Don't allow path traversal paths on the base file helpers

base/platform_file_posix.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 "base/platform_file.h"
 
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 23 matching lines @@
 }
 #else
 typedef struct stat64 stat_wrapper_t;
 static int CallFstat(int fd, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
   return fstat64(fd, sb);
 }
 #endif
 
 // TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
-PlatformFile CreatePlatformFile(const FilePath& name, int flags,
-                                bool* created, PlatformFileError* error_code) {
+PlatformFile CreatePlatformFileAllowTraversal(const FilePath& name,
+                                              int flags,
+                                              bool* created,
+                                              PlatformFileError* error_code) {
   base::ThreadRestrictions::AssertIOAllowed();
 
   int open_flags = 0;
   if (flags & PLATFORM_FILE_CREATE)
     open_flags = O_CREAT | O_EXCL;
 
   if (created)
     *created = false;
 
   if (flags & PLATFORM_FILE_CREATE_ALWAYS) {
@@ skipping 253 matching lines @@
   info->is_directory = S_ISDIR(file_info.st_mode);
   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
   info->size = file_info.st_size;
   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
   return true;
 }
 
 }  // namespace base