iwlwifi: mvm: fix access to BSS elements

BugLink: https://bugs.launchpad.net/bugs/1946802
[ Upstream commit 6c608cd6962ebdf84fd3de6d42f88ed64d2f4e1b ]

BSS elements are protected using RCU, so we need to use
RCU properly to access them, fix that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210805130823.fd8b5791ab44.Iba26800a6301078d3782fb249c476dd8ac2bf3c6@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index 09b1a6beee77c06c6a11367b8efc80bababa4ff8..081cbc9ec736824bf2b411fb80bd168523b176cc 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -2970,16 +2970,20 @@ static void iwl_mvm_check_he_obss_narrow_bw_ru_iter(struct wiphy *wiphy,
                                                    void *_data)
 {
        struct iwl_mvm_he_obss_narrow_bw_ru_data *data = _data;
+       const struct cfg80211_bss_ies *ies;
        const struct element *elem;
 
-       elem = cfg80211_find_elem(WLAN_EID_EXT_CAPABILITY, bss->ies->data,
-                                 bss->ies->len);
+       rcu_read_lock();
+       ies = rcu_dereference(bss->ies);
+       elem = cfg80211_find_elem(WLAN_EID_EXT_CAPABILITY, ies->data,
+                                 ies->len);
 
        if (!elem || elem->datalen < 10 ||
            !(elem->data[10] &
              WLAN_EXT_CAPA10_OBSS_NARROW_BW_RU_TOLERANCE_SUPPORT)) {
                data->tolerated = false;
        }
+       rcu_read_unlock();
 }
 
 static void iwl_mvm_check_he_obss_narrow_bw_ru(struct ieee80211_hw *hw,