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authorDuoming Zhou <duoming@zju.edu.cn>2022-10-09 14:37:31 +0800
committerDavid S. Miller <davem@davemloft.net>2022-10-09 19:11:54 +0100
commit175302f6b79ebbb207c2d58d6d3e679465de23b0 (patch)
tree3e4623c4784e110645f8eb3c38562d65f6e33b1a /drivers/isdn
parentaabf6155dfb83262ef9a10af4bef945e7aba9b8e (diff)
downloadlwn-175302f6b79ebbb207c2d58d6d3e679465de23b0.tar.gz
lwn-175302f6b79ebbb207c2d58d6d3e679465de23b0.zip
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.c3
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);
}