[PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[fgao]

From: Gao Feng <fgao@ikuai8.com>

In the commit <93557f53e1fb> ("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>
---
 v2: Add the SHA1 ID in the description, per Sergei
 v1: Initial version

 net/ipv4/netfilter/nf_nat_snmp_basic.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

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;
 }
 
-- 
1.9.1

Re: [PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[Sergei Shtylyov]

On 3/20/2017 12:55 PM, fgao@ikuai8.com wrote:

> From: Gao Feng <fgao@ikuai8.com>
>
> In the commit <93557f53e1fb> ("netfilter: nf_conntrack: nf_conntrack snmp

    Angle brackets not needed. :-)
    The commit citing style is the same as for the Fixes: tag.

> 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>
[...]

MBR, Sergei

Re: [PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[Feng Gao]

On Mon, Mar 20, 2017 at 6:09 PM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> On 3/20/2017 12:55 PM, fgao@ikuai8.com wrote:
>
>> From: Gao Feng <fgao@ikuai8.com>
>>
>> In the commit <93557f53e1fb> ("netfilter: nf_conntrack: nf_conntrack snmp
>
>
>    Angle brackets not needed. :-)
>    The commit citing style is the same as for the Fixes: tag.

The checkpatch.pl reports the following error, if remove the angle brackets.

ERROR: Please use git commit description style 'commit <12+ chars of
sha1> ("<title line>")' - ie: 'commit fatal: ambig ("evision or path
not in the working tree.")'
#7:
In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp

total: 1 errors, 0 warnings, 0 checks, 27 lines checked


Regards
Feng

>
>> 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>
>
> [...]
>
> MBR, Sergei
>

Re: [PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[Sergei Shtylyov]

On 03/20/2017 01:15 PM, Feng Gao wrote:

>>> From: Gao Feng <fgao@ikuai8.com>
>>>
>>> In the commit <93557f53e1fb> ("netfilter: nf_conntrack: nf_conntrack snmp
>>
>>
>>    Angle brackets not needed. :-)
>>    The commit citing style is the same as for the Fixes: tag.
>
> The checkpatch.pl reports the following error, if remove the angle brackets.

    Because it stops recognizing the commit ID! :-)

> ERROR: Please use git commit description style 'commit <12+ chars of
> sha1> ("<title line>")' - ie: 'commit fatal: ambig ("evision or path
> not in the working tree.")'

    So check the patch in the correct tree because that seems to be the 
problem... Angle brackets are surely not required.

> #7:
> In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp
>
> total: 1 errors, 0 warnings, 0 checks, 27 lines checked
>
>
> Regards
> Feng

[...]

MBR, Sergei

Re: [PATCH nf v2 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register

[Feng Gao]

On Tue, Mar 21, 2017 at 12:35 AM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> On 03/20/2017 01:15 PM, Feng Gao wrote:
>
>>>> From: Gao Feng <fgao@ikuai8.com>
>>>>
>>>> In the commit <93557f53e1fb> ("netfilter: nf_conntrack: nf_conntrack
>>>> snmp
>>>
>>>
>>>
>>>    Angle brackets not needed. :-)
>>>    The commit citing style is the same as for the Fixes: tag.
>>
>>
>> The checkpatch.pl reports the following error, if remove the angle
>> brackets.
>
>
>    Because it stops recognizing the commit ID! :-)
>
>> ERROR: Please use git commit description style 'commit <12+ chars of
>> sha1> ("<title line>")' - ie: 'commit fatal: ambig ("evision or path
>> not in the working tree.")'
>
>
>    So check the patch in the correct tree because that seems to be the
> problem... Angle brackets are surely not required.

Actually I didn't add the angle brackets firstly, but it fail to pass
the check_patch.pl check.
So I had to modify it.

Ok, I removed the angle brackets now, just ignored the error report of
check_patch.pl.

Best Regards
Feng

>
>> #7:
>> In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp
>>
>> total: 1 errors, 0 warnings, 0 checks, 27 lines checked
>>
>>
>> Regards
>> Feng
>
>
> [...]
>
> MBR, Sergei
>