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authorJohannes Berg <johannes.berg@intel.com>2024-01-29 13:14:13 +0100
committerJohannes Berg <johannes.berg@intel.com>2024-02-02 13:08:58 +0100
commit177fbbcb4ed6b306c1626a277fac3fb1c495a4c7 (patch)
treed0876dedc6f496b77821bdbf1e91d4c7dfc0f55d
parentaa125f229076a8230a171d519dbdb2a862145d33 (diff)
wifi: cfg80211: detect stuck ECSA element in probe resp
We recently added some validation that we don't try to connect to an AP that is currently in a channel switch process, since that might want the channel to be quiet or we might not be able to connect in time to hear the switching in a beacon. This was in commit c09c4f31998b ("wifi: mac80211: don't connect to an AP while it's in a CSA process"). However, we promptly got a report that this caused new connection failures, and it turns out that the AP that we now cannot connect to is permanently advertising an extended channel switch announcement, even with quiet. The AP in question was an Asus RT-AC53, with firmware 3.0.0.4.380_10760-g21a5898. As a first step, attempt to detect that we're dealing with such a situation, so mac80211 can use this later. Reported-by: coldolt <andypalmadi@gmail.com> Closes: https://lore.kernel.org/linux-wireless/CAJvGw+DQhBk_mHXeu6RTOds5iramMW2FbMB01VbKRA4YbHHDTA@mail.gmail.com/ Fixes: c09c4f31998b ("wifi: mac80211: don't connect to an AP while it's in a CSA process") Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com> Link: https://msgid.link/20240129131413.246972c8775e.Ibf834d7f52f9951a353b6872383da710a7358338@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-rw-r--r--include/net/cfg80211.h4
-rw-r--r--net/wireless/scan.c59
2 files changed, 62 insertions, 1 deletions
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index cf79656ce09c..2b54fdd8ca15 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2910,6 +2910,8 @@ struct cfg80211_bss_ies {
* own the beacon_ies, but they're just pointers to the ones from the
* @hidden_beacon_bss struct)
* @proberesp_ies: the information elements from the last Probe Response frame
+ * @proberesp_ecsa_stuck: ECSA element is stuck in the Probe Response frame,
+ * cannot rely on it having valid data
* @hidden_beacon_bss: in case this BSS struct represents a probe response from
* a BSS that hides the SSID in its beacon, this points to the BSS struct
* that holds the beacon data. @beacon_ies is still valid, of course, and
@@ -2950,6 +2952,8 @@ struct cfg80211_bss {
u8 chains;
s8 chain_signal[IEEE80211_MAX_CHAINS];
+ u8 proberesp_ecsa_stuck:1;
+
u8 bssid_index;
u8 max_bssid_indicator;
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 2249b1a89d1c..389a52c29bfc 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1731,6 +1731,61 @@ static void cfg80211_update_hidden_bsses(struct cfg80211_internal_bss *known,
}
}
+static void cfg80211_check_stuck_ecsa(struct cfg80211_registered_device *rdev,
+ struct cfg80211_internal_bss *known,
+ const struct cfg80211_bss_ies *old)
+{
+ const struct ieee80211_ext_chansw_ie *ecsa;
+ const struct element *elem_new, *elem_old;
+ const struct cfg80211_bss_ies *new, *bcn;
+
+ if (known->pub.proberesp_ecsa_stuck)
+ return;
+
+ new = rcu_dereference_protected(known->pub.proberesp_ies,
+ lockdep_is_held(&rdev->bss_lock));
+ if (WARN_ON(!new))
+ return;
+
+ if (new->tsf - old->tsf < USEC_PER_SEC)
+ return;
+
+ elem_old = cfg80211_find_elem(WLAN_EID_EXT_CHANSWITCH_ANN,
+ old->data, old->len);
+ if (!elem_old)
+ return;
+
+ elem_new = cfg80211_find_elem(WLAN_EID_EXT_CHANSWITCH_ANN,
+ new->data, new->len);
+ if (!elem_new)
+ return;
+
+ bcn = rcu_dereference_protected(known->pub.beacon_ies,
+ lockdep_is_held(&rdev->bss_lock));
+ if (bcn &&
+ cfg80211_find_elem(WLAN_EID_EXT_CHANSWITCH_ANN,
+ bcn->data, bcn->len))
+ return;
+
+ if (elem_new->datalen != elem_old->datalen)
+ return;
+ if (elem_new->datalen < sizeof(struct ieee80211_ext_chansw_ie))
+ return;
+ if (memcmp(elem_new->data, elem_old->data, elem_new->datalen))
+ return;
+
+ ecsa = (void *)elem_new->data;
+
+ if (!ecsa->mode)
+ return;
+
+ if (ecsa->new_ch_num !=
+ ieee80211_frequency_to_channel(known->pub.channel->center_freq))
+ return;
+
+ known->pub.proberesp_ecsa_stuck = 1;
+}
+
static bool
cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
struct cfg80211_internal_bss *known,
@@ -1750,8 +1805,10 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
/* Override possible earlier Beacon frame IEs */
rcu_assign_pointer(known->pub.ies,
new->pub.proberesp_ies);
- if (old)
+ if (old) {
+ cfg80211_check_stuck_ecsa(rdev, known, old);
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
+ }
}
if (rcu_access_pointer(new->pub.beacon_ies)) {