[PATCH 018/270] net: fix secpath kmemleak

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Mon Nov 26 16:55:08 UTC 2012

3.5.7u1 -stable review patch.  If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet at google.com>

commit 3d861f661006606bf159fd6bd973e83dbf21d0f9 upstream.

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

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 at gmail.com>
Signed-off-by: Eric Dumazet <edumazet at google.com>
Bisected-by: Mike Kazantsev <mk.fraggod at gmail.com>
Tested-by: Mike Kazantsev <mk.fraggod at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
 net/core/skbuff.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d124306..015f3a7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3350,10 +3350,12 @@ 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 {
+	}

More information about the kernel-team mailing list