wifi: nl80211: reject cooked mode if it is set along with other flags

It is possible to set both MONITOR_FLAG_COOK_FRAMES and MONITOR_FLAG_ACTIVE
flags simultaneously on the same monitor interface from the userspace. This
causes a sub-interface to be created with no IEEE80211_SDATA_IN_DRIVER bit
set because the monitor interface is in the cooked state and it takes
precedence over all other states. When the interface is then being deleted
the kernel calls WARN_ONCE() from check_sdata_in_driver() because of missing
that bit.

Fix this by rejecting MONITOR_FLAG_COOK_FRAMES if it is set along with
other flags.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 66f7ac50ed7c ("nl80211: Add monitor interface configuration flags")
Cc: stable@vger.kernel.org
Reported-by: syzbot+2e5c1e55b9e5c28a3da7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2e5c1e55b9e5c28a3da7
Signed-off-by: Vitaliy Shevtsov <v.shevtsov@mt-integration.ru>
Link: https://patch.msgid.link/20250131152657.5606-1-v.shevtsov@mt-integration.ru
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d7d3da0f6833d5c0db79777cb85b58bb87c47efa..fdb2aac951d18ce7a6cb5505f22666362349c35c 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4220,6 +4220,11 @@ static int parse_monitor_flags(struct nlattr *nla, u32 *mntrflags)
                if (flags[flag])
                        *mntrflags |= (1<<flag);
 
+       /* cooked monitor mode is incompatible with other modes */
+       if (*mntrflags & MONITOR_FLAG_COOK_FRAMES &&
+           *mntrflags != MONITOR_FLAG_COOK_FRAMES)
+               return -EOPNOTSUPP;
+
        *mntrflags |= MONITOR_FLAG_CHANGED;
 
        return 0;