From 0cab694ab7bca62eb42dbfae209c08edc8d229c4 Mon Sep 17 00:00:00 2001 From: Debabrata Banerjee Date: Wed, 13 Dec 2017 15:33:37 -0500 Subject: [PATCH] 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 7034b566a4e7 ("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 Acked-by: Pablo Neira Ayuso --- net/netfilter/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 004af030ef1a..d869ea50623e 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -364,6 +364,11 @@ next_hook: 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; }