ath9k: Fix STA disconnect issue due to received MIC failed bcast frames

AR_RxKeyIdxValid will not be set for bcast/mcast frames and so relying
this status for MIC failed frames is buggy.

Due to this, MIC failure events for broadcast frames are not sent to
supplicant resulted in AP disconnecting the STA.

Able to pass Wifi Test case 5.2.18 with this fix.

Cc: Stable <stable@kernel.org> (2.6.36+)
Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/mac.c

@@ -703,8 +703,7 @@ int ath9k_hw_rxprocdesc(struct ath_hw *ah, struct ath_desc *ds,
 			rs->rs_phyerr = phyerr;
 		} else if (ads.ds_rxstatus8 & AR_DecryptCRCErr)
 			rs->rs_status |= ATH9K_RXERR_DECRYPT;
-		else if ((ads.ds_rxstatus8 & AR_MichaelErr) &&
-		         rs->rs_keyix != ATH9K_RXKEYIX_INVALID)
+		else if (ads.ds_rxstatus8 & AR_MichaelErr)
 			rs->rs_status |= ATH9K_RXERR_MIC;
 		else if (ads.ds_rxstatus8 & AR_KeyMiss)
 			rs->rs_status |= ATH9K_RXERR_DECRYPT;

drivers/net/wireless/ath/ath9k/recv.c

@@ -838,6 +838,10 @@ static bool ath9k_rx_accept(struct ath_common *common,
 			    struct ath_rx_status *rx_stats,
 			    bool *decrypt_error)
 {
+#define is_mc_or_valid_tkip_keyix ((is_mc ||			\
+		(rx_stats->rs_keyix != ATH9K_RXKEYIX_INVALID && \
+		test_bit(rx_stats->rs_keyix, common->tkip_keymap))))
+
 	struct ath_hw *ah = common->ah;
 	__le16 fc;
 	u8 rx_status_len = ah->caps.rx_status_len;
@@ -879,15 +883,18 @@ static bool ath9k_rx_accept(struct ath_common *common,
 		if (rx_stats->rs_status & ATH9K_RXERR_DECRYPT) {
 			*decrypt_error = true;
 		} else if (rx_stats->rs_status & ATH9K_RXERR_MIC) {
+			bool is_mc;
 			/*
 			 * The MIC error bit is only valid if the frame
 			 * is not a control frame or fragment, and it was
 			 * decrypted using a valid TKIP key.
 			 */
+			is_mc = !!is_multicast_ether_addr(hdr->addr1);
+
 			if (!ieee80211_is_ctl(fc) &&
 			    !ieee80211_has_morefrags(fc) &&
 			    !(le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG) &&
-			    test_bit(rx_stats->rs_keyix, common->tkip_keymap))
+			    is_mc_or_valid_tkip_keyix)
 				rxs->flag |= RX_FLAG_MMIC_ERROR;
 			else
 				rx_stats->rs_status &= ~ATH9K_RXERR_MIC;