wimax: i2400: Fix memory leak in i2400m_op_rfkill_sw_toggle

mainline inclusion
from mainline-v5.4-rc6
commit 6f3ef5c25cc762687a7341c18cbea5af54461407
category: bugfix
bugzilla: 13690
CVE: CVE-2019-19051

-------------------------------------------------

In the implementation of i2400m_op_rfkill_sw_toggle() the allocated
buffer for cmd should be released before returning. The
documentation for i2400m_msg_to_dev() says when it returns the buffer
can be reused. Meaning cmd should be released in either case. Move
kfree(cmd) before return to be reached by all execution paths.

Fixes: 2507e6ab7a9a ("wimax: i2400: fix memory leak")
Signed-off-by: NNavid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NWenan Mao <maowenan@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/wimax/i2400m/op-rfkill.c

@@ -142,12 +142,12 @@ int i2400m_op_rfkill_sw_toggle(struct wimax_dev *wimax_dev,
 			"%d\n", result);
 	result = 0;
 error_cmd:
-	kfree(cmd);
 	kfree_skb(ack_skb);
 error_msg_to_dev:
 error_alloc:
 	d_fnend(4, dev, "(wimax_dev %p state %d) = %d\n",
 		wimax_dev, state, result);
+	kfree(cmd);
 	return result;
 }