[PATCH] libertas: Fix re-enabling IEEE PS with WPA/WPA2

[Andrey Yurovsky]

On Tue, Jun 16, 2009 at 12:53 PM, Dan Williams<dcbw at redhat.com> wrote:
> On Mon, 2009-06-15 at 13:01 -0700, Andrey Yurovsky wrote:
>> With IEEE PS enabled, the driver will temporarily take the device out of
>> PS mode to issue commands and then re-enable PS once the commands have
>> completed.  With WPA or WPA2 security, the driver fails to re-enable PS
>> mode because of a check for key lengths that are always zero.
>>
>> This patch removes the key lengths check (the local copy of the keys is
>> not maintained) and fixes IEEE PS mode with WPA or WPA2 security.
>> Tested on GSPI and SDIO interfaces with V9 firmware.
>
> I have no idea what this code was trying to do originally (I'm pretty
> sure it's a left-over from the vendor driver), but it seems like maybe
> it was ensuring that the adapter did *not* return to power-save mode
> until the supplicant had set the GTK?  There's a window where the GTK
> won't be set, and we probably shouldn't be entering PS mode until that
> window is closed.  Old sd8385 code from a Motorola phone has:
>
>        if ((Adapter->PSMode != Wlan802_11PowerModeCAM) &&
>                        (Adapter->PSState == PS_STATE_FULL_POWER) &&
>                        (Adapter->MediaConnectStatus ==
>                         WlanMediaStateConnected)) {
>                if(Adapter->SecInfo.WPAEnabled
>                        || Adapter->SecInfo.WPA2Enabled
>                ) {
>                        if(Adapter->IsGTK_SET == TRUE) {
>                                PRINTM(INFO, "EXEC_NEXT_CMD: WPA enabled and GTK_SET"
>                                        " go back to PS_SLEEP");
>                                PSSleep(priv, 0);
>                        }
>                } else
>                {
>                        PRINTM(INFO, "EXEC_NEXT_CMD: Command PendQ is empty,"
>                                " go back to PS_SLEEP");
>                        PSSleep(priv, 0);
>                }
>        }
>
> Says to me, "if WPA is enabled but the GTK hasn't been set yet, don't go
> to sleep".
>
> Does that sound like a plausible explanation of what the original bits
> intended to do?  Like I said, it was inherited, but there might have
> been a good reason for it.

That might be the original intention, but assoc_helper_wpa_keys() sets
both and lbs_cmd_802_11_key_material() then clears out the driver's
copy, which is then (incorrectly) checked when deciding whether to go
back to sleep.  As I understand it, the execution path for WPA/WPA2
association shouldn't cause this situation where WPA is enabled but
the GTK isn't set yet and we're deciding to go back to sleep.  Do you
agree?  Should we even be keeping the 'driver copy' of the keys?  I
don't see why we want to do that.  Thanks,

  -Andrey

>> Signed-off-by: Andrey Yurovsky <andrey at cozybit.com>
>> ---
>>  drivers/net/wireless/libertas/cmd.c |   29 +++++++----------------------
>>  1 files changed, 7 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/net/wireless/libertas/cmd.c b/drivers/net/wireless/libertas/cmd.c
>> index 01db705..5825396 100644
>> --- a/drivers/net/wireless/libertas/cmd.c
>> +++ b/drivers/net/wireless/libertas/cmd.c
>> @@ -1782,32 +1782,17 @@ int lbs_execute_next_command(struct lbs_private *priv)
>>               lbs_deb_host("EXEC_NEXT_CMD: sending command 0x%04x\n",
>>                           le16_to_cpu(cmd->command));
>>               lbs_submit_command(priv, cmdnode);
>> -     } else {
>> +     } else if ((priv->psmode != LBS802_11POWERMODECAM) &&
>> +                (priv->psstate == PS_STATE_FULL_POWER) &&
>> +                ((priv->connect_status == LBS_CONNECTED) ||
>> +                (priv->mesh_connect_status == LBS_CONNECTED))) {
>>               /*
>>                * check if in power save mode, if yes, put the device back
>>                * to PS mode
>>                */
>> -             if ((priv->psmode != LBS802_11POWERMODECAM) &&
>> -                 (priv->psstate == PS_STATE_FULL_POWER) &&
>> -                 ((priv->connect_status == LBS_CONNECTED) ||
>> -                 (priv->mesh_connect_status == LBS_CONNECTED))) {
>> -                     if (priv->secinfo.WPAenabled ||
>> -                         priv->secinfo.WPA2enabled) {
>> -                             /* check for valid WPA group keys */
>> -                             if (priv->wpa_mcast_key.len ||
>> -                                 priv->wpa_unicast_key.len) {
>> -                                     lbs_deb_host(
>> -                                            "EXEC_NEXT_CMD: WPA enabled and GTK_SET"
>> -                                            " go back to PS_SLEEP");
>> -                                     lbs_ps_sleep(priv, 0);
>> -                             }
>> -                     } else {
>> -                             lbs_deb_host(
>> -                                    "EXEC_NEXT_CMD: cmdpendingq empty, "
>> -                                    "go back to PS_SLEEP");
>> -                             lbs_ps_sleep(priv, 0);
>> -                     }
>> -             }
>> +             lbs_deb_host("EXEC_NEXT_CMD: cmdpendingq empty, "
>> +                             "go back to PS_SLEEP");
>> +             lbs_ps_sleep(priv, 0);
>>       }
>>
>>       ret = 0;
>
>