[PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Qianfeng Rong]

Use kcalloc to allocate 'adapter->chan_stats' memory (max 900 bytes)
instead of vmalloc for efficiency and zero-initialize it for security
per Dan Carpenter's suggestion.

Cc: stable@vger.kernel.org
Fixes: bf35443314ac ("mwifiex: channel statistics support for mwifiex")
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
---
v2: Change vmalloc_array/vfree to kcalloc/kfree.
---
 drivers/net/wireless/marvell/mwifiex/cfg80211.c | 5 +++--
 drivers/net/wireless/marvell/mwifiex/main.c     | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 3498743d5ec0..4c8c7a5fdf23 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -4673,8 +4673,9 @@ int mwifiex_init_channel_scan_gap(struct mwifiex_adapter *adapter)
 	 * additional active scan request for hidden SSIDs on passive channels.
 	 */
 	adapter->num_in_chan_stats = 2 * (n_channels_bg + n_channels_a);
-	adapter->chan_stats = vmalloc(array_size(sizeof(*adapter->chan_stats),
-						 adapter->num_in_chan_stats));
+	adapter->chan_stats = kcalloc(adapter->num_in_chan_stats,
+				      sizeof(*adapter->chan_stats),
+				      GFP_KERNEL);
 
 	if (!adapter->chan_stats)
 		return -ENOMEM;
diff --git a/drivers/net/wireless/marvell/mwifiex/main.c b/drivers/net/wireless/marvell/mwifiex/main.c
index 7b50a88a18e5..1ec069bc8ea1 100644
--- a/drivers/net/wireless/marvell/mwifiex/main.c
+++ b/drivers/net/wireless/marvell/mwifiex/main.c
@@ -642,7 +642,7 @@ static int _mwifiex_fw_dpc(const struct firmware *firmware, void *context)
 	goto done;
 
 err_add_intf:
-	vfree(adapter->chan_stats);
+	kfree(adapter->chan_stats);
 err_init_chan_scan:
 	wiphy_unregister(adapter->wiphy);
 	wiphy_free(adapter->wiphy);
@@ -1485,7 +1485,7 @@ static void mwifiex_uninit_sw(struct mwifiex_adapter *adapter)
 	wiphy_free(adapter->wiphy);
 	adapter->wiphy = NULL;
 
-	vfree(adapter->chan_stats);
+	kfree(adapter->chan_stats);
 	mwifiex_free_cmd_buffers(adapter);
 }
 
-- 
2.34.1

Re: [PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Markus Elfring]

> Use kcalloc to allocate 'adapter->chan_stats' memory …

I find the summary phrase and change description improvable.

Regards,
Markus

Re: [PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Dan Carpenter]

On Thu, Aug 14, 2025 at 09:15:31PM +0800, Qianfeng Rong wrote:
> Use kcalloc to allocate 'adapter->chan_stats' memory (max 900 bytes)
> instead of vmalloc for efficiency and zero-initialize it for security
> per Dan Carpenter's suggestion.
> 

This patch is okay, but lets re-write the commit message:

Subject: wifi: mwifiex: Initialize the chan_stats array to zero

The adapter->chan_stats[] array is initialized in
mwifiex_init_channel_scan_gap() with vmalloc(), which doesn't zero out
memory.  The array is filled in mwifiex_update_chan_statistics()
and then the user can query the data in mwifiex_cfg80211_dump_survey().

There are two potential issues here.  What if the user calls
mwifiex_cfg80211_dump_survey() before the data has been filled in.
Also the mwifiex_update_chan_statistics() function doesn't necessarily
initialize the whole array.  Since the array was not initialized at
the start that could result in an information leak.

Also this array is pretty small.  It's a maximum of 900 bytes so it's
more appropriate to use kcalloc() instead vmalloc().

regards,
dan carpenter

Re: [PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Qianfeng Rong]

在 2025/8/14 22:50, Dan Carpenter 写道:
> On Thu, Aug 14, 2025 at 09:15:31PM +0800, Qianfeng Rong wrote:
>> Use kcalloc to allocate 'adapter->chan_stats' memory (max 900 bytes)
>> instead of vmalloc for efficiency and zero-initialize it for security
>> per Dan Carpenter's suggestion.
>>
> This patch is okay, but lets re-write the commit message:
>
> Subject: wifi: mwifiex: Initialize the chan_stats array to zero
>
> The adapter->chan_stats[] array is initialized in
> mwifiex_init_channel_scan_gap() with vmalloc(), which doesn't zero out
> memory.  The array is filled in mwifiex_update_chan_statistics()
> and then the user can query the data in mwifiex_cfg80211_dump_survey().
>
> There are two potential issues here.  What if the user calls
> mwifiex_cfg80211_dump_survey() before the data has been filled in.
> Also the mwifiex_update_chan_statistics() function doesn't necessarily
> initialize the whole array.  Since the array was not initialized at
> the start that could result in an information leak.
>
> Also this array is pretty small.  It's a maximum of 900 bytes so it's
> more appropriate to use kcalloc() instead vmalloc().
Ok，Thank you for your correction, I will release the next version soon.
>
> regards,
> dan carpenter

Best regards,
Qianfeng

>

Re: [v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Markus Elfring]

> This patch is okay, but lets re-write the commit message:
…

Can such feedback trigger further collateral evolution?

Will any related software design options become more interesting?

Regards,
Markus

Re: [PATCH v2] wifi: mwifiex: use kcalloc to apply for chan_stats

[Johannes Berg]

On Thu, 2025-08-14 at 16:33 +0200, Markus Elfring wrote:
> > Use kcalloc to allocate 'adapter->chan_stats' memory …
> 
> I find the summary phrase and change description improvable.

We all find your behaviour improvable. Go away and leave the wireless
list alone.

johannes