2021-12-27 16:58:20

by Christophe JAILLET

Subject: [PATCH] ath: dfs_pattern_detector: Avoid open coded arithmetic in memory allocation

kmalloc_array()/kcalloc() should be used to avoid potential overflow when
a multiplication is needed to compute the size of the requested memory.

kmalloc_array() can be used here instead of kcalloc() because the array is
fully initialized in the next 'for' loop.

Finally, 'cd->detectors' is defined as 'struct pri_detector **detectors;'.
So 'cd->detectors' and '*cd->detectors' are both some pointer.
So use a more logical 'sizeof(*cd->detectors)'.

Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/net/wireless/ath/dfs_pattern_detector.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/dfs_pattern_detector.c b/drivers/net/wireless/ath/dfs_pattern_detector.c
index 75cb53a3ec15..27f4d74a41c8 100644
--- a/drivers/net/wireless/ath/dfs_pattern_detector.c
+++ b/drivers/net/wireless/ath/dfs_pattern_detector.c
@@ -197,7 +197,7 @@ static void channel_detector_exit(struct dfs_pattern_detector *dpd,
static struct channel_detector *
channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
{
- u32 sz, i;
+ u32 i;
struct channel_detector *cd;

cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
@@ -206,8 +206,8 @@ channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)

INIT_LIST_HEAD(&cd->head);
cd->freq = freq;
- sz = sizeof(cd->detectors) * dpd->num_radar_types;
- cd->detectors = kzalloc(sz, GFP_ATOMIC);
+ cd->detectors = kmalloc_array(dpd->num_radar_types,
+ sizeof(*cd->detectors), GFP_ATOMIC);
if (cd->detectors == NULL)
goto fail;

--
2.32.0

2022-01-18 02:24:41

by Kalle Valo

Subject: Re: [PATCH] ath: dfs_pattern_detector: Avoid open coded arithmetic in memory allocation

Christophe JAILLET <[email protected]> wrote:

> kmalloc_array()/kcalloc() should be used to avoid potential overflow when
> a multiplication is needed to compute the size of the requested memory.
>
> kmalloc_array() can be used here instead of kcalloc() because the array is
> fully initialized in the next 'for' loop.
>
> Finally, 'cd->detectors' is defined as 'struct pri_detector **detectors;'.
> So 'cd->detectors' and '*cd->detectors' are both some pointer.
> So use a more logical 'sizeof(*cd->detectors)'.
>
> Signed-off-by: Christophe JAILLET <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

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

a063b650ce5d ath: dfs_pattern_detector: Avoid open coded arithmetic in memory allocation

--
https://patchwork.kernel.org/project/linux-wireless/patch/0fbcd32a0384ac1f87c5a3549e505e4becc60226.1640624216.git.christophe.jaillet@wanadoo.fr/

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