[ 26/95] ath9k: fix decrypt_error initialization in ath_rx_tasklet()

From: Ben Hutchings
Date: Sun Sep 09 2012 - 19:39:06 EST

3.2-stable review patch. If anyone has any objections, please let me know.


From: Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx>

commit e1352fde5682ab1bdd2a9e5d75c22d1fe210ef77 upstream.

ath_rx_tasklet() calls ath9k_rx_skb_preprocess() and ath9k_rx_skb_postprocess()
in a loop over the received frames. The decrypt_error flag is
initialized to false
just outside ath_rx_tasklet() loop. ath9k_rx_accept(), called by
only sets decrypt_error to true and never to false.
Then ath_rx_tasklet() calls ath9k_rx_skb_postprocess() and passes
decrypt_error to it.
So, after a decryption error, in ath9k_rx_skb_postprocess(), we can
have a leftover value
from another processed frame. In that case, the frame will not be marked with
RX_FLAG_DECRYPTED even if it is decrypted correctly.
When using CCMP encryption this issue can lead to connection stuck
because of CCMP
PN corruption and a waste of CPU time since mac80211 tries to decrypt an already
deciphered frame with ieee80211_aes_ccm_decrypt.
Fix the issue initializing decrypt_error flag at the begging of the
ath_rx_tasklet() loop.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
drivers/net/wireless/ath/ath9k/recv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -1782,7 +1782,6 @@ int ath_rx_tasklet(struct ath_softc *sc,
struct ieee80211_hw *hw = sc->hw;
struct ieee80211_hdr *hdr;
int retval;
- bool decrypt_error = false;
struct ath_rx_status rs;
enum ath9k_rx_qtype qtype;
bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
@@ -1804,6 +1803,7 @@ int ath_rx_tasklet(struct ath_softc *sc,
tsf_lower = tsf & 0xffffffff;

do {
+ bool decrypt_error = false;
/* If handling rx interrupt and flush is in progress => exit */
if ((sc->sc_flags & SC_OP_RXFLUSH) && (flush == 0))

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