1030 lines
34 KiB
C
1030 lines
34 KiB
C
/*
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* TLS 1.2 and 1.3 client-side functions
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS ( https://tls.mbed.org )
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*/
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#include "common.h"
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#if defined(MBEDTLS_SSL_CLI_C)
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3) || defined(MBEDTLS_SSL_PROTO_TLS1_2)
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#include <string.h>
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#include "mbedtls/debug.h"
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#include "mbedtls/error.h"
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#include "mbedtls/platform.h"
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#include "ssl_client.h"
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#include "ssl_misc.h"
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#include "ssl_tls13_keys.h"
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#include "ssl_debug_helpers.h"
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#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
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MBEDTLS_CHECK_RETURN_CRITICAL
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static int ssl_write_hostname_ext(mbedtls_ssl_context *ssl,
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unsigned char *buf,
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const unsigned char *end,
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size_t *olen)
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{
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unsigned char *p = buf;
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size_t hostname_len;
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*olen = 0;
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if (ssl->hostname == NULL) {
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return 0;
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}
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MBEDTLS_SSL_DEBUG_MSG(3,
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("client hello, adding server name extension: %s",
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ssl->hostname));
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hostname_len = strlen(ssl->hostname);
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, hostname_len + 9);
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/*
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* Sect. 3, RFC 6066 (TLS Extensions Definitions)
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*
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* In order to provide any of the server names, clients MAY include an
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* extension of type "server_name" in the (extended) client hello. The
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* "extension_data" field of this extension SHALL contain
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* "ServerNameList" where:
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*
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* struct {
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* NameType name_type;
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* select (name_type) {
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* case host_name: HostName;
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* } name;
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* } ServerName;
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*
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* enum {
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* host_name(0), (255)
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* } NameType;
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*
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* opaque HostName<1..2^16-1>;
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*
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* struct {
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* ServerName server_name_list<1..2^16-1>
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* } ServerNameList;
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*
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*/
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MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SERVERNAME, p, 0);
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p += 2;
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MBEDTLS_PUT_UINT16_BE(hostname_len + 5, p, 0);
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p += 2;
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MBEDTLS_PUT_UINT16_BE(hostname_len + 3, p, 0);
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p += 2;
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*p++ = MBEDTLS_BYTE_0(MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME);
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MBEDTLS_PUT_UINT16_BE(hostname_len, p, 0);
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p += 2;
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memcpy(p, ssl->hostname, hostname_len);
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*olen = hostname_len + 9;
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
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mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_SERVERNAME);
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
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return 0;
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}
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#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
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#if defined(MBEDTLS_SSL_ALPN)
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/*
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* ssl_write_alpn_ext()
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*
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* Structure of the application_layer_protocol_negotiation extension in
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* ClientHello:
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*
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* opaque ProtocolName<1..2^8-1>;
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*
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* struct {
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* ProtocolName protocol_name_list<2..2^16-1>
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* } ProtocolNameList;
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*
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*/
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MBEDTLS_CHECK_RETURN_CRITICAL
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static int ssl_write_alpn_ext(mbedtls_ssl_context *ssl,
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unsigned char *buf,
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const unsigned char *end,
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size_t *out_len)
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{
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unsigned char *p = buf;
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*out_len = 0;
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if (ssl->conf->alpn_list == NULL) {
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return 0;
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}
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MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, adding alpn extension"));
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/* Check we have enough space for the extension type (2 bytes), the
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* extension length (2 bytes) and the protocol_name_list length (2 bytes).
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*/
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 6);
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MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ALPN, p, 0);
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/* Skip writing extension and list length for now */
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p += 6;
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/*
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* opaque ProtocolName<1..2^8-1>;
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*
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* struct {
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* ProtocolName protocol_name_list<2..2^16-1>
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* } ProtocolNameList;
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*/
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for (const char **cur = ssl->conf->alpn_list; *cur != NULL; cur++) {
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/*
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* mbedtls_ssl_conf_set_alpn_protocols() checked that the length of
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* protocol names is less than 255.
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*/
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size_t protocol_name_len = strlen(*cur);
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 1 + protocol_name_len);
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*p++ = (unsigned char) protocol_name_len;
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memcpy(p, *cur, protocol_name_len);
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p += protocol_name_len;
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}
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*out_len = p - buf;
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/* List length = *out_len - 2 (ext_type) - 2 (ext_len) - 2 (list_len) */
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MBEDTLS_PUT_UINT16_BE(*out_len - 6, buf, 4);
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/* Extension length = *out_len - 2 (ext_type) - 2 (ext_len) */
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MBEDTLS_PUT_UINT16_BE(*out_len - 4, buf, 2);
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
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mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_ALPN);
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
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return 0;
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}
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#endif /* MBEDTLS_SSL_ALPN */
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#if defined(MBEDTLS_SSL_TLS1_2_SOME_ECC) || \
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defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
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/*
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* Function for writing a supported groups (TLS 1.3) or supported elliptic
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* curves (TLS 1.2) extension.
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*
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* The "extension_data" field of a supported groups extension contains a
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* "NamedGroupList" value (TLS 1.3 RFC8446):
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* enum {
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* secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
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* x25519(0x001D), x448(0x001E),
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* ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
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* ffdhe6144(0x0103), ffdhe8192(0x0104),
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* ffdhe_private_use(0x01FC..0x01FF),
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* ecdhe_private_use(0xFE00..0xFEFF),
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* (0xFFFF)
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* } NamedGroup;
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* struct {
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* NamedGroup named_group_list<2..2^16-1>;
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* } NamedGroupList;
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*
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* The "extension_data" field of a supported elliptic curves extension contains
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* a "NamedCurveList" value (TLS 1.2 RFC 8422):
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* enum {
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* deprecated(1..22),
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* secp256r1 (23), secp384r1 (24), secp521r1 (25),
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* x25519(29), x448(30),
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* reserved (0xFE00..0xFEFF),
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* deprecated(0xFF01..0xFF02),
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* (0xFFFF)
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* } NamedCurve;
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* struct {
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* NamedCurve named_curve_list<2..2^16-1>
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* } NamedCurveList;
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*
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* The TLS 1.3 supported groups extension was defined to be a compatible
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* generalization of the TLS 1.2 supported elliptic curves extension. They both
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* share the same extension identifier.
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*
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*/
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#define SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_2_FLAG 1
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#define SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_3_FLAG 2
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MBEDTLS_CHECK_RETURN_CRITICAL
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static int ssl_write_supported_groups_ext(mbedtls_ssl_context *ssl,
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unsigned char *buf,
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const unsigned char *end,
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int flags,
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size_t *out_len)
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{
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unsigned char *p = buf;
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unsigned char *named_group_list; /* Start of named_group_list */
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size_t named_group_list_len; /* Length of named_group_list */
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const uint16_t *group_list = mbedtls_ssl_get_groups(ssl);
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*out_len = 0;
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MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, adding supported_groups extension"));
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/* Check if we have space for header and length fields:
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* - extension_type (2 bytes)
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* - extension_data_length (2 bytes)
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* - named_group_list_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 6);
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p += 6;
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named_group_list = p;
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if (group_list == NULL) {
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return MBEDTLS_ERR_SSL_BAD_CONFIG;
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}
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for (; *group_list != 0; group_list++) {
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int propose_group = 0;
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MBEDTLS_SSL_DEBUG_MSG(1, ("got supported group(%04x)", *group_list));
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#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
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if (flags & SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_3_FLAG) {
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#if defined(PSA_WANT_ALG_ECDH)
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if (mbedtls_ssl_tls13_named_group_is_ecdhe(*group_list) &&
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(mbedtls_ssl_get_ecp_group_id_from_tls_id(*group_list) !=
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MBEDTLS_ECP_DP_NONE)) {
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propose_group = 1;
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}
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#endif
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#if defined(PSA_WANT_ALG_FFDH)
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if (mbedtls_ssl_tls13_named_group_is_ffdh(*group_list)) {
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propose_group = 1;
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}
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#endif
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}
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#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */
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#if defined(MBEDTLS_SSL_TLS1_2_SOME_ECC)
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if ((flags & SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_2_FLAG) &&
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mbedtls_ssl_tls12_named_group_is_ecdhe(*group_list) &&
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(mbedtls_ssl_get_ecp_group_id_from_tls_id(*group_list) !=
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MBEDTLS_ECP_DP_NONE)) {
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propose_group = 1;
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}
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#endif /* MBEDTLS_SSL_TLS1_2_SOME_ECC */
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if (propose_group) {
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
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MBEDTLS_PUT_UINT16_BE(*group_list, p, 0);
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p += 2;
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MBEDTLS_SSL_DEBUG_MSG(3, ("NamedGroup: %s ( %x )",
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mbedtls_ssl_named_group_to_str(*group_list),
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*group_list));
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}
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}
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/* Length of named_group_list */
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named_group_list_len = p - named_group_list;
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if (named_group_list_len == 0) {
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MBEDTLS_SSL_DEBUG_MSG(1, ("No group available."));
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return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
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}
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/* Write extension_type */
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MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, buf, 0);
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/* Write extension_data_length */
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MBEDTLS_PUT_UINT16_BE(named_group_list_len + 2, buf, 2);
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/* Write length of named_group_list */
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MBEDTLS_PUT_UINT16_BE(named_group_list_len, buf, 4);
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MBEDTLS_SSL_DEBUG_BUF(3, "Supported groups extension",
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buf + 4, named_group_list_len + 2);
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*out_len = p - buf;
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
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mbedtls_ssl_tls13_set_hs_sent_ext_mask(
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ssl, MBEDTLS_TLS_EXT_SUPPORTED_GROUPS);
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
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return 0;
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}
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#endif /* MBEDTLS_SSL_TLS1_2_SOME_ECC ||
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MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */
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MBEDTLS_CHECK_RETURN_CRITICAL
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static int ssl_write_client_hello_cipher_suites(
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mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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int *tls12_uses_ec,
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size_t *out_len)
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{
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unsigned char *p = buf;
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const int *ciphersuite_list;
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unsigned char *cipher_suites; /* Start of the cipher_suites list */
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size_t cipher_suites_len;
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*tls12_uses_ec = 0;
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*out_len = 0;
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/*
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* Ciphersuite list
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*
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* This is a list of the symmetric cipher options supported by
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* the client, specifically the record protection algorithm
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* ( including secret key length ) and a hash to be used with
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* HKDF, in descending order of client preference.
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*/
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ciphersuite_list = ssl->conf->ciphersuite_list;
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/* Check there is space for the cipher suite list length (2 bytes). */
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
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p += 2;
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/* Write cipher_suites
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* CipherSuite cipher_suites<2..2^16-2>;
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*/
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cipher_suites = p;
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for (size_t i = 0; ciphersuite_list[i] != 0; i++) {
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int cipher_suite = ciphersuite_list[i];
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const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(cipher_suite);
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if (mbedtls_ssl_validate_ciphersuite(ssl, ciphersuite_info,
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ssl->handshake->min_tls_version,
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ssl->tls_version) != 0) {
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continue;
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}
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#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
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(defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED) || \
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defined(MBEDTLS_ECDSA_C) || \
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defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED))
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*tls12_uses_ec |= mbedtls_ssl_ciphersuite_uses_ec(ciphersuite_info);
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#endif
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MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, add ciphersuite: %04x, %s",
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(unsigned int) cipher_suite,
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ciphersuite_info->name));
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/* Check there is space for the cipher suite identifier (2 bytes). */
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
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MBEDTLS_PUT_UINT16_BE(cipher_suite, p, 0);
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p += 2;
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}
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/*
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* Add TLS_EMPTY_RENEGOTIATION_INFO_SCSV
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*/
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int renegotiating = 0;
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#if defined(MBEDTLS_SSL_RENEGOTIATION)
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renegotiating = (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE);
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#endif
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if (!renegotiating) {
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MBEDTLS_SSL_DEBUG_MSG(3, ("adding EMPTY_RENEGOTIATION_INFO_SCSV"));
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MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
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MBEDTLS_PUT_UINT16_BE(MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO, p, 0);
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p += 2;
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}
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/* Write the cipher_suites length in number of bytes */
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cipher_suites_len = p - cipher_suites;
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MBEDTLS_PUT_UINT16_BE(cipher_suites_len, buf, 0);
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MBEDTLS_SSL_DEBUG_MSG(3,
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("client hello, got %" MBEDTLS_PRINTF_SIZET " cipher suites",
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cipher_suites_len/2));
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/* Output the total length of cipher_suites field. */
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*out_len = p - buf;
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return 0;
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}
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|
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/*
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* Structure of the TLS 1.3 ClientHello message:
|
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*
|
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* struct {
|
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* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
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* Random random;
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* opaque legacy_session_id<0..32>;
|
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* CipherSuite cipher_suites<2..2^16-2>;
|
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* opaque legacy_compression_methods<1..2^8-1>;
|
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* Extension extensions<8..2^16-1>;
|
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* } ClientHello;
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*
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* Structure of the (D)TLS 1.2 ClientHello message:
|
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*
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* struct {
|
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* ProtocolVersion client_version;
|
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* Random random;
|
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* SessionID session_id;
|
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* opaque cookie<0..2^8-1>; // DTLS 1.2 ONLY
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* CipherSuite cipher_suites<2..2^16-2>;
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* CompressionMethod compression_methods<1..2^8-1>;
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* select (extensions_present) {
|
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* case false:
|
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* struct {};
|
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* case true:
|
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* Extension extensions<0..2^16-1>;
|
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* };
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* } ClientHello;
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*/
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MBEDTLS_CHECK_RETURN_CRITICAL
|
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static int ssl_write_client_hello_body(mbedtls_ssl_context *ssl,
|
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unsigned char *buf,
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unsigned char *end,
|
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size_t *out_len,
|
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size_t *binders_len)
|
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{
|
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int ret;
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mbedtls_ssl_handshake_params *handshake = ssl->handshake;
|
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unsigned char *p = buf;
|
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unsigned char *p_extensions_len; /* Pointer to extensions length */
|
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size_t output_len; /* Length of buffer used by function */
|
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size_t extensions_len; /* Length of the list of extensions*/
|
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int tls12_uses_ec = 0;
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|
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*out_len = 0;
|
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*binders_len = 0;
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|
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#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
|
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unsigned char propose_tls12 =
|
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(handshake->min_tls_version <= MBEDTLS_SSL_VERSION_TLS1_2)
|
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&&
|
|
(MBEDTLS_SSL_VERSION_TLS1_2 <= ssl->tls_version);
|
|
#endif
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
unsigned char propose_tls13 =
|
|
(handshake->min_tls_version <= MBEDTLS_SSL_VERSION_TLS1_3)
|
|
&&
|
|
(MBEDTLS_SSL_VERSION_TLS1_3 <= ssl->tls_version);
|
|
#endif
|
|
|
|
/*
|
|
* Write client_version (TLS 1.2) or legacy_version (TLS 1.3)
|
|
*
|
|
* In all cases this is the TLS 1.2 version.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
|
|
mbedtls_ssl_write_version(p, ssl->conf->transport,
|
|
MBEDTLS_SSL_VERSION_TLS1_2);
|
|
p += 2;
|
|
|
|
/* ...
|
|
* Random random;
|
|
* ...
|
|
*
|
|
* The random bytes have been prepared by ssl_prepare_client_hello() into
|
|
* the handshake->randbytes buffer and are copied here into the output
|
|
* buffer.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, MBEDTLS_CLIENT_HELLO_RANDOM_LEN);
|
|
memcpy(p, handshake->randbytes, MBEDTLS_CLIENT_HELLO_RANDOM_LEN);
|
|
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, random bytes",
|
|
p, MBEDTLS_CLIENT_HELLO_RANDOM_LEN);
|
|
p += MBEDTLS_CLIENT_HELLO_RANDOM_LEN;
|
|
|
|
/* TLS 1.2:
|
|
* ...
|
|
* SessionID session_id;
|
|
* ...
|
|
* with
|
|
* opaque SessionID<0..32>;
|
|
*
|
|
* TLS 1.3:
|
|
* ...
|
|
* opaque legacy_session_id<0..32>;
|
|
* ...
|
|
*
|
|
* The (legacy) session identifier bytes have been prepared by
|
|
* ssl_prepare_client_hello() into the ssl->session_negotiate->id buffer
|
|
* and are copied here into the output buffer.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, ssl->session_negotiate->id_len + 1);
|
|
*p++ = (unsigned char) ssl->session_negotiate->id_len;
|
|
memcpy(p, ssl->session_negotiate->id, 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);
|
|
|
|
/* DTLS 1.2 ONLY
|
|
* ...
|
|
* opaque cookie<0..2^8-1>;
|
|
* ...
|
|
*/
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && defined(MBEDTLS_SSL_PROTO_DTLS)
|
|
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
|
|
#if !defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
uint8_t cookie_len = 0;
|
|
#else
|
|
uint16_t cookie_len = 0;
|
|
#endif /* !MBEDTLS_SSL_PROTO_TLS1_3 */
|
|
|
|
if (handshake->cookie != NULL) {
|
|
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, cookie",
|
|
handshake->cookie,
|
|
handshake->cookie_len);
|
|
cookie_len = handshake->cookie_len;
|
|
}
|
|
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, cookie_len + 1);
|
|
*p++ = (unsigned char) cookie_len;
|
|
if (cookie_len > 0) {
|
|
memcpy(p, handshake->cookie, cookie_len);
|
|
p += cookie_len;
|
|
}
|
|
}
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_SSL_PROTO_DTLS */
|
|
|
|
/* Write cipher_suites */
|
|
ret = ssl_write_client_hello_cipher_suites(ssl, p, end,
|
|
&tls12_uses_ec,
|
|
&output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
|
|
/* Write legacy_compression_methods (TLS 1.3) or
|
|
* compression_methods (TLS 1.2)
|
|
*
|
|
* For every TLS 1.3 ClientHello, this vector MUST contain exactly
|
|
* one byte set to zero, which corresponds to the 'null' compression
|
|
* method in prior versions of TLS.
|
|
*
|
|
* For TLS 1.2 ClientHello, for security reasons we do not support
|
|
* compression anymore, thus also just the 'null' compression method.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
|
|
*p++ = 1;
|
|
*p++ = MBEDTLS_SSL_COMPRESS_NULL;
|
|
|
|
/* Write extensions */
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
/* Keeping track of the included extensions */
|
|
handshake->sent_extensions = MBEDTLS_SSL_EXT_MASK_NONE;
|
|
#endif
|
|
|
|
/* First write extensions, then the total length */
|
|
MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2);
|
|
p_extensions_len = p;
|
|
p += 2;
|
|
|
|
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
|
|
/* Write server name extension */
|
|
ret = ssl_write_hostname_ext(ssl, p, end, &output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
|
|
|
|
#if defined(MBEDTLS_SSL_ALPN)
|
|
ret = ssl_write_alpn_ext(ssl, p, end, &output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
#endif /* MBEDTLS_SSL_ALPN */
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
if (propose_tls13) {
|
|
ret = mbedtls_ssl_tls13_write_client_hello_exts(ssl, p, end,
|
|
&output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
}
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_SSL_TLS1_2_SOME_ECC) || \
|
|
defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
|
|
{
|
|
int ssl_write_supported_groups_ext_flags = 0;
|
|
|
|
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
|
|
if (propose_tls13 && mbedtls_ssl_conf_tls13_some_ephemeral_enabled(ssl)) {
|
|
ssl_write_supported_groups_ext_flags |=
|
|
SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_3_FLAG;
|
|
}
|
|
#endif
|
|
#if defined(MBEDTLS_SSL_TLS1_2_SOME_ECC)
|
|
if (propose_tls12 && tls12_uses_ec) {
|
|
ssl_write_supported_groups_ext_flags |=
|
|
SSL_WRITE_SUPPORTED_GROUPS_EXT_TLS1_2_FLAG;
|
|
}
|
|
#endif
|
|
if (ssl_write_supported_groups_ext_flags != 0) {
|
|
ret = ssl_write_supported_groups_ext(ssl, p, end,
|
|
ssl_write_supported_groups_ext_flags,
|
|
&output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
}
|
|
}
|
|
#endif /* MBEDTLS_SSL_TLS1_2_SOME_ECC ||
|
|
MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */
|
|
|
|
#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
|
|
if (
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
(propose_tls13 && mbedtls_ssl_conf_tls13_ephemeral_enabled(ssl)) ||
|
|
#endif
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
|
|
propose_tls12 ||
|
|
#endif
|
|
0) {
|
|
ret = mbedtls_ssl_write_sig_alg_ext(ssl, p, end, &output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
}
|
|
#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
|
|
if (propose_tls12) {
|
|
ret = mbedtls_ssl_tls12_write_client_hello_exts(ssl, p, end,
|
|
tls12_uses_ec,
|
|
&output_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
}
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
|
|
|
|
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
|
|
/* The "pre_shared_key" extension (RFC 8446 Section 4.2.11)
|
|
* MUST be the last extension in the ClientHello.
|
|
*/
|
|
if (propose_tls13 && mbedtls_ssl_conf_tls13_some_psk_enabled(ssl)) {
|
|
ret = mbedtls_ssl_tls13_write_identities_of_pre_shared_key_ext(
|
|
ssl, p, end, &output_len, binders_len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
p += output_len;
|
|
}
|
|
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */
|
|
|
|
/* Write the length of the list of extensions. */
|
|
extensions_len = p - p_extensions_len - 2;
|
|
|
|
if (extensions_len == 0) {
|
|
p = p_extensions_len;
|
|
} else {
|
|
MBEDTLS_PUT_UINT16_BE(extensions_len, p_extensions_len, 0);
|
|
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, total extension length: %" \
|
|
MBEDTLS_PRINTF_SIZET, extensions_len));
|
|
MBEDTLS_SSL_DEBUG_BUF(3, "client hello extensions",
|
|
p_extensions_len, extensions_len);
|
|
}
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
MBEDTLS_SSL_PRINT_EXTS(
|
|
3, MBEDTLS_SSL_HS_CLIENT_HELLO, handshake->sent_extensions);
|
|
#endif
|
|
|
|
*out_len = p - buf;
|
|
return 0;
|
|
}
|
|
|
|
MBEDTLS_CHECK_RETURN_CRITICAL
|
|
static int ssl_generate_random(mbedtls_ssl_context *ssl)
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *randbytes = ssl->handshake->randbytes;
|
|
size_t gmt_unix_time_len = 0;
|
|
|
|
/*
|
|
* Generate the random bytes
|
|
*
|
|
* TLS 1.2 case:
|
|
* struct {
|
|
* uint32 gmt_unix_time;
|
|
* opaque random_bytes[28];
|
|
* } Random;
|
|
*
|
|
* TLS 1.3 case:
|
|
* opaque Random[32];
|
|
*/
|
|
if (ssl->tls_version == MBEDTLS_SSL_VERSION_TLS1_2) {
|
|
#if defined(MBEDTLS_HAVE_TIME)
|
|
mbedtls_time_t gmt_unix_time = mbedtls_time(NULL);
|
|
MBEDTLS_PUT_UINT32_BE(gmt_unix_time, randbytes, 0);
|
|
gmt_unix_time_len = 4;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG(3,
|
|
("client hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
|
|
(long long) gmt_unix_time));
|
|
#endif /* MBEDTLS_HAVE_TIME */
|
|
}
|
|
|
|
ret = ssl->conf->f_rng(ssl->conf->p_rng,
|
|
randbytes + gmt_unix_time_len,
|
|
MBEDTLS_CLIENT_HELLO_RANDOM_LEN - gmt_unix_time_len);
|
|
return ret;
|
|
}
|
|
|
|
MBEDTLS_CHECK_RETURN_CRITICAL
|
|
static int ssl_prepare_client_hello(mbedtls_ssl_context *ssl)
|
|
{
|
|
int ret;
|
|
size_t session_id_len;
|
|
mbedtls_ssl_session *session_negotiate = ssl->session_negotiate;
|
|
|
|
if (session_negotiate == NULL) {
|
|
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
|
|
}
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
|
|
defined(MBEDTLS_SSL_SESSION_TICKETS) && \
|
|
defined(MBEDTLS_HAVE_TIME)
|
|
|
|
/* Check if a tls13 ticket has been configured. */
|
|
if (ssl->handshake->resume != 0 &&
|
|
session_negotiate->tls_version == MBEDTLS_SSL_VERSION_TLS1_3 &&
|
|
session_negotiate->ticket != NULL) {
|
|
mbedtls_time_t now = mbedtls_time(NULL);
|
|
uint64_t age = (uint64_t) (now - session_negotiate->ticket_received);
|
|
if (session_negotiate->ticket_received > now ||
|
|
age > session_negotiate->ticket_lifetime) {
|
|
/* Without valid ticket, disable session resumption.*/
|
|
MBEDTLS_SSL_DEBUG_MSG(
|
|
3, ("Ticket expired, disable session resumption"));
|
|
ssl->handshake->resume = 0;
|
|
}
|
|
}
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 &&
|
|
MBEDTLS_SSL_SESSION_TICKETS &&
|
|
MBEDTLS_HAVE_TIME */
|
|
|
|
if (ssl->conf->f_rng == NULL) {
|
|
MBEDTLS_SSL_DEBUG_MSG(1, ("no RNG provided"));
|
|
return MBEDTLS_ERR_SSL_NO_RNG;
|
|
}
|
|
|
|
/* Bet on the highest configured version if we are not in a TLS 1.2
|
|
* renegotiation or session resumption.
|
|
*/
|
|
#if defined(MBEDTLS_SSL_RENEGOTIATION)
|
|
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
|
|
ssl->handshake->min_tls_version = ssl->tls_version;
|
|
} else
|
|
#endif
|
|
{
|
|
if (ssl->handshake->resume) {
|
|
ssl->tls_version = session_negotiate->tls_version;
|
|
ssl->handshake->min_tls_version = ssl->tls_version;
|
|
} else {
|
|
ssl->handshake->min_tls_version = ssl->conf->min_tls_version;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generate the random bytes, except when responding to a verify request
|
|
* where we MUST reuse the previously generated random bytes
|
|
* (RFC 6347 4.2.1).
|
|
*/
|
|
#if defined(MBEDTLS_SSL_PROTO_DTLS)
|
|
if ((ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) ||
|
|
(ssl->handshake->cookie == NULL))
|
|
#endif
|
|
{
|
|
ret = ssl_generate_random(ssl);
|
|
if (ret != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "Random bytes generation failed", ret);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Prepare session identifier. At that point, the length of the session
|
|
* identifier in the SSL context `ssl->session_negotiate->id_len` is equal
|
|
* to zero, except in the case of a TLS 1.2 session renegotiation or
|
|
* session resumption.
|
|
*/
|
|
session_id_len = session_negotiate->id_len;
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
|
|
if (ssl->tls_version == MBEDTLS_SSL_VERSION_TLS1_2) {
|
|
if (session_id_len < 16 || session_id_len > 32 ||
|
|
#if defined(MBEDTLS_SSL_RENEGOTIATION)
|
|
ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
|
|
#endif
|
|
ssl->handshake->resume == 0) {
|
|
session_id_len = 0;
|
|
}
|
|
|
|
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
|
|
/*
|
|
* RFC 5077 section 3.4: "When presenting a ticket, the client MAY
|
|
* generate and include a Session ID in the TLS ClientHello."
|
|
*/
|
|
int renegotiating = 0;
|
|
#if defined(MBEDTLS_SSL_RENEGOTIATION)
|
|
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
|
|
renegotiating = 1;
|
|
}
|
|
#endif
|
|
if (!renegotiating) {
|
|
if ((session_negotiate->ticket != NULL) &&
|
|
(session_negotiate->ticket_len != 0)) {
|
|
session_id_len = 32;
|
|
}
|
|
}
|
|
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
|
|
}
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
|
|
|
|
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
|
|
if (ssl->tls_version == MBEDTLS_SSL_VERSION_TLS1_3) {
|
|
/*
|
|
* Create a legacy session identifier for the purpose of middlebox
|
|
* compatibility only if one has not been created already, which is
|
|
* the case if we are here for the TLS 1.3 second ClientHello.
|
|
*
|
|
* Versions of TLS before TLS 1.3 supported a "session resumption"
|
|
* feature which has been merged with pre-shared keys in TLS 1.3
|
|
* version. A client which has a cached session ID set by a pre-TLS 1.3
|
|
* server SHOULD set this field to that value. In compatibility mode,
|
|
* this field MUST be non-empty, so a client not offering a pre-TLS 1.3
|
|
* session MUST generate a new 32-byte value. This value need not be
|
|
* random but SHOULD be unpredictable to avoid implementations fixating
|
|
* on a specific value (also known as ossification). Otherwise, it MUST
|
|
* be set as a zero-length vector ( i.e., a zero-valued single byte
|
|
* length field ).
|
|
*/
|
|
session_id_len = 32;
|
|
}
|
|
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
|
|
|
|
if (session_id_len != session_negotiate->id_len) {
|
|
session_negotiate->id_len = session_id_len;
|
|
if (session_id_len > 0) {
|
|
ret = ssl->conf->f_rng(ssl->conf->p_rng,
|
|
session_negotiate->id,
|
|
session_id_len);
|
|
if (ret != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "creating session id failed", ret);
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
|
|
defined(MBEDTLS_SSL_SESSION_TICKETS) && \
|
|
defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
|
|
if (ssl->tls_version == MBEDTLS_SSL_VERSION_TLS1_3 &&
|
|
ssl->handshake->resume) {
|
|
int hostname_mismatch = ssl->hostname != NULL ||
|
|
session_negotiate->hostname != NULL;
|
|
if (ssl->hostname != NULL && session_negotiate->hostname != NULL) {
|
|
hostname_mismatch = strcmp(
|
|
ssl->hostname, session_negotiate->hostname) != 0;
|
|
}
|
|
|
|
if (hostname_mismatch) {
|
|
MBEDTLS_SSL_DEBUG_MSG(
|
|
1, ("Hostname mismatch the session ticket, "
|
|
"disable session resumption."));
|
|
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
|
|
}
|
|
} else {
|
|
return mbedtls_ssl_session_set_hostname(session_negotiate,
|
|
ssl->hostname);
|
|
}
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 &&
|
|
MBEDTLS_SSL_SESSION_TICKETS &&
|
|
MBEDTLS_SSL_SERVER_NAME_INDICATION */
|
|
|
|
return 0;
|
|
}
|
|
/*
|
|
* Write ClientHello handshake message.
|
|
* Handler for MBEDTLS_SSL_CLIENT_HELLO
|
|
*/
|
|
int mbedtls_ssl_write_client_hello(mbedtls_ssl_context *ssl)
|
|
{
|
|
int ret = 0;
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len, binders_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write client hello"));
|
|
|
|
MBEDTLS_SSL_PROC_CHK(ssl_prepare_client_hello(ssl));
|
|
|
|
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg(
|
|
ssl, MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
&buf, &buf_len));
|
|
|
|
MBEDTLS_SSL_PROC_CHK(ssl_write_client_hello_body(ssl, buf,
|
|
buf + buf_len,
|
|
&msg_len,
|
|
&binders_len));
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && defined(MBEDTLS_SSL_PROTO_DTLS)
|
|
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
|
|
ssl->out_msglen = msg_len + 4;
|
|
mbedtls_ssl_send_flight_completed(ssl);
|
|
|
|
/*
|
|
* The two functions below may try to send data on the network and
|
|
* can return with the MBEDTLS_ERR_SSL_WANT_READ error code when they
|
|
* fail to do so and the transmission has to be retried later. In that
|
|
* case as in fatal error cases, we return immediately. But we must have
|
|
* set the handshake state to the next state at that point to ensure
|
|
* that we will not write and send again a ClientHello when we
|
|
* eventually succeed in sending the pending data.
|
|
*/
|
|
mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_HELLO);
|
|
|
|
if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret);
|
|
return ret;
|
|
}
|
|
|
|
if ((ret = mbedtls_ssl_flight_transmit(ssl)) != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_flight_transmit", ret);
|
|
return ret;
|
|
}
|
|
} else
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_SSL_PROTO_DTLS */
|
|
{
|
|
|
|
ret = mbedtls_ssl_add_hs_hdr_to_checksum(ssl,
|
|
MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
msg_len);
|
|
if (ret != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_add_hs_hdr_to_checksum", ret);
|
|
return ret;
|
|
}
|
|
ret = ssl->handshake->update_checksum(ssl, buf, msg_len - binders_len);
|
|
if (ret != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "update_checksum", ret);
|
|
return ret;
|
|
}
|
|
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
|
|
if (binders_len > 0) {
|
|
MBEDTLS_SSL_PROC_CHK(
|
|
mbedtls_ssl_tls13_write_binders_of_pre_shared_key_ext(
|
|
ssl, buf + msg_len - binders_len, buf + msg_len));
|
|
ret = ssl->handshake->update_checksum(ssl, buf + msg_len - binders_len,
|
|
binders_len);
|
|
if (ret != 0) {
|
|
MBEDTLS_SSL_DEBUG_RET(1, "update_checksum", ret);
|
|
return ret;
|
|
}
|
|
}
|
|
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */
|
|
|
|
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(ssl,
|
|
buf_len,
|
|
msg_len));
|
|
|
|
/*
|
|
* Set next state. Note that if TLS 1.3 is proposed, this may be
|
|
* overwritten by mbedtls_ssl_tls13_finalize_client_hello().
|
|
*/
|
|
mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_HELLO);
|
|
|
|
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
|
|
if (ssl->handshake->min_tls_version <= MBEDTLS_SSL_VERSION_TLS1_3 &&
|
|
MBEDTLS_SSL_VERSION_TLS1_3 <= ssl->tls_version) {
|
|
ret = mbedtls_ssl_tls13_finalize_client_hello(ssl);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write client hello"));
|
|
return ret;
|
|
}
|
|
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 || MBEDTLS_SSL_PROTO_TLS1_2 */
|
|
#endif /* MBEDTLS_SSL_CLI_C */
|