From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Liping Zhang <zlpnobody@163.com>
Cc: netfilter-devel@vger.kernel.org,
Liping Zhang <liping.zhang@spreadtrum.com>
Subject: Re: [PATCH nf] netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT
Date: Thu, 25 Aug 2016 12:56:24 +0200 [thread overview]
Message-ID: <20160825105624.GA5242@salvia> (raw)
In-Reply-To: <1471798938-28241-1-git-send-email-zlpnobody@163.com>
On Mon, Aug 22, 2016 at 01:02:18AM +0800, Liping Zhang wrote:
> From: Liping Zhang <liping.zhang@spreadtrum.com>
>
> After I add the nft rule "nft add rule filter prerouting reject
> with tcp reset", kernel panic happened on my system:
> NULL pointer dereference at ...
> IP: [<ffffffff81b9db2f>] nf_send_reset+0xaf/0x400
> Call Trace:
> [<ffffffff81b9da80>] ? nf_reject_ip_tcphdr_get+0x160/0x160
> [<ffffffffa0928061>] nft_reject_ipv4_eval+0x61/0xb0 [nft_reject_ipv4]
> [<ffffffffa08e836a>] nft_do_chain+0x1fa/0x890 [nf_tables]
> [<ffffffffa08e8170>] ? __nft_trace_packet+0x170/0x170 [nf_tables]
> [<ffffffffa06e0900>] ? nf_ct_invert_tuple+0xb0/0xc0 [nf_conntrack]
> [<ffffffffa07224d4>] ? nf_nat_setup_info+0x5d4/0x650 [nf_nat]
> [...]
>
> Because in the PREROUTING chain, routing information is not exist,
> then we will dereference the NULL pointer and oops happen.
>
> So we restrict reject expression to INPUT, FORWARD and OUTPUT chain.
> This is consistent with iptables REJECT target.
Good catch, applied, thanks.
prev parent reply other threads:[~2016-08-25 10:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-21 17:02 [PATCH nf] netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT Liping Zhang
2016-08-25 10:56 ` Pablo Neira Ayuso [this message]
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