net: bridge: fix ioctl old_deviceless bridge argument

[ Upstream commit d95a562 ]

Commit 561d835 ("bridge: use ndo_siocdevprivate") changed the
source and destination arguments of copy_{to,from}_user in bridge's
old_deviceless() from args[1] to uarg breaking SIOC{G,S}IFBR ioctls.

Commit cbd7ad2 ("net: bridge: fix ioctl old_deviceless bridge
argument") fixed only BRCTL_{ADD,DEL}_BRIDGES commands leaving
BRCTL_GET_BRIDGES one untouched.

The fixes BRCTL_GET_BRIDGES as well and has been tested with busybox's
brctl.

Example of broken brctl:
$ brctl show
bridge name     bridge id               STP enabled     interfaces
brctl: can't get bridge name for index 0: No such device or address

Example of fixed brctl:
$ brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.000000000000       no

Fixes: 561d835 ("bridge: use ndo_siocdevprivate")
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/all/20211223153139.7661-2-repk@triplefau.lt/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

net/bridge/br_ioctl.c

@@ -337,7 +337,7 @@ static int old_deviceless(struct net *net, void __user *uarg)
 
 		args[2] = get_bridge_ifindices(net, indices, args[2]);
 
-		ret = copy_to_user(uarg, indices,
+		ret = copy_to_user((void __user *)args[1], indices,
 				   array_size(args[2], sizeof(int)))
 			? -EFAULT : args[2];