2020-09-15 05:59:55

by zhuguangqing83

[permalink] [raw]
Subject: [PATCH] thermal: Fix slab-out-of-bounds in thermal_cooling_device_stats_update()

From: zhuguangqing <[email protected]>

In function thermal_cooling_device_stats_update(), if the input parameter
new_state is greater or equal to stats->max_states, then it will cause
slab-out-of-bounds error when execute the code as follows:
stats->trans_table[stats->state * stats->max_states + new_state]++;

Two functions call the function thermal_cooling_device_stats_update().
1. cur_state_store()
2. thermal_cdev_set_cur_state()
Both of the two functions call cdev->ops->set_cur_state(cdev, state)
before thermal_cooling_device_stats_update(), if the return value is
not 0, then thermal_cooling_device_stats_update() will not be called.
So if all cdev->ops->set_cur_state(cdev, state) check validity of the
parameter state, then it's ok. Unfortunately, it's not now.

We have two methods to avoid the slab-out-of-bounds error in
thermal_cooling_device_stats_update().
1. Check the validity of the parameter state in all
cdev->ops->set_cur_state(cdev, state).
2. Check the validity of the parameter state in
thermal_cooling_device_stats_update().

Use method 2 in this patch. Because the modification is simple and
resolve the problem in the scope of "#ifdef CONFIG_THERMAL_STATISTICS".

Signed-off-by: zhuguangqing <[email protected]>
---
drivers/thermal/thermal_sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 8c231219e15d..9c49f744d79d 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -756,7 +756,7 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,

spin_lock(&stats->lock);

- if (stats->state == new_state)
+ if (stats->state == new_state || new_state >= stats->max_states)
goto unlock;

update_time_in_state(stats);
--
2.17.1


2020-11-17 07:20:30

by Zhang Rui

[permalink] [raw]
Subject: Re: [PATCH] thermal: Fix slab-out-of-bounds in thermal_cooling_device_stats_update()

On Tue, 2020-09-15 at 13:58 +0800, [email protected] wrote:
> From: zhuguangqing <[email protected]>
>
> In function thermal_cooling_device_stats_update(), if the input
> parameter
> new_state is greater or equal to stats->max_states, then it will
> cause
> slab-out-of-bounds error when execute the code as follows:
> stats->trans_table[stats->state * stats->max_states + new_state]++;
>
> Two functions call the function
> thermal_cooling_device_stats_update().
> 1. cur_state_store()
> 2. thermal_cdev_set_cur_state()
> Both of the two functions call cdev->ops->set_cur_state(cdev, state)
> before thermal_cooling_device_stats_update(), if the return value is
> not 0, then thermal_cooling_device_stats_update() will not be called.
> So if all cdev->ops->set_cur_state(cdev, state) check validity of the
> parameter state, then it's ok. Unfortunately, it's not now.
>
> We have two methods to avoid the slab-out-of-bounds error in
> thermal_cooling_device_stats_update().
> 1. Check the validity of the parameter state in all
> cdev->ops->set_cur_state(cdev, state).
> 2. Check the validity of the parameter state in
> thermal_cooling_device_stats_update().
>
> Use method 2 in this patch. Because the modification is simple and
> resolve the problem in the scope of "#ifdef
> CONFIG_THERMAL_STATISTICS".
>
> Signed-off-by: zhuguangqing <[email protected]>

Hi, Daniel,

this patch is a similar fix as

https://patchwork.kernel.org/project/linux-pm/patch/[email protected]/

I think we'd better take the original fix from Takashi Iwai.
And I will refresh and submit the patches that supports dynamic cooling
states later when I have time.

thanks,
rui
> ---
> drivers/thermal/thermal_sysfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/thermal_sysfs.c
> b/drivers/thermal/thermal_sysfs.c
> index 8c231219e15d..9c49f744d79d 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -756,7 +756,7 @@ void thermal_cooling_device_stats_update(struct
> thermal_cooling_device *cdev,
>
> spin_lock(&stats->lock);
>
> - if (stats->state == new_state)
> + if (stats->state == new_state || new_state >= stats-
> >max_states)
> goto unlock;
>
> update_time_in_state(stats);