[PATCH 6.0 29/34] wifi: cfg80211: update hidden BSSes to avoid WARN_ON

Greg Kroah-Hartman
2022-10-13T18:16:43Z

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

commit c90b93b5b782891ebfda49d4e5da36632fefd5d1 upstream.

When updating beacon elements in a non-transmitted BSS,
also update the hidden sub-entries to the same beacon
elements, so that a future update through other paths
won't trigger a WARN_ON().

The warning is triggered because the beacon elements in
the hidden BSSes that are children of the BSS should
always be the same as in the parent.

Reported-by: Sönke Huster <shuster@seemoo.tu-darmstadt.de>
Tested-by: Sönke Huster <shuster@seemoo.tu-darmstadt.de>
Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/wireless/scan.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)

--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1607,6 +1607,23 @@ struct cfg80211_non_tx_bss {
u8 bssid_index;
};

+static void cfg80211_update_hidden_bsses(struct cfg80211_internal_bss *known,
+ const struct cfg80211_bss_ies *new_ies,
+ const struct cfg80211_bss_ies *old_ies)
+{
+ struct cfg80211_internal_bss *bss;
+
+ /* Assign beacon IEs to all sub entries */
+ list_for_each_entry(bss, &known->hidden_list, hidden_list) {
+ const struct cfg80211_bss_ies *ies;
+
+ ies = rcu_access_pointer(bss->pub.beacon_ies);
+ WARN_ON(ies != old_ies);
+
+ rcu_assign_pointer(bss->pub.beacon_ies, new_ies);
+ }
+}
+
static bool
cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
struct cfg80211_internal_bss *known,
@@ -1630,7 +1647,6 @@ cfg80211_update_known_bss(struct cfg8021
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
} else if (rcu_access_pointer(new->pub.beacon_ies)) {
const struct cfg80211_bss_ies *old;
- struct cfg80211_internal_bss *bss;

if (known->pub.hidden_beacon_bss &&
!list_empty(&known->hidden_list)) {
@@ -1658,16 +1674,7 @@ cfg80211_update_known_bss(struct cfg8021
if (old == rcu_access_pointer(known->pub.ies))
rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies);

- /* Assign beacon IEs to all sub entries */
- list_for_each_entry(bss, &known->hidden_list, hidden_list) {
- const struct cfg80211_bss_ies *ies;
-
- ies = rcu_access_pointer(bss->pub.beacon_ies);
- WARN_ON(ies != old);
-
- rcu_assign_pointer(bss->pub.beacon_ies,
- new->pub.beacon_ies);
- }
+ cfg80211_update_hidden_bsses(known, new->pub.beacon_ies, old);

if (old)
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
@@ -2360,6 +2367,8 @@ cfg80211_update_notlisted_nontrans(struc
} else {
old = rcu_access_pointer(nontrans_bss->beacon_ies);
rcu_assign_pointer(nontrans_bss->beacon_ies, new_ies);
+ cfg80211_update_hidden_bsses(bss_from_pub(nontrans_bss),
+ new_ies, old);
rcu_assign_pointer(nontrans_bss->ies, new_ies);
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);