From: Brian Norris briannorris@chromium.org
commit 05aaa5c97dce4c10a9e7eae2f1569a684e0c5ced upstream.
In a very similar spirit to commit c470bdc1aaf3 ("mac80211: don't WARN on bad WMM parameters from buggy APs"), an AP may not transmit a fully-formed WMM IE. For example, it may miss or repeat an Access Category. The above loop won't catch that and will instead leave one of the four ACs zeroed out. This triggers the following warning in drv_conf_tx()
wlan0: invalid CW_min/CW_max: 0/0
and it may leave one of the hardware queues unconfigured. If we detect such a case, let's just print a warning and fall back to the defaults.
Tested with a hacked version of hostapd, intentionally corrupting the IEs in hostapd_eid_wmm().
Cc: stable@vger.kernel.org Signed-off-by: Brian Norris briannorris@chromium.org Link: https://lore.kernel.org/r/20190726224758.210953-1-briannorris@chromium.org Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/mac80211/mlme.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -2041,6 +2041,16 @@ ieee80211_sta_wmm_params(struct ieee8021 ieee80211_regulatory_limit_wmm_params(sdata, ¶ms[ac], ac); }
+ /* WMM specification requires all 4 ACIs. */ + for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { + if (params[ac].cw_min == 0) { + sdata_info(sdata, + "AP has invalid WMM params (missing AC %d), using defaults\n", + ac); + return false; + } + } + for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { mlme_dbg(sdata, "WMM AC=%d acm=%d aifs=%d cWmin=%d cWmax=%d txop=%d uapsd=%d, downgraded=%d\n",