[nf,1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

Submitted by 高峰 on March 20, 2017, 1:44 a.m.

Details

Message ID 1489974248-60293-1-git-send-email-fgao@ikuai8.com
State Changes Requested
Delegated to: Pablo Neira
Headers show

Commit Message

高峰 March 20, 2017, 1:44 a.m.
From: Gao Feng <fgao@ikuai8.com>

In the commit ("netfilter: nf_conntrack: nf_conntrack snmp helper"),
the snmp_helper is replaced by nf_nat_snmp_hook. So the snmp_helper
is never registered. But it still tries to unregister the snmp_helper,
it could cause the panic.

Now remove the useless snmp_helper and the unregister call in the
error handler.

Fixes: 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp helper")

Signed-off-by: Gao Feng <fgao@ikuai8.com>
---
 net/ipv4/netfilter/nf_nat_snmp_basic.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

Comments

Sergei Shtylyov March 20, 2017, 9:37 a.m.
Hello!

On 3/20/2017 4:44 AM, fgao@ikuai8.com wrote:

> From: Gao Feng <fgao@ikuai8.com>
>
> In the commit ("netfilter: nf_conntrack: nf_conntrack snmp helper"),

    Need to specify the 12-digit SHA1 ID as well.

> the snmp_helper is replaced by nf_nat_snmp_hook. So the snmp_helper
> is never registered. But it still tries to unregister the snmp_helper,
> it could cause the panic.
>
> Now remove the useless snmp_helper and the unregister call in the
> error handler.
>
> Fixes: 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp helper")
>
> Signed-off-by: Gao Feng <fgao@ikuai8.com>
[...]

MBR, Sergei

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Feng Gao March 20, 2017, 9:57 a.m.
On Mon, Mar 20, 2017 at 5:37 PM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> Hello!
>
> On 3/20/2017 4:44 AM, fgao@ikuai8.com wrote:
>
>> From: Gao Feng <fgao@ikuai8.com>
>>
>> In the commit ("netfilter: nf_conntrack: nf_conntrack snmp helper"),
>
>
>    Need to specify the 12-digit SHA1 ID as well.

Thanks Sergei.
I didn't know it is asked to add SHA1 ID into description, thanks your reminder.

I have sent the v2 patch.

Regards
Feng

>
>> the snmp_helper is replaced by nf_nat_snmp_hook. So the snmp_helper
>> is never registered. But it still tries to unregister the snmp_helper,
>> it could cause the panic.
>>
>> Now remove the useless snmp_helper and the unregister call in the
>> error handler.
>>
>> Fixes: 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp helper")
>>
>> Signed-off-by: Gao Feng <fgao@ikuai8.com>
>
> [...]
>
> MBR, Sergei
>
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Patch hide | download patch | download mbox

diff --git a/net/ipv4/netfilter/nf_nat_snmp_basic.c b/net/ipv4/netfilter/nf_nat_snmp_basic.c
index c9b52c3..5787364 100644
--- a/net/ipv4/netfilter/nf_nat_snmp_basic.c
+++ b/net/ipv4/netfilter/nf_nat_snmp_basic.c
@@ -1260,16 +1260,6 @@  static int help(struct sk_buff *skb, unsigned int protoff,
 	.timeout	= 180,
 };
 
-static struct nf_conntrack_helper snmp_helper __read_mostly = {
-	.me			= THIS_MODULE,
-	.help			= help,
-	.expect_policy		= &snmp_exp_policy,
-	.name			= "snmp",
-	.tuple.src.l3num	= AF_INET,
-	.tuple.src.u.udp.port	= cpu_to_be16(SNMP_PORT),
-	.tuple.dst.protonum	= IPPROTO_UDP,
-};
-
 static struct nf_conntrack_helper snmp_trap_helper __read_mostly = {
 	.me			= THIS_MODULE,
 	.help			= help,
@@ -1294,10 +1284,8 @@  static int __init nf_nat_snmp_basic_init(void)
 	RCU_INIT_POINTER(nf_nat_snmp_hook, help);
 
 	ret = nf_conntrack_helper_register(&snmp_trap_helper);
-	if (ret < 0) {
-		nf_conntrack_helper_unregister(&snmp_helper);
+	if (ret < 0)
 		return ret;
-	}
 	return ret;
 }