ws2_32: Manage shorter length for IPV6_DONTFRAG.

dlls/ws2_32/socket.c

@@ -1810,6 +1810,12 @@ int WINAPI getsockopt( SOCKET s, int level, int optname, char *optval, int *optl
         switch(optname)
         {
         case IPV6_DONTFRAG:
+            if (*optlen < 1 || !optval)
+            {
+                SetLastError( WSAEFAULT );
+                return SOCKET_ERROR;
+            }
+            if (*optlen < sizeof(DWORD)) *optlen = 1;
             return server_getsockopt( s, IOCTL_AFD_WINE_GET_IPV6_DONTFRAG, optval, optlen );
 
         case IPV6_HOPLIMIT:
@@ -3161,7 +3167,13 @@ int WINAPI setsockopt( SOCKET s, int level, int optname, const char *optval, int
             return server_setsockopt( s, IOCTL_AFD_WINE_SET_IPV6_ADD_MEMBERSHIP, optval, optlen );
 
         case IPV6_DONTFRAG:
-            return server_setsockopt( s, IOCTL_AFD_WINE_SET_IPV6_DONTFRAG, optval, optlen );
+            if (!optlen || !optval)
+            {
+                SetLastError( WSAEFAULT );
+                return SOCKET_ERROR;
+            }
+            memcpy( &value, optval, min( optlen, sizeof(value) ));
+            return server_setsockopt( s, IOCTL_AFD_WINE_SET_IPV6_DONTFRAG, (char *)&value, sizeof(value) );
 
         case IPV6_DROP_MEMBERSHIP:
             return server_setsockopt( s, IOCTL_AFD_WINE_SET_IPV6_DROP_MEMBERSHIP, optval, optlen );

dlls/ws2_32/tests/sock.c

@@ -1189,6 +1189,7 @@ static void test_set_getsockopt(void)
         {AF_INET, SOCK_DGRAM, IPPROTO_IP, IP_RECVTTL, FALSE, {0, 0, 4}, {0}, TRUE, TRUE},
         {AF_INET, SOCK_DGRAM, IPPROTO_IP, IP_TOS, TRUE, {1, 1, 4}, {0}, FALSE},
         {AF_INET, SOCK_DGRAM, IPPROTO_IP, IP_TTL, TRUE, {1, 1, 4}, {0}, FALSE},
+        {AF_INET6, SOCK_STREAM, IPPROTO_IPV6, IPV6_DONTFRAG, TRUE, {1, 1, 4}, {0}, TRUE, TRUE},
     };
     SOCKET s, s2;
     int i, j, err, lasterr;