tests: Prevent rare failure of gcry_pk_decrypt test.

* tests/basic.c (check_pubkey_crypt): Add special mode 1.
(main): Add option --loop.

--

This failure has been reported by Jussi Kivilinna.  The new loop
option was needed to track that down.  It took me up to 100 iterations
to trigger the bug.  With the fix applied I am currently at 1000
iteration with no problems.  Command line to evoke the problem was:

  ./basic --pubkey --verbose --loop -1 --die

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 59 insertions, 16 deletions

diff --git a/tests/basic.c b/tests/basic.c
index 789297f1..6ffc3f5a 100644
--- a/tests/basic.c
+++ b/tests/basic.c
@@ -5302,6 +5302,7 @@ check_pubkey_crypt (int n, gcry_sexp_t skey, gcry_sexp_t pkey, int algo)
     int unpadded;
     int encrypt_expected_rc;
     int decrypt_expected_rc;
+    int special;
   } datas[] =
     {
       {	GCRY_PK_RSA,
@@ -5385,14 +5386,14 @@ check_pubkey_crypt (int n, gcry_sexp_t skey, gcry_sexp_t pkey, int algo)
 	"(flags oaep)",
 	1,
 	0,
-	GPG_ERR_ENCODING_PROBLEM },
+	GPG_ERR_ENCODING_PROBLEM, 1 },
       { GCRY_PK_RSA,
         "(data\n (flags oaep)\n"
 	" (value #11223344556677889900AA#))\n",
 	"(flags pkcs1)",
 	1,
 	0,
-	GPG_ERR_ENCODING_PROBLEM },
+	GPG_ERR_ENCODING_PROBLEM, 1 },
       {	0,
         "(data\n (flags pss)\n"
 	" (value #11223344556677889900AA#))\n",
@@ -5424,6 +5425,8 @@ check_pubkey_crypt (int n, gcry_sexp_t skey, gcry_sexp_t pkey, int algo)
 
       if (!rc)
 	{
+          int expect_mismatch = 0;
+
 	  /* Insert decoding hint to CIPH. */
 	  if (datas[dataidx].hint)
 	    {
@@ -5460,7 +5463,16 @@ check_pubkey_crypt (int n, gcry_sexp_t skey, gcry_sexp_t pkey, int algo)
 	      ciph = list;
 	    }
 	  rc = gcry_pk_decrypt (&plain, ciph, skey);
-	  if (gcry_err_code (rc) != datas[dataidx].decrypt_expected_rc)
+          if (!rc && datas[dataidx].special == 1)
+            {
+              /* It may happen that OAEP formatted data which is
+                 decrypted as pkcs#1 data returns a valid pkcs#1
+                 frame.  However, the returned value will not be
+                 identical - thus we expect a mismatch and test further on
+                 whether this mismatch actually happened.  */
+              expect_mismatch = 1;
+            }
+	  else if (gcry_err_code (rc) != datas[dataidx].decrypt_expected_rc)
             {
               if (verbose)
                 {
@@ -5488,8 +5500,19 @@ check_pubkey_crypt (int n, gcry_sexp_t skey, gcry_sexp_t pkey, int algo)
 		  s1 = gcry_sexp_nth_data (p1, 1, &n1);
 		  s2 = gcry_sexp_nth_data (p2, 1, &n2);
 		  if (n1 != n2 || memcmp (s1, s2, n1))
-		    fail ("gcry_pk_encrypt/gcry_pk_decrypt do not roundtrip\n");
+                    {
+                      if (expect_mismatch)
+                        expect_mismatch = 0;
+                      else
+                        fail ("gcry_pk_encrypt/gcry_pk_decrypt "
+                              "do not roundtrip\n");
+                    }
 		}
+
+              if (expect_mismatch)
+                fail ("gcry_pk_encrypt/gcry_pk_decrypt "
+                      "expected mismatch did not happen\n");
+
 	      gcry_sexp_release (p1);
 	      gcry_sexp_release (p2);
 	    }
@@ -5925,6 +5948,8 @@ main (int argc, char **argv)
   int use_fips = 0;
   int selftest_only = 0;
   int pubkey_only = 0;
+  int loop = 0;
+  unsigned int loopcount = 0;
 
   if (argc)
     { argc--; argv++; }
@@ -5961,7 +5986,6 @@ main (int argc, char **argv)
       else if (!strcmp (*argv, "--pubkey"))
         {
           pubkey_only = 1;
-          verbose += 2;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--die"))
@@ -5969,6 +5993,15 @@ main (int argc, char **argv)
           die_on_error = 1;
           argc--; argv++;
         }
+      else if (!strcmp (*argv, "--loop"))
+        {
+          argc--; argv++;
+          if (argc)
+            {
+              loop = atoi (*argv);
+              argc--; argv++;
+            }
+        }
     }
 
   gcry_control (GCRYCTL_SET_VERBOSITY, (int)verbose);
@@ -5996,19 +6029,29 @@ main (int argc, char **argv)
   /* No valuable keys are create, so we can speed up our RNG. */
   gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
 
-  if (pubkey_only)
-    check_pubkey ();
-  else if (!selftest_only)
+  do
     {
-      check_ciphers ();
-      check_cipher_modes ();
-      check_bulk_cipher_modes ();
-      check_digests ();
-      check_hmac ();
-      check_mac ();
-      check_pubkey ();
+      if (pubkey_only)
+        check_pubkey ();
+      else if (!selftest_only)
+        {
+          check_ciphers ();
+          check_cipher_modes ();
+          check_bulk_cipher_modes ();
+          check_digests ();
+          check_hmac ();
+          check_mac ();
+          check_pubkey ();
+        }
+      loopcount++;
+      if (loop)
+        {
+          fprintf (stderr, "Test iteration %u completed.\n", loopcount);
+          if (loop != -1)
+            loop--;
+        }
     }
-
+  while (loop);
 
   if (in_fips_mode && !selftest_only)
     {