Deleted duplicate function point_zero_p. Support n == 0 in test_ecc_mul_h instead.

ChangeLog

 2014-09-17  Niels Möller  <nisse@lysator.liu.se>
 
+	* testsuite/testutils.c (ecc_curves): Include curve25519 in list.
+	(test_ecc_mul_a): Include reference points for curve25519 (with
+	Edwards coordinates). Allow n == 0 and n == 1, comparing to zero
+	and the generator, respectively.
+	* testsuite/ecc-add-test.c (point_zero_p): Deleted function.
+	(test_main): Replace calls to point_zero_p by calls to
+	test_ecc_mul_h with n == 0.
+	* testsuite/ecc-dup-test.c: Likewise.
+
 	* testsuite/ecc-modinv-test.c (mpn_zero_p): Moved function, to...
 	* testsuite/testutils.c (mpn_zero_p): New location. Also make
 	non-static.
 
-	* testsuite/testutils.c (ecc_curves): Include curve25519 in list.
-	(test_ecc_mul_a): Include reference points for curve25519 (with
-	Edwards coordinates). Allow n == 1, and compare to the generator.
-
 	* testsuite/ecdsa-keygen-test.c (ecc_valid_p): Add special case
 	for curve25519.
 

testsuite/ecc-add-test.c

 #include "testutils.h"
 
-/* For curve25519 (or other edwards curves) only. */
-static int
-point_zero_p (const struct ecc_curve *ecc, const mp_limb_t *p)
-{  
-  mp_limb_t *d;
-  int ret;
-  mp_size_t i;
-
-  /* Zero point has Y = Z (mod p), or y = Y/Z = 1, which also implies
-     x == 0. */
-  d = xalloc_limbs (ecc->size);
-  ecc_modp_sub (ecc, d, p + ecc->size, p + 2*ecc->size);
-  while (mpn_cmp (d, ecc->p, ecc->size) >= 0)
-    mpn_sub_n (d, d, ecc->p, ecc->size);
-
-  for (i = 0, ret = 1; i < ecc->size; i++)
-    if (d[i])
-      {
-	ret = 0;
-	break;
-      }
-  
-  free (d);
-  return ret;
-}
-
 void
 test_main (void)
 {
@@ -50,12 +24,10 @@ test_main (void)
 	  ecc_a_to_j (ecc, g, ecc->g);
 
 	  ecc_add_ehh (ecc, p, z, z, scratch);
-	  if (!point_zero_p (ecc, p))
-	    die ("dup of zero point failed.\n");
+	  test_ecc_mul_h (i, 0, p);
 
 	  ecc_add_eh (ecc, p, z, z, scratch);
-	  if (!point_zero_p (ecc, p))
-	    die ("dup of zero point failed.\n");
+	  test_ecc_mul_h (i, 0, p);
 
 	  ecc_add_ehh (ecc, p, g, p, scratch);
 	  test_ecc_mul_h (i, 1, p);

testsuite/ecc-dup-test.c

 #include "testutils.h"
 
-/* For curve25519 (or other edwards curves) only. */
-static int
-point_zero_p (const struct ecc_curve *ecc, const mp_limb_t *p)
-{  
-  mp_limb_t *d;
-  int ret;
-  mp_size_t i;
-
-  /* Zero point has Y = Z (mod p), or y = Y/Z = 1, which also implies
-     x == 0. */
-  d = xalloc_limbs (ecc->size);
-  ecc_modp_sub (ecc, d, p + ecc->size, p + 2*ecc->size);
-  while (mpn_cmp (d, ecc->p, ecc->size) >= 0)
-    mpn_sub_n (d, d, ecc->p, ecc->size);
-
-  for (i = 0, ret = 1; i < ecc->size; i++)
-    if (d[i])
-      {
-	ret = 0;
-	break;
-      }
-  
-  free (d);
-  return ret;
-}
-
 void
 test_main (void)
 {
@@ -48,8 +22,7 @@ test_main (void)
 	  ecc_a_to_j (ecc, g, ecc->g);
 
 	  ecc_dup_eh (ecc, p, z, scratch);
-	  if (!point_zero_p (ecc, p))
-	    die ("dup of zero point failed.\n");
+	  test_ecc_mul_h (i, 0, p);
 
 	  ecc_dup_eh (ecc, p, g, scratch);
 	  test_ecc_mul_h (i, 2, p);

testsuite/testutils.c

@@ -1387,8 +1387,26 @@ test_ecc_mul_a (unsigned curve, unsigned n, const mp_limb_t *p)
     }
   };
   assert (curve < 6);
-  assert (n >= 1 && n <= 4);
-  if (n == 1)
+  assert (n <= 4);
+  if (n == 0)
+    {
+      /* Makes sense for curve25519 only */
+      const struct ecc_curve *ecc = ecc_curves[curve];
+      assert (ecc->bit_size == 255);
+      if (!mpn_zero_p (p, ecc->size)
+	  || mpn_cmp (p + ecc->size, ecc->unit, ecc->size) != 0)
+	{
+	  fprintf (stderr, "Incorrect point (expected (0, 1))!\n"
+		   "got: x = ");
+	  write_mpn (stderr, 16, p, ecc->size);
+	  fprintf (stderr, "\n"
+		   "     y = ");
+	  write_mpn (stderr, 16, p + ecc->size, ecc->size);
+	  fprintf (stderr, "\n");
+	  abort();
+	}
+    }
+  else if (n == 1)
     {
       const struct ecc_curve *ecc = ecc_curves[curve];
       if (mpn_cmp (p, ecc->g, 2*ecc->size) != 0)