diff options
| author | Duoming Zhou <duoming@zju.edu.cn> | 2022-10-09 14:37:31 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-10-09 19:11:54 +0100 |
| commit | 175302f6b79ebbb207c2d58d6d3e679465de23b0 (patch) | |
| tree | 3e4623c4784e110645f8eb3c38562d65f6e33b1a /drivers/isdn | |
| parent | aabf6155dfb83262ef9a10af4bef945e7aba9b8e (diff) | |
mISDN: hfcpci: Fix use-after-free bug in hfcpci_softirq
The function hfcpci_softirq() is a timer handler. If it
is running, the timer_pending() will return 0 and the
del_timer_sync() in HFC_cleanup() will not be executed.
As a result, the use-after-free bug will happen. The
process is shown below:
(cleanup routine) | (timer handler)
HFC_cleanup() | hfcpci_softirq()
if (timer_pending(&hfc_tl)) |
del_timer_sync() |
... | ...
pci_unregister_driver(hc) |
driver_unregister | driver_for_each_device
bus_remove_driver | _hfcpci_softirq
driver_detach | ...
put_device(dev) //[1]FREE |
| dev_get_drvdata(dev) //[2]USE
The device is deallocated is position [1] and used in
position [2].
Fix by removing the "timer_pending" check in HFC_cleanup(),
which makes sure that the hfcpci_softirq() have finished
before the resource is deallocated.
Fixes: 009fc857c5f6 ("mISDN: fix possible use-after-free in HFC_cleanup()")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
| -rw-r--r-- | drivers/isdn/hardware/mISDN/hfcpci.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c index af17459c1a5c..e964a8dd8512 100644 --- a/drivers/isdn/hardware/mISDN/hfcpci.c +++ b/drivers/isdn/hardware/mISDN/hfcpci.c @@ -2345,8 +2345,7 @@ HFC_init(void) static void __exit HFC_cleanup(void) { - if (timer_pending(&hfc_tl)) - del_timer_sync(&hfc_tl); + del_timer_sync(&hfc_tl); pci_unregister_driver(&hfc_driver); } |