There are use-after-free bugs caused by tst_timer. The root cause
is that there are no functions to stop tst_timer in idt77252_exit().
One of the possible race conditions is shown below:
(thread 1) | (thread 2)
| idt77252_init_one
| init_card
| fill_tst
| mod_timer(&card->tst_timer, ...)
idt77252_exit | (wait a time)
| tst_timer
|
| ...
kfree(card) // FREE |
| card->soft_tst[e] // USE
The idt77252_dev is deallocated in idt77252_exit() and used in
timer handler.
This patch adds del_timer_sync() in idt77252_exit() in order that
the timer handler could be stopped before the idt77252_dev is
deallocated.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Duoming Zhou <[email protected]>
---
drivers/atm/idt77252.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index 81ce81a75fc..681cb378679 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -3752,6 +3752,7 @@ static void __exit idt77252_exit(void)
card = idt77252_chain;
dev = card->atmdev;
idt77252_chain = card->next;
+ del_timer_sync(&card->tst_timer);
if (dev->phy->stop)
dev->phy->stop(dev);
--
2.17.1
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:
On Fri, 5 Aug 2022 15:00:08 +0800 you wrote:
> There are use-after-free bugs caused by tst_timer. The root cause
> is that there are no functions to stop tst_timer in idt77252_exit().
> One of the possible race conditions is shown below:
>
> (thread 1) | (thread 2)
> | idt77252_init_one
> | init_card
> | fill_tst
> | mod_timer(&card->tst_timer, ...)
> idt77252_exit | (wait a time)
> | tst_timer
> |
> | ...
> kfree(card) // FREE |
> | card->soft_tst[e] // USE
>
> [...]
Here is the summary with links:
- atm: idt77252: fix use-after-free bugs caused by tst_timer
https://git.kernel.org/netdev/net/c/3f4093e2bf46
You are awesome, thank you!
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