libtls: Implement HKDF for TLS 1.3
authorPascal K <pascal.knecht@hsr.ch>
Thu, 21 May 2020 05:57:14 +0000 (07:57 +0200)
committerTobias Brunner <tobias@strongswan.org>
Fri, 12 Feb 2021 10:45:44 +0000 (11:45 +0100)
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>
src/libcharon/Android.mk
src/libtls/Makefile.am
src/libtls/tests/Makefile.am
src/libtls/tests/suites/test_hkdf.c [new file with mode: 0644]
src/libtls/tests/tls_tests.h
src/libtls/tls_hkdf.c [new file with mode: 0644]
src/libtls/tls_hkdf.h [new file with mode: 0644]

index 885b2e7..0fd8b57 100644 (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
 
index 2aa3b7f..db31b80 100644 (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
index 456383f..2220ff4 100644 (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
diff --git a/src/libtls/tests/suites/test_hkdf.c b/src/libtls/tests/suites/test_hkdf.c
new file mode 100644 (file)
index 0000000..529c6d5
--- /dev/null
@@ -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;
+}
index 489b2dd..b0d0d57 100644 (file)
@@ -13,5 +13,6 @@
  * for more details.
  */
 
+TEST_SUITE(hkdf_suite_create)
 TEST_SUITE(socket_suite_create)
 TEST_SUITE(suites_suite_create)
diff --git a/src/libtls/tls_hkdf.c b/src/libtls/tls_hkdf.c
new file mode 100644 (file)
index 0000000..d0c44f5
--- /dev/null
@@ -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;
+}
diff --git a/src/libtls/tls_hkdf.h b/src/libtls/tls_hkdf.h
new file mode 100644 (file)
index 0000000..a820b02
--- /dev/null
@@ -0,0 +1,128 @@
+/*
+ * 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_ @}*/