[PATCH 4.19 178/313] mac80211: fix radiotap vendor presence bitmap handling

Greg Kroah-Hartman
2019-02-11T14:47:04Z

[ Upstream commit efc38dd7d5fa5c8cdd0c917c5d00947aa0539443 ]

Due to the alignment handling, it actually matters where in the code
we add the 4 bytes for the presence bitmap to the length; the first
field is the timestamp with 8 byte alignment so we need to add the
space for the extra vendor namespace presence bitmap *before* we do
any alignment for the fields.

Move the presence bitmap length accounting to the right place to fix
the alignment for the data properly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mac80211/rx.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 5e2b4a41acf1..51ad330bf8e8 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -142,6 +142,9 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
/* allocate extra bitmaps */
if (status->chains)
len += 4 * hweight8(status->chains);
+ /* vendor presence bitmap */
+ if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA)
+ len += 4;

if (ieee80211_have_rx_timestamp(status)) {
len = ALIGN(len, 8);
@@ -197,8 +200,6 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA) {
struct ieee80211_vendor_radiotap *rtap = (void *)skb->data;

- /* vendor presence bitmap */
- len += 4;
/* alignment for fixed 6-byte vendor data header */
len = ALIGN(len, 2);
/* vendor data header */
--
2.19.1