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Message-Id: <20190627004122.21671-9-sashal@kernel.org>
Date: Wed, 26 Jun 2019 20:41:09 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Guillaume Nault <gnault@...hat.com>,
Pablo Neira Ayuso <pablo@...filter.org>,
Sasha Levin <sashal@...nel.org>,
netfilter-devel@...r.kernel.org, coreteam@...filter.org,
netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.9 09/21] netfilter: ipv6: nf_defrag: accept duplicate fragments again
From: Guillaume Nault <gnault@...hat.com>
[ Upstream commit 8a3dca632538c550930ce8bafa8c906b130d35cf ]
When fixing the skb leak introduced by the conversion to rbtree, I
forgot about the special case of duplicate fragments. The condition
under the 'insert_error' label isn't effective anymore as
nf_ct_frg6_gather() doesn't override the returned value anymore. So
duplicate fragments now get NF_DROP verdict.
To accept duplicate fragments again, handle them specially as soon as
inet_frag_queue_insert() reports them. Return -EINPROGRESS which will
translate to NF_STOLEN verdict, like any accepted fragment. However,
such packets don't carry any new information and aren't queued, so we
just drop them immediately.
Fixes: a0d56cb911ca ("netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments")
Signed-off-by: Guillaume Nault <gnault@...hat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
net/ipv6/netfilter/nf_conntrack_reasm.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index e6114a6710e0..0b53d1907e4a 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -264,8 +264,14 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
prev = fq->q.fragments_tail;
err = inet_frag_queue_insert(&fq->q, skb, offset, end);
- if (err)
+ if (err) {
+ if (err == IPFRAG_DUP) {
+ /* No error for duplicates, pretend they got queued. */
+ kfree_skb(skb);
+ return -EINPROGRESS;
+ }
goto insert_error;
+ }
if (dev)
fq->iif = dev->ifindex;
@@ -303,8 +309,6 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
return -EINPROGRESS;
insert_error:
- if (err == IPFRAG_DUP)
- goto err;
inet_frag_kill(&fq->q);
err:
skb_dst_drop(skb);
--
2.20.1
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