Rewrite non-temporal instructions

src/trusted/validator_ragel/dfa_validate_64.c

Index: src/trusted/validator_ragel/dfa_validate_64.c
diff --git a/src/trusted/validator_ragel/dfa_validate_64.c b/src/trusted/validator_ragel/dfa_validate_64.c
index f91d36fe95be581edacec83c3c3a303e2dec2f6e..87013d67591cffa176fa03ff789e45e1cf1029d2 100644
--- a/src/trusted/validator_ragel/dfa_validate_64.c
+++ b/src/trusted/validator_ragel/dfa_validate_64.c
@@ -40,8 +40,14 @@ static NaClValidationStatus ApplyDfaValidator_x86_64(
   enum NaClValidationStatus status = NaClValidationFailed;
   void *query = NULL;
   struct StubOutCallbackData callback_data;
+  /* For revalidation */
+  struct StubOutCallbackData reval_callback_data;
+  Bool reval_result = FALSE;
+
   callback_data.flags = flags;
   callback_data.did_rewrite = 0;
+  reval_callback_data.flags = flags;
+  reval_callback_data.did_rewrite = 0;
   UNREFERENCED_PARAMETER(guest_addr);
 
   if (stubout_mode)
@@ -76,8 +82,18 @@ static NaClValidationStatus ApplyDfaValidator_x86_64(
   } else {
     if (ValidateChunkAMD64(data, size, 0 /*options*/, cpu_features,
                            NaClDfaStubOutUnsupportedInstruction,
-                           &callback_data))
+                           &callback_data)) {
+      /* If code is rewritten, revalidate. */
+      if (callback_data.did_rewrite == 1) {
+        reval_result = ValidateChunkAMD64(data, size, 0 /*options*/,
+                                          cpu_features,
+                                          NaClDfaStubOutUnsupportedInstruction,
+                                          &reval_callback_data);
+        CHECK(reval_result);
+        CHECK(reval_callback_data.did_rewrite == 0);

[bradn, 2015/08/04 22:03:30]

This should return Failure instead of being a check.

[ruiq, 2015/08/05 20:11:02]

Done.

+      }
       status = NaClValidationSucceeded;
+    }
   }
 
   if (status != NaClValidationSucceeded && errno == ENOMEM)