2019-07-29 03:04:30

by Jia-Ju Bai

Subject: [PATCH] ath6kl: Fix a possible null-pointer dereference in ath6kl_htc_mbox_create()

In ath6kl_htc_mbox_create(), when kzalloc() on line 2855 fails,
target->dev is assigned to NULL, and ath6kl_htc_mbox_cleanup(target) is
called on line 2885.

In ath6kl_htc_mbox_cleanup(), target->dev is used on line 2895:
ath6kl_hif_cleanup_scatter(target->dev->ar);

Thus, a null-pointer dereference may occur.

To fix this bug, kfree(target) is called and NULL is returned when
kzalloc() on line 2855 fails.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/net/wireless/ath/ath6kl/htc_mbox.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath6kl/htc_mbox.c b/drivers/net/wireless/ath/ath6kl/htc_mbox.c
index 65c31da43c47..998947ef63b6 100644
--- a/drivers/net/wireless/ath/ath6kl/htc_mbox.c
+++ b/drivers/net/wireless/ath/ath6kl/htc_mbox.c
@@ -2855,8 +2855,8 @@ static void *ath6kl_htc_mbox_create(struct ath6kl *ar)
target->dev = kzalloc(sizeof(*target->dev), GFP_KERNEL);
if (!target->dev) {
ath6kl_err("unable to allocate memory\n");
- status = -ENOMEM;
- goto err_htc_cleanup;
+ kfree(target);
+ return NULL;
}

spin_lock_init(&target->htc_lock);
--
2.17.0

2019-09-04 06:22:40

by Kalle Valo

Subject: Re: [PATCH] ath6kl: Fix a possible null-pointer dereference in ath6kl_htc_mbox_create()

Jia-Ju Bai <[email protected]> wrote:

> In ath6kl_htc_mbox_create(), when kzalloc() on line 2855 fails,
> target->dev is assigned to NULL, and ath6kl_htc_mbox_cleanup(target) is
> called on line 2885.
>
> In ath6kl_htc_mbox_cleanup(), target->dev is used on line 2895:
> ath6kl_hif_cleanup_scatter(target->dev->ar);
>
> Thus, a null-pointer dereference may occur.
>
> To fix this bug, kfree(target) is called and NULL is returned when
> kzalloc() on line 2855 fails.
>
> This bug is found by a static analysis tool STCheck written by us.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

0e7bf23e4967 ath6kl: Fix a possible null-pointer dereference in ath6kl_htc_mbox_create()

--
https://patchwork.kernel.org/patch/11063157/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches