diff options
| author |   Lin Ma <linma@zju.edu.cn> | 2021-11-08 18:37:59 +0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2021-11-09 11:49:12 +0000 |
| commit | 0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 (patch) | |
| tree | 170686756f3248243afccecb824ca94187b50809 /drivers/net/hamradio/6pack.c | |
| parent | hamradio: defer ax25 kfree after unregister_netdev (diff) | |
| download | linux-dev-0b9111922b1f399aba6ed1e1b8f2079c3da1aed8.tar.xz linux-dev-0b9111922b1f399aba6ed1e1b8f2079c3da1aed8.zip | |
hamradio: defer 6pack kfree after unregister_netdev
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>
Diffstat (limited to 'drivers/net/hamradio/6pack.c')
| -rw-r--r-- | drivers/net/hamradio/6pack.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c index f4e8793e995d..fb0a3825edd0 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -672,11 +672,13 @@ 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. */ + unregister_netdev(sp->dev); + + /* Free all 6pack frame buffers after unreg. */ kfree(sp->rbuff); kfree(sp->xbuff); - unregister_netdev(sp->dev); + free_netdev(sp->dev); } /* Perform I/O control on an active 6pack channel. */ |