[nrf fromlist] modules: mbedtls: Expose MBEDTLS_PLATFORM_NO_STD_FUNCTIONS

The commit adds Kconfig options that allows users to select
 - MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
 - MBEDTLS_PLATFORM_SNPRINTF_ALT
allowing Mbed TLS to use own definitions of STD functions.

Upstream PR #: 87135

Signed-off-by: Dominik Ermel <[email protected]>

Author: de-nordic

modules/mbedtls/Kconfig.tls-generic

@@ -406,6 +406,22 @@ config MBEDTLS_GENPRIME_ENABLED
 config MBEDTLS_ASN1_PARSE_C
 	bool "Support for ASN1 parser functions"
 
+config MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+	bool "Use Mbed TLS provided standard functions"
+	help
+	  This replaces, within Mbed TLS, usage of functions like alloc, calloc,
+	  free, snprintf, or printf with MmbedTLS specific implantations.
+	  This option may be useful if system is compiled in without some
+	  of these functions and Mbed TLS needs them internally.
+
+if MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+
+config MBEDTLS_PLATFORM_SNPRINTF_ALT
+	bool "Use Mbed TLS provided sprintf"
+	help
+
+endif # MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+
 config MBEDTLS_PEM_CERTIFICATE_FORMAT
 	bool "Support for PEM certificate format"
 	help

modules/mbedtls/configs/config-tls-generic.h

@@ -23,6 +23,13 @@
 #define MBEDTLS_PLATFORM_ZEROIZE_ALT
 #endif
 
+#if defined(CONFIG_MBEDTLS_PLATFORM_NO_STD_FUNCTIONS)
+#define MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+#if defined(CONFIG_MBEDTLS_PLATFORM_SNPRINTF_ALT)
+#define MBEDTLS_PLATFORM_SNPRINTF_ALT
+#endif /* defined(MBEDTLS_PLATFORM_SNPRINTF_ALT) */
+#endif /* defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS) */
+
 #if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR)
 #define MBEDTLS_ENTROPY_HARDWARE_ALT
 #else