bool ReadSymbolicLink(const FilePath& symlink_path,
                      FilePath* target_path) {
  DCHECK(!symlink_path.empty());
  DCHECK(target_path);
  char buf[PATH_MAX];
  ssize_t count = ::readlink(symlink_path.value().c_str(), buf, arraysize(buf));

  if (count <= 0) {
    target_path->clear();
    return false;
  }

  *target_path = FilePath(FilePath::StringType(buf, count));
  return true;
}

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.