Commit 3d861f66 authored Oct 22, 2012 by Eric Dumazet Committed by David S. Miller Oct 22, 2012

net: fix secpath kmemleak



Mike Kazantsev found 3.5 kernels and beyond were leaking memory,
and tracked the faulty commit to a1c7fff7 ("net:
netdev_alloc_skb() use build_skb()")

While this commit seems fine, it uncovered a bug introduced
in commit bad43ca8 ("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>

parent 8a6e29d6

net/core/skbuff.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -3379,11 +3379,13 @@ EXPORT_SYMBOL(__skb_warn_lro_forwarding);

		void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
		{
		if (head_stolen)
		if (head_stolen) {
		skb_release_head_state(skb);
		kmem_cache_free(skbuff_head_cache, skb);
		else
		} else {
		__kfree_skb(skb);
		}
		}
		EXPORT_SYMBOL(kfree_skb_partial);

		/**