Document and test that memcpy_if may have src == dest
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 ac4dd7a..2fafa94 100644
--- a/tests/suites/test_suite_constant_time.function
+++ b/tests/suites/test_suite_constant_time.function
@@ -224,6 +224,7 @@
ASSERT_ALLOC(result, size + offset);
ASSERT_ALLOC(expected, size + offset);
+ /* Apply offset to result only */
for (int i = 0; i < size + offset; i++) {
src[i] = 1;
result[i] = 0xff;
@@ -243,6 +244,8 @@
ASSERT_COMPARE(expected, size, result + offset, size);
+
+ /* Apply offset to src only */
for (int i = 0; i < size + offset; i++) {
src[i] = 1;
result[i] = 0xff;
@@ -261,6 +264,8 @@
ASSERT_COMPARE(expected, size, result, size);
+
+ /* Apply offset to src and src2 */
for (int i = 0; i < size + offset; i++) {
src[i] = 1;
src2[i] = 2;
@@ -281,6 +286,25 @@
TEST_CF_PUBLIC(result, size + offset);
ASSERT_COMPARE(expected, size, result, size);
+
+
+ /* result == src == dest */
+ for (int i = 0; i < size + offset; i++) {
+ src[i] = 2;
+ expected[i] = 2;
+ }
+
+ TEST_CF_SECRET(&secret_eq, sizeof(secret_eq));
+ TEST_CF_SECRET(src, size + offset);
+ TEST_CF_SECRET(result, size + offset);
+
+ mbedtls_ct_memcpy_if(mbedtls_ct_bool(secret_eq), src + offset, src + offset, src + offset, size);
+
+ TEST_CF_PUBLIC(&secret_eq, sizeof(secret_eq));
+ TEST_CF_PUBLIC(src, size + offset);
+ TEST_CF_PUBLIC(result, size + offset);
+
+ ASSERT_COMPARE(expected, size, src + offset, size);
exit:
mbedtls_free(src);
mbedtls_free(src2);