net: bridge: fix ioctl old_deviceless bridge argument

Commit ad2f99aedf8f ("net: bridge: move bridge ioctls out of .ndo_do_ioctl")
changed the source of the argument copy in bridge's old_deviceless() from
args[1] (user ptr to device name) to uarg (ptr to ioctl arguments) causing
wrong device name to be used.

Example (broken, bridge exists but is up):
$ brctl delbr bridge
bridge bridge doesn't exist; can't delete it

Example (working):
$ brctl delbr bridge
bridge bridge is still up; can't delete it

Fixes: ad2f99aedf8f ("net: bridge: move bridge ioctls out of .ndo_do_ioctl")
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 2f848de3e75505e9b73e0667f53f1750737d110b..793b0db9d9a36f75032f293953ac97aa9bf1ad11 100644 (file)
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -351,7 +351,7 @@ static int old_deviceless(struct net *net, void __user *uarg)
                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                        return -EPERM;
 
-               if (copy_from_user(buf, uarg, IFNAMSIZ))
+               if (copy_from_user(buf, (void __user *)args[1], IFNAMSIZ))
                        return -EFAULT;
 
                buf[IFNAMSIZ-1] = 0;