Re: [PATCH 3/5] mac80211: remove unused status flag checks

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2010-08-11 at 15:12 +0300, Juuso Oikarinen wrote:

> > > The decryption code verifies whether or not
> > > a given frame was decrypted and verified by
> > > hardware. This is unnecessary, as the crypto
> > > RX handler already does it long before the
> > > decryption code is even invoked, so remove
> > > that code to avoid confusion.
> > > 
> > > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> > > ---
> > >  net/mac80211/wpa.c |   26 ++++++--------------------
> > >  1 file changed, 6 insertions(+), 20 deletions(-)
> > > 
> > 
> > This patch for some reason seems to break wl1271 WPA - association
> > succeeds but encrypted data transfer fails.
> > 
> > I still don't know why, but I'm looking into it.
> > 
> 
> It appears, that in function ieee80211_rx_h_decrypt we go here:
> 
> 	if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
> 		rx->key = stakey;
> 		/* Skip decryption if the frame is not protected. */
> 		if (!ieee80211_has_protected(hdr->frame_control))
> 			return RX_CONTINUE;
> 
> And here, as the frame is protected, we go out of the if, and end up in
> tkip_decrypt, which with this patch no longer checks whether the frame
> is already decrypted.
> 
> The frame then ends up dropped.

Err, you're right, sorry about that. There are too many paths here. How
about this patch?

johannes

--- wireless-testing.orig/net/mac80211/rx.c	2010-08-11 14:37:13.000000000 +0200
+++ wireless-testing/net/mac80211/rx.c	2010-08-11 14:38:13.000000000 +0200
@@ -873,6 +873,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_
 
 	if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
 		rx->key = stakey;
+		if ((status->flag & RX_FLAG_DECRYPTED) &&
+		    (status->flag & RX_FLAG_IV_STRIPPED))
+			return RX_CONTINUE;
 		/* Skip decryption if the frame is not protected. */
 		if (!ieee80211_has_protected(fc))
 			return RX_CONTINUE;