mbedtls/tests/suites/test_suite_constant_time.function

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/* BEGIN_HEADER */
/** \file test_suite_constant_time.function
*
* Functional testing of functions in the constant_time module.
*
* The tests are instrumented with #TEST_CF_SECRET and #TEST_CF_PUBLIC
* (see tests/include/test/constant_flow.h) so that running the tests
* under MSan or Valgrind will detect a non-constant-time implementation.
*/
#include <mbedtls/constant_time.h>
#include <constant_time_internal.h>
#include <constant_time_invasive.h>
#include <test/constant_flow.h>
/* END_HEADER */
/* BEGIN_CASE */
void mbedtls_ct_memcmp_null()
{
uint32_t x;
TEST_ASSERT(mbedtls_ct_memcmp(&x, NULL, 0) == 0);
TEST_ASSERT(mbedtls_ct_memcmp(NULL, &x, 0) == 0);
TEST_ASSERT(mbedtls_ct_memcmp(NULL, NULL, 0) == 0);
}
/* END_CASE */
/* BEGIN_CASE */
void mbedtls_ct_memcmp(int same, int size, int offset)
{
uint8_t *a = NULL, *b = NULL;
ASSERT_ALLOC(a, size + offset);
ASSERT_ALLOC(b, size + offset);
TEST_CF_SECRET(a + offset, size);
TEST_CF_SECRET(b + offset, size);
/* Construct data that matches, if same == -1, otherwise
* same gives the number of bytes (after the initial offset)
* that will match; after that it will differ.
*/
for (int i = 0; i < size + offset; i++) {
a[i] = i & 0xff;
if (same == -1 || (i - offset) < same) {
b[i] = a[i];
} else {
b[i] = (i + 1) & 0xff;
}
}
int reference = memcmp(a + offset, b + offset, size);
int actual = mbedtls_ct_memcmp(a + offset, b + offset, size);
TEST_CF_PUBLIC(a + offset, size);
TEST_CF_PUBLIC(b + offset, size);
if (same == -1 || same >= size) {
TEST_ASSERT(reference == 0);
TEST_ASSERT(actual == 0);
} else {
TEST_ASSERT(reference != 0);
TEST_ASSERT(actual != 0);
}
exit:
mbedtls_free(a);
mbedtls_free(b);
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SSL_SOME_SUITES_USE_MAC */
void mbedtls_ct_memcpy_if_eq(int eq, int size, int offset)
{
uint8_t *src = NULL, *result = NULL, *expected = NULL;
ASSERT_ALLOC(src, size + offset);
ASSERT_ALLOC(result, size + offset);
ASSERT_ALLOC(expected, size + offset);
for (int i = 0; i < size + offset; i++) {
src[i] = 1;
result[i] = 0xff;
expected[i] = eq ? 1 : 0xff;
}
mbedtls_ct_memcpy_if_eq(result + offset, src, size, eq, 1);
ASSERT_COMPARE(expected, size, result + offset, size);
for (int i = 0; i < size + offset; i++) {
src[i] = 1;
result[i] = 0xff;
expected[i] = eq ? 1 : 0xff;
}
mbedtls_ct_memcpy_if_eq(result, src + offset, size, eq, 1);
ASSERT_COMPARE(expected, size, result, size);
exit:
mbedtls_free(src);
mbedtls_free(result);
mbedtls_free(expected);
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC:MBEDTLS_TEST_HOOKS */
void ssl_cf_memcpy_offset(int offset_min, int offset_max, int len)
{
unsigned char *dst = NULL;
unsigned char *src = NULL;
size_t src_len = offset_max + len;
size_t secret;
ASSERT_ALLOC(dst, len);
ASSERT_ALLOC(src, src_len);
/* Fill src in a way that we can detect if we copied the right bytes */
mbedtls_test_rnd_std_rand(NULL, src, src_len);
for (secret = offset_min; secret <= (size_t) offset_max; secret++) {
mbedtls_test_set_step((int) secret);
TEST_CF_SECRET(&secret, sizeof(secret));
mbedtls_ct_memcpy_offset(dst, src, secret,
offset_min, offset_max, len);
TEST_CF_PUBLIC(&secret, sizeof(secret));
TEST_CF_PUBLIC(dst, len);
ASSERT_COMPARE(dst, len, src + secret, len);
}
exit:
mbedtls_free(dst);
mbedtls_free(src);
}
/* END_CASE */