]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
usbnet: smsc95xx: Fix use-after-free after removal
authorTuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Sun, 21 Jun 2020 10:43:26 +0000 (13:43 +0300)
committerDavid S. Miller <davem@davemloft.net>
Mon, 22 Jun 2020 23:34:31 +0000 (16:34 -0700)
commitb835a71ef64a61383c414d6bf2896d2c0161deca
tree47baa98d5f2391248c50c4eef2f30ef6e30d79f5
parentf3fe412b0a634286a6a3753c3f9ff201e6bec716
usbnet: smsc95xx: Fix use-after-free after removal

Syzbot reports an use-after-free in workqueue context:

BUG: KASAN: use-after-free in mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 __smsc95xx_mdio_read drivers/net/usb/smsc95xx.c:217 [inline]
 smsc95xx_mdio_read+0x583/0x870 drivers/net/usb/smsc95xx.c:278
 check_carrier+0xd1/0x2e0 drivers/net/usb/smsc95xx.c:644
 process_one_work+0x777/0xf90 kernel/workqueue.c:2274
 worker_thread+0xa8f/0x1430 kernel/workqueue.c:2420
 kthread+0x2df/0x300 kernel/kthread.c:255

It looks like that smsc95xx_unbind() is freeing the structures that are
still in use by the concurrently running workqueue callback. Thus switch
to using cancel_delayed_work_sync() to ensure the work callback really
is no longer active.

Reported-by: syzbot+29dc7d4ae19b703ff947@syzkaller.appspotmail.com
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/usb/smsc95xx.c