diff options
| author | Lin Ma <linma@zju.edu.cn> | 2021-11-08 13:37:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-20 10:34:03 +0300 |
| commit | c799c18a287e024e1c885da329aad8f719b255c3 (patch) | |
| tree | 701dacb39d033a6ffc2c42f0780acd5a5386fd8a | |
| parent | 8e663865f5284124196bc04e010e7344d8a278f3 (diff) | |
| download | linux-c799c18a287e024e1c885da329aad8f719b255c3.tar.xz | |
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: Xu Jia <xujia39@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 4650ca28a516..167c300a5f80 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -674,9 +674,11 @@ 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. */ |