mbedtls: move entropy polling functions to a dedicated file

This commit just moves some code around. For sake of cleanliness
a new file is added to hold the entropy parsing functions
for Mbed TLS.

Signed-off-by: Valerio Setti <[email protected]>

Author: valeriosetti

modules/mbedtls/CMakeLists.txt

@@ -115,6 +115,7 @@ zephyr_interface_library_named(mbedTLS)
       ${ZEPHYR_CURRENT_MODULE_DIR}/library/version_features.c
       ${ZEPHYR_CURRENT_MODULE_DIR}/library/version.c
       zephyr_init.c
+      zephyr_entropy.c
     )
 
     zephyr_library_sources(${mbedtls_base_src})

modules/mbedtls/zephyr_entropy.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/random/random.h>
+#include <mbedtls/entropy.h>
+#include <psa/crypto.h>
+
+
+#if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR) || defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+static int get_random_data(uint8_t *output, size_t output_size, bool allow_non_cs)
+{
+	int ret = MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED;
+
+#if defined(CONFIG_CSPRNG_ENABLED)
+	ret = sys_csrand_get(output, output_size);
+	if (ret == 0) {
+		return 0;
+	}
+#endif /* CONFIG_CSPRNG_ENABLED */
+
+	if (allow_non_cs) {
+		sys_rand_get(output, output_size);
+		ret = 0;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR || CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+
+#if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR)
+int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len,
+			  size_t *olen)
+{
+	int ret;
+	uint16_t request_len = len > UINT16_MAX ? UINT16_MAX : len;
+
+	ARG_UNUSED(data);
+
+	if (output == NULL || olen == NULL || len == 0) {
+		return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+	}
+
+	ret = get_random_data(output, len, true);
+	if (ret < 0) {
+		return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+	}
+
+	*olen = request_len;
+
+	return 0;
+}
+#endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR */
+
+#if defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+psa_status_t mbedtls_psa_external_get_random(
+	mbedtls_psa_external_random_context_t *context,
+	uint8_t *output, size_t output_size, size_t *output_length)
+{
+	(void) context;
+	int ret;
+
+	ret = get_random_data(output, output_size,
+		IS_ENABLED(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG));
+	if (ret != 0) {
+		return PSA_ERROR_GENERIC_ERROR;
+	}
+
+	*output_length = output_size;
+
+	return PSA_SUCCESS;
+}
+#endif /* CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */

modules/mbedtls/zephyr_init.c

@@ -6,18 +6,15 @@
 
 /*
  * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2024 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <zephyr/init.h>
 #include <zephyr/app_memory/app_memdomain.h>
-#include <zephyr/drivers/entropy.h>
-#include <zephyr/random/random.h>
-#include <mbedtls/entropy.h>
 #include <mbedtls/platform_time.h>
 
-
 #include <mbedtls/debug.h>
 
 #if defined(CONFIG_MBEDTLS)
@@ -29,7 +26,7 @@
 #endif
 
 #if defined(CONFIG_MBEDTLS_ENABLE_HEAP) && \
-					defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
+	defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
 #include <mbedtls/memory_buffer_alloc.h>
 
 #if !defined(CONFIG_MBEDTLS_HEAP_SIZE)
@@ -83,68 +80,3 @@ mbedtls_ms_time_t mbedtls_ms_time(void)
 {
 	return (mbedtls_ms_time_t)k_uptime_get();
 }
-
-#if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR) || defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
-static int get_random_data(uint8_t *output, size_t output_size, bool allow_non_cs)
-{
-	int ret = MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED;
-
-#if defined(CONFIG_CSPRNG_ENABLED)
-	ret = sys_csrand_get(output, output_size);
-	if (ret == 0) {
-		return 0;
-	}
-#endif /* CONFIG_CSPRNG_ENABLED */
-
-	if (allow_non_cs) {
-		sys_rand_get(output, output_size);
-		ret = 0;
-	}
-
-	return ret;
-}
-#endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR || CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
-
-#if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR)
-int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len,
-			  size_t *olen)
-{
-	int ret;
-	uint16_t request_len = len > UINT16_MAX ? UINT16_MAX : len;
-
-	ARG_UNUSED(data);
-
-	if (output == NULL || olen == NULL || len == 0) {
-		return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
-	}
-
-	ret = get_random_data(output, len, true);
-	if (ret < 0) {
-		return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
-	}
-
-	*olen = request_len;
-
-	return 0;
-}
-#endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR */
-
-#if defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
-psa_status_t mbedtls_psa_external_get_random(
-	mbedtls_psa_external_random_context_t *context,
-	uint8_t *output, size_t output_size, size_t *output_length)
-{
-	(void) context;
-	int ret;
-
-	ret = get_random_data(output, output_size,
-		IS_ENABLED(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG));
-	if (ret != 0) {
-		return PSA_ERROR_GENERIC_ERROR;
-	}
-
-	*output_length = output_size;
-
-	return PSA_SUCCESS;
-}
-#endif /* CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */