ath9k: fix reliability issues with TKIP MIC verification

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@27481 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 73 insertions, 0 deletions

diff --git a/package/mac80211/patches/550-ath9k_mmic_verify.patch b/package/mac80211/patches/550-ath9k_mmic_verify.patch
new file mode 100644
index 000000000..d280dff99
--- /dev/null
+++ b/package/mac80211/patches/550-ath9k_mmic_verify.patch
@@ -0,0 +1,73 @@
+--- a/drivers/net/wireless/ath/ath9k/recv.c
++++ b/drivers/net/wireless/ath/ath9k/recv.c
+@@ -814,16 +814,17 @@ static bool ath9k_rx_accept(struct ath_c
+ 			    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))))
+-
++	bool is_mc, is_valid_tkip, mic_error = false;
+ 	struct ath_hw *ah = common->ah;
+ 	__le16 fc;
+ 	u8 rx_status_len = ah->caps.rx_status_len;
+ 
+ 	fc = hdr->frame_control;
+ 
++	is_mc = !!is_multicast_ether_addr(hdr->addr1);
++	is_valid_tkip = rx_stats->rs_keyix != ATH9K_RXKEYIX_INVALID &&
++		test_bit(rx_stats->rs_keyix, common->tkip_keymap);
++
+ 	if (!rx_stats->rs_datalen)
+ 		return false;
+         /*
+@@ -853,19 +854,19 @@ static bool ath9k_rx_accept(struct ath_c
+ 		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.
++			 * decrypted using a valid TKIP key. For multicast
++			 * frames the hardware will not return a valid
++			 * key index, so accept the MIC bit for those
++			 * as well.
+ 			 */
+-			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) &&
+-			    is_mc_or_valid_tkip_keyix)
+-				rxs->flag |= RX_FLAG_MMIC_ERROR;
++			    (is_mc || is_valid_tkip))
++				mic_error = true;
+ 			else
+ 				rx_stats->rs_status &= ~ATH9K_RXERR_MIC;
+ 		}
+@@ -886,6 +887,22 @@ static bool ath9k_rx_accept(struct ath_c
+ 			}
+ 		}
+ 	}
++
++	/*
++	 * For unicast frames the MIC error bit can have false positives,
++	 * so all MIC error reports need to be validated in software.
++	 * False negatives are not common, so skip software verification
++	 * if the hardware considers the MIC valid.
++	 */
++	if (is_valid_tkip && ieee80211_is_data_present(hdr->frame_control) &&
++	    !(rx_stats->rs_status & (ATH9K_RXERR_DECRYPT | ATH9K_RXERR_CRC |
++				     ATH9K_RXERR_MIC))) {
++		/* Strip the Michael MIC */
++		rx_stats->rs_datalen -= 8;
++		rxs->flag |= RX_FLAG_MMIC_STRIPPED;
++	} else if (is_mc && mic_error) {
++		rxs->flag |= RX_FLAG_MMIC_ERROR;
++	}
+ 	return true;
+ }
+