net/l2tp: don't fall back on UDP [get|set]sockopt

commit 3cf521f7dc87c031617fd47e4b7aa2593c2f3daf upstream.

The l2tp [get|set]sockopt() code has fallen back to the UDP functions
for socket option levels != SOL_PPPOL2TP since day one, but that has
never actually worked, since the l2tp socket isn't an inet socket.

As David Miller points out:

  "If we wanted this to work, it'd have to look up the tunnel and then
   use tunnel->sk, but I wonder how useful that would be"

Since this can never have worked so nobody could possibly have depended
on that functionality, just remove the broken code and return -EINVAL.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: James Chapman <jchapman@katalix.com>
Acked-by: David Miller <davem@davemloft.net>
Cc: Phil Turnbull <phil.turnbull@oracle.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index e0f0934..437fb59 100644 (file)
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1351,7 +1351,7 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
        int err;
 
        if (level != SOL_PPPOL2TP)
-               return udp_prot.setsockopt(sk, level, optname, optval, optlen);
+               return -EINVAL;
 
        if (optlen < sizeof(int))
                return -EINVAL;
@@ -1477,7 +1477,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level,
        struct pppol2tp_session *ps;
 
        if (level != SOL_PPPOL2TP)
-               return udp_prot.getsockopt(sk, level, optname, optval, optlen);
+               return -EINVAL;
 
        if (get_user(len, (int __user *) optlen))
                return -EFAULT;