static bool _valid_hex(char *s, const char *file, const char *func, const int line)
{
	bool ret = false;
	int i, len;

	if (unlikely(!s)) {
		applog(LOG_ERR, "Null string passed to valid_hex from"IN_FMT_FFL, file, func, line);
		return ret;
	}
	len = strlen(s);
	if (unlikely(!len)) {
		applog(LOG_ERR, "Zero length string passed to valid_hex from"IN_FMT_FFL, file, func, line);
		return ret;
	}
	for (i = 0; i < len; i++) {
		unsigned char idx = s[i];

		if (unlikely(hex2bin_tbl[idx] < 0)) {
			applog(LOG_ERR, "Invalid char %x passed to valid_hex from"IN_FMT_FFL, idx, file, func, line);
			return ret;
		}
	}
	ret = true;
	return ret;
}
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.