mac80211: fix monitor mode tx radiotap header handling

When an injected frame gets buffered for a powersave STA or filtered
and retransmitted, mac80211 attempts to parse the radiotap header
again, which doesn't work because it's gone at that point.
This patch adds a new flag for checking the availability of a radiotap
header, so that it only attempts to parse it once, reusing the tx info
on the next call to ieee80211_tx().
This fixes severe issues with rekeying in AP mode.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 14c70452c245..e7b1cdc7651b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1108,7 +1108,7 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
         tx->flags |= IEEE80211_TX_FRAGMENTED;
 
         /* process and remove the injection radiotap header */
-        if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED)) {
+        if (unlikely(info->flags & IEEE80211_TX_INTFL_HAS_RADIOTAP)) {
                 if (!__ieee80211_parse_tx_radiotap(tx, skb))
                         return TX_DROP;
 
@@ -1117,6 +1117,7 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
                  * the radiotap header that was present and pre-filled
                  * 'tx' with tx control information.
                  */
+                info->flags &= ~IEEE80211_TX_INTFL_HAS_RADIOTAP;
         }
 
         /*
@@ -1499,7 +1500,8 @@ static void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
                 int hdrlen;
                 u16 len_rthdr;
 
-                info->flags |= IEEE80211_TX_CTL_INJECTED;
+                info->flags |= IEEE80211_TX_CTL_INJECTED |
+                               IEEE80211_TX_INTFL_HAS_RADIOTAP;
 
                 len_rthdr = ieee80211_get_radiotap_len(skb->data);
                 hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);