[PATCH 6.0 28/34] wifi: mac80211: fix crash in beacon protection for P2P-device

Greg Kroah-Hartman
2022-10-13T18:13:06Z

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

commit b2d03cabe2b2e150ff5a381731ea0355459be09f upstream.

If beacon protection is active but the beacon cannot be
decrypted or is otherwise malformed, we call the cfg80211
API to report this to userspace, but that uses a netdev
pointer, which isn't present for P2P-Device. Fix this to
call it only conditionally to ensure cfg80211 won't crash
in the case of P2P-Device.

This fixes CVE-2022-42722.

Reported-by: Sönke Huster <shuster@seemoo.tu-darmstadt.de>
Fixes: 9eaf183af741 ("mac80211: Report beacon protection failures to user space")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/mac80211/rx.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1967,10 +1967,11 @@ ieee80211_rx_h_decrypt(struct ieee80211_

if (mmie_keyidx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS ||
mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS +
- NUM_DEFAULT_BEACON_KEYS) {
- cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
- skb->data,
- skb->len);
+ NUM_DEFAULT_BEACON_KEYS) {
+ if (rx->sdata->dev)
+ cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
+ skb->data,
+ skb->len);
return RX_DROP_MONITOR; /* unexpected BIP keyidx */
}

@@ -2121,7 +2122,8 @@ ieee80211_rx_h_decrypt(struct ieee80211_
/* either the frame has been decrypted or will be dropped */
status->flag |= RX_FLAG_DECRYPTED;

- if (unlikely(ieee80211_is_beacon(fc) && result == RX_DROP_UNUSABLE))
+ if (unlikely(ieee80211_is_beacon(fc) && result == RX_DROP_UNUSABLE &&
+ rx->sdata->dev))
cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
skb->data, skb->len);