Add single-bit difference tests
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/suites/test_suite_constant_time.function b/tests/suites/test_suite_constant_time.function
index 0e2cfdc..2424064 100644
--- a/tests/suites/test_suite_constant_time.function
+++ b/tests/suites/test_suite_constant_time.function
@@ -173,6 +173,47 @@
/* END_CASE */
/* BEGIN_CASE */
+void mbedtls_ct_memcmp_single_bit_diff()
+{
+ uint8_t *a = NULL, *b = NULL;
+ size_t size = 32;
+ TEST_CALLOC(a, size);
+ TEST_CALLOC(b, size);
+
+ TEST_CF_SECRET(a, size);
+ TEST_CF_SECRET(b, size);
+ int result = mbedtls_ct_memcmp(a, b, size);
+ TEST_CF_PUBLIC(a, size);
+ TEST_CF_PUBLIC(b, size);
+
+ TEST_EQUAL(result, 0);
+
+ for (size_t offset = 0; offset < size; offset++) {
+ for (size_t bit_offset = 0; bit_offset < 8; bit_offset++) {
+ /* Set a single bit to be different at given offset, to test that we
+ detect single-bit differences */
+ a[offset] = 1 << bit_offset;
+
+ TEST_CF_SECRET(a, size);
+ TEST_CF_SECRET(b, size);
+ result = mbedtls_ct_memcmp(a, b, size);
+ TEST_CF_PUBLIC(a, size);
+ TEST_CF_PUBLIC(b, size);
+
+ TEST_ASSERT(result != 0);
+
+ a[offset] = 0;
+ }
+ }
+
+
+exit:
+ mbedtls_free(a);
+ mbedtls_free(b);
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
void mbedtls_ct_memcmp(int same, int size, int offset)
{
uint8_t *a = NULL, *b = NULL;