1 files changed, 45 insertions, 0 deletions
diff --git a/tests/src/fake_external_rng_for_test.c b/tests/src/fake_external_rng_for_test.c
new file mode 100644
index 00000000000..c0bfde51aa0
--- /dev/null
+++ b/tests/src/fake_external_rng_for_test.c
@@ -0,0 +1,45 @@
+/** \file fake_external_rng_for_test.c
+ *
+ * \brief Helper functions to test PSA crypto functionality.
+ */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#include <test/fake_external_rng_for_test.h>
+
+#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+#include <test/random.h>
+#include <psa/crypto.h>
+
+static int test_insecure_external_rng_enabled = 0;
+
+void mbedtls_test_enable_insecure_external_rng(void)
+{
+    test_insecure_external_rng_enabled = 1;
+}
+
+void mbedtls_test_disable_insecure_external_rng(void)
+{
+    test_insecure_external_rng_enabled = 0;
+}
+
+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;
+
+    if (!test_insecure_external_rng_enabled) {
+        return PSA_ERROR_INSUFFICIENT_ENTROPY;
+    }
+
+    /* This implementation is for test purposes only!
+     * Use the libc non-cryptographic random generator. */
+    mbedtls_test_rnd_std_rand(NULL, output, output_size);
+    *output_length = output_size;
+    return PSA_SUCCESS;
+}
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */