file_reader(void *cls, uint64_t pos, char *buf, size_t max)
#else
static int
file_reader(void *cls, uint64_t pos, char *buf, int max)
#endif
{
	FILE *file = cls;

	fseeko(file, pos, SEEK_SET);
	return fread(buf, 1, max, file);
}

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.