[PATCH 1/1] NET: ipv6, fix potential null dereference

[Jiri Slaby]

Stanse found a potential null dereference in snmp6_unregister_dev.
There is a check for idev being NULL, but it is dereferenced
earlier. Move the dereference after the check.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Cc: "Pekka Savola (ipv6)" <pekkas@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
---
 net/ipv6/proc.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index c9605c3..53f4ef5 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -256,11 +256,12 @@ int snmp6_register_dev(struct inet6_dev *idev)
 
 int snmp6_unregister_dev(struct inet6_dev *idev)
 {
-	struct net *net = dev_net(idev->dev);
-	if (!net->mib.proc_net_devsnmp6)
-		return -ENOENT;
+	struct net *net;
 	if (!idev || !idev->stats.proc_dir_entry)
 		return -EINVAL;
+	net = dev_net(idev->dev);
+	if (!net->mib.proc_net_devsnmp6)
+		return -ENOENT;
 	remove_proc_entry(idev->stats.proc_dir_entry->name,
 			  net->mib.proc_net_devsnmp6);
 	idev->stats.proc_dir_entry = NULL;
-- 
1.6.5.7

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