[ 16/25] net/l2tp: dont fall back on UDP [get|set]sockopt

From: Willy Tarreau
Date: Sat Dec 06 2014 - 13:00:12 EST

2.6.32-longterm review patch. If anyone has any objections, please let me know.


From: Sasha Levin <sasha.levin@xxxxxxxxxx>

(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@xxxxxxxxxx>
Acked-by: James Chapman <jchapman@xxxxxxxxxxx>
Acked-by: David Miller <davem@xxxxxxxxxxxxx>
Cc: Phil Turnbull <phil.turnbull@xxxxxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Cc: Willy Tarreau <w@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

[geissert: adjust file paths and context for 2.6.32]
[wt: fixes CVE-2014-4943]
Signed-off-by: Willy Tarreau <w@xxxxxx>
drivers/net/pppol2tp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index 4cdc1cf..4c8f019 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -2190,7 +2190,7 @@ 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;
@@ -2314,7 +2314,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level,
int err;

if (level != SOL_PPPOL2TP)
- return udp_prot.getsockopt(sk, level, optname, optval, optlen);
+ return -EINVAL;

if (get_user(len, (int __user *) optlen))
return -EFAULT;

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