From: gfree.w...@vip.163.com Date: Tue, 9 May 2017 18:27:33 +0800 > From: Gao Feng <gfree.w...@vip.163.com> > > The current codes only deal with the case that the skb is dropped, it > may meet one use-after-free issue when NF_HOOK returns 0 that means > the skb is stolen by one netfilter rule or hook. > > When one netfilter rule or hook stoles the skb and return NF_STOLEN, > it means the skb is taken by the rule, and other modules should not > touch this skb ever. Maybe the skb is queued or freed directly by the > rule. > > Now uses the nf_hook instead of NF_HOOK to get the result of netfilter, > and check the return value of nf_hook. Only when its value equals 1, it > means the skb could go ahead. Or reset the skb as NULL. > > BTW, because vrf_rcv_finish is empty function, so needn't invoke it > even though nf_hook returns 1. But we need to modify vrf_rcv_finish > to deal with the NF_STOLEN case. > > There are two cases when skb is stolen. > 1. The skb is stolen and freed directly. > There is nothing we need to do, and vrf_rcv_finish isn't invoked. > 2. The skb is queued and reinjected again. > The vrf_rcv_finish would be invoked as okfn, so need to free the > skb in it. > > Signed-off-by: Gao Feng <gfree.w...@vip.163.com>
Applied and queued up for -stable, thanks.
