl->session_negotiate->id_len ); |
| p += ssl->session_negotiate->id_len; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id, |
| ssl->session_negotiate->id_len ); |
| } |
| |
| /* ... |
| * CipherSuite cipher_suite; |
| * ... |
| * with CipherSuite defined as: |
| * uint8 CipherSuite[2]; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 ); |
| MBEDTLS_PUT_UINT16_BE( ssl->session_negotiate->ciphersuite, p, 0 ); |
| p += 2; |
| MBEDTLS_SSL_DEBUG_MSG( 3, |
| ( "server hello, chosen ciphersuite: %s ( id=%d )", |
| mbedtls_ssl_get_ciphersuite_name( |
| ssl->session_negotiate->ciphersuite ), |
| ssl->session_negotiate->ciphersuite ) ); |
| |
| /* ... |
| * uint8 legacy_compression_method = 0; |
| * ... |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 ); |
| *p++ = 0x0; |
| |
| /* ... |
| * Extension extensions<6..2^16-1>; |
| * ... |
| * struct { |
| * ExtensionType extension_type; (2 bytes) |
| * opaque extension_data<0..2^16-1>; |
| * } Extension; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 ); |
| p_extensions_len = p; |
| p += 2; |
| |
| if( ( ret = ssl_tls13_write_server_hello_supported_versions_ext( |
| ssl, p, end, &output_len ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_write_server_hello_supported_versions_ext", ret ); |
| return( ret ); |
| } |
| p += output_len; |
| |
| if( mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) ) |
| { |
| if( is_hrr ) |
| ret = ssl_tls13_write_hrr_key_share_ext( ssl, p, end, &output_len ); |
| else |
| ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len ); |
| if( ret != 0 ) |
| return( ret ); |
| p += output_len; |
| } |
| |
| MBEDTLS_PUT_UINT16_BE( p - p_extensions_len - 2, p_extensions_len, 0 ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "server hello extensions", |
| p_extensions_len, p - p_extensions_len ); |
| |
| *out_len = p - buf; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "server hello", buf, *out_len ); |
| |
| return( ret ); |
| } |
| |
| static int ssl_tls13_finalize_write_server_hello( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| ret = mbedtls_ssl_tls13_compute_handshake_transform( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, |
| "mbedtls_ssl_tls13_compute_handshake_transform", |
| ret ); |
| return( ret ); |
| } |
| |
| mbedtls_ssl_set_outbound_transform( ssl, |
| ssl->handshake->transform_handshake ); |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ( "switching to handshake transform for outbound data" ) ); |
| |
| return( ret ); |
| } |
| |
| static int ssl_tls13_write_server_hello( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_server_hello( ssl ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl, |
| MBEDTLS_SSL_HS_SERVER_HELLO, &buf, &buf_len ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_server_hello_body( ssl, buf, |
| buf + buf_len, |
| &msg_len, |
| 0 ) ); |
| |
| mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_write_server_hello( ssl ) ); |
| |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS ); |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); |
| return( ret ); |
| } |
| |
| |
| /* |
| * Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST |
| */ |
| static int ssl_tls13_write_hello_retry_request_coordinate( |
| mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| if( ssl->handshake->hello_retry_request_count > 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Too many HRRs" ) ); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| } |
| |
| /* |
| * Create stateless transcript hash for HRR |
| */ |
| MBEDTLS_SSL_DEBUG_MSG( 4, ( "Reset transcript for HRR" ) ); |
| ret = mbedtls_ssl_reset_transcript_for_hrr( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_reset_transcript_for_hrr", ret ); |
| return( ret ); |
| } |
| mbedtls_ssl_session_reset_msg_layer( ssl, 0 ); |
| |
| return( 0 ); |
| } |
| |
| static int ssl_tls13_write_hello_retry_request( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello retry request" ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_hello_retry_request_coordinate( ssl ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, |
| &buf, &buf_len ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_server_hello_body( ssl, buf, |
| buf + buf_len, |
| &msg_len, |
| 1 ) ); |
| mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len ); |
| |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( ssl, buf_len, |
| msg_len ) ); |
| |
| ssl->handshake->hello_retry_request_count++; |
| |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO ); |
| |
| cleanup: |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello retry request" ) ); |
| return( ret ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS |
| */ |
| |
| /* |
| * struct { |
| * Extension extensions<0..2 ^ 16 - 1>; |
| * } EncryptedExtensions; |
| * |
| */ |
| static int ssl_tls13_write_encrypted_extensions_body( mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len ) |
| { |
| unsigned char *p = buf; |
| size_t extensions_len = 0; |
| unsigned char *p_extensions_len; |
| |
| *out_len = 0; |
| |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 ); |
| p_extensions_len = p; |
| p += 2; |
| |
| ((void) ssl); |
| |
| extensions_len = ( p - p_extensions_len ) - 2; |
| MBEDTLS_PUT_UINT16_BE( extensions_len, p_extensions_len, 0 ); |
| |
| *out_len = p - buf; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "encrypted extensions", buf, *out_len ); |
| |
| return( 0 ); |
| } |
| |
| static int ssl_tls13_write_encrypted_extensions( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write encrypted extensions" ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl, |
| MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, &buf, &buf_len ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_encrypted_extensions_body( |
| ssl, buf, buf + buf_len, &msg_len ) ); |
| |
| mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, buf, msg_len ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len ) ); |
| |
| #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) |
| if( mbedtls_ssl_tls13_some_psk_enabled( ssl ) ) |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED ); |
| else |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CERTIFICATE_REQUEST ); |
| #else |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED ); |
| #endif |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write encrypted extensions" ) ); |
| return( ret ); |
| } |
| |
| #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) |
| #define SSL_CERTIFICATE_REQUEST_SEND_REQUEST 0 |
| #define SSL_CERTIFICATE_REQUEST_SKIP 1 |
| /* Coordination: |
| * Check whether a CertificateRequest message should be written. |
| * Returns a negative code on failure, or |
| * - SSL_CERTIFICATE_REQUEST_SEND_REQUEST |
| * - SSL_CERTIFICATE_REQUEST_SKIP |
| * indicating if the writing of the CertificateRequest |
| * should be skipped or not. |
| */ |
| static int ssl_tls13_certificate_request_coordinate( mbedtls_ssl_context *ssl ) |
| { |
| int authmode; |
| |
| authmode = ssl->conf->authmode; |
| |
| if( authmode == MBEDTLS_SSL_VERIFY_NONE ) |
| return( SSL_CERTIFICATE_REQUEST_SKIP ); |
| |
| ssl->handshake->certificate_request_sent = 1; |
| |
| return( SSL_CERTIFICATE_REQUEST_SEND_REQUEST ); |
| } |
| |
| /* |
| * struct { |
| * opaque certificate_request_context<0..2^8-1>; |
| * Extension extensions<2..2^16-1>; |
| * } CertificateRequest; |
| * |
| */ |
| static int ssl_tls13_write_certificate_request_body( mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| const unsigned char *end, |
| size_t *out_len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| size_t output_len = 0; |
| unsigned char *p_extensions_len; |
| |
| *out_len = 0; |
| |
| /* Check if we have enough space: |
| * - certificate_request_context (1 byte) |
| * - extensions length (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR( p, end, 3 ); |
| |
| /* |
| * Write certificate_request_context |
| */ |
| /* |
| * We use a zero length context for the normal handshake |
| * messages. For post-authentication handshake messages |
| * this request context would be set to a non-zero value. |
| */ |
| *p++ = 0x0; |
| |
| /* |
| * Write extensions |
| */ |
| /* The extensions must contain the signature_algorithms. */ |
| p_extensions_len = p; |
| p += 2; |
| ret = mbedtls_ssl_write_sig_alg_ext( ssl, p, end, &output_len ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| p += output_len; |
| MBEDTLS_PUT_UINT16_BE( p - p_extensions_len - 2, p_extensions_len, 0 ); |
| |
| *out_len = p - buf; |
| |
| return( 0 ); |
| } |
| |
| static int ssl_tls13_write_certificate_request( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); |
| |
| MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_certificate_request_coordinate( ssl ) ); |
| |
| if( ret == SSL_CERTIFICATE_REQUEST_SEND_REQUEST ) |
| { |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl, |
| MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, &buf, &buf_len ) ); |
| |
| MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_certificate_request_body( |
| ssl, buf, buf + buf_len, &msg_len ) ); |
| |
| mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, buf, msg_len ); |
| |
| MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len ) ); |
| } |
| else if( ret == SSL_CERTIFICATE_REQUEST_SKIP ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) ); |
| ret = 0; |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| goto cleanup; |
| } |
| |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_CERTIFICATE ); |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) ); |
| return( ret ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_CERTIFICATE |
| */ |
| static int ssl_tls13_write_server_certificate( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| if( mbedtls_ssl_own_cert( ssl ) == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "No certificate available." ) ); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| } |
| |
| ret = mbedtls_ssl_tls13_write_certificate( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CERTIFICATE_VERIFY ); |
| return( 0 ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_CERTIFICATE_VERIFY |
| */ |
| static int ssl_tls13_write_certificate_verify( mbedtls_ssl_context *ssl ) |
| { |
| int ret = mbedtls_ssl_tls13_write_certificate_verify( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED ); |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_FINISHED |
| */ |
| static int ssl_tls13_write_server_finished( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ret = mbedtls_ssl_tls13_write_finished_message( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| ret = mbedtls_ssl_tls13_compute_application_transform( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE ); |
| return( ret ); |
| } |
| |
| if( ssl->handshake->certificate_request_sent ) |
| { |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Switch to handshake keys for inbound traffic" ) ); |
| mbedtls_ssl_set_inbound_transform( ssl, ssl->handshake->transform_handshake ); |
| } |
| else |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED ); |
| return( 0 ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_CLIENT_FINISHED |
| */ |
| static int ssl_tls13_process_client_finished( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ! ssl->handshake->certificate_request_sent ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, |
| ( "Switch to handshake traffic keys for inbound traffic" ) ); |
| mbedtls_ssl_set_inbound_transform( ssl, ssl->handshake->transform_handshake ); |
| } |
| ret = mbedtls_ssl_tls13_process_finished_message( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| ret = mbedtls_ssl_tls13_generate_resumption_master_secret( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, |
| "mbedtls_ssl_tls13_generate_resumption_master_secret ", ret ); |
| } |
| |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HANDSHAKE_WRAPUP ); |
| return( 0 ); |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_HANDSHAKE_WRAPUP |
| */ |
| static int ssl_tls13_handshake_wrapup( mbedtls_ssl_context *ssl ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) ); |
| |
| mbedtls_ssl_tls13_handshake_wrapup( ssl ); |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HANDSHAKE_OVER ); |
| return( 0 ); |
| } |
| |
| /* |
| * TLS 1.3 State Machine -- server side |
| */ |
| int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL ) |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "tls13 server state: %s(%d)", |
| mbedtls_ssl_states_str( ssl->state ), |
| ssl->state ) ); |
| |
| switch( ssl->state ) |
| { |
| /* start state */ |
| case MBEDTLS_SSL_HELLO_REQUEST: |
| mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO ); |
| ret = 0; |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_HELLO: |
| ret = ssl_tls13_process_client_hello( ssl ); |
| if( ret != 0 ) |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_process_client_hello", ret ); |
| break; |
| |
| case MBEDTLS_SSL_HELLO_RETRY_REQUEST: |
| ret = ssl_tls13_write_hello_retry_request( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_hello_retry_request", ret ); |
| return( ret ); |
| } |
| break; |
| |
| case MBEDTLS_SSL_SERVER_HELLO: |
| ret = ssl_tls13_write_server_hello( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS: |
| ret = ssl_tls13_write_encrypted_extensions( ssl ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_encrypted_extensions", ret ); |
| return( ret ); |
| } |
| break; |
| |
| #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) |
| case MBEDTLS_SSL_CERTIFICATE_REQUEST: |
| ret = ssl_tls13_write_certificate_request( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_SERVER_CERTIFICATE: |
| ret = ssl_tls13_write_server_certificate( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_CERTIFICATE_VERIFY: |
| ret = ssl_tls13_write_certificate_verify( ssl ); |
| break; |
| #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ |
| |
| case MBEDTLS_SSL_SERVER_FINISHED: |
| ret = ssl_tls13_write_server_finished( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_FINISHED: |
| ret = ssl_tls13_process_client_finished( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_HANDSHAKE_WRAPUP: |
| ret = ssl_tls13_handshake_wrapup( ssl ); |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_CERTIFICATE: |
| ret = mbedtls_ssl_tls13_process_certificate( ssl ); |
| if( ret == 0 && ssl->session_negotiate->peer_cert != NULL ) |
| { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY ); |
| } |
| else |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_FINISHED ); |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY: |
| ret = mbedtls_ssl_tls13_process_certificate_verify( ssl ); |
| if( ret == 0 ) |
| { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_FINISHED ); |
| } |
| break; |
| |
| default: |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) ); |
| return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); |
| } |
| |
| return( ret ); |
| } |
| |
| #endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_TLS1_3 */ |
