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libtls: Implement HKDF for TLS 1.3 

TLS 1.3 uses HMAC-based Extract-and-Expand Key Derivation Function (HKDF)
as defined in RFC 5869 to compute traffic secrets.

Co-authored-by: bytinbit <meline.sieber@hsr.ch>
This commit is contained in:
Pascal K 2020-05-21 07:57:14 +02:00 committed by Tobias Brunner
parent 3d83d348f4
commit 02d7405512
7 changed files with 1086 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/libcharon/Android.mk
View File

@ -221,9 +221,9 @@ ifneq ($(or $(call plugin_enabled, eap-tls), $(call plugin_enabled, eap-ttls), \
LOCAL_C_INCLUDES += $(LOCAL_PATH)/../libtls/
LOCAL_SRC_FILES += $(addprefix ../libtls/, \
tls_protection.c tls_compression.c tls_fragmentation.c tls_alert.c \
tls_crypto.c tls_prf.c tls_socket.c tls_eap.c tls_cache.c tls_peer.c \
tls_crypto.c tls_prf.c tls_hkdf.c tls_socket.c tls_eap.c tls_cache.c \
tls_aead_expl.c tls_aead_impl.c tls_aead_null.c tls_aead_seq.c tls_aead.c \
tls_server.c tls.c \
tls_peer.c tls_server.c tls.c \
)
endif

8
src/libtls/Makefile.am
View File

@ -10,9 +10,9 @@ AM_LDFLAGS = \
ipseclib_LTLIBRARIES = libtls.la
libtls_la_SOURCES = \
tls_protection.c tls_compression.c tls_fragmentation.c tls_alert.c \
tls_crypto.c tls_prf.c tls_socket.c tls_eap.c tls_cache.c tls_peer.c \
tls_crypto.c tls_prf.c tls_hkdf.c tls_socket.c tls_eap.c tls_cache.c \
tls_aead_expl.c tls_aead_impl.c tls_aead_null.c tls_aead_seq.c tls_aead.c \
tls_server.c tls.c
tls_peer.c tls_server.c tls.c
libtls_la_LIBADD = \
$(top_builddir)/src/libstrongswan/libstrongswan.la
@ -25,8 +25,8 @@ if USE_DEV_HEADERS
tls_includedir = ${dev_headers}/tls
nobase_tls_include_HEADERS = \
tls_protection.h tls_compression.h tls_fragmentation.h tls_alert.h \
tls_crypto.h tls_prf.h tls_socket.h tls_eap.h tls_cache.h tls_peer.h \
tls_server.h tls_handshake.h tls_application.h tls_aead.h tls.h
tls_crypto.h tls_prf.h tls_hkdf.h tls_socket.h tls_eap.h tls_cache.h \
tls_peer.h tls_server.h tls_handshake.h tls_application.h tls_aead.h tls.h
endif
SUBDIRS = . tests

1
src/libtls/tests/Makefile.am
View File

@ -3,6 +3,7 @@ TESTS = tls_tests
check_PROGRAMS = $(TESTS)
tls_tests_SOURCES = \
suites/test_hkdf.c \
suites/test_socket.c \
suites/test_suites.c \
tls_tests.h tls_tests.c

439
src/libtls/tests/suites/test_hkdf.c Normal file
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@ -0,0 +1,439 @@
/*
* Copyright (C) 2020 Pascal Knecht
* Copyright (C) 2020 Méline Sieber
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include <test_suite.h>
#include "tls_hkdf.h"
START_TEST(test_ulfheim_handshake)
{
chunk_t handshake = chunk_from_chars(
/* Client Hello */
0x01, 0x00, 0x00, 0xc6, 0x03, 0x03, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0xe0,
0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8,
0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 0x00,
0x06, 0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0x01,
0x00, 0x00, 0x77, 0x00, 0x00, 0x00, 0x18, 0x00,
0x16, 0x00, 0x00, 0x13, 0x65, 0x78, 0x61, 0x6d,
0x70, 0x6c, 0x65, 0x2e, 0x75, 0x6c, 0x66, 0x68,
0x65, 0x69, 0x6d, 0x2e, 0x6e, 0x65, 0x74, 0x00,
0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00,
0x17, 0x00, 0x18, 0x00, 0x0d, 0x00, 0x14, 0x00,
0x12, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05,
0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06,
0x01, 0x02, 0x01, 0x00, 0x33, 0x00, 0x26, 0x00,
0x24, 0x00, 0x1d, 0x00, 0x20, 0x35, 0x80, 0x72,
0xd6, 0x36, 0x58, 0x80, 0xd1, 0xae, 0xea, 0x32,
0x9a, 0xdf, 0x91, 0x21, 0x38, 0x38, 0x51, 0xed,
0x21, 0xa2, 0x8e, 0x3b, 0x75, 0xe9, 0x65, 0xd0,
0xd2, 0xcd, 0x16, 0x62, 0x54, 0x00, 0x2d, 0x00,
0x02, 0x01, 0x01, 0x00, 0x2b, 0x00, 0x03, 0x02,
0x03, 0x04,
/* Server Hello */
0x02, 0x00, 0x00, 0x76, 0x03, 0x03, 0x70, 0x71,
0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81,
0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x20, 0xe0,
0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8,
0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 0x13,
0x01, 0x00, 0x00, 0x2e, 0x00, 0x33, 0x00, 0x24,
0x00, 0x1d, 0x00, 0x20, 0x9f, 0xd7, 0xad, 0x6d,
0xcf, 0xf4, 0x29, 0x8d, 0xd3, 0xf9, 0x6d, 0x5b,
0x1b, 0x2a, 0xf9, 0x10, 0xa0, 0x53, 0x5b, 0x14,
0x88, 0xd7, 0xf8, 0xfa, 0xbb, 0x34, 0x9a, 0x98,
0x28, 0x80, 0xb6, 0x15, 0x00, 0x2b, 0x00, 0x02,
0x03, 0x04,
);
chunk_t ecdhe = chunk_from_chars(
0xdf, 0x4a, 0x29, 0x1b, 0xaa, 0x1e, 0xb7, 0xcf,
0xa6, 0x93, 0x4b, 0x29, 0xb4, 0x74, 0xba, 0xad,
0x26, 0x97, 0xe2, 0x9f, 0x1f, 0x92, 0x0d, 0xcc,
0x77, 0xc8, 0xa0, 0xa0, 0x88, 0x44, 0x76, 0x24,
);
chunk_t expected_client_handshake_traffic_secret = chunk_from_chars(
0xff, 0x0e, 0x5b, 0x96, 0x52, 0x91, 0xc6, 0x08,
0xc1, 0xe8, 0xcd, 0x26, 0x7e, 0xef, 0xc0, 0xaf,
0xcc, 0x5e, 0x98, 0xa2, 0x78, 0x63, 0x73, 0xf0,
0xdb, 0x47, 0xb0, 0x47, 0x86, 0xd7, 0x2a, 0xea,
);
chunk_t expected_server_handshake_traffic_secret = chunk_from_chars(
0xa2, 0x06, 0x72, 0x65, 0xe7, 0xf0, 0x65, 0x2a,
0x92, 0x3d, 0x5d, 0x72, 0xab, 0x04, 0x67, 0xc4,
0x61, 0x32, 0xee, 0xb9, 0x68, 0xb6, 0xa3, 0x2d,
0x31, 0x1c, 0x80, 0x58, 0x68, 0x54, 0x88, 0x14,
);
chunk_t expected_client_handshake_key = chunk_from_chars(
0x71, 0x54, 0xf3, 0x14, 0xe6, 0xbe, 0x7d, 0xc0,
0x08, 0xdf, 0x2c, 0x83, 0x2b, 0xaa, 0x1d, 0x39,
);
chunk_t expected_client_handshake_iv = chunk_from_chars(
0x71, 0xab, 0xc2, 0xca, 0xe4, 0xc6, 0x99, 0xd4,
0x7c, 0x60, 0x02, 0x68,
);
chunk_t expected_server_handshake_key = chunk_from_chars(
0x84, 0x47, 0x80, 0xa7, 0xac, 0xad, 0x9f, 0x98,
0x0f, 0xa2, 0x5c, 0x11, 0x4e, 0x43, 0x40, 0x2a,
);
chunk_t expected_server_handshake_iv = chunk_from_chars(
0x4c, 0x04, 0x2d, 0xdc, 0x12, 0x0a, 0x38, 0xd1,
0x41, 0x7f, 0xc8, 0x15,
);
chunk_t expected_client_finished_key = chunk_from_chars(
0x7c, 0x60, 0xf8, 0xd6, 0x34, 0x6f, 0x4a, 0x96,
0x91, 0xd2, 0xae, 0x64, 0x5a, 0x78, 0x85, 0xe0,
0x10, 0x4a, 0xdf, 0xf9, 0x8e, 0xba, 0x98, 0x1c,
0xa2, 0xf9, 0x9e, 0xf6, 0x2b, 0xdd, 0x8f, 0xaa,
);
chunk_t expected_server_finished_key = chunk_from_chars(
0xea, 0x84, 0xab, 0xd2, 0xad, 0xa0, 0xb5, 0xc6,
0x4c, 0x08, 0x07, 0xa3, 0x26, 0xb6, 0xfd, 0x94,
0xa9, 0x59, 0x7e, 0x39, 0xca, 0x62, 0x10, 0x60,
0x7c, 0x0d, 0x3c, 0x8c, 0x76, 0x68, 0x65, 0x71,
);
chunk_t c_secret, c_key, c_iv, s_secret, s_key, s_iv, c_finished,
s_finished;
tls_hkdf_t *hkdf = tls_hkdf_create(HASH_SHA256, chunk_empty);
hkdf->set_shared_secret(hkdf, ecdhe);
/* Generate client handshake traffic secret */
ck_assert(hkdf->generate_secret(hkdf, TLS_HKDF_C_HS_TRAFFIC, handshake,
&c_secret));
ck_assert_chunk_eq(expected_client_handshake_traffic_secret, c_secret);
ck_assert(hkdf->derive_key(hkdf, FALSE, 16, &c_key));
ck_assert_chunk_eq(expected_client_handshake_key, c_key);
ck_assert(hkdf->derive_iv(hkdf, FALSE, 12, &c_iv));
ck_assert_chunk_eq(expected_client_handshake_iv, c_iv);
ck_assert(hkdf->derive_finished(hkdf, TRUE, &c_finished));
ck_assert_chunk_eq(expected_client_finished_key, c_finished);
/* Generate server handshake traffic secret */
ck_assert(hkdf->generate_secret(hkdf, TLS_HKDF_S_HS_TRAFFIC, handshake,
&s_secret));
ck_assert_chunk_eq(expected_server_handshake_traffic_secret, s_secret);
ck_assert(hkdf->derive_key(hkdf, TRUE, 16, &s_key));
ck_assert_chunk_eq(expected_server_handshake_key, s_key);
ck_assert(hkdf->derive_iv(hkdf, TRUE, 12, &s_iv));
ck_assert_chunk_eq(expected_server_handshake_iv, s_iv);
ck_assert(hkdf->derive_finished(hkdf, TRUE, &s_finished));
ck_assert_chunk_eq(expected_server_finished_key, s_finished);
hkdf->destroy(hkdf);
chunk_free(&c_secret);
chunk_free(&c_key);
chunk_free(&c_iv);
chunk_free(&s_secret);
chunk_free(&s_key);
chunk_free(&s_iv);
chunk_free(&c_finished);
chunk_free(&s_finished);
}
END_TEST
START_TEST(test_ulfheim_traffic)
{
chunk_t handshake = chunk_from_chars(
/* Client Hello */
0x01, 0x00, 0x00, 0xc6, 0x03, 0x03, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0xe0,
0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8,
0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 0x00,
0x06, 0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0x01,
0x00, 0x00, 0x77, 0x00, 0x00, 0x00, 0x18, 0x00,
0x16, 0x00, 0x00, 0x13, 0x65, 0x78, 0x61, 0x6d,
0x70, 0x6c, 0x65, 0x2e, 0x75, 0x6c, 0x66, 0x68,
0x65, 0x69, 0x6d, 0x2e, 0x6e, 0x65, 0x74, 0x00,
0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00,
0x17, 0x00, 0x18, 0x00, 0x0d, 0x00, 0x14, 0x00,
0x12, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05,
0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06,
0x01, 0x02, 0x01, 0x00, 0x33, 0x00, 0x26, 0x00,
0x24, 0x00, 0x1d, 0x00, 0x20, 0x35, 0x80, 0x72,
0xd6, 0x36, 0x58, 0x80, 0xd1, 0xae, 0xea, 0x32,
0x9a, 0xdf, 0x91, 0x21, 0x38, 0x38, 0x51, 0xed,
0x21, 0xa2, 0x8e, 0x3b, 0x75, 0xe9, 0x65, 0xd0,
0xd2, 0xcd, 0x16, 0x62, 0x54, 0x00, 0x2d, 0x00,
0x02, 0x01, 0x01, 0x00, 0x2b, 0x00, 0x03, 0x02,
0x03, 0x04,
/* Server Hello */
0x02, 0x00, 0x00, 0x76, 0x03, 0x03, 0x70, 0x71,
0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81,
0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x20, 0xe0,
0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8,
0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 0x13,
0x01, 0x00, 0x00, 0x2e, 0x00, 0x33, 0x00, 0x24,
0x00, 0x1d, 0x00, 0x20, 0x9f, 0xd7, 0xad, 0x6d,
0xcf, 0xf4, 0x29, 0x8d, 0xd3, 0xf9, 0x6d, 0x5b,
0x1b, 0x2a, 0xf9, 0x10, 0xa0, 0x53, 0x5b, 0x14,
0x88, 0xd7, 0xf8, 0xfa, 0xbb, 0x34, 0x9a, 0x98,
0x28, 0x80, 0xb6, 0x15, 0x00, 0x2b, 0x00, 0x02,
0x03, 0x04,
/* Server Encrypted Extension */
0x08, 0x00, 0x00, 0x02, 0x00, 0x00,
/* Server Certificate */
0x0b, 0x00, 0x03, 0x2e, 0x00, 0x00, 0x03, 0x2a,
0x00, 0x03, 0x25, 0x30, 0x82, 0x03, 0x21, 0x30,
0x82, 0x02, 0x09, 0xa0, 0x03, 0x02, 0x01, 0x02,
0x02, 0x08, 0x15, 0x5a, 0x92, 0xad, 0xc2, 0x04,
0x8f, 0x90, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86,
0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x0b, 0x05,
0x00, 0x30, 0x22, 0x31, 0x0b, 0x30, 0x09, 0x06,
0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53,
0x31, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04,
0x0a, 0x13, 0x0a, 0x45, 0x78, 0x61, 0x6d, 0x70,
0x6c, 0x65, 0x20, 0x43, 0x41, 0x30, 0x1e, 0x17,
0x0d, 0x31, 0x38, 0x31, 0x30, 0x30, 0x35, 0x30,
0x31, 0x33, 0x38, 0x31, 0x37, 0x5a, 0x17, 0x0d,
0x31, 0x39, 0x31, 0x30, 0x30, 0x35, 0x30, 0x31,
0x33, 0x38, 0x31, 0x37, 0x5a, 0x30, 0x2b, 0x31,
0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06,
0x13, 0x02, 0x55, 0x53, 0x31, 0x1c, 0x30, 0x1a,
0x06, 0x03, 0x55, 0x04, 0x03, 0x13, 0x13, 0x65,
0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x75,
0x6c, 0x66, 0x68, 0x65, 0x69, 0x6d, 0x2e, 0x6e,
0x65, 0x74, 0x30, 0x82, 0x01, 0x22, 0x30, 0x0d,
0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d,
0x01, 0x01, 0x01, 0x05, 0x00, 0x03, 0x82, 0x01,
0x0f, 0x00, 0x30, 0x82, 0x01, 0x0a, 0x02, 0x82,
0x01, 0x01, 0x00, 0xc4, 0x80, 0x36, 0x06, 0xba,
0xe7, 0x47, 0x6b, 0x08, 0x94, 0x04, 0xec, 0xa7,
0xb6, 0x91, 0x04, 0x3f, 0xf7, 0x92, 0xbc, 0x19,
0xee, 0xfb, 0x7d, 0x74, 0xd7, 0xa8, 0x0d, 0x00,
0x1e, 0x7b, 0x4b, 0x3a, 0x4a, 0xe6, 0x0f, 0xe8,
0xc0, 0x71, 0xfc, 0x73, 0xe7, 0x02, 0x4c, 0x0d,
0xbc, 0xf4, 0xbd, 0xd1, 0x1d, 0x39, 0x6b, 0xba,
0x70, 0x46, 0x4a, 0x13, 0xe9, 0x4a, 0xf8, 0x3d,
0xf3, 0xe1, 0x09, 0x59, 0x54, 0x7b, 0xc9, 0x55,
0xfb, 0x41, 0x2d, 0xa3, 0x76, 0x52, 0x11, 0xe1,
0xf3, 0xdc, 0x77, 0x6c, 0xaa, 0x53, 0x37, 0x6e,
0xca, 0x3a, 0xec, 0xbe, 0xc3, 0xaa, 0xb7, 0x3b,
0x31, 0xd5, 0x6c, 0xb6, 0x52, 0x9c, 0x80, 0x98,
0xbc, 0xc9, 0xe0, 0x28, 0x18, 0xe2, 0x0b, 0xf7,
0xf8, 0xa0, 0x3a, 0xfd, 0x17, 0x04, 0x50, 0x9e,
0xce, 0x79, 0xbd, 0x9f, 0x39, 0xf1, 0xea, 0x69,
0xec, 0x47, 0x97, 0x2e, 0x83, 0x0f, 0xb5, 0xca,
0x95, 0xde, 0x95, 0xa1, 0xe6, 0x04, 0x22, 0xd5,
0xee, 0xbe, 0x52, 0x79, 0x54, 0xa1, 0xe7, 0xbf,
0x8a, 0x86, 0xf6, 0x46, 0x6d, 0x0d, 0x9f, 0x16,
0x95, 0x1a, 0x4c, 0xf7, 0xa0, 0x46, 0x92, 0x59,
0x5c, 0x13, 0x52, 0xf2, 0x54, 0x9e, 0x5a, 0xfb,
0x4e, 0xbf, 0xd7, 0x7a, 0x37, 0x95, 0x01, 0x44,
0xe4, 0xc0, 0x26, 0x87, 0x4c, 0x65, 0x3e, 0x40,
0x7d, 0x7d, 0x23, 0x07, 0x44, 0x01, 0xf4, 0x84,
0xff, 0xd0, 0x8f, 0x7a, 0x1f, 0xa0, 0x52, 0x10,
0xd1, 0xf4, 0xf0, 0xd5, 0xce, 0x79, 0x70, 0x29,
0x32, 0xe2, 0xca, 0xbe, 0x70, 0x1f, 0xdf, 0xad,
0x6b, 0x4b, 0xb7, 0x11, 0x01, 0xf4, 0x4b, 0xad,
0x66, 0x6a, 0x11, 0x13, 0x0f, 0xe2, 0xee, 0x82,
0x9e, 0x4d, 0x02, 0x9d, 0xc9, 0x1c, 0xdd, 0x67,
0x16, 0xdb, 0xb9, 0x06, 0x18, 0x86, 0xed, 0xc1,
0xba, 0x94, 0x21, 0x02, 0x03, 0x01, 0x00, 0x01,
0xa3, 0x52, 0x30, 0x50, 0x30, 0x0e, 0x06, 0x03,
0x55, 0x1d, 0x0f, 0x01, 0x01, 0xff, 0x04, 0x04,
0x03, 0x02, 0x05, 0xa0, 0x30, 0x1d, 0x06, 0x03,
0x55, 0x1d, 0x25, 0x04, 0x16, 0x30, 0x14, 0x06,
0x08, 0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x03,
0x02, 0x06, 0x08, 0x2b, 0x06, 0x01, 0x05, 0x05,
0x07, 0x03, 0x01, 0x30, 0x1f, 0x06, 0x03, 0x55,
0x1d, 0x23, 0x04, 0x18, 0x30, 0x16, 0x80, 0x14,
0x89, 0x4f, 0xde, 0x5b, 0xcc, 0x69, 0xe2, 0x52,
0xcf, 0x3e, 0xa3, 0x00, 0xdf, 0xb1, 0x97, 0xb8,
0x1d, 0xe1, 0xc1, 0x46, 0x30, 0x0d, 0x06, 0x09,
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,
0x0b, 0x05, 0x00, 0x03, 0x82, 0x01, 0x01, 0x00,
0x59, 0x16, 0x45, 0xa6, 0x9a, 0x2e, 0x37, 0x79,
0xe4, 0xf6, 0xdd, 0x27, 0x1a, 0xba, 0x1c, 0x0b,
0xfd, 0x6c, 0xd7, 0x55, 0x99, 0xb5, 0xe7, 0xc3,
0x6e, 0x53, 0x3e, 0xff, 0x36, 0x59, 0x08, 0x43,
0x24, 0xc9, 0xe7, 0xa5, 0x04, 0x07, 0x9d, 0x39,
0xe0, 0xd4, 0x29, 0x87, 0xff, 0xe3, 0xeb, 0xdd,
0x09, 0xc1, 0xcf, 0x1d, 0x91, 0x44, 0x55, 0x87,
0x0b, 0x57, 0x1d, 0xd1, 0x9b, 0xdf, 0x1d, 0x24,
0xf8, 0xbb, 0x9a, 0x11, 0xfe, 0x80, 0xfd, 0x59,
0x2b, 0xa0, 0x39, 0x8c, 0xde, 0x11, 0xe2, 0x65,
0x1e, 0x61, 0x8c, 0xe5, 0x98, 0xfa, 0x96, 0xe5,
0x37, 0x2e, 0xef, 0x3d, 0x24, 0x8a, 0xfd, 0xe1,
0x74, 0x63, 0xeb, 0xbf, 0xab, 0xb8, 0xe4, 0xd1,
0xab, 0x50, 0x2a, 0x54, 0xec, 0x00, 0x64, 0xe9,
0x2f, 0x78, 0x19, 0x66, 0x0d, 0x3f, 0x27, 0xcf,
0x20, 0x9e, 0x66, 0x7f, 0xce, 0x5a, 0xe2, 0xe4,
0xac, 0x99, 0xc7, 0xc9, 0x38, 0x18, 0xf8, 0xb2,
0x51, 0x07, 0x22, 0xdf, 0xed, 0x97, 0xf3, 0x2e,
0x3e, 0x93, 0x49, 0xd4, 0xc6, 0x6c, 0x9e, 0xa6,
0x39, 0x6d, 0x74, 0x44, 0x62, 0xa0, 0x6b, 0x42,
0xc6, 0xd5, 0xba, 0x68, 0x8e, 0xac, 0x3a, 0x01,
0x7b, 0xdd, 0xfc, 0x8e, 0x2c, 0xfc, 0xad, 0x27,
0xcb, 0x69, 0xd3, 0xcc, 0xdc, 0xa2, 0x80, 0x41,
0x44, 0x65, 0xd3, 0xae, 0x34, 0x8c, 0xe0, 0xf3,
0x4a, 0xb2, 0xfb, 0x9c, 0x61, 0x83, 0x71, 0x31,
0x2b, 0x19, 0x10, 0x41, 0x64, 0x1c, 0x23, 0x7f,
0x11, 0xa5, 0xd6, 0x5c, 0x84, 0x4f, 0x04, 0x04,
0x84, 0x99, 0x38, 0x71, 0x2b, 0x95, 0x9e, 0xd6,
0x85, 0xbc, 0x5c, 0x5d, 0xd6, 0x45, 0xed, 0x19,
0x90, 0x94, 0x73, 0x40, 0x29, 0x26, 0xdc, 0xb4,
0x0e, 0x34, 0x69, 0xa1, 0x59, 0x41, 0xe8, 0xe2,
0xcc, 0xa8, 0x4b, 0xb6, 0x08, 0x46, 0x36, 0xa0,
0x00, 0x00,
/* Server Certificate Verify */
0x0f, 0x00, 0x01, 0x04, 0x08, 0x04, 0x01, 0x00,
0x17, 0xfe, 0xb5, 0x33, 0xca, 0x6d, 0x00, 0x7d,
0x00, 0x58, 0x25, 0x79, 0x68, 0x42, 0x4b, 0xbc,
0x3a, 0xa6, 0x90, 0x9e, 0x9d, 0x49, 0x55, 0x75,
0x76, 0xa5, 0x20, 0xe0, 0x4a, 0x5e, 0xf0, 0x5f,
0x0e, 0x86, 0xd2, 0x4f, 0xf4, 0x3f, 0x8e, 0xb8,
0x61, 0xee, 0xf5, 0x95, 0x22, 0x8d, 0x70, 0x32,
0xaa, 0x36, 0x0f, 0x71, 0x4e, 0x66, 0x74, 0x13,
0x92, 0x6e, 0xf4, 0xf8, 0xb5, 0x80, 0x3b, 0x69,
0xe3, 0x55, 0x19, 0xe3, 0xb2, 0x3f, 0x43, 0x73,
0xdf, 0xac, 0x67, 0x87, 0x06, 0x6d, 0xcb, 0x47,
0x56, 0xb5, 0x45, 0x60, 0xe0, 0x88, 0x6e, 0x9b,
0x96, 0x2c, 0x4a, 0xd2, 0x8d, 0xab, 0x26, 0xba,
0xd1, 0xab, 0xc2, 0x59, 0x16, 0xb0, 0x9a, 0xf2,
0x86, 0x53, 0x7f, 0x68, 0x4f, 0x80, 0x8a, 0xef,
0xee, 0x73, 0x04, 0x6c, 0xb7, 0xdf, 0x0a, 0x84,
0xfb, 0xb5, 0x96, 0x7a, 0xca, 0x13, 0x1f, 0x4b,
0x1c, 0xf3, 0x89, 0x79, 0x94, 0x03, 0xa3, 0x0c,
0x02, 0xd2, 0x9c, 0xbd, 0xad, 0xb7, 0x25, 0x12,
0xdb, 0x9c, 0xec, 0x2e, 0x5e, 0x1d, 0x00, 0xe5,
0x0c, 0xaf, 0xcf, 0x6f, 0x21, 0x09, 0x1e, 0xbc,
0x4f, 0x25, 0x3c, 0x5e, 0xab, 0x01, 0xa6, 0x79,
0xba, 0xea, 0xbe, 0xed, 0xb9, 0xc9, 0x61, 0x8f,
0x66, 0x00, 0x6b, 0x82, 0x44, 0xd6, 0x62, 0x2a,
0xaa, 0x56, 0x88, 0x7c, 0xcf, 0xc6, 0x6a, 0x0f,
0x38, 0x51, 0xdf, 0xa1, 0x3a, 0x78, 0xcf, 0xf7,
0x99, 0x1e, 0x03, 0xcb, 0x2c, 0x3a, 0x0e, 0xd8,
0x7d, 0x73, 0x67, 0x36, 0x2e, 0xb7, 0x80, 0x5b,
0x00, 0xb2, 0x52, 0x4f, 0xf2, 0x98, 0xa4, 0xda,
0x48, 0x7c, 0xac, 0xde, 0xaf, 0x8a, 0x23, 0x36,
0xc5, 0x63, 0x1b, 0x3e, 0xfa, 0x93, 0x5b, 0xb4,
0x11, 0xe7, 0x53, 0xca, 0x13, 0xb0, 0x15, 0xfe,
0xc7, 0xe4, 0xa7, 0x30, 0xf1, 0x36, 0x9f, 0x9e,
/* Server Handshake Finish */
0x14, 0x00, 0x00, 0x20, 0xea, 0x6e, 0xe1, 0x76,
0xdc, 0xcc, 0x4a, 0xf1, 0x85, 0x9e, 0x9e, 0x4e,
0x93, 0xf7, 0x97, 0xea, 0xc9, 0xa7, 0x8c, 0xe4,
0x39, 0x30, 0x1e, 0x35, 0x27, 0x5a, 0xd4, 0x3f,
0x3c, 0xdd, 0xbd, 0xe3,
);
chunk_t ecdhe = chunk_from_chars(
0xdf, 0x4a, 0x29, 0x1b, 0xaa, 0x1e, 0xb7, 0xcf,
0xa6, 0x93, 0x4b, 0x29, 0xb4, 0x74, 0xba, 0xad,
0x26, 0x97, 0xe2, 0x9f, 0x1f, 0x92, 0x0d, 0xcc,
0x77, 0xc8, 0xa0, 0xa0, 0x88, 0x44, 0x76, 0x24,
);
chunk_t expected_client_application_key = chunk_from_chars(
0x49, 0x13, 0x4b, 0x95, 0x32, 0x8f, 0x27, 0x9f,
0x01, 0x83, 0x86, 0x05, 0x89, 0xac, 0x67, 0x07,
);
chunk_t expected_client_application_iv = chunk_from_chars(
0xbc, 0x4d, 0xd5, 0xf7, 0xb9, 0x8a, 0xcf, 0xf8,
0x54, 0x66, 0x26, 0x1d,
);
chunk_t expected_server_application_key = chunk_from_chars(
0x0b, 0x6d, 0x22, 0xc8, 0xff, 0x68, 0x09, 0x7e,
0xa8, 0x71, 0xc6, 0x72, 0x07, 0x37, 0x73, 0xbf,
);
chunk_t expected_server_application_iv = chunk_from_chars(
0x1b, 0x13, 0xdd, 0x9f, 0x8d, 0x8f, 0x17, 0x09,
0x1d, 0x34, 0xb3, 0x49,
);
chunk_t c_key, c_iv, s_key, s_iv;
tls_hkdf_t *hkdf = tls_hkdf_create(HASH_SHA256, chunk_empty);
hkdf->set_shared_secret(hkdf, ecdhe);
/* Generate client application traffic secret */
ck_assert(hkdf->generate_secret(hkdf, TLS_HKDF_C_AP_TRAFFIC, handshake, NULL));
ck_assert(hkdf->derive_key(hkdf, FALSE, 16, &c_key));
ck_assert_chunk_eq(expected_client_application_key, c_key);
ck_assert(hkdf->derive_iv(hkdf, FALSE, 12, &c_iv));
ck_assert_chunk_eq(expected_client_application_iv, c_iv);
/* Generate server application traffic secret */
ck_assert(hkdf->generate_secret(hkdf, TLS_HKDF_S_AP_TRAFFIC, handshake, NULL));
ck_assert(hkdf->derive_key(hkdf, TRUE, 16, &s_key));
ck_assert_chunk_eq(expected_server_application_key, s_key);
ck_assert(hkdf->derive_iv(hkdf, TRUE, 12, &s_iv));
ck_assert_chunk_eq(expected_server_application_iv, s_iv);
hkdf->destroy(hkdf);
chunk_free(&c_key);
chunk_free(&c_iv);
chunk_free(&s_key);
chunk_free(&s_iv);
}
END_TEST
Suite *hkdf_suite_create()
{
Suite *s;
TCase *tc;
s = suite_create("HKDF TLS 1.3");
tc = tcase_create("Ulfheim Keys");
tcase_add_test(tc, test_ulfheim_handshake);
tcase_add_test(tc, test_ulfheim_traffic);
suite_add_tcase(s, tc);
return s;
}

1
src/libtls/tests/tls_tests.h
View File

@ -13,5 +13,6 @@
* for more details.
*/
TEST_SUITE(hkdf_suite_create)
TEST_SUITE(socket_suite_create)
TEST_SUITE(suites_suite_create)

511
src/libtls/tls_hkdf.c Normal file
View File

@ -0,0 +1,511 @@
/*
* Copyright (C) 2020 Pascal Knecht
* Copyright (C) 2020 Méline Sieber
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "tls_hkdf.h"
#include <bio/bio_writer.h>
#include <crypto/prf_plus.h>
typedef struct private_tls_hkdf_t private_tls_hkdf_t;
typedef enum hkdf_phase {
HKDF_PHASE_0,
HKDF_PHASE_1,
HKDF_PHASE_2,
HKDF_PHASE_3,
} hkdf_phase;
struct private_tls_hkdf_t {
/**
* Public tls_hkdf_t interface.
*/
struct tls_hkdf_t public;
/**
* Phase we are in.
*/
hkdf_phase phase;
/**
* Hash algorithm used.
*/
hash_algorithm_t hash_algorithm;
/**
* Pseudorandom function used.
*/
prf_t *prf;
/**
* Hasher used.
*/
hasher_t *hasher;
/**
* (EC)DHE as IKM to switch from phase 1 to phase 2
*/
chunk_t shared_secret;
/**
* IKM used.
*/
chunk_t ikm;
/**
* PRK used.
*/
chunk_t prk;
/**
* OKM used.
*/
chunk_t okm;
/**
* Current implementation needs a copy of derived secrets to calculate the
* proper finished key.
*/
chunk_t client_traffic_secret;
chunk_t server_traffic_secret;
};
static char *hkdf_labels[] = {
"tls13 ext binder",
"tls13 res binder",
"tls13 c e traffic",
"tls13 e exp master",
"tls13 c hs traffic",
"tls13 s hs traffic",
"tls13 c ap traffic",
"tls13 s ap traffic",
"tls13 exp master",
"tls13 res master",
};
/**
* Step 1: Extract, as defined in RFC 5869, section 2.2:
* HKDF-Extract(salt, IKM) -> PRK
*/
static bool extract(private_tls_hkdf_t *this, chunk_t salt, chunk_t ikm,
chunk_t *prk)
{
if (!this->prf->set_key(this->prf, salt))
{
DBG1(DBG_TLS, "unable to set PRF salt");
return FALSE;
}
chunk_clear(prk);
if(!this->prf->allocate_bytes(this->prf, ikm, prk))
{
DBG1(DBG_TLS, "unable to allocate PRF space");
return FALSE;
}
DBG4(DBG_TLS, "PRK: %B", prk);
return TRUE;
}
/**
* Step 2: Expand as defined in RFC 5869, section 2.3:
* HKDF-Expand(PRK, info, L) -> OKM
*/
static bool expand(private_tls_hkdf_t *this, chunk_t prk, chunk_t info,
size_t length, chunk_t *okm)
{
if (!this->prf->set_key(this->prf, prk))
{
DBG1(DBG_TLS, "unable to set PRF PRK");
return FALSE;
}
prf_plus_t *prf_plus = prf_plus_create(this->prf, TRUE, info);
chunk_clear(&this->okm);
if (!prf_plus || !prf_plus->allocate_bytes(prf_plus, length, okm))
{
DBG1(DBG_TLS, "unable to allocate PRF plus space");
DESTROY_IF(prf_plus);
chunk_clear(okm);
return FALSE;
}
DESTROY_IF(prf_plus);
DBG4(DBG_TLS, "OKM: %B", okm);
return TRUE;
}
/**
* Expand-Label as defined in RFC 8446, section 7.1:
* HKDF-Expand-Label(Secret, Label, Context, Length) -> OKM
*/
static bool expand_label(private_tls_hkdf_t *this, chunk_t secret,
chunk_t label, chunk_t context, uint16_t length,
chunk_t *key)
{
bool success;
if (label.len < 7 || label.len > 255 || context.len > 255)
{
return FALSE;
}
/* HKDFLabel as defined in RFC 8446, section 7.1 */
bio_writer_t *writer = bio_writer_create(0);
writer->write_uint16(writer, length);
writer->write_data8(writer, label);
writer->write_data8(writer, context);
success = expand(this, secret, writer->get_buf(writer), length, key);
writer->destroy(writer);
return success;
}
/**
* Derive-Secret as defined in RFC 8446, section 7.1:
* Derive-Secret(Secret, Label, Message) -> OKM
*/
static bool derive_secret(private_tls_hkdf_t *this, chunk_t label,
chunk_t messages)
{
bool success;
chunk_t context;
if (!this->hasher ||
!this->hasher->allocate_hash(this->hasher, messages, &context))
{
DBG1(DBG_TLS, "%N not supported", hash_algorithm_names,
this->hash_algorithm);
return FALSE;
}
success = expand_label(this, this->prk, label, context,
this->hasher->get_hash_size(this->hasher),
&this->okm);
chunk_free(&context);
return success;
}
static bool move_to_phase_1(private_tls_hkdf_t *this)
{
chunk_t salt_zero;
switch (this->phase)
{
case HKDF_PHASE_0:
salt_zero = chunk_alloca(this->hasher->get_hash_size(this->hasher));
chunk_copy_pad(salt_zero, chunk_empty, 0);
if (!extract(this, salt_zero, this->ikm, &this->prk))
{
DBG1(DBG_TLS, "unable to extract PRK");
return FALSE;
}
this->phase = HKDF_PHASE_1;
return TRUE;
case HKDF_PHASE_1:
return TRUE;
default:
DBG1(DBG_TLS, "invalid HKDF phase");
return FALSE;
}
}
static bool move_to_phase_2(private_tls_hkdf_t *this)
{
chunk_t derived;
switch (this->phase)
{
case HKDF_PHASE_0:
if (!move_to_phase_1(this))
{
DBG1(DBG_TLS, "unable to move to phase 1");
return FALSE;
}
/* fall-through */
case HKDF_PHASE_1:
derived = chunk_from_str("tls13 derived");
if (!derive_secret(this, derived, chunk_empty))
{
DBG1(DBG_TLS, "unable to derive secret");
return FALSE;
}
if (!this->shared_secret.ptr)
{
DBG1(DBG_TLS, "no shared secret set");
return FALSE;
}
else
{
chunk_clear(&this->ikm);
this->ikm = chunk_clone(this->shared_secret);
}
if (!extract(this, this->okm, this->ikm, &this->prk))
{
DBG1(DBG_TLS, "unable extract PRK");
return FALSE;
}
this->phase = HKDF_PHASE_2;
return TRUE;
case HKDF_PHASE_2:
return TRUE;
default:
DBG1(DBG_TLS, "invalid HKDF phase");
return FALSE;
}
}
static bool move_to_phase_3(private_tls_hkdf_t *this)
{
chunk_t derived, ikm_zero;
switch (this->phase)
{
case HKDF_PHASE_0:
case HKDF_PHASE_1:
if (!move_to_phase_2(this))
{
DBG1(DBG_TLS, "unable to move to phase 2");
return FALSE;
}
/* fall-through */
case HKDF_PHASE_2:
/* prepare okm for next extract */
derived = chunk_from_str("tls13 derived");
if (!derive_secret(this, derived, chunk_empty))
{
DBG1(DBG_TLS, "unable to derive secret");
return FALSE;
}
ikm_zero = chunk_alloca(this->hasher->get_hash_size(this->hasher));
chunk_copy_pad(ikm_zero, chunk_empty, 0);
if (!extract(this, this->okm, ikm_zero, &this->prk))
{
DBG1(DBG_TLS, "unable extract PRK");
return FALSE;
}
this->phase = HKDF_PHASE_3;
return TRUE;
case HKDF_PHASE_3:
return TRUE;
default:
DBG1(DBG_TLS, "invalid HKDF phase");
return FALSE;
}
}
static void return_secret(private_tls_hkdf_t *this, chunk_t key,
chunk_t *secret)
{
*secret = chunk_alloc(key.len);
chunk_copy_pad(*secret, key, 0);
}
static bool get_shared_label_keys(private_tls_hkdf_t *this, chunk_t label,
bool is_server, size_t length, chunk_t *key)
{
chunk_t result, secret;
if (is_server)
{
secret = chunk_clone(this->server_traffic_secret);
}
else
{
secret = chunk_clone(this->client_traffic_secret);
}
if (!expand_label(this, secret, label, chunk_empty, length, &result))
{
DBG1(DBG_TLS, "unable to derive secret");
chunk_clear(&secret);
chunk_clear(&result);
return FALSE;
}
if (key)
{
return_secret(this, result, key);
}
chunk_clear(&secret);
chunk_clear(&result);
return TRUE;
}
METHOD(tls_hkdf_t, set_shared_secret, void,
private_tls_hkdf_t *this, chunk_t shared_secret)
{
this->shared_secret = chunk_clone(shared_secret);
}
METHOD(tls_hkdf_t, generate_secret, bool,
private_tls_hkdf_t *this, enum tls_hkdf_labels_t label, chunk_t messages,
chunk_t *secret)
{
switch (label)
{
case TLS_HKDF_EXT_BINDER:
case TLS_HKDF_RES_BINDER:
case TLS_HKDF_C_E_TRAFFIC:
case TLS_HKDF_E_EXP_MASTER:
if (!move_to_phase_1(this))
{
DBG1(DBG_TLS, "unable to move to phase 1");
return FALSE;
}
break;
case TLS_HKDF_C_HS_TRAFFIC:
case TLS_HKDF_S_HS_TRAFFIC:
if (!move_to_phase_2(this))
{
DBG1(DBG_TLS, "unable to move to phase 2");
return FALSE;
}
break;
case TLS_HKDF_C_AP_TRAFFIC:
case TLS_HKDF_S_AP_TRAFFIC:
case TLS_HKDF_EXP_MASTER:
case TLS_HKDF_RES_MASTER:
if (!move_to_phase_3(this))
{
DBG1(DBG_TLS, "unable to move to phase 3");
return FALSE;
}
break;
default:
DBG1(DBG_TLS, "invalid HKDF label");
return FALSE;
}
if (!derive_secret(this, chunk_from_str(hkdf_labels[label]), messages))
{
DBG1(DBG_TLS, "unable to derive secret");
return FALSE;
}
if (label == TLS_HKDF_C_HS_TRAFFIC || label == TLS_HKDF_C_AP_TRAFFIC)
{
chunk_clear(&this->client_traffic_secret);
this->client_traffic_secret = chunk_clone(this->okm);
}
if (label == TLS_HKDF_S_HS_TRAFFIC || label == TLS_HKDF_S_AP_TRAFFIC)
{
chunk_clear(&this->server_traffic_secret);
this->server_traffic_secret = chunk_clone(this->okm);
}
if (secret)
{
return_secret(this, this->okm, secret);
}
return TRUE;
}
METHOD(tls_hkdf_t, derive_key, bool,
private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *key)
{
return get_shared_label_keys(this, chunk_from_str("tls13 key"), is_server,
length, key);
}
METHOD(tls_hkdf_t, derive_iv, bool,
private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *iv)
{
return get_shared_label_keys(this, chunk_from_str("tls13 iv"), is_server,
length, iv);
}
METHOD(tls_hkdf_t, derive_finished, bool,
private_tls_hkdf_t *this, bool is_server, chunk_t *finished)
{
return get_shared_label_keys(this, chunk_from_str("tls13 finished"),
is_server,
this->hasher->get_hash_size(this->hasher),
finished);
}
METHOD(tls_hkdf_t, destroy, void,
private_tls_hkdf_t *this)
{
chunk_free(&this->ikm);
chunk_clear(&this->prk);
chunk_clear(&this->shared_secret);
chunk_clear(&this->okm);
chunk_clear(&this->client_traffic_secret);
chunk_clear(&this->server_traffic_secret);
DESTROY_IF(this->prf);
DESTROY_IF(this->hasher);
free(this);
}
tls_hkdf_t *tls_hkdf_create(hash_algorithm_t hash_algorithm, chunk_t psk)
{
private_tls_hkdf_t *this;
pseudo_random_function_t prf_algorithm;
switch (hash_algorithm)
{
case HASH_SHA256:
prf_algorithm = PRF_HMAC_SHA2_256;
break;
case HASH_SHA384:
prf_algorithm = PRF_HMAC_SHA2_384;
break;
default:
DBG1(DBG_TLS, "not supported hash algorithm");
return NULL;
}
INIT(this,
.public = {
.set_shared_secret = _set_shared_secret,
.generate_secret = _generate_secret,
.derive_key = _derive_key,
.derive_iv = _derive_iv,
.derive_finished = _derive_finished,
.destroy = _destroy,
},
.phase = HKDF_PHASE_0,
.hash_algorithm = hash_algorithm,
.prf = lib->crypto->create_prf(lib->crypto, prf_algorithm),
.hasher = lib->crypto->create_hasher(lib->crypto, hash_algorithm),
);
if (!psk.ptr)
{
this->ikm = chunk_alloc(this->hasher->get_hash_size(this->hasher));
chunk_copy_pad(this->ikm, chunk_empty, 0);
}
else
{
this->ikm = chunk_clone(psk);
}
if (!this->prf || !this->hasher)
{
DBG1(DBG_TLS, "unable to initialise HKDF");
destroy(this);
return NULL;
}
return &this->public;
}

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/*
* Copyright (C) 2020 Pascal Knecht
* Copyright (C) 2020 Méline Sieber
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup tls_hkdf tls_hkdf
* @{ @ingroup libtls
*/
#ifndef TLS_HKDF_H_
#define TLS_HKDF_H_
#include <library.h>
#include <crypto/hashers/hasher.h>
typedef struct tls_hkdf_t tls_hkdf_t;
/**
* TLS HKDF labels
*/
enum tls_hkdf_labels_t {
TLS_HKDF_EXT_BINDER,
TLS_HKDF_RES_BINDER,
TLS_HKDF_C_E_TRAFFIC,
TLS_HKDF_E_EXP_MASTER,
TLS_HKDF_C_HS_TRAFFIC,
TLS_HKDF_S_HS_TRAFFIC,
TLS_HKDF_C_AP_TRAFFIC,
TLS_HKDF_S_AP_TRAFFIC,
TLS_HKDF_EXP_MASTER,
TLS_HKDF_RES_MASTER,
};
/**
* TLS HKDF helper functions.
*/
struct tls_hkdf_t {
/**
* Set the (EC)DHE shared secret of this connection.
*
* @param shared_secret input key material to use
*/
void (*set_shared_secret)(tls_hkdf_t *this, chunk_t shared_secret);
/**
* Allocate secret of the requested label.
*
* Space for returned secret is allocated and must be freed by the caller.
*
* @param label HKDF label of requested secret
* @param messages handshake messages
* @param secret secret will be written into this chunk, if used
* @return TRUE if secrets derived successfully
*/
bool (*generate_secret)(tls_hkdf_t *this, enum tls_hkdf_labels_t label,
chunk_t messages, chunk_t *secret);
/**
* Allocate traffic encryption key bytes.
*
* Key used to encrypt traffic data as defined in RFC 8446, section 7.3.
* Space for returned secret is allocated and must be freed by the caller.
*
* @param is_server TRUE if server, FALSE if client derives secret
* @param length key length, in bytes
* @param key secret will be written into this chunk
* @return TRUE if secrets derived successfully
*/
bool (*derive_key)(tls_hkdf_t *this, bool is_server, size_t length,
chunk_t *key);
/**
* Allocate traffic IV bytes.
*
* IV used to encrypt traffic data as defined in RFC 8446, section 7.3.
* Space for returned secret is allocated and must be freed by the caller.
*
* @param is_server TRUE if server, FALSE if client derives secret
* @param length key length, in bytes
* @param iv IV will be written into this chunk
* @return TRUE if secrets derived successfully
*/
bool (*derive_iv)(tls_hkdf_t *this, bool is_server, size_t length,
chunk_t *iv);
/**
* Allocate finished key bytes.
*
* Key used to compute Finished messages as defined in RFC 8446,
* section 4.4.4. Space for returned secret is allocated and must be freed
* by the caller.
*
* @param is_server TRUE if server, FALSE if client derives secret
* @param finished key will be written into this chunk
* @return TRUE if secrets derived successfully
*/
bool (*derive_finished)(tls_hkdf_t *this, bool is_server,
chunk_t *finished);
/**
* Destroy a tls_hkdf_t
*/
void (*destroy)(tls_hkdf_t *this);
};
/**
* Create a tls_hkdf instance.
*
* @param hash_algorithm hash algorithm to use
* @param psk Pre shared key if available otherwise NULL
* @return TLS HKDF helper
*/
tls_hkdf_t *tls_hkdf_create(hash_algorithm_t hash_algorithm, chunk_t psk);
#endif /** TLS_HKDF_H_ @}*/