Rewrite non-temporal instructions

src/trusted/validator_ragel/dfa_validate_32.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* Implement the Validator API for the x86-32 architecture. */
 #include <errno.h>
 #include <string.h>
 
@@ skipping 22 matching lines @@
     uint32_t flags,
     int readonly_text,
     const NaClCPUFeatures *f,
     const struct NaClValidationMetadata *metadata,
     struct NaClValidationCache *cache) {
   /* TODO(jfb) Use a safe cast here. */
   NaClCPUFeaturesX86 *cpu_features = (NaClCPUFeaturesX86 *) f;
   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)
     return NaClValidationFailedNotImplemented;
   if (!NaClArchSupportedX86(cpu_features))
     return NaClValidationFailedCpuNotSupported;
   if (size & kBundleMask)
     return NaClValidationFailed;
 
   /*
@@ skipping 14 matching lines @@
   }
 
   if (readonly_text) {
     if (ValidateChunkIA32(data, size, 0 /*options*/, cpu_features,
                           NaClDfaProcessValidationError,
                           NULL))
       status = NaClValidationSucceeded;
   } else {
     if (ValidateChunkIA32(data, size, 0 /*options*/, cpu_features,
                           NaClDfaStubOutUnsupportedInstruction,
-                          &callback_data))
-      status = NaClValidationSucceeded;
+                          &callback_data)) {
+      /* If code is rewritten, revalidate. */
+      if (callback_data.did_rewrite == 1) {
+        reval_result = ValidateChunkIA32(data, size, 0 /*options*/,
+                                         cpu_features,
+                                         NaClDfaStubOutUnsupportedInstruction,
+                                         &reval_callback_data);
+        if (reval_result && reval_callback_data.did_rewrite == 0)
+          status = NaClValidationSucceeded;
+      } else {
+        status = NaClValidationSucceeded;
+      }
+    }
   }
+
   if (status != NaClValidationSucceeded && errno == ENOMEM)
     status = NaClValidationFailedOutOfMemory;
 
   /* Cache the result if validation succeeded and the code was not modified. */
   if (query != NULL) {
     if (status == NaClValidationSucceeded && callback_data.did_rewrite == 0)
       cache->SetKnownToValidate(query);
     cache->DestroyQuery(query);
   }
 
@@ skipping 272 matching lines @@
   sizeof(NaClCPUFeaturesX86),
   NaClSetAllCPUFeaturesX86,
   NaClGetCurrentCPUFeaturesX86,
   NaClFixCPUFeaturesX86,
   IsOnInstBoundary_x86_32,
 };
 
 const struct NaClValidatorInterface *NaClDfaValidatorCreate_x86_32(void) {
   return &validator;
 }