148ca04518
There are UAF bugs caused by rose_t0timer_expiry(). The
root cause is that del_timer() could not stop the timer
handler that is running and there is no synchronization.
One of the race conditions is shown below:
(thread 1) | (thread 2)
| rose_device_event
| rose_rt_device_down
| rose_remove_neigh
rose_t0timer_expiry | rose_stop_t0timer(rose_neigh)
... | del_timer(&neigh->t0timer)
| kfree(rose_neigh) //[1]FREE
neigh->dce_mode //[2]USE |
The rose_neigh is deallocated in position [1] and use in
position [2].
The crash trace triggered by POC is like below:
BUG: KASAN: use-after-free in expire_timers+0x144/0x320
Write of size 8 at addr ffff888009b19658 by task swapper/0/0
...
Call Trace:
<IRQ>
dump_stack_lvl+0xbf/0xee
print_address_description+0x7b/0x440
print_report+0x101/0x230
? expire_timers+0x144/0x320
kasan_report+0xed/0x120
? expire_timers+0x144/0x320
expire_timers+0x144/0x320
__run_timers+0x3ff/0x4d0
run_timer_softirq+0x41/0x80
__do_softirq+0x233/0x544
...
This patch changes rose_stop_ftimer() and rose_stop_t0timer()
in rose_remove_neigh() to del_timer_sync() in order that the
timer handler could be finished before the resources such as
rose_neigh and so on are deallocated. As a result, the UAF
bugs could be mitigated.
Fixes:
|
||
|---|---|---|
| .. | ||
| Makefile | ||
| af_rose.c | ||
| rose_dev.c | ||
| rose_in.c | ||
| rose_link.c | ||
| rose_loopback.c | ||
| rose_out.c | ||
| rose_route.c | ||
| rose_subr.c | ||
| rose_timer.c | ||
| sysctl_net_rose.c | ||