diff options
| author | Lin Ma <linma@zju.edu.cn> | 2021-11-08 18:37:59 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-09 09:03:20 +0200 |
| commit | 7361a35bf33064da203e521357acc4fccb8927e5 (patch) | |
| tree | 7473a2626dd0805d37ce10f86795b9aa9b42ca2c /drivers | |
| parent | 7dea5913000c6a2974a00d9af8e7ffb54e47eac1 (diff) | |
hamradio: defer 6pack kfree after unregister_netdev
commit 0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 upstream.
There is a possible race condition (use-after-free) like below
(USE) | (FREE)
dev_queue_xmit |
__dev_queue_xmit |
__dev_xmit_skb |
sch_direct_xmit | ...
xmit_one |
netdev_start_xmit | tty_ldisc_kill
__netdev_start_xmit | 6pack_close
sp_xmit | kfree
sp_encaps |
|
According to the patch "defer ax25 kfree after unregister_netdev", this
patch reorder the kfree after the unregister_netdev to avoid the possible
UAF as the unregister_netdev() is well synchronized and won't return if
there is a running routine.
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/hamradio/6pack.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c index 02d6f3ad9aca..82507a688efe 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -679,9 +679,11 @@ static void sixpack_close(struct tty_struct *tty) del_timer_sync(&sp->tx_t); del_timer_sync(&sp->resync_t); - /* Free all 6pack frame buffers. */ + /* Free all 6pack frame buffers after unreg. */ kfree(sp->rbuff); kfree(sp->xbuff); + + free_netdev(sp->dev); } /* Perform I/O control on an active 6pack channel. */ |