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().

Cc: [email protected]
Fixes: bf35443 ("mwifiex: channel statistics support for mwifiex")
Suggested-by: Dan Carpenter <[email protected]>
Signed-off-by: Qianfeng Rong <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

Author: qianfengrong

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;

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);
 }