Beware of print-read inconsistency when serializing GURLs.

content/public/common/common_param_traits.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/public/common/common_param_traits.h"
 
 #include "content/public/common/content_constants.h"
 #include "content/public/common/referrer.h"
 #include "net/base/host_port_pair.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ skipping 32 matching lines @@
     return true;
   }
 };
 
 }  // namespace
 
 namespace IPC {
 
 void ParamTraits<GURL>::Write(Message* m, const GURL& p) {
   DCHECK(p.possibly_invalid_spec().length() <= content::kMaxURLChars);
+
+  // Beware of print-parse inconsistency which would change an invalid
+  // URL into a valid one. Ideally, the message would contain this flag
+  // so that the read side could make the check, but performing it here
+  // avoids changing the on-the-wire representation of such a fundamental
+  // type as GURL. See https://crbug.com/166486 for additional work in
+  // this area.
+  if (!p.is_valid()) {
+    GURL reconstructed_url(p.possibly_invalid_spec());
+    if (reconstructed_url.is_valid()) {
+      DLOG(WARNING) << "GURL string " << p.possibly_invalid_spec()
+                    << " (marked invalid) but parsed as valid.";
+      m->WriteString(std::string());
+      return;
+    }
+  }
+
   m->WriteString(p.possibly_invalid_spec());
   // TODO(brettw) bug 684583: Add encoding for query params.
 }
 
 bool ParamTraits<GURL>::Read(const Message* m, PickleIterator* iter, GURL* p) {
   std::string s;
   if (!m->ReadString(iter, &s) || s.length() > content::kMaxURLChars) {
     *p = GURL();
     return false;
   }
@@ skipping 242 matching lines @@
 #undef CONTENT_PUBLIC_COMMON_COMMON_PARAM_TRAITS_MACROS_H_
 #include "content/public/common/common_param_traits_macros.h"
 }  // namespace IPC
 
 // Generate param traits log methods.
 #include "ipc/param_traits_log_macros.h"
 namespace IPC {
 #undef CONTENT_PUBLIC_COMMON_COMMON_PARAM_TRAITS_MACROS_H_
 #include "content/public/common/common_param_traits_macros.h"
 }  // namespace IPC