Add tests for Issue #8687

Signed-off-by: Jonathan Winzig <jwinzig@hilscher.com>
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index b59fd48..7690dc0 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -752,3 +752,24 @@
     USE_PSA_DONE();
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void x509_set_extension_length_check(int val_len)
+{
+    int ret = 0;
+
+    mbedtls_x509write_csr ctx;
+    mbedtls_x509write_csr_init(&ctx);
+
+    unsigned char buf[EXT_KEY_USAGE_TMP_BUF_MAX_LENGTH] = { 0 };
+    unsigned char *p = buf + sizeof(buf);
+
+    ret = mbedtls_x509_set_extension(&(ctx.MBEDTLS_PRIVATE(extensions)),
+                                     MBEDTLS_OID_EXTENDED_KEY_USAGE,
+                                     MBEDTLS_OID_SIZE(MBEDTLS_OID_EXTENDED_KEY_USAGE),
+                                     0,
+                                     p,
+                                     val_len);
+    TEST_ASSERT(ret == MBEDTLS_ERR_X509_BAD_INPUT_DATA || ret == MBEDTLS_ERR_X509_ALLOC_FAILED);
+}
+/* END_CASE */