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| author | Johannes Berg <johannes.berg@intel.com> | 2026-09-04 16:55:04 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2026-09-09 14:51:26 +0200 |
| commit | 068843ed0902c552a13860c5ec6b2ca65b57a065 (patch) | |
| tree | 3ea863228adc9055750cee5404ca09ec83a1cccb | |
| parent | dab68a74e90b8e07f08ed9deaa5884857a3cfe89 (diff) | |
| download | linux-next-068843ed0902c552a13860c5ec6b2ca65b57a065.tar.gz linux-next-068843ed0902c552a13860c5ec6b2ca65b57a065.zip | |
wifi: cfg80211: only group hidden BSSes with beacon entries
When a probe response for an unknown BSS comes in, __cfg80211_bss_update()
looks for an existing entry with the same BSSID and a hidden (zero-length
or NUL-filled) SSID, and if it finds one it groups them, using the beacon
IEs from the existing entry.
But that could find another entry without a beacon, if it was also from a
probe response (with SSID), so there's a group without beacon elements.
If a beacon with a hidden SSID for that BSSID arrives later,
cfg80211_combine_bsses() goes looking for the probe response entries that
belong to it - i.e. entries with the same BSSID and channel that have no
beacon IEs - and finds those two. They are already grouped with each
other, so it hits its
WARN_ON_ONCE(bss->pub.hidden_beacon_bss)
WARN_ON_ONCE(!list_empty(&bss->hidden_list))
which are there because an entry without beacon elements is not supposed
to be part of a group yet.
Only combine entries when a beacon was already received, ones that are
kept separate will be combined when a beacon arrives.
Assisted-by: LLM
Fixes: 4593c4cbe1c9 ("cfg80211: fix BSS list hidden SSID lookup")
Reported-by: syzbot+1a797e1c81be78a2ace7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1a797e1c81be78a2ace7
Link: https://patch.msgid.link/20260904165614.bcfa64715745.Iad740347c86de56d4ff4f96a95f3c3afc47c42de@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
| -rw-r--r-- | net/wireless/scan.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 4fe114f6aee3..604b10ef0f94 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -2077,6 +2077,13 @@ __cfg80211_bss_update(struct cfg80211_registered_device *rdev, if (!hidden) hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_NUL); + /* + * Only group with an entry with beacon data, otherwise + * beacon data can never be filled/updated. + */ + if (hidden && + !rcu_access_pointer(hidden->pub.beacon_ies)) + hidden = NULL; if (hidden) { new->pub.hidden_beacon_bss = &hidden->pub; list_add(&new->hidden_list, |