Fixes a crash when xdg_mime library is unable to handle a long file path....

net/base/mime_util.cc

 // Copyright (c) 2010 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 <map>
 #include <string>
 
 #include "net/base/mime_util.h"
 #include "net/base/platform_mime_util.h"
 
@@ skipping 120 matching lines @@
       if (!*extensions)
         break;
       extensions += 1;  // skip over comma
     }
   }
   return NULL;
 }
 
 bool MimeUtil::GetMimeTypeFromExtension(const FilePath::StringType& ext,
                                         string* result) const {
+  // Fixes a crash when xdg_mime library is unable to handle a long file path.
+  const unsigned kMaxFilePathSize = 65536;
+  if (ext.length() > kMaxFilePathSize)
+    return false;
+
   // We implement the same algorithm as Mozilla for mapping a file extension to
   // a mime type.  That is, we first check a hard-coded list (that cannot be
   // overridden), and then if not found there, we defer to the system registry.
   // Finally, we scan a secondary hard-coded list to catch types that we can
   // deduce but that we also want to allow the OS to override.
 
 #if defined(OS_WIN)
   string ext_narrow_str = WideToUTF8(ext);
 #elif defined(OS_POSIX)
   const string& ext_narrow_str = ext;
@@ skipping 369 matching lines @@
   return GetMimeUtil()->IsSupportedStrictMediaMimeType(mime_type, codecs);
 }
 
 void ParseCodecString(const std::string& codecs,
                       std::vector<std::string>* codecs_out,
                       const bool strip) {
   GetMimeUtil()->ParseCodecString(codecs, codecs_out, strip);
 }
 
 }  // namespace net