Searched hist:bd1c06a4f5e2b2c96b9ff09a13983efb2d013b18 (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/drivers/char/ipmi/ |
| H A D | ipmi_si_intf.c | diff bd1c06a4f5e2b2c96b9ff09a13983efb2d013b18 Mon Jan 15 01:58:12 CST 2018 Masamitsu Yamazaki <m-yamazaki@ah.jp.nec.com> ipmi: Clear smi_info->thread to prevent use-after-free during module unload
During code inspection, I found an use-after-free possibility during unloading
ipmi_si in the polling mode.
If start_new_msg() is called after kthread_stop(), the function will try to
wake up non-existing kthread using the dangling pointer.
Possible scenario is when a new internal message is generated after
ipmi_unregister_smi()[*1] and remains after stop_timer_and_thread()
in clenaup_one_si() [*2].
Use-after-free could occur as follows depending on BMC replies.
cleanup_one_si
=> ipmi_unregister_smi
[*1]
=> stop_timer_and_thread
=> kthread_stop(smi_info->thread)
[*2]
=> poll
=> smi_event_handler
=> start_new_msg
=> if (smi_info->thread)
wake_up_process(smi_info->thread) <== use-after-free!!
Although currently it seems no such message is generated in the polling mode,
some changes might introduce that in thefuture. For example in the interrupt
mode, disable_si_irq() does that at [*2].
So let's prevent such a critical issue possibility now.
Signed-off-by: Yamazaki Masamitsu <m-yamazaki@ah.jp.nec.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
|