Commit 0cab694a authored Dec 13, 2017 by Debabrata Banerjee Committed by Greg Kroah-Hartman Dec 16, 2017

Fix handling of verdicts after NF_QUEUE



[This fix is only needed for v4.9 stable since v4.10+ does not have the issue]

A verdict of NF_STOLEN after NF_QUEUE will cause an incorrect return value
and a potential kernel panic via double free of skb's

This was broken by commit 7034b566 ("netfilter: fix nf_queue handling")
and subsequently fixed in v4.10 by commit c63cbc460419 ("netfilter:
use switch() to handle verdict cases from nf_hook_slow()"). However that
commit cannot be cleanly cherry-picked to v4.9

Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent cf00fd3d

net/netfilter/core.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -364,6 +364,11 @@ int nf_hook_slow(struct sk_buff skb, struct nf_hook_state state)
		ret = nf_queue(skb, state, &entry, verdict);
		if (ret == 1 && entry)
		goto next_hook;
		} else {
		/* Implicit handling for NF_STOLEN, as well as any other
		* non conventional verdicts.
		*/
		ret = 0;
		}
		return ret;
		}