Re: [PATCH ath-current v2] wifi: ath10k: Fix connection after GTK rekeying

[Baochen Qiang <baochen.qiang@oss.qualcomm.com>]

On 9/2/2025 10:32 PM, Loic Poulain wrote:
> It appears that not all hardware/firmware implementations support
> group key deletion correctly, which can lead to connection hangs
> and deauthentication following GTK rekeying (delete and install).
> 
> To avoid this issue, instead of attempting to delete the key using
> the special WMI_CIPHER_NONE value, we now replace the key with an
> invalid (random) value.
> 
> This behavior has been observed with WCN39xx chipsets.
> 
> Tested-on: WCN3990 hw1.0 WLAN.HL.3.3.7.c2-00931-QCAHLSWMTPLZ-1
> Reported-by: "Alexey Klimov" <alexey.klimov@linaro.org>
> Closes: https://lore.kernel.org/all/DAWJQ2NIKY28.1XOG35E4A682G@linaro.org
> Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
> ---
>  v2: use random value instead of predictable zero value for key
>      Add Tested-on tag
> 
>  drivers/net/wireless/ath/ath10k/mac.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
> index 24dd794e31ea..154ac7a70982 100644
> --- a/drivers/net/wireless/ath/ath10k/mac.c
> +++ b/drivers/net/wireless/ath/ath10k/mac.c
> @@ -16,6 +16,7 @@
>  #include <linux/acpi.h>
>  #include <linux/of.h>
>  #include <linux/bitfield.h>
> +#include <linux/random.h>
>  
>  #include "hif.h"
>  #include "core.h"
> @@ -290,8 +291,15 @@ static int ath10k_send_key(struct ath10k_vif *arvif,
>  		key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
>  
>  	if (cmd == DISABLE_KEY) {
> -		arg.key_cipher = ar->wmi_key_cipher[WMI_CIPHER_NONE];
> -		arg.key_data = NULL;
> +		if (flags & WMI_KEY_GROUP) {
> +			/* Not all hardware handles group-key deletion operation
> +			 * correctly. Replace the key with a junk value to invalidate it.
> +			 */
> +			get_random_bytes(key->key, key->keylen);
> +		} else {
> +			arg.key_cipher = ar->wmi_key_cipher[WMI_CIPHER_NONE];
> +			arg.key_data = NULL;
> +		}
>  	}
>  
>  	return ath10k_wmi_vdev_install_key(arvif->ar, &arg);

Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>