bt-host: add option to use PSA APIs instead of TinyCrypt

By enabling CONFIG_BT_USE_PSA_API the user can specify to use
PSA APIs instead of TinyCrypt for crypto operations in bluetooth
host module.

This commit also extends tests/bluetooth/gatt in order to
add a PSA test.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>

subsys/bluetooth/host/CMakeLists.txt

@@ -31,10 +31,13 @@ if(CONFIG_BT_HCI_HOST)
     CONFIG_BT_OBSERVER
     scan.c
     )
-  zephyr_library_sources_ifdef(
+
-    CONFIG_BT_HOST_CRYPTO
+  if(CONFIG_BT_USE_PSA_API)
-    crypto.c
+    zephyr_library_sources_ifdef(CONFIG_BT_HOST_CRYPTO    crypto_psa.c)
-    )
+  else()
+    zephyr_library_sources_ifdef(CONFIG_BT_HOST_CRYPTO    crypto_tc.c)
+  endif()
+
   zephyr_library_sources_ifdef(
     CONFIG_BT_ECC
     ecc.c
@@ -108,6 +111,13 @@ if(CONFIG_BT_CONN_DISABLE_SECURITY)
     )
 endif()
 
+if(CONFIG_BT_USE_PSA_API)
+    zephyr_library_link_libraries_ifdef(CONFIG_MBEDTLS mbedTLS)
+    zephyr_library_include_directories_ifdef(CONFIG_BUILD_WITH_TFM
+      $<TARGET_PROPERTY:tfm,TFM_BINARY_DIR>/api_ns/interface/include
+    )
+endif()
+
 # Bluetooth Mesh has test dependencies in the host.
 # In order to compile Bsim tests with these test features
 # and PSA enabled, the libraries must be linked.

subsys/bluetooth/host/Kconfig

@@ -139,8 +139,9 @@ rsource "../audio/Kconfig"
 config BT_HOST_CRYPTO
 	bool "Use crypto functionality implemented in the Bluetooth host"
 	default y if !BT_CTLR_CRYPTO
-	select TINYCRYPT
+	select TINYCRYPT if !BT_USE_PSA_API
-	select TINYCRYPT_AES
+	select TINYCRYPT_AES if !BT_USE_PSA_API
+	select PSA_WANT_KEY_TYPE_AES if BT_USE_PSA_API
 	help
 	  The option adds the AES encryption support using TinyCrypt
 	  library if this is not provided by the controller implementation.
@@ -148,9 +149,9 @@ config BT_HOST_CRYPTO
 config BT_HOST_CRYPTO_PRNG
 	bool "Use Tinycrypt library for random number generation"
 	default y
-	select TINYCRYPT_SHA256
+	select TINYCRYPT_SHA256 if !BT_USE_PSA_API
-	select TINYCRYPT_SHA256_HMAC
+	select TINYCRYPT_SHA256_HMAC if !BT_USE_PSA_API
-	select TINYCRYPT_SHA256_HMAC_PRNG
+	select TINYCRYPT_SHA256_HMAC_PRNG if !BT_USE_PSA_API
 	depends on BT_HOST_CRYPTO
 	help
 	  When selected, will use tinycrypt library for random number generation.

subsys/bluetooth/host/Kconfig.gatt

@@ -107,9 +107,11 @@ config BT_GATT_CACHING
 	bool "GATT Caching support"
 	default y
 	depends on BT_GATT_SERVICE_CHANGED
-	select TINYCRYPT
+	select TINYCRYPT if !BT_USE_PSA_API
-	select TINYCRYPT_AES
+	select TINYCRYPT_AES if !BT_USE_PSA_API
-	select TINYCRYPT_AES_CMAC
+	select TINYCRYPT_AES_CMAC if !BT_USE_PSA_API
+	select PSA_WANT_KEY_TYPE_AES if BT_USE_PSA_API
+	select PSA_WANT_ALG_CMAC if BT_USE_PSA_API
 	help
 	  This option enables support for GATT Caching. When enabled the stack
 	  will register Client Supported Features and Database Hash

subsys/bluetooth/host/crypto_psa.c

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2017 Nordic Semiconductor ASA
+ * Copyright (c) 2015-2016 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <string.h>
+#include <errno.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/sys/check.h>
+
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/crypto.h>
+
+#include "psa/crypto.h"
+
+#include "common/bt_str.h"
+
+#include "hci_core.h"
+
+#define LOG_LEVEL CONFIG_BT_HCI_CORE_LOG_LEVEL
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(bt_host_crypto);
+
+int prng_init(void)
+{
+	if (psa_crypto_init() != PSA_SUCCESS) {
+		return -EIO;
+	}
+	return 0;
+}
+
+#if defined(CONFIG_BT_HOST_CRYPTO_PRNG)
+int bt_rand(void *buf, size_t len)
+{
+	if (psa_generate_random(buf, len) == PSA_SUCCESS) {
+		return 0;
+	}
+
+	return -EIO;
+}
+#else /* !CONFIG_BT_HOST_CRYPTO_PRNG */
+int bt_rand(void *buf, size_t len)
+{
+	CHECKIF(buf == NULL || len == 0) {
+		return -EINVAL;
+	}
+
+	return bt_hci_le_rand(buf, len);
+}
+#endif /* CONFIG_BT_HOST_CRYPTO_PRNG */
+
+int bt_encrypt_le(const uint8_t key[16], const uint8_t plaintext[16],
+		  uint8_t enc_data[16])
+{
+	psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
+	psa_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
+	psa_status_t status, destroy_status;
+	size_t out_len;
+	uint8_t tmp[16];
+
+	CHECKIF(key == NULL || plaintext == NULL || enc_data == NULL) {
+		return -EINVAL;
+	}
+
+	LOG_DBG("key %s", bt_hex(key, 16));
+	LOG_DBG("plaintext %s", bt_hex(plaintext, 16));
+
+	sys_memcpy_swap(tmp, key, 16);
+
+	psa_set_key_type(&attr, PSA_KEY_TYPE_AES);
+	psa_set_key_bits(&attr, 128);
+	psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_ENCRYPT);
+	psa_set_key_algorithm(&attr, PSA_ALG_ECB_NO_PADDING);
+	if (psa_import_key(&attr, tmp, 16, &key_id) != PSA_SUCCESS) {
+		LOG_ERR("Failed to import AES key");
+		return -EINVAL;
+	}
+
+	sys_memcpy_swap(tmp, plaintext, 16);
+
+	status = psa_cipher_encrypt(key_id, PSA_ALG_ECB_NO_PADDING, tmp, 16,
+					enc_data, 16, &out_len);
+	if (status != PSA_SUCCESS) {
+		LOG_ERR("AES encryption failed");
+	}
+
+	destroy_status = psa_destroy_key(key_id);
+	if (destroy_status != PSA_SUCCESS) {
+		LOG_ERR("Failed to destroy AES key");
+	}
+
+	if ((status != PSA_SUCCESS) || (destroy_status != PSA_SUCCESS)) {
+		return -EIO;
+	}
+
+	sys_mem_swap(enc_data, 16);
+
+	LOG_DBG("enc_data %s", bt_hex(enc_data, 16));
+
+	return 0;
+}
+
+int bt_encrypt_be(const uint8_t key[16], const uint8_t plaintext[16],
+		  uint8_t enc_data[16])
+{
+	psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
+	psa_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
+	psa_status_t status, destroy_status;
+	size_t out_len;
+
+	CHECKIF(key == NULL || plaintext == NULL || enc_data == NULL) {
+		return -EINVAL;
+	}
+
+	LOG_DBG("key %s", bt_hex(key, 16));
+	LOG_DBG("plaintext %s", bt_hex(plaintext, 16));
+
+	psa_set_key_type(&attr, PSA_KEY_TYPE_AES);
+	psa_set_key_bits(&attr, 128);
+	psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_ENCRYPT);
+	psa_set_key_algorithm(&attr, PSA_ALG_ECB_NO_PADDING);
+	if (psa_import_key(&attr, key, 16, &key_id) != PSA_SUCCESS) {
+		LOG_ERR("Failed to import AES key");
+		return -EINVAL;
+	}
+
+	status = psa_cipher_encrypt(key_id, PSA_ALG_ECB_NO_PADDING,
+				plaintext, 16, enc_data, 16, &out_len);
+	if (status != PSA_SUCCESS) {
+		LOG_ERR("AES encryption failed");
+	}
+
+	destroy_status = psa_destroy_key(key_id);
+	if (destroy_status != PSA_SUCCESS) {
+		LOG_ERR("Failed to destroy AES key");
+	}
+
+	if ((status != PSA_SUCCESS) || (destroy_status != PSA_SUCCESS)) {
+		return -EIO;
+	}
+
+	LOG_DBG("enc_data %s", bt_hex(enc_data, 16));
+
+	return 0;
+}

subsys/bluetooth/host/gatt.c

@@ -21,11 +21,15 @@
 #include <zephyr/settings/settings.h>
 
 #if defined(CONFIG_BT_GATT_CACHING)
+#if defined(CONFIG_BT_USE_PSA_API)
+#include "psa/crypto.h"
+#else /* CONFIG_BT_USE_PSA_API */
 #include <tinycrypt/constants.h>
 #include <tinycrypt/utils.h>
 #include <tinycrypt/aes.h>
 #include <tinycrypt/cmac_mode.h>
 #include <tinycrypt/ccm_mode.h>
+#endif /* CONFIG_BT_USE_PSA_API */
 #endif /* CONFIG_BT_GATT_CACHING */
 
 #include <zephyr/bluetooth/hci.h>
@@ -693,11 +697,93 @@ static ssize_t cf_write(struct bt_conn *conn, const struct bt_gatt_attr *attr,
 	return len;
 }
 
+#if defined(CONFIG_BT_USE_PSA_API)
 struct gen_hash_state {
-	struct tc_cmac_struct state;
+	psa_mac_operation_t operation;
+	psa_key_id_t key;
 	int err;
 };
 
+static int db_hash_setup(struct gen_hash_state *state, uint8_t *key)
+{
+	psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
+
+	psa_set_key_type(&key_attr, PSA_KEY_TYPE_AES);
+	psa_set_key_bits(&key_attr, 128);
+	psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_SIGN_MESSAGE);
+	psa_set_key_algorithm(&key_attr, PSA_ALG_CMAC);
+
+	if (psa_import_key(&key_attr, key, 16, &(state->key)) != PSA_SUCCESS) {
+		LOG_ERR("Unable to import the key for AES CMAC");
+		return -EIO;
+	}
+	state->operation = psa_mac_operation_init();
+	if (psa_mac_sign_setup(&(state->operation), state->key,
+			       PSA_ALG_CMAC) != PSA_SUCCESS) {
+		LOG_ERR("CMAC operation init failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int db_hash_update(struct gen_hash_state *state, uint8_t *data, size_t len)
+{
+	if (psa_mac_update(&(state->operation), data, len) != PSA_SUCCESS) {
+		LOG_ERR("CMAC update failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int db_hash_finish(struct gen_hash_state *state)
+{
+	size_t mac_length;
+
+	if (psa_mac_sign_finish(&(state->operation), db_hash.hash, 16,
+				&mac_length) != PSA_SUCCESS) {
+		LOG_ERR("CMAC finish failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+#else /* CONFIG_BT_USE_PSA_API */
+struct gen_hash_state {
+	struct tc_cmac_struct state;
+	struct tc_aes_key_sched_struct sched;
+	int err;
+};
+
+static int db_hash_setup(struct gen_hash_state *state, uint8_t *key)
+{
+	if (tc_cmac_setup(&(state->state), key, &(state->sched)) == TC_CRYPTO_FAIL) {
+		LOG_ERR("CMAC setup failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int db_hash_update(struct gen_hash_state *state, uint8_t *data, size_t len)
+{
+	if (tc_cmac_update(&state->state, data, len) == TC_CRYPTO_FAIL) {
+		LOG_ERR("CMAC update failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int db_hash_finish(struct gen_hash_state *state)
+{
+	if (tc_cmac_final(db_hash.hash, &(state->state)) == TC_CRYPTO_FAIL) {
+		LOG_ERR("CMAC finish failed");
+		return -EIO;
+	}
+	return 0;
+}
+
+
+#endif /* CONFIG_BT_USE_PSA_API */
+
 union hash_attr_value {
 	/* Bluetooth Core Specification Version 5.3 | Vol 3, Part G
 	 * Table 3.1: Service declaration
@@ -755,15 +841,15 @@ static uint8_t gen_hash_m(const struct bt_gatt_attr *attr, uint16_t handle,
 	case BT_UUID_GATT_CHRC_VAL:
 	case BT_UUID_GATT_CEP_VAL:
 		value = sys_cpu_to_le16(handle);
-		if (tc_cmac_update(&state->state, (uint8_t *)&value,
+		if (db_hash_update(state, (uint8_t *)&value,
-				   sizeof(handle)) == TC_CRYPTO_FAIL) {
+				   sizeof(handle)) != 0) {
 			state->err = -EINVAL;
 			return BT_GATT_ITER_STOP;
 		}
 
 		value = sys_cpu_to_le16(u16->val);
-		if (tc_cmac_update(&state->state, (uint8_t *)&value,
+		if (db_hash_update(state, (uint8_t *)&value,
-				   sizeof(u16->val)) == TC_CRYPTO_FAIL) {
+				   sizeof(u16->val)) != 0) {
 			state->err = -EINVAL;
 			return BT_GATT_ITER_STOP;
 		}
@@ -774,8 +860,7 @@ static uint8_t gen_hash_m(const struct bt_gatt_attr *attr, uint16_t handle,
 			return BT_GATT_ITER_STOP;
 		}
 
-		if (tc_cmac_update(&state->state, data, len) ==
+		if (db_hash_update(state, data, len) != 0) {
-		    TC_CRYPTO_FAIL) {
 			state->err = -EINVAL;
 			return BT_GATT_ITER_STOP;
 		}
@@ -788,18 +873,19 @@ static uint8_t gen_hash_m(const struct bt_gatt_attr *attr, uint16_t handle,
 	case BT_UUID_GATT_CPF_VAL:
 	case BT_UUID_GATT_CAF_VAL:
 		value = sys_cpu_to_le16(handle);
-		if (tc_cmac_update(&state->state, (uint8_t *)&value,
+		if (db_hash_update(state, (uint8_t *)&value,
-				   sizeof(handle)) == TC_CRYPTO_FAIL) {
+				   sizeof(handle)) != 0) {
 			state->err = -EINVAL;
 			return BT_GATT_ITER_STOP;
 		}
 
 		value = sys_cpu_to_le16(u16->val);
-		if (tc_cmac_update(&state->state, (uint8_t *)&value,
+		if (db_hash_update(state, (uint8_t *)&value,
-				   sizeof(u16->val)) == TC_CRYPTO_FAIL) {
+				   sizeof(u16->val)) != 0) {
 			state->err = -EINVAL;
 			return BT_GATT_ITER_STOP;
 		}
+
 		break;
 	default:
 		return BT_GATT_ITER_CONTINUE;
@@ -825,18 +911,15 @@ static void db_hash_store(void)
 static void db_hash_gen(void)
 {
 	uint8_t key[16] = {};
-	struct tc_aes_key_sched_struct sched;
 	struct gen_hash_state state;
 
-	if (tc_cmac_setup(&state.state, key, &sched) == TC_CRYPTO_FAIL) {
+	if (db_hash_setup(&state, key) != 0) {
-		LOG_ERR("Unable to setup AES CMAC");
 		return;
 	}
 
 	bt_gatt_foreach_attr(0x0001, 0xffff, gen_hash_m, &state);
 
-	if (tc_cmac_final(db_hash.hash, &state.state) == TC_CRYPTO_FAIL) {
+	if (db_hash_finish(&state) != 0) {
-		LOG_ERR("Unable to calculate hash");
 		return;
 	}
 

tests/bluetooth/gatt/testcase.yaml

@@ -14,3 +14,21 @@ tests:
     tags:
       - bluetooth
       - gatt
+  bluetooth.gatt.psa:
+    filter: CONFIG_PSA_CRYPTO_CLIENT
+    extra_args:
+      - EXTRA_DTC_OVERLAY_FILE="test.overlay"
+    platform_allow:
+      - native_posix
+      - native_posix/native/64
+      - native_sim
+      - native_sim/native/64
+      - qemu_x86
+      - qemu_cortex_m3
+      - nrf5340dk/nrf5340/cpuapp/ns
+      - nrf52840dk/nrf52840
+    integration_platforms:
+      - native_sim
+    tags:
+      - bluetooth
+      - gatt