l2tp: do not use udp_ioctl()
authorEric Dumazet <edumazet@google.com>
Fri, 10 Feb 2017 00:15:52 +0000 (16:15 -0800)
committerDavid S. Miller <davem@davemloft.net>
Fri, 10 Feb 2017 20:57:34 +0000 (15:57 -0500)
commit72fb96e7bdbbdd4421b0726992496531060f3636
treeedd4c429c973566b233252d3d55343a2bea7c9e9
parent74470954857c264168d2b5a113904cf0cfd27d18
l2tp: do not use udp_ioctl()

udp_ioctl(), as its name suggests, is used by UDP protocols,
but is also used by L2TP :(

L2TP should use its own handler, because it really does not
look the same.

SIOCINQ for instance should not assume UDP checksum or headers.

Thanks to Andrey and syzkaller team for providing the report
and a nice reproducer.

While crashes only happen on recent kernels (after commit
7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue")), this
probably needs to be backported to older kernels.

Fixes: 7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue")
Fixes: 85584672012e ("udp: Fix udp_poll() and ioctl()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp/l2tp_core.h
net/l2tp/l2tp_ip.c
net/l2tp/l2tp_ip6.c