ext/sockets: bound interface name copy in from_zval_write_ifindex()

The SIOCGIFINDEX fallback checked ZSTR_LEN against sizeof(ifr.ifr_name)
but did not return on overflow, then memcpy'd ZSTR_LEN+1 bytes into the
fixed ifr_name buffer, so an over-long interface name overran the stack.
This regressed in 3e9b530, which replaced the original bounded
strlcpy with an unguarded memcpy. Restore the strlcpy plus else-if guard,
matching PHP-8.4.

Closes GH-22379

Author: iliaal

ext/sockets/conversions.c

@@ -1270,11 +1270,10 @@ static void from_zval_write_ifindex(const zval *zv, char *uinteger, ser_context
 #elif defined(SIOCGIFINDEX)
 		{
 			struct ifreq ifr;
-			if (ZSTR_LEN(str) >= sizeof(ifr.ifr_name)) {
+			if (strlcpy(ifr.ifr_name, ZSTR_VAL(str), sizeof(ifr.ifr_name))
+					>= sizeof(ifr.ifr_name)) {
 				do_from_zval_err(ctx, "the interface name \"%s\" is too large ", ZSTR_VAL(str));
-			}
-			memcpy(ifr.ifr_name, ZSTR_VAL(str), ZSTR_LEN(str) + 1);
-			if (ioctl(ctx->sock->bsd_socket, SIOCGIFINDEX, &ifr) < 0) {
+			} else if (ioctl(ctx->sock->bsd_socket, SIOCGIFINDEX, &ifr) < 0) {
 				if (errno == ENODEV) {
 					do_from_zval_err(ctx, "no interface with name \"%s\" could be "
 							"found", ZSTR_VAL(str));