[PATCH net] netfilter: nf_queue:fix reinject verdict handling

[PATCH net] netfilter: nf_queue:fix reinject verdict handling

[Jagdish Motwani]

From: Jagdish Motwani <jagdish.motwani@sophos.com>

In case of more than 1 nf_queues, hooks between them are being executed
more than once.

Signed-off-by: Jagdish Motwani <jagdish.motwani@sophos.com>
---
 net/netfilter/nf_queue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 9dc1d6e..b5b2be5 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -255,6 +255,7 @@ static unsigned int nf_iterate(struct sk_buff *skb,
 repeat:
 		verdict = nf_hook_entry_hookfn(hook, skb, state);
 		if (verdict != NF_ACCEPT) {
+			*index = i;
 			if (verdict != NF_REPEAT)
 				return verdict;
 			goto repeat;
-- 
2.9.5

Re: [PATCH net] netfilter: nf_queue:fix reinject verdict handling

[Pablo Neira Ayuso]

Hi Jagdish,

On Thu, May 09, 2019 at 12:01:14AM +0530, Jagdish Motwani wrote:
> From: Jagdish Motwani <jagdish.motwani@sophos.com>
> 
> In case of more than 1 nf_queues, hooks between them are being executed
> more than once.

This refers to NF_REPEAT, correct?

I think this broke with 960632ece6949. If so, it would be good to add
the following tag to this patch then. It's useful for robots
collecting fixes for -stable kernels.

Fixes: 960632ece694 ("netfilter: convert hook list to an array")

> Signed-off-by: Jagdish Motwani <jagdish.motwani@sophos.com>

Thanks.

RE: [PATCH net] netfilter: nf_queue:fix reinject verdict handling

[Jagdish Motwani]

Hi Pablo,

The case I am referring to is : If there are more than 1  hooks returning NF_QUEUE verdict.
When the first queue reinjects the packet, 'nf_reinject' starts traversing hooks with hook_index (i).
However if it again receives a NF_QUEUE verdict (by some other netfilter hook), it queue with the wrong hook_index.
So, when the second queue reinjects the packet, it re-executes some hooks in between the first 2 hooks.

Thanks, I will mark :  Fixes: 960632ece694 ("netfilter: convert hook list to an array") and update the description also.

Regards,
Jagdish
-----Original Message-----
From: Pablo Neira Ayuso <pablo@netfilter.org>
Sent: Monday, May 13, 2019 2:52 PM
To: Jagdish Motwani <j.k.motwani@gmail.com>
Cc: netdev@vger.kernel.org; Jagdish Motwani <Jagdish.Motwani@Sophos.com>; Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>; Florian Westphal <fw@strlen.de>; David S. Miller <davem@davemloft.net>; netfilter-devel@vger.kernel.org; coreteam@netfilter.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] netfilter: nf_queue:fix reinject verdict handling

Hi Jagdish,


On Thu, May 09, 2019 at 12:01:14AM +0530, Jagdish Motwani wrote:
> From: Jagdish Motwani <jagdish.motwani@sophos.com>
>
> In case of more than 1 nf_queues, hooks between them are being
> executed more than once.

This refers to NF_REPEAT, correct?

I think this broke with 960632ece6949. If so, it would be good to add the following tag to this patch then. It's useful for robots collecting fixes for -stable kernels.

Fixes: 960632ece694 ("netfilter: convert hook list to an array")

> Signed-off-by: Jagdish Motwani <jagdish.motwani@sophos.com>

Thanks.

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Re: [PATCH net] netfilter: nf_queue:fix reinject verdict handling

[Pablo Neira Ayuso]

On Mon, May 13, 2019 at 10:36:51AM +0000, Jagdish Motwani wrote:
> Hi Pablo,
> 
> The case I am referring to is : If there are more than 1  hooks
> returning NF_QUEUE verdict.  When the first queue reinjects the
> packet, 'nf_reinject' starts traversing hooks with hook_index (i).
> However if it again receives a NF_QUEUE verdict (by some other
> netfilter hook), it queue with the wrong hook_index.  So, when the
> second queue reinjects the packet, it re-executes some hooks in
> between the first 2 hooks.

Please, include this description in the patch. And thanks for
explaining.

> Thanks, I will mark :  Fixes: 960632ece694 ("netfilter: convert hook list to an array") and update the description also.

Thanks, will wait for v2.