Delete valgrind magic in pss-test.

* testsuite/pss-test.c: Delete magic to let valgrind to check if
pss_encode_mgf1 is side-channel silent with respect to the salt
and digest inputs. It turns out that the most significant bits of
the padded bignum, and hence its size, depends on these inputs.
Which results in a data-dependent branch in the normalization code
of at the end of gmp's mpz_import.

diff --git a/ChangeLog b/ChangeLog
index 369712bdbe2239940909721765d6d0c73da9a2db..ba6a1b93a2bcfa3f8f870829e998a07d3ee54ee1 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2017-04-09  Niels Möller  <nisse@lysator.liu.se>
+
+       * testsuite/pss-test.c: Delete magic to let valgrind to check if
+       pss_encode_mgf1 is side-channel silent with respect to the salt
+       and digest inputs. It turns out that the most significant bits of
+       the padded bignum, and hence its size, depends on these inputs.
+       Which results in a data-dependent branch in the normalization code
+       of at the end of gmp's mpz_import.
+
 2017-04-04  Niels Möller  <nisse@lysator.liu.se>
 
        * pss.c (pss_verify_mgf1): Use const for input mpz_t argument.

diff --git a/testsuite/pss-test.c b/testsuite/pss-test.c
index 81226554c5bba4c696e892b43ca611c36e089377..f6ba697c6773d6790537cae8087af2b17402c211 100644 (file)
--- a/testsuite/pss-test.c
+++ b/testsuite/pss-test.c
@@ -2,38 +2,6 @@
 
 #include "pss.h"
 
-#if HAVE_VALGRIND_MEMCHECK_H
-# include <valgrind/memcheck.h>
-
-static void
-test_unmark_mpz(mpz_t m)
-{
-  VALGRIND_MAKE_MEM_DEFINED (m, sizeof(*m));
-  VALGRIND_MAKE_MEM_DEFINED (&m->_mp_d, sizeof(mp_limb_t) * mpz_size(m));
-}
-
-static int
-pss_encode_mgf1_for_test(mpz_t m, size_t bits,
-                        const struct nettle_hash *hash,
-                        size_t salt_length, const uint8_t *salt,
-                        const uint8_t *digest)
-{
-  int res;
-
-  /* Makes valgrind trigger on any branches depending on the input
-     data. */
-  VALGRIND_MAKE_MEM_UNDEFINED (salt, salt_length);
-  VALGRIND_MAKE_MEM_UNDEFINED (digest, hash->digest_size);
-
-  res = pss_encode_mgf1 (m, bits, hash, salt_length, salt, digest);
-  VALGRIND_MAKE_MEM_DEFINED (&res, sizeof(res));
-  test_unmark_mpz (m);
-  return res;
-}
-#else
-#define pss_encode_mgf1_for_test pss_encode_mgf1
-#endif
-
 void
 test_main(void)
 {