tests: Add decrypt filter unit tests.

This commit implements unit tests for decryption stream filter in SUIT.
As a result of tests implementation and run, minor changes to error
handling were added to decryption filter implementation. Also, some
parameter renamig was applied.

Ref: NCSDK-30925

Signed-off-by: Michal Kozikowski <[email protected]>

subsys/suit/stream/stream_filters/include/suit_decrypt_filter.h

@@ -18,17 +18,17 @@ extern "C" {
 /**
  * @brief Get decrypt filter object
  *
- * @param[out] dec_sink  Pointer to destination sink_stream to pass decrypted data
+ * @param[out] in_sink   Pointer to input sink_stream to pass encrypted data
  * @param[in]  enc_info  Pointer to the structure with encryption info.
  * @param[in]  class_id  Pointer to the manifest class ID of the destination component
- * @param[in]  enc_sink  Pointer to source sink_stream to be filled with encrypted data
+ * @param[in]  out_sink  Pointer to output sink_stream to be filled with decrypted data
  *
  * @return SUIT_PLAT_SUCCESS if success otherwise error code
  */
-suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *dec_sink,
+suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *in_sink,
 					struct suit_encryption_info *enc_info,
 					const suit_manifest_class_id_t *class_id,
-					struct stream_sink *enc_sink);
+					struct stream_sink *out_sink);
 
 #ifdef __cplusplus
 }

subsys/suit/stream/stream_filters/src/suit_decrypt_filter.c

@@ -24,7 +24,7 @@ LOG_MODULE_REGISTER(suit_decrypt_filter, CONFIG_SUIT_LOG_LEVEL);
 struct decrypt_ctx {
 	mbedtls_svc_key_id_t cek_key_id;
 	psa_aead_operation_t operation;
-	struct stream_sink enc_sink;
+	struct stream_sink out_sink;
 	size_t tag_size;
 	size_t stored_tag_bytes;
 	uint8_t tag[PSA_AEAD_TAG_MAX_SIZE];
@@ -67,8 +67,8 @@ static suit_plat_err_t erase(void *ctx)
 		decrypt_ctx->stored_tag_bytes = 0;
 		memset(decrypt_ctx->tag, 0, sizeof(decrypt_ctx->tag));
 
-		if (decrypt_ctx->enc_sink.erase != NULL) {
-			res = decrypt_ctx->enc_sink.erase(decrypt_ctx->enc_sink.ctx);
+		if (decrypt_ctx->out_sink.erase != NULL) {
+			res = decrypt_ctx->out_sink.erase(decrypt_ctx->out_sink.ctx);
 		}
 	} else {
 		res = SUIT_PLAT_ERR_INVAL;
@@ -131,7 +131,7 @@ static suit_plat_err_t write(void *ctx, const uint8_t *buf, size_t size)
 			goto cleanup;
 		}
 
-		err = decrypt_ctx->enc_sink.write(decrypt_ctx->enc_sink.ctx, decrypted_buf,
+		err = decrypt_ctx->out_sink.write(decrypt_ctx->out_sink.ctx, decrypted_buf,
 						  decrypted_len);
 
 		if (err != SUIT_PLAT_SUCCESS) {
@@ -195,13 +195,15 @@ static suit_plat_err_t flush(void *ctx)
 		} else {
 			LOG_INF("Firmware decryption successful");
 
-			/* Using enc_sink without a write API is blocked by the filter constructor.
+			/* Using out_sink without a write API is blocked by the filter constructor.
 			 */
 			if (decrypted_len > 0) {
-				res = decrypt_ctx->enc_sink.write(decrypt_ctx->enc_sink.ctx,
+				res = decrypt_ctx->out_sink.write(decrypt_ctx->out_sink.ctx,
 								  decrypted_buf, decrypted_len);
 				if (res != SUIT_PLAT_SUCCESS) {
 					LOG_ERR("Failed to write decrypted data: %d", res);
+					/* Revert all the changes so that no decrypted data remains */
+					erase(decrypt_ctx);
 				}
 			}
 		}
@@ -236,16 +238,16 @@ static suit_plat_err_t release(void *ctx)
 
 	suit_plat_err_t res = flush(ctx);
 
-	if (decrypt_ctx->enc_sink.release != NULL) {
+	if (decrypt_ctx->out_sink.release != NULL) {
 		suit_plat_err_t release_ret =
-			decrypt_ctx->enc_sink.release(decrypt_ctx->enc_sink.ctx);
+			decrypt_ctx->out_sink.release(decrypt_ctx->out_sink.ctx);
 
 		if (res == SUIT_SUCCESS) {
 			res = release_ret;
 		}
 	}
 
-	zeroize(&decrypt_ctx->enc_sink, sizeof(struct stream_sink));
+	zeroize(&decrypt_ctx->out_sink, sizeof(struct stream_sink));
 
 	decrypt_ctx->in_use = false;
 
@@ -261,8 +263,8 @@ static suit_plat_err_t used_storage(void *ctx, size_t *size)
 		return SUIT_PLAT_ERR_INVAL;
 	}
 
-	if (decrypt_ctx->enc_sink.used_storage != NULL) {
-		return decrypt_ctx->enc_sink.used_storage(decrypt_ctx->enc_sink.ctx, size);
+	if (decrypt_ctx->out_sink.used_storage != NULL) {
+		return decrypt_ctx->out_sink.used_storage(decrypt_ctx->out_sink.ctx, size);
 	}
 
 	return SUIT_PLAT_ERR_UNSUPPORTED;
@@ -344,10 +346,10 @@ static suit_plat_err_t get_psa_alg_info(enum suit_cose_alg cose_alg_id, psa_algo
 	return SUIT_PLAT_SUCCESS;
 }
 
-suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *dec_sink,
+suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *in_sink,
 					struct suit_encryption_info *enc_info,
 					const suit_manifest_class_id_t *class_id,
-					struct stream_sink *enc_sink)
+					struct stream_sink *out_sink)
 {
 	suit_plat_err_t ret = SUIT_PLAT_SUCCESS;
 
@@ -356,8 +358,8 @@ suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *dec_sink,
 		return SUIT_PLAT_ERR_BUSY;
 	}
 
-	if ((enc_info == NULL) || (enc_sink == NULL) || (dec_sink == NULL) ||
-	    (enc_sink->write == NULL) || class_id == NULL) {
+	if ((enc_info == NULL) || (out_sink == NULL) || (in_sink == NULL) ||
+	    (out_sink->write == NULL) || class_id == NULL) {
 		return SUIT_PLAT_ERR_INVAL;
 	}
 
@@ -403,23 +405,30 @@ suit_plat_err_t suit_decrypt_filter_get(struct stream_sink *dec_sink,
 
 	status = psa_aead_update_ad(&ctx.operation, enc_info->aad.value, enc_info->aad.len);
 
+	if (status != PSA_SUCCESS) {
+		LOG_ERR("Failed to pass additional data for authentication operation: %d", status);
+		psa_aead_abort(&ctx.operation);
+		ctx.in_use = false;
+		return SUIT_PLAT_ERR_CRASH;
+	}
+
 	ctx.stored_tag_bytes = 0;
-	memcpy(&ctx.enc_sink, enc_sink, sizeof(struct stream_sink));
+	memcpy(&ctx.out_sink, out_sink, sizeof(struct stream_sink));
 
-	dec_sink->ctx = &ctx;
+	in_sink->ctx = &ctx;
 
-	dec_sink->write = write;
-	dec_sink->erase = erase;
-	dec_sink->release = release;
-	dec_sink->flush = flush;
-	if (enc_sink->used_storage != NULL) {
-		dec_sink->used_storage = used_storage;
+	in_sink->write = write;
+	in_sink->erase = erase;
+	in_sink->release = release;
+	in_sink->flush = flush;
+	if (out_sink->used_storage != NULL) {
+		in_sink->used_storage = used_storage;
 	} else {
-		dec_sink->used_storage = NULL;
+		in_sink->used_storage = NULL;
 	}
 
 	/* Seeking is not possible on encrypted payload. */
-	dec_sink->seek = NULL;
+	in_sink->seek = NULL;
 
 	return SUIT_PLAT_SUCCESS;
 }

tests/subsys/suit/unit/mocks/include/mock_suit_crypto.h

@@ -18,6 +18,15 @@ FAKE_VALUE_FUNC(psa_status_t, psa_hash_abort, psa_hash_operation_t *);
 FAKE_VALUE_FUNC(psa_status_t, psa_hash_verify, psa_hash_operation_t *, const uint8_t *, size_t);
 FAKE_VALUE_FUNC(psa_status_t, psa_verify_message, mbedtls_svc_key_id_t, psa_algorithm_t,
 		const uint8_t *, size_t, const uint8_t *, size_t);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_update, psa_aead_operation_t *, const uint8_t *, size_t,
+		uint8_t *, size_t, size_t *);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_abort, psa_aead_operation_t *);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_verify, psa_aead_operation_t *, uint8_t *, size_t, size_t *,
+		const uint8_t *, size_t);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_set_nonce, psa_aead_operation_t *, const uint8_t *, size_t);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_update_ad, psa_aead_operation_t *, const uint8_t *, size_t);
+FAKE_VALUE_FUNC(psa_status_t, psa_aead_decrypt_setup, psa_aead_operation_t *,
+		mbedtls_svc_key_id_t, psa_algorithm_t);
 
 static inline void mock_suit_crypto_reset(void)
 {
@@ -26,6 +35,12 @@ static inline void mock_suit_crypto_reset(void)
 	RESET_FAKE(psa_hash_abort);
 	RESET_FAKE(psa_hash_verify);
 	RESET_FAKE(psa_verify_message);
+	RESET_FAKE(psa_aead_update);
+	RESET_FAKE(psa_aead_abort);
+	RESET_FAKE(psa_aead_verify);
+	RESET_FAKE(psa_aead_set_nonce);
+	RESET_FAKE(psa_aead_update_ad);
+	RESET_FAKE(psa_aead_decrypt_setup);
 }
 
 #endif /* MOCK_SUIT_CRYPTO_H__ */

tests/subsys/suit/unit/mocks/include/mock_suit_mci.h

@@ -48,6 +48,8 @@ FAKE_VALUE_FUNC(int, suit_mci_manifest_parent_child_declaration_validate,
 FAKE_VALUE_FUNC(int, suit_mci_manifest_process_dependency_validate,
 		const suit_manifest_class_id_t *, const suit_manifest_class_id_t *);
 FAKE_VALUE_FUNC(int, suit_mci_init);
+FAKE_VALUE_FUNC(int, suit_mci_fw_encryption_key_id_validate, const suit_manifest_class_id_t *,
+		uint32_t);
 
 static inline void mock_suit_mci_reset(void)
 {
@@ -74,6 +76,7 @@ static inline void mock_suit_mci_reset(void)
 	RESET_FAKE(suit_mci_manifest_process_dependency_validate);
 	RESET_FAKE(suit_mci_manifest_parent_child_declaration_validate);
 	RESET_FAKE(suit_mci_init);
+	RESET_FAKE(suit_mci_fw_encryption_key_id_validate);
 }
 
 #endif /* MOCK_SUIT_MCI_H__ */

tests/subsys/suit/unit/suit_decrypt_filter/CMakeLists.txt

@@ -0,0 +1,20 @@
+#
+# Copyright (c) 2023 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+include(../cmake/test_template.cmake)
+
+project(suit_decrypt_filter)
+target_include_directories(testbinary PRIVATE
+    ${SUIT_SUBSYS_DIR}/stream/stream_filters/include
+    ${SUIT_SUBSYS_DIR}/utils/include/
+)
+
+target_sources(testbinary PRIVATE
+  src/main.c
+  ${SUIT_SUBSYS_DIR}/stream/stream_filters/src/suit_decrypt_filter.c
+)

tests/subsys/suit/unit/suit_decrypt_filter/Kconfig

@@ -0,0 +1,10 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+# Include and define MOCK_* Kconfigs
+rsource "../mocks/Kconfig"
+
+source "Kconfig.zephyr"

tests/subsys/suit/unit/suit_decrypt_filter/prj.conf

@@ -0,0 +1,16 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_MOCK_SUIT_PROCESSOR=y
+CONFIG_MOCK_SUIT_PLATFORM=y
+CONFIG_MOCK_DIGEST_SINK=y
+CONFIG_MOCK_GENERIC_ADDRESS_STREAMER=y
+CONFIG_MOCK_SUIT_UTILS=y
+CONFIG_MOCK_SUIT_MEMPTR_STORAGE=y
+CONFIG_MOCK_SUIT_CRYPTO=y
+CONFIG_MOCK_SUIT_MCI=y
+CONFIG_MOCK_SUIT_METADATA=y
+CONFIG_MOCK_SUIT_PLATFORM_INTERNAL=y