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 overriding all flags if MONITOR_FLAG_COOK_FRAMES is set because this flag is incompatible with other monitor flags being set. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 66f7ac50ed7c (nl80211: Add monitor interface configuration flags) Reported-by: syzbot+2e5c1e55b9e5c28a3da7@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=2e5c1e55b9e5c28a3da7 Signed-off-by: Vitaliy Shevtsov <v.shevtsov@xxxxxxxxxxxxxxxxx> --- net/wireless/nl80211.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index d7d3da0f6833..1338b0a06f8d 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -4220,6 +4220,10 @@ static int parse_monitor_flags(struct nlattr *nla, u32 *mntrflags) if (flags[flag]) *mntrflags |= (1<<flag); + /* MONITOR_FLAG_COOK_FRAMES must override all other flags */ + if (*mntrflags & MONITOR_FLAG_COOK_FRAMES) + *mntrflags = MONITOR_FLAG_COOK_FRAMES; + *mntrflags |= MONITOR_FLAG_CHANGED; return 0; -- 2.48.1
