From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 6/6] netfilter: ipv6: nf_defrag: drop skb dst before queueing
Date: Mon, 9 Jul 2018 19:19:04 +0200 [thread overview]
Message-ID: <20180709171904.2460-7-pablo@netfilter.org> (raw)
In-Reply-To: <20180709171904.2460-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
Eric Dumazet reports:
Here is a reproducer of an annoying bug detected by syzkaller on our production kernel
[..]
./b78305423 enable_conntrack
Then :
sleep 60
dmesg | tail -10
[ 171.599093] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 181.631024] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 191.687076] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 201.703037] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 211.711072] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 221.959070] unregister_netdevice: waiting for lo to become free. Usage count = 2
Reproducer sends ipv6 fragment that hits nfct defrag via LOCAL_OUT hook.
skb gets queued until frag timer expiry -- 1 minute.
Normally nf_conntrack_reasm gets called during prerouting, so skb has
no dst yet which might explain why this wasn't spotted earlier.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/ipv6/netfilter/nf_conntrack_reasm.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index a452d99c9f52..e4d9e6976d3c 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -585,6 +585,8 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user)
fq->q.meat == fq->q.len &&
nf_ct_frag6_reasm(fq, skb, dev))
ret = 0;
+ else
+ skb_dst_drop(skb);
out_unlock:
spin_unlock_bh(&fq->q.lock);
--
2.11.0
next prev parent reply other threads:[~2018-07-09 17:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 17:18 [PATCH 0/6] Netfilter fixes for net Pablo Neira Ayuso
2018-07-09 17:18 ` [PATCH 1/6] netfilter: x_tables: set module owner for icmp(6) matches Pablo Neira Ayuso
2018-07-09 17:19 ` [PATCH 2/6] netfilter: nf_tproxy: fix possible non-linear access to transport header Pablo Neira Ayuso
2018-07-09 17:19 ` [PATCH 3/6] netfilter: nf_tables: place all set backends in one single module Pablo Neira Ayuso
2018-07-09 17:19 ` [PATCH 4/6] netfilter: nft_compat: explicitly reject ERROR and standard target Pablo Neira Ayuso
2018-07-09 17:19 ` [PATCH 5/6] netfilter: nf_conntrack: Fix possible possible crash on module loading Pablo Neira Ayuso
2018-07-09 17:19 ` Pablo Neira Ayuso [this message]
2018-07-09 21:24 ` [PATCH 0/6] Netfilter fixes for net David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180709171904.2460-7-pablo@netfilter.org \
--to=pablo@netfilter.org \
--cc=davem@davemloft.net \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).