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TofMassilia13320Grom-
TofMassilia13320
authored and
Grom-
committed
[api] Add stse_establish_host_key_authenticated
1 parent cb7bbd2 commit 8c2cdae

2 files changed

Lines changed: 298 additions & 24 deletions

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‎api/stse_symmetric_keys_management.c‎

Lines changed: 266 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -17,7 +17,8 @@
1717

1818
/* Includes ------------------------------------------------------------------*/
1919

20-
#include <api/stse_symmetric_keys_management.h>
20+
#include "api/stse_symmetric_keys_management.h"
21+
#include "services/stsafea/stsafea_public_key_slots.h"
2122

2223
#define STSAFEA_HOST_KEY_WRAPPING_AUTHENTICATION_TAG_LENGTH STSE_KEK_ENVELOPE_MAC_SIZE
2324
#define STSE_HOST_KEY_ENVELOPE_FRONT_PADDING_LENGTH 3U
@@ -685,8 +686,8 @@ stse_ReturnCode_t stse_host_key_provisioning_wrapped_authenticated(
685686
#ifdef STSE_CONF_USE_HOST_KEY_ESTABLISHMENT
686687
stse_ReturnCode_t stse_establish_host_key(
687688
stse_Handler_t *pSTSE,
688-
stse_ecc_key_type_t host_ecdh_key_type,
689-
stsafea_host_key_type_t host_keys_type,
689+
stse_ecc_key_type_t ecdh_key_type,
690+
stsafea_host_key_type_t host_secure_channel_keys_type,
690691
PLAT_UI8 *host_mac_key,
691692
PLAT_UI8 *host_cipher_key) {
692693
stse_ReturnCode_t ret;
@@ -696,18 +697,18 @@ stse_ReturnCode_t stse_establish_host_key(
696697
return (STSE_API_HANDLER_NOT_INITIALISED);
697698
}
698699

699-
if (host_keys_type == STSAFEA_AES_INVALID_HOST_KEY || host_mac_key == NULL || host_cipher_key == NULL
700+
if (host_secure_channel_keys_type == STSAFEA_AES_INVALID_HOST_KEY || host_mac_key == NULL || host_cipher_key == NULL
700701
#ifdef STSE_CONF_ECC_EDWARD_25519
701-
|| host_ecdh_key_type == STSE_ECC_KT_ED25519
702+
|| ecdh_key_type == STSE_ECC_KT_ED25519
702703
#endif /* STSE_CONF_ECC_EDWARD_25519 */
703704
) {
704705
return STSE_API_INVALID_PARAMETER;
705706
}
706707

707708
/* - allocate ECDHE buffer sizes according to ECC key type */
708-
PLAT_UI16 pub_key_size = stse_ecc_info_table[host_ecdh_key_type].public_key_size;
709-
PLAT_UI16 priv_key_size = stse_ecc_info_table[host_ecdh_key_type].private_key_size;
710-
PLAT_UI16 shared_secret_size = stse_ecc_info_table[host_ecdh_key_type].shared_secret_size;
709+
PLAT_UI16 pub_key_size = stse_ecc_info_table[ecdh_key_type].public_key_size;
710+
PLAT_UI16 priv_key_size = stse_ecc_info_table[ecdh_key_type].private_key_size;
711+
PLAT_UI16 shared_secret_size = stse_ecc_info_table[ecdh_key_type].shared_secret_size;
711712
PLAT_UI16 hkdf_info_size = 2 * pub_key_size;
712713

713714
PLAT_UI8 host_ecdhe_public_key[pub_key_size];
@@ -720,13 +721,13 @@ stse_ReturnCode_t stse_establish_host_key(
720721
PLAT_UI8 pHkdf_info[hkdf_info_size];
721722

722723
/* - Initialize the OKM length with the confirmation key length */
723-
PLAT_UI16 host_mac_key_length = host_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_MAC_KEY_SIZE : STSAFEA_HOST_AES_128_MAC_KEY_SIZE;
724-
PLAT_UI16 host_cipher_key_length = host_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_CIPHER_KEY_SIZE : STSAFEA_HOST_AES_128_CIPHER_KEY_SIZE;
724+
PLAT_UI16 host_mac_key_length = host_secure_channel_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_MAC_KEY_SIZE : STSAFEA_HOST_AES_128_MAC_KEY_SIZE;
725+
PLAT_UI16 host_cipher_key_length = host_secure_channel_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_CIPHER_KEY_SIZE : STSAFEA_HOST_AES_128_CIPHER_KEY_SIZE;
725726
PLAT_UI8 okm_buffer[host_mac_key_length + host_cipher_key_length];
726727

727728
/* - Generate local host ECDHE key pair */
728729
ret = stse_platform_ecc_generate_key_pair(
729-
host_ecdh_key_type,
730+
ecdh_key_type,
730731
host_ecdhe_private_key,
731732
host_ecdhe_public_key);
732733
if (ret != STSE_OK) {
@@ -739,7 +740,7 @@ stse_ReturnCode_t stse_establish_host_key(
739740
/* - Generate ECDHE key pair on target SE */
740741
ret = stsafea_generate_ECDHE_key_pair(
741742
pSTSE,
742-
host_ecdh_key_type,
743+
ecdh_key_type,
743744
stsafe_ecdhe_public_key);
744745
if (ret != STSE_OK) {
745746
/* Clear key pairs info on SE ECDHE key pair generation error */
@@ -751,7 +752,7 @@ stse_ReturnCode_t stse_establish_host_key(
751752

752753
/* - Process Diffie-Hellman on host side */
753754
ret = stse_platform_ecc_ecdh(
754-
host_ecdh_key_type,
755+
ecdh_key_type,
755756
stsafe_ecdhe_public_key,
756757
host_ecdhe_private_key,
757758
shared_secret);
@@ -775,7 +776,7 @@ stse_ReturnCode_t stse_establish_host_key(
775776
ret = stse_platform_hmac_sha256_compute(pHkdf_salt,
776777
STSAFEA_KEK_HKDF_SALT_SIZE,
777778
shared_secret,
778-
stse_ecc_info_table[host_ecdh_key_type].shared_secret_size,
779+
stse_ecc_info_table[ecdh_key_type].shared_secret_size,
779780
pHkdf_info,
780781
2 * pub_key_size,
781782
okm_buffer,
@@ -793,9 +794,9 @@ stse_ReturnCode_t stse_establish_host_key(
793794
/* - Establish the host keys through STSAFE */
794795
ret = stsafea_establish_host_key(
795796
pSTSE,
796-
host_ecdh_key_type,
797+
ecdh_key_type,
797798
host_ecdhe_public_key,
798-
host_keys_type);
799+
host_secure_channel_keys_type);
799800

800801
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
801802
if (ret != STSE_OK) {
@@ -813,6 +814,255 @@ stse_ReturnCode_t stse_establish_host_key(
813814

814815
return ret;
815816
}
817+
818+
stse_ReturnCode_t stse_establish_host_key_authenticated(
819+
stse_Handler_t *pSTSE,
820+
stse_ecc_key_type_t ecdh_key_type,
821+
stsafea_host_key_type_t host_secure_channel_keys_type,
822+
stse_hash_algorithm_t tbs_hash_algo,
823+
PLAT_UI8 tbs_public_key_slot,
824+
PLAT_UI8 *tbs_private_key,
825+
PLAT_UI8 *host_mac_key,
826+
PLAT_UI8 *host_cipher_key) {
827+
stse_ReturnCode_t ret;
828+
829+
/* - Check function parameters */
830+
if (pSTSE == NULL) {
831+
return (STSE_API_HANDLER_NOT_INITIALISED);
832+
}
833+
834+
if (host_secure_channel_keys_type == STSAFEA_AES_INVALID_HOST_KEY || host_mac_key == NULL || host_cipher_key == NULL
835+
#ifdef STSE_CONF_ECC_EDWARD_25519
836+
|| ecdh_key_type == STSE_ECC_KT_ED25519
837+
#endif /* STSE_CONF_ECC_EDWARD_25519 */
838+
) {
839+
return STSE_API_INVALID_PARAMETER;
840+
}
841+
842+
/* - allocate ECDHE buffer sizes according to ECC key type */
843+
PLAT_UI16 pub_key_size = stse_ecc_info_table[ecdh_key_type].public_key_size;
844+
PLAT_UI16 priv_key_size = stse_ecc_info_table[ecdh_key_type].private_key_size;
845+
PLAT_UI16 shared_secret_size = stse_ecc_info_table[ecdh_key_type].shared_secret_size;
846+
PLAT_UI16 hkdf_info_size = 2 * pub_key_size;
847+
848+
PLAT_UI8 host_ecdhe_public_key[pub_key_size];
849+
PLAT_UI8 host_ecdhe_private_key[priv_key_size];
850+
PLAT_UI8 stsafe_ecdhe_public_key[pub_key_size];
851+
852+
PLAT_UI8 shared_secret[2 * shared_secret_size];
853+
854+
PLAT_UI8 pHkdf_salt[STSAFEA_KEK_HKDF_SALT_SIZE] = STSAFEA_KEK_HKDF_SALT;
855+
PLAT_UI8 pHkdf_info[hkdf_info_size];
856+
857+
/* Get public key slot type & configuration */
858+
PLAT_UI8 tbs_presence_flag = 0;
859+
stsafea_generic_public_key_configuration_flags_t tbs_configuration_flags = {0};
860+
stse_ecc_key_type_t tbs_key_type;
861+
ret = stsafea_query_generic_public_key_slot_info(pSTSE, tbs_public_key_slot, &tbs_presence_flag, &tbs_configuration_flags, &tbs_key_type);
862+
if (ret != STSE_OK) {
863+
return ret;
864+
}
865+
if (tbs_presence_flag == 0) {
866+
return STSE_API_KEY_NOT_FOUND;
867+
}
868+
if (tbs_configuration_flags.establish_host_key == 0) {
869+
return STSE_API_INVALID_SIGNATURE;
870+
}
871+
872+
/* Allocate signature buffer */
873+
PLAT_UI8 signature[stse_ecc_info_table[tbs_key_type].signature_size];
874+
875+
/* - Initialize the OKM length with the confirmation key length */
876+
PLAT_UI16 host_mac_key_length = host_secure_channel_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_MAC_KEY_SIZE : STSAFEA_HOST_AES_128_MAC_KEY_SIZE;
877+
PLAT_UI16 host_cipher_key_length = host_secure_channel_keys_type == STSAFEA_AES_256_HOST_KEY ? STSAFEA_HOST_AES_256_CIPHER_KEY_SIZE : STSAFEA_HOST_AES_128_CIPHER_KEY_SIZE;
878+
PLAT_UI8 okm_buffer[host_mac_key_length + host_cipher_key_length];
879+
880+
/* - Generate local host ECDHE key pair */
881+
ret = stse_platform_ecc_generate_key_pair(
882+
ecdh_key_type,
883+
host_ecdhe_private_key,
884+
host_ecdhe_public_key);
885+
if (ret != STSE_OK) {
886+
/* Clear generated keypair on ECC key generation failure */
887+
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
888+
memset(host_ecdhe_private_key, 0, sizeof(host_ecdhe_private_key));
889+
return (STSE_UNEXPECTED_ERROR);
890+
}
891+
892+
/* - Generate ECDHE key pair on target SE */
893+
ret = stsafea_generate_ECDHE_key_pair(
894+
pSTSE,
895+
ecdh_key_type,
896+
stsafe_ecdhe_public_key);
897+
if (ret != STSE_OK) {
898+
/* Clear key pairs info on SE ECDHE key pair generation error */
899+
memset(stsafe_ecdhe_public_key, 0, sizeof(stsafe_ecdhe_public_key));
900+
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
901+
memset(host_ecdhe_private_key, 0, sizeof(host_ecdhe_private_key));
902+
return ret;
903+
}
904+
905+
/* - Process Diffie-Hellman on host side */
906+
ret = stse_platform_ecc_ecdh(
907+
ecdh_key_type,
908+
stsafe_ecdhe_public_key,
909+
host_ecdhe_private_key,
910+
shared_secret);
911+
memset(host_ecdhe_private_key, 0, sizeof(host_ecdhe_private_key));
912+
if (ret != STSE_OK) {
913+
memset(stsafe_ecdhe_public_key, 0, sizeof(stsafe_ecdhe_public_key));
914+
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
915+
return (STSE_UNEXPECTED_ERROR);
916+
}
917+
918+
/* - Derive host keys from shared secret */
919+
memcpy(pHkdf_info,
920+
host_ecdhe_public_key,
921+
pub_key_size);
922+
923+
memcpy(pHkdf_info + pub_key_size,
924+
stsafe_ecdhe_public_key,
925+
pub_key_size);
926+
927+
ret = stse_platform_hmac_sha256_compute(pHkdf_salt,
928+
STSAFEA_KEK_HKDF_SALT_SIZE,
929+
shared_secret,
930+
stse_ecc_info_table[ecdh_key_type].shared_secret_size,
931+
pHkdf_info,
932+
2 * pub_key_size,
933+
okm_buffer,
934+
host_mac_key_length + host_cipher_key_length);
935+
memset(shared_secret, 0, sizeof(shared_secret));
936+
if (ret != STSE_OK) {
937+
memset(stsafe_ecdhe_public_key, 0, sizeof(stsafe_ecdhe_public_key));
938+
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
939+
memset(okm_buffer, 0, sizeof(okm_buffer));
940+
return (STSE_UNEXPECTED_ERROR);
941+
}
942+
943+
/* Allocate TBS buffer */
944+
PLAT_UI16 tbs_pub_key_length = pub_key_size;
945+
#ifdef STSE_CONF_ECC_CURVE_25519
946+
if (ecdh_key_type == STSE_ECC_KT_CURVE25519) {
947+
tbs_pub_key_length += STSE_ECC_GENERIC_LENGTH_SIZE;
948+
} else
949+
#endif
950+
{
951+
tbs_pub_key_length += STSE_NIST_BRAINPOOL_POINT_REPRESENTATION_ID_SIZE + 2 * STSE_ECC_GENERIC_LENGTH_SIZE;
952+
}
953+
PLAT_UI16 tbs_length = stse_ecc_info_table[ecdh_key_type].curve_id_total_length + 2 * tbs_pub_key_length;
954+
PLAT_UI8 pTBS[tbs_length];
955+
956+
/* Copy curve ID into TBS buffer */
957+
memcpy(pTBS,
958+
(PLAT_UI8 *)&stse_ecc_info_table[ecdh_key_type].curve_id,
959+
stse_ecc_info_table[ecdh_key_type].curve_id_total_length);
960+
PLAT_UI16 copy_index = stse_ecc_info_table[ecdh_key_type].curve_id_total_length;
961+
962+
/* Copy Host ECDHE public key into TBS */
963+
#ifdef STSE_CONF_ECC_CURVE_25519
964+
if (ecdh_key_type != STSE_ECC_KT_CURVE25519)
965+
#endif
966+
{
967+
pTBS[copy_index] = STSE_NIST_BRAINPOOL_POINT_REPRESENTATION_ID;
968+
copy_index += STSE_NIST_BRAINPOOL_POINT_REPRESENTATION_ID_SIZE;
969+
}
970+
971+
pTBS[copy_index] = UI16_B1(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
972+
pTBS[copy_index + 1] = UI16_B0(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
973+
copy_index += STSE_ECC_GENERIC_LENGTH_SIZE;
974+
975+
memcpy(pTBS + copy_index,
976+
host_ecdhe_public_key,
977+
stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
978+
copy_index += stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size;
979+
980+
#ifdef STSE_CONF_ECC_CURVE_25519
981+
if (ecdh_key_type != STSE_ECC_KT_CURVE25519)
982+
#endif
983+
{
984+
pTBS[copy_index] = UI16_B1(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
985+
pTBS[copy_index + 1] = UI16_B0(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
986+
copy_index += STSE_ECC_GENERIC_LENGTH_SIZE;
987+
988+
memcpy(pTBS + copy_index,
989+
host_ecdhe_public_key + stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size,
990+
stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
991+
copy_index += stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size;
992+
}
993+
994+
/* Copy STSAFE-A public key into TBS */
995+
#ifdef STSE_CONF_ECC_CURVE_25519
996+
if (ecdh_key_type != STSE_ECC_KT_CURVE25519)
997+
#endif
998+
{
999+
pTBS[copy_index] = STSE_NIST_BRAINPOOL_POINT_REPRESENTATION_ID;
1000+
copy_index += STSE_NIST_BRAINPOOL_POINT_REPRESENTATION_ID_SIZE;
1001+
}
1002+
1003+
pTBS[copy_index] = UI16_B1(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1004+
pTBS[copy_index + 1] = UI16_B0(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1005+
copy_index += STSE_ECC_GENERIC_LENGTH_SIZE;
1006+
1007+
memcpy(pTBS + copy_index,
1008+
stsafe_ecdhe_public_key,
1009+
stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1010+
copy_index += stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size;
1011+
1012+
#ifdef STSE_CONF_ECC_CURVE_25519
1013+
if (ecdh_key_type != STSE_ECC_KT_CURVE25519)
1014+
#endif
1015+
{
1016+
pTBS[copy_index] = UI16_B1(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1017+
pTBS[copy_index + 1] = UI16_B0(stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1018+
copy_index += STSE_ECC_GENERIC_LENGTH_SIZE;
1019+
1020+
memcpy(pTBS + copy_index,
1021+
stsafe_ecdhe_public_key + stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size,
1022+
stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size);
1023+
copy_index += stse_ecc_info_table[ecdh_key_type].coordinate_or_key_size;
1024+
}
1025+
1026+
memset(stsafe_ecdhe_public_key, 0, sizeof(stsafe_ecdhe_public_key));
1027+
1028+
/* Generate signature */
1029+
ret = stsafea_sign_for_generic_public_key_slot(pSTSE,
1030+
tbs_key_type,
1031+
tbs_private_key,
1032+
tbs_hash_algo,
1033+
tbs_length,
1034+
pTBS,
1035+
signature);
1036+
if (ret != STSE_OK) {
1037+
memset(okm_buffer, 0, sizeof(okm_buffer));
1038+
return ret;
1039+
}
1040+
1041+
/* - Establish the host keys through STSAFE with authentication */
1042+
ret = stsafea_establish_host_key_authenticated(pSTSE,
1043+
ecdh_key_type,
1044+
host_ecdhe_public_key,
1045+
host_secure_channel_keys_type,
1046+
tbs_public_key_slot,
1047+
tbs_key_type,
1048+
tbs_hash_algo,
1049+
signature);
1050+
memset(host_ecdhe_public_key, 0, sizeof(host_ecdhe_public_key));
1051+
if (ret != STSE_OK) {
1052+
memset(okm_buffer, 0, sizeof(okm_buffer));
1053+
return ret;
1054+
}
1055+
1056+
memcpy(host_mac_key,
1057+
okm_buffer,
1058+
host_mac_key_length);
1059+
memcpy(host_cipher_key,
1060+
okm_buffer + host_mac_key_length,
1061+
host_cipher_key_length);
1062+
memset(okm_buffer, 0, sizeof(okm_buffer));
1063+
1064+
return ret;
1065+
}
8161066
#endif /* STSE_CONF_USE_HOST_KEY_ESTABLISHMENT */
8171067

8181068
/* ------------------------------------------------------------------------------------------

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