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[SRU,OEM-5.17,1/1] atm: idt77252: fix use-after-free bugs caused by tst_timer

Message ID 20230602145323.697951-2-thibault.ferrante@canonical.com
State New
Headers show
Series CVE-2022-3635 | expand

Commit Message

Thibault Ferrante June 2, 2023, 2:53 p.m. UTC 
From: Duoming Zhou <duoming@zju.edu.cn>

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 <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220805070008.18007-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/atm/idt77252.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Roxana Nicolescu June 2, 2023, 3:38 p.m. UTC | #1 
On 02/06/2023 16:53, Thibault Ferrante wrote:
> From: Duoming Zhou <duoming@zju.edu.cn>
>
> 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 <duoming@zju.edu.cn>
> Link: https://lore.kernel.org/r/20220805070008.18007-1-duoming@zju.edu.cn
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There are 3 things missing here:
1. (cherry-picked from commit <commit>) I recommend using -x when you 
use git cherry-pick.
2. CVE number
3. Your SOB (option -s is useful too)

Ex:
(cherry-picked from commit 3f4093e2bf4673f218c0bf17d8362337c400e77b (If 
I am not mistaken)
CVE-2022-3635
Signed-off-by: Thibault Ferrante <thibault.ferrante@canonical.com>

> ---
>   drivers/atm/idt77252.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
> index 81ce81a75fc6..681cb3786794 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);


Hi,

I gave some feedback inline.

Roxana
diff mbox series

Patch

diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index 81ce81a75fc6..681cb3786794 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);