Don't call psa_crypto_init in unit tests when not required for TLS 1.3

For backward compatibility with Mbed TLS <=3.5.x, applications must be able
to make a TLS connection with a peer that supports both TLS 1.2 and TLS 1.3,
regardless of whether they call psa_crypto_init(). Since Mbed TLS 3.6.0,
we enable TLS 1.3 in the default configuration, so we must take care of
calling psa_crypto_init() if needed. This is a change from TLS 1.3 in
previous versions, where enabling MBEDTLS_SSL_PROTO_TLS1_3 was a user
choice and could have additional requirement.

This commit changes our unit tests to validate that the library
does not have the compatibility-breaking requirement.

Signed-off-by: Gilles Peskine <[email protected]>

tests/include/test/psa_crypto_helpers.h

@@ -334,9 +334,18 @@ uint64_t mbedtls_test_parse_binary_string(data_t *bin_string);
  * This is like #PSA_DONE except it does nothing under the same conditions as
  * #USE_PSA_INIT.
  */
-#if defined(MBEDTLS_USE_PSA_CRYPTO) || defined(MBEDTLS_SSL_PROTO_TLS1_3)
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
 #define USE_PSA_INIT() PSA_INIT()
 #define USE_PSA_DONE() PSA_DONE()
+#elif defined(MBEDTLS_SSL_PROTO_TLS1_3)
+/* TLS 1.3 must work without having called psa_crypto_init(), for backward
+ * compatibility with Mbed TLS <= 3.5 when connecting with a peer that
+ * supports both TLS 1.2 and TLS 1.3. See mbedtls_ssl_tls13_crypto_init()
+ * and https://github.com/Mbed-TLS/mbedtls/issues/9072 . */
+#define USE_PSA_INIT() ((void) 0)
+/* TLS 1.3 may have initialized the PSA subsystem. Shut it down cleanly,
+ * otherwise Asan and Valgrind would notice a resource leak. */
+#define USE_PSA_DONE() PSA_DONE()
 #else /* MBEDTLS_USE_PSA_CRYPTO || MBEDTLS_SSL_PROTO_TLS1_3 */
 /* Define empty macros so that we can use them in the preamble and teardown
  * of every test function that uses PSA conditionally based on
@@ -408,13 +417,12 @@ uint64_t mbedtls_test_parse_binary_string(data_t *bin_string);
  * This is like #PSA_DONE except it does nothing under the same conditions as
  * #MD_OR_USE_PSA_INIT.
  */
-#if defined(MBEDTLS_MD_SOME_PSA) || \
-    defined(MBEDTLS_USE_PSA_CRYPTO) || defined(MBEDTLS_SSL_PROTO_TLS1_3)
+#if defined(MBEDTLS_MD_SOME_PSA)
 #define MD_OR_USE_PSA_INIT()   PSA_INIT()
 #define MD_OR_USE_PSA_DONE()   PSA_DONE()
 #else
-#define MD_OR_USE_PSA_INIT() ((void) 0)
-#define MD_OR_USE_PSA_DONE() ((void) 0)
+#define MD_OR_USE_PSA_INIT()   USE_PSA_INIT()
+#define MD_OR_USE_PSA_DONE()   USE_PSA_DONE()
 #endif
 
 /** \def AES_PSA_INIT