mac80211: accept public action frames with mismatched BSSID

Arik's patch "mac80211: allow action frames with unknown
BSSID in GO mode" allowed any action frames in P2P mode
to go through, but only to cooked monitor interfaces as
the IEEE80211_RX_RA_MATCH was still cleared. As a result
my no-monitor patches broke invitation responses.

Instead of allowing any action frames in P2P GO mode to
go through with a wrong BSSID like that patch did, allow
all public action frames. They will never be processed
by mac80211, but can be reported via nl80211 then.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 27 insertions, 3 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 66cedf6eb5c2..17f2a768e2ad 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1695,6 +1695,23 @@ static inline bool ieee80211_is_robust_mgmt_frame(struct ieee80211_hdr *hdr)
 }
 
 /**
+ * ieee80211_is_public_action - check if frame is a public action frame
+ * @hdr: the frame
+ * @len: length of the frame
+ */
+static inline bool ieee80211_is_public_action(struct ieee80211_hdr *hdr,
+                                              size_t len)
+{
+        struct ieee80211_mgmt *mgmt = (void *)hdr;
+
+        if (len < IEEE80211_MIN_ACTION_SIZE)
+                return false;
+        if (!ieee80211_is_action(hdr->frame_control))
+                return false;
+        return mgmt->u.action.category == WLAN_CATEGORY_PUBLIC;
+}
+
+/**
  * ieee80211_fhss_chan_to_freq - get channel frequency
  * @channel: the FHSS channel
  *
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 2a85fdfebde2..7d226417ef46 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2797,10 +2797,17 @@ static int prepare_for_handlers(struct ieee80211_rx_data *rx,
                                 return 0;
                 } else if (!ieee80211_bssid_match(bssid,
                                         sdata->vif.addr)) {
+                        /*
+                         * Accept public action frames even when the
+                         * BSSID doesn't match, this is used for P2P
+                         * and location updates. Note that mac80211
+                         * itself never looks at these frames.
+                         */
+                        if (!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
+                            ieee80211_is_public_action(hdr, skb->len))
+                                return 1;
                         if (!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
-                            !ieee80211_is_beacon(hdr->frame_control) &&
-                            !(ieee80211_is_action(hdr->frame_control) &&
-                              sdata->vif.p2p))
+                            !ieee80211_is_beacon(hdr->frame_control))
                                 return 0;
                         status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
                 }