linux/net/l2tp
Guillaume Nault 54652eb12c l2tp: hold tunnel while looking up sessions in l2tp_netlink
l2tp_tunnel_find() doesn't take a reference on the returned tunnel.
Therefore, it's unsafe to use it because the returned tunnel can go
away on us anytime.

Fix this by defining l2tp_tunnel_get(), which works like
l2tp_tunnel_find(), but takes a reference on the returned tunnel.
Caller then has to drop this reference using l2tp_tunnel_dec_refcount().

As l2tp_tunnel_dec_refcount() needs to be moved to l2tp_core.h, let's
simplify the patch and not move the L2TP_REFCNT_DEBUG part. This code
has been broken (not even compiling) in May 2012 by
commit a4ca44fa57 ("net: l2tp: Standardize logging styles")
and fixed more than two years later by
commit 29abe2fda5 ("l2tp: fix missing line continuation"). So it
doesn't appear to be used by anyone.

Same thing for l2tp_tunnel_free(); instead of moving it to l2tp_core.h,
let's just simplify things and call kfree_rcu() directly in
l2tp_tunnel_dec_refcount(). Extra assertions and debugging code
provided by l2tp_tunnel_free() didn't help catching any of the
reference counting and socket handling issues found while working on
this series.

Fixes: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28 11:34:58 -07:00
..
Kconfig l2tp: Call udp_sock_create 2014-07-14 16:12:15 -07:00
l2tp_core.c l2tp: hold tunnel while looking up sessions in l2tp_netlink 2017-08-28 11:34:58 -07:00
l2tp_core.h l2tp: hold tunnel while looking up sessions in l2tp_netlink 2017-08-28 11:34:58 -07:00
l2tp_debugfs.c net, l2tp: convert l2tp_tunnel.ref_count from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
l2tp_eth.c l2tp: cast l2tp traffic counter to unsigned 2017-06-10 16:14:27 -04:00
l2tp_ip6.c l2tp: fix race in l2tp_recv_common() 2017-04-01 20:16:41 -07:00
l2tp_ip.c l2tp: fix race in l2tp_recv_common() 2017-04-01 20:16:41 -07:00
l2tp_netlink.c l2tp: hold tunnel while looking up sessions in l2tp_netlink 2017-08-28 11:34:58 -07:00
l2tp_ppp.c net, l2tp: convert l2tp_tunnel.ref_count from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
Makefile l2tp: introduce L2TPv3 IP encapsulation support for IPv6 2012-05-01 09:30:55 -04:00