iwlwifi: mvm: fix beacon protection checks

Unfortunately, since beacon protection isn't fully available
yet, we didn't notice that there are problems with it and
that the replay detection isn't working correctly. We were
relying only on mac80211, since iwl_mvm_rx_crypto() exits
when !ieee80211_has_protected(), which is of course true for
protected (but not encrypted) management frames.

Fix this to properly detect protected (but not encrypted)
management frames and handle them - we continue to only care
about beacons since for others everything can and will be
checked in mac80211.

Change-Id: I09c262a8f6f9852cc8f513cdcb31a7f8f87dd8af
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Fixes: b1fdc2505abc ("iwlwifi: mvm: advertise BIGTK client support if available")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index c21736f..af5a6dd 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -272,10 +272,10 @@
 	rx_status->chain_signal[2] = S8_MIN;
 }
 
-static int iwl_mvm_rx_mgmt_crypto(struct ieee80211_sta *sta,
-				  struct ieee80211_hdr *hdr,
-				  struct iwl_rx_mpdu_desc *desc,
-				  u32 status)
+static int iwl_mvm_rx_mgmt_prot(struct ieee80211_sta *sta,
+				struct ieee80211_hdr *hdr,
+				struct iwl_rx_mpdu_desc *desc,
+				u32 status)
 {
 	struct iwl_mvm_sta *mvmsta;
 	struct iwl_mvm_vif *mvmvif;
@@ -285,6 +285,9 @@
 	u32 len = le16_to_cpu(desc->mpdu_len);
 	const u8 *frame = (void *)hdr;
 
+	if ((status & IWL_RX_MPDU_STATUS_SEC_MASK) == IWL_RX_MPDU_STATUS_SEC_NONE)
+		return 0;
+
 	/*
 	 * For non-beacon, we don't really care. But beacons may
 	 * be filtered out, and we thus need the firmware's replay
@@ -356,6 +359,10 @@
 	    IWL_RX_MPDU_STATUS_SEC_UNKNOWN && !mvm->monitor_on)
 		return -1;
 
+	if (unlikely(ieee80211_is_mgmt(hdr->frame_control) &&
+		     !ieee80211_has_protected(hdr->frame_control)))
+		return iwl_mvm_rx_mgmt_prot(sta, hdr, desc, status);
+
 	if (!ieee80211_has_protected(hdr->frame_control) ||
 	    (status & IWL_RX_MPDU_STATUS_SEC_MASK) ==
 	    IWL_RX_MPDU_STATUS_SEC_NONE)
@@ -411,7 +418,7 @@
 		stats->flag |= RX_FLAG_DECRYPTED;
 		return 0;
 	case RX_MPDU_RES_STATUS_SEC_CMAC_GMAC_ENC:
-		return iwl_mvm_rx_mgmt_crypto(sta, hdr, desc, status);
+		break;
 	default:
 		/*
 		 * Sometimes we can get frames that were not decrypted