Commit 2a55e64d authored Aug 31, 2018 by Thadeu Lima de Souza Cascardo Committed by Greg Kroah-Hartman Nov 04, 2018

xfrm6: call kfree_skb when skb is toobig



[ Upstream commit 215ab0f021c9fea3c18b75e7d522400ee6a49990 ]

After commit d6990976af7c5d8f55903bfb4289b6fb030bf754 ("vti6: fix PMTU caching
and reporting on xmit"), some too big skbs might be potentially passed down to
__xfrm6_output, causing it to fail to transmit but not free the skb, causing a
leak of skb, and consequentially a leak of dst references.

After running pmtu.sh, that shows as failure to unregister devices in a namespace:

[  311.397671] unregister_netdevice: waiting for veth_b to become free. Usage count = 1

The fix is to call kfree_skb in case of transmit failures.

Fixes: dd767856 ("xfrm6: Don't call icmpv6_send on local error")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 3b5d5128

net/ipv6/xfrm6_output.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -170,9 +170,11 @@ static int __xfrm6_output(struct net net, struct sock sk, struct sk_buff *skb)

		if (toobig && xfrm6_local_dontfrag(skb)) {
		xfrm6_local_rxpmtu(skb, mtu);
		kfree_skb(skb);
		return -EMSGSIZE;
		} else if (!skb->ignore_df && toobig && skb->sk) {
		xfrm_local_error(skb, mtu);
		kfree_skb(skb);
		return -EMSGSIZE;
		}