ath9k: fix reliability issues with TKIP MIC verification

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

diff --git a/package/mac80211/patches/550-ath9k_mmic_verify.patch b/package/mac80211/patches/550-ath9k_mmic_verify.patch
new file mode 100644 (file)
index 0000000..d280dff
--- /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;
+ }
+