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mac80211: don't WARN on short WMM parameters from AP 

In a very similar spirit to commit c470bdc1aa ("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>
This commit is contained in:
Brian Norris 2019-07-26 15:47:58 -07:00 committed by Johannes Berg
parent e6f4051123
commit 05aaa5c97d
1 changed files with 10 additions and 0 deletions
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10
net/mac80211/mlme.c
View File

@ -2042,6 +2042,16 @@ ieee80211_sta_wmm_params(struct ieee80211_local *local,
ieee80211_regulatory_limit_wmm_params(sdata, &params[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",