From 095d81cee742fc31e1218077ca6ca8f0df07c613 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 15 Oct 2013 12:25:07 +0200 Subject: [PATCH] mac80211: disable WMM with invalid parameters Some APs (notably a Sitecom WL-153 v1 with firmware 1.45) are sending invalid WMM parameters setting AIFSN, ECWmin and ECWmax to zero. The spec mandates that the value of AIFSN is at least 2, and some cards (e.g. Intel with the iwldvm driver) can't transmit when the invalid QoS parameters are actually uploaded to the firmware. Since there's little chance of being able to guess the values that the AP actually meant, disable WMM if such an invalid case is found. Since ECWmin/ECWmax are allowed to be zero, only verify AIFSN >= 2 and ECWmin <= ECWmax. Reviewed-by: Eliad Peller Reported-by: Antonio Quartulli Signed-off-by: Johannes Berg --- net/mac80211/ieee80211_i.h | 1 + net/mac80211/mlme.c | 95 ++++++++++++++++++++++++++++++++++---- 2 files changed, 87 insertions(+), 9 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 611abfcfb5eb..076409526bcb 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -335,6 +335,7 @@ enum ieee80211_sta_flags { IEEE80211_STA_DISABLE_VHT = BIT(11), IEEE80211_STA_DISABLE_80P80MHZ = BIT(12), IEEE80211_STA_DISABLE_160MHZ = BIT(13), + IEEE80211_STA_DISABLE_WMM = BIT(14), }; struct ieee80211_mgd_auth_data { diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 86e4ad56b573..54ebc8155b49 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -2717,7 +2717,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata, */ ifmgd->wmm_last_param_set = -1; - if (elems.wmm_param) + if (!(ifmgd->flags & IEEE80211_STA_DISABLE_WMM) && elems.wmm_param) ieee80211_sta_wmm_params(local, sdata, elems.wmm_param, elems.wmm_param_len); else @@ -3152,7 +3152,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, ieee80211_sta_process_chanswitch(sdata, rx_status->mactime, &elems, true); - if (ieee80211_sta_wmm_params(local, sdata, elems.wmm_param, + if (!(ifmgd->flags & IEEE80211_STA_DISABLE_WMM) && + ieee80211_sta_wmm_params(local, sdata, elems.wmm_param, elems.wmm_param_len)) changed |= BSS_CHANGED_QOS; @@ -4135,6 +4136,44 @@ int ieee80211_mgd_auth(struct ieee80211_sub_if_data *sdata, return err; } +static bool ieee80211_usable_wmm_params(struct ieee80211_sub_if_data *sdata, + const u8 *wmm_param, int len) +{ + const u8 *pos; + size_t left; + + if (len < 8) + return false; + + if (wmm_param[5] != 1 /* version */) + return false; + + pos = wmm_param + 8; + left = len - 8; + + for (; left >= 4; left -= 4, pos += 4) { + u8 aifsn = pos[0] & 0x0f; + u8 ecwmin = pos[1] & 0x0f; + u8 ecwmax = (pos[1] & 0xf0) >> 4; + int aci = (pos[0] >> 5) & 0x03; + + if (aifsn < 2) { + sdata_info(sdata, + "AP has invalid WMM params (AIFSN=%d for ACI %d), disabling WMM\n", + aifsn, aci); + return false; + } + if (ecwmin > ecwmax) { + sdata_info(sdata, + "AP has invalid WMM params (ECWmin/max=%d/%d for ACI %d), disabling WMM\n", + ecwmin, ecwmax, aci); + return false; + } + } + + return true; +} + int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata, struct cfg80211_assoc_request *req) { @@ -4192,9 +4231,45 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata, } /* prepare assoc data */ - + ifmgd->beacon_crc_valid = false; + assoc_data->wmm = bss->wmm_used && + (local->hw.queues >= IEEE80211_NUM_ACS); + if (assoc_data->wmm) { + /* try to check validity of WMM params IE */ + const struct cfg80211_bss_ies *ies; + const u8 *wp, *start, *end; + + rcu_read_lock(); + ies = rcu_dereference(req->bss->ies); + start = ies->data; + end = start + ies->len; + + while (true) { + wp = cfg80211_find_vendor_ie( + WLAN_OUI_MICROSOFT, + WLAN_OUI_TYPE_MICROSOFT_WMM, + start, end - start); + if (!wp) + break; + start = wp + wp[1] + 2; + /* if this IE is too short, try the next */ + if (wp[1] <= 4) + continue; + /* if this IE is WMM params, we found what we wanted */ + if (wp[6] == 1) + break; + } + + if (!wp || !ieee80211_usable_wmm_params(sdata, wp + 2, + wp[1] - 2)) { + assoc_data->wmm = false; + ifmgd->flags |= IEEE80211_STA_DISABLE_WMM; + } + rcu_read_unlock(); + } + /* * IEEE802.11n does not allow TKIP/WEP as pairwise ciphers in HT mode. * We still associate in non-HT mode (11a/b/g) if any one of these @@ -4224,18 +4299,22 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata, /* Also disable HT if we don't support it or the AP doesn't use WMM */ sband = local->hw.wiphy->bands[req->bss->channel->band]; if (!sband->ht_cap.ht_supported || - local->hw.queues < IEEE80211_NUM_ACS || !bss->wmm_used) { + local->hw.queues < IEEE80211_NUM_ACS || !bss->wmm_used || + ifmgd->flags & IEEE80211_STA_DISABLE_WMM) { ifmgd->flags |= IEEE80211_STA_DISABLE_HT; - if (!bss->wmm_used) + if (!bss->wmm_used && + !(ifmgd->flags & IEEE80211_STA_DISABLE_WMM)) netdev_info(sdata->dev, "disabling HT as WMM/QoS is not supported by the AP\n"); } /* disable VHT if we don't support it or the AP doesn't use WMM */ if (!sband->vht_cap.vht_supported || - local->hw.queues < IEEE80211_NUM_ACS || !bss->wmm_used) { + local->hw.queues < IEEE80211_NUM_ACS || !bss->wmm_used || + ifmgd->flags & IEEE80211_STA_DISABLE_WMM) { ifmgd->flags |= IEEE80211_STA_DISABLE_VHT; - if (!bss->wmm_used) + if (!bss->wmm_used && + !(ifmgd->flags & IEEE80211_STA_DISABLE_WMM)) netdev_info(sdata->dev, "disabling VHT as WMM/QoS is not supported by the AP\n"); } @@ -4264,8 +4343,6 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata, sdata->smps_mode = ifmgd->req_smps; assoc_data->capability = req->bss->capability; - assoc_data->wmm = bss->wmm_used && - (local->hw.queues >= IEEE80211_NUM_ACS); assoc_data->supp_rates = bss->supp_rates; assoc_data->supp_rates_len = bss->supp_rates_len; -- 2.20.1