aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts

stable inclusion
from stable-v4.19.311
commit ad80c34944d7175fa1f5c7a55066020002921a99
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8TQCT
CVE: CVE-2023-6270

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

[ Upstream commit f98364e926626c678fb4b9004b75cacf92ff0662 ]

This patch is against CVE-2023-6270. The description of cve is:

  A flaw was found in the ATA over Ethernet (AoE) driver in the Linux
  kernel. The aoecmd_cfg_pkts() function improperly updates the refcnt on
  `struct net_device`, and a use-after-free can be triggered by racing
  between the free on the struct and the access through the `skbtxq`
  global queue. This could lead to a denial of service condition or
  potential code execution.

In aoecmd_cfg_pkts(), it always calls dev_put(ifp) when skb initial
code is finished. But the net_device ifp will still be used in
later tx()->dev_queue_xmit() in kthread. Which means that the
dev_put(ifp) should NOT be called in the success path of skb
initial code in aoecmd_cfg_pkts(). Otherwise tx() may run into
use-after-free because the net_device is freed.

This patch removed the dev_put(ifp) in the success path in
aoecmd_cfg_pkts(), and added dev_put() after skb xmit in tx().

Link: https://nvd.nist.gov/vuln/detail/CVE-2023-6270


Fixes: 7562f876 ("[NET]: Rework dev_base via list_head (v3)")
Signed-off-by: Chun-Yi Lee <jlee@suse.com>
Link: https://lore.kernel.org/r/20240305082048.25526-1-jlee@suse.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>