Patch "netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
netfilter-nf_nat_snmp-fix-panic-when-snmp_trap_helper-fails-to-register.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Gao Feng <[email protected]>
Date: Sat, 25 Mar 2017 18:24:36 +0800
Subject: netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register

From: Gao Feng <[email protected]>

[ Upstream commit 75c689dca98851d65ef5a27e5ce26b625b68751c ]

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.

---
 net/ipv4/netfilter/nf_nat_snmp_basic.c |   19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

@@ -1260,16 +1260,6 @@ static const struct nf_conntrack_expect_
 	.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,

@@ -1288,17 +1278,10 @@ static struct nf_conntrack_helper snmp_t
 
 static int __init nf_nat_snmp_basic_init(void)
 {
-	int ret = 0;
-
 	BUG_ON(nf_nat_snmp_hook != NULL);
 	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);
-		return ret;
-	}
-	return ret;
+	return nf_conntrack_helper_register(&snmp_trap_helper);
 }
 
 static void __exit nf_nat_snmp_basic_fini(void)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/netfilter-nf_nat_snmp-fix-panic-when-snmp_trap_helper-fails-to-register.patch