PHP_FUNCTION(gethostbyaddr)
{
	char *addr;
	int addr_len;
	char *hostname;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &addr, &addr_len) == FAILURE) {
		return;
	}

	hostname = php_gethostbyaddr(addr);

	if (hostname == NULL) {
#if HAVE_IPV6 && HAVE_INET_PTON
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Address is not a valid IPv4 or IPv6 address");
#else
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Address is not in a.b.c.d form");
#endif
		RETVAL_FALSE;
	} else {
		RETVAL_STRING(hostname, 0);
	}
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.