From c593b2f48edc8810cdd2cde770a23fa8f80a8807 Mon Sep 17 00:00:00 2001
From: Paul Gofman <pgofman@codeweavers.com>
Date: Tue, 8 Mar 2022 12:22:44 +0300
Subject: [PATCH] ws2_32: Return WSAEFAULT from setsockopt() for
 IP_MULTICAST_LOOP with zero optlen.

Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
---
 dlls/ws2_32/socket.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/dlls/ws2_32/socket.c b/dlls/ws2_32/socket.c
index dacb41a0403..816ca828b90 100644
--- a/dlls/ws2_32/socket.c
+++ b/dlls/ws2_32/socket.c
@@ -2981,6 +2981,11 @@ int WINAPI setsockopt( SOCKET s, int level, int optname, const char *optval, int
             return server_setsockopt( s, IOCTL_AFD_WINE_SET_IP_MULTICAST_IF, optval, optlen );
 
         case IP_MULTICAST_LOOP:
+            if (!optlen)
+            {
+                SetLastError( WSAEFAULT );
+                return -1;
+            }
             return server_setsockopt( s, IOCTL_AFD_WINE_SET_IP_MULTICAST_LOOP, optval, optlen );
 
         case IP_MULTICAST_TTL: