net: fix secpath kmemleak
authorEric Dumazet <edumazet@google.com>
Mon, 22 Oct 2012 09:03:40 +0000 (09:03 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 17 Nov 2012 21:18:52 +0000 (13:18 -0800)
commit7a77dd0168e94667ca4f44a33721380dfc1fd104
tree9bc7509ff6a22b10b7481f55a6968d06f49ea82f
parent48ff12fe363a34b854b1703ecb62d57cf9c65e9c
net: fix secpath kmemleak

[ Upstream commit 3d861f661006606bf159fd6bd973e83dbf21d0f9 ]

Mike Kazantsev found 3.5 kernels and beyond were leaking memory,
and tracked the faulty commit to a1c7fff7e18f59e ("net:
netdev_alloc_skb() use build_skb()")

While this commit seems fine, it uncovered a bug introduced
in commit bad43ca8325 ("net: introduce skb_try_coalesce()), in function
kfree_skb_partial()"):

If head is stolen, we free the sk_buff,
without removing references on secpath (skb->sp).

So IPsec + IP defrag/reassembly (using skb coalescing), or
TCP coalescing could leak secpath objects.

Fix this bug by calling skb_release_head_state(skb) to properly
release all possible references to linked objects.

Reported-by: Mike Kazantsev <mk.fraggod@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Bisected-by: Mike Kazantsev <mk.fraggod@gmail.com>
Tested-by: Mike Kazantsev <mk.fraggod@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/core/skbuff.c