[PATCH 5.5 031/176] mac80211: consider more elements in parsing CRC

Greg Kroah-Hartman
2020-03-03T18:13:46Z

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit a04564c99bb4a92f805a58e56b2d22cc4978f152 ]

We only use the parsing CRC for checking if a beacon changed,
and elements with an ID > 63 cannot be represented in the
filter. Thus, like we did before with WMM and Cisco vendor
elements, just statically add these forgotten items to the
CRC:
- WLAN_EID_VHT_OPERATION
- WLAN_EID_OPMODE_NOTIF

I guess that in most cases when VHT/HE operation change, the HT
operation also changed, and so the change was picked up, but we
did notice that pure operating mode notification changes were
ignored.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20200131111300.891737-22-luca@coelho.fi
[restrict to VHT for the mac80211 branch]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mac80211/util.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 32a7a53833c01..739e90555d8b9 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1063,16 +1063,22 @@ _ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
elem_parse_failed = true;
break;
case WLAN_EID_VHT_OPERATION:
- if (elen >= sizeof(struct ieee80211_vht_operation))
+ if (elen >= sizeof(struct ieee80211_vht_operation)) {
elems->vht_operation = (void *)pos;
- else
- elem_parse_failed = true;
+ if (calc_crc)
+ crc = crc32_be(crc, pos - 2, elen + 2);
+ break;
+ }
+ elem_parse_failed = true;
break;
case WLAN_EID_OPMODE_NOTIF:
- if (elen > 0)
+ if (elen > 0) {
elems->opmode_notif = pos;
- else
- elem_parse_failed = true;
+ if (calc_crc)
+ crc = crc32_be(crc, pos - 2, elen + 2);
+ break;
+ }
+ elem_parse_failed = true;
break;
case WLAN_EID_MESH_ID:
elems->mesh_id = pos;
--
2.20.1