From c8eaf3479e521e973eb2d4111b8ee8f5b7b564ab Mon Sep 17 00:00:00 2001 From: Filip Matusiak Date: Wed, 2 Nov 2016 10:04:26 +0100 Subject: [PATCH] mac80211: Ignore VHT IE from peer with wrong rx_mcs_map This is a workaround for VHT-enabled STAs which break the spec and have the VHT-MCS Rx map filled in with value 3 for all eight spacial streams, an example is AR9462 in AP mode. As per spec, in section 22.1.1 Introduction to the VHT PHY A VHT STA shall support at least single spactial stream VHT-MCSs 0 to 7 (transmit and receive) in all supported channel widths. Some devices in STA mode will get firmware assert when trying to associate, examples are QCA9377 & QCA6174. Packet example of broken VHT Cap IE of AR9462: Tag: VHT Capabilities (IEEE Std 802.11ac/D3.1) Tag Number: VHT Capabilities (IEEE Std 802.11ac/D3.1) (191) Tag length: 12 VHT Capabilities Info: 0x00000000 VHT Supported MCS Set Rx MCS Map: 0xffff .... .... .... ..11 = Rx 1 SS: Not Supported (0x0003) .... .... .... 11.. = Rx 2 SS: Not Supported (0x0003) .... .... ..11 .... = Rx 3 SS: Not Supported (0x0003) .... .... 11.. .... = Rx 4 SS: Not Supported (0x0003) .... ..11 .... .... = Rx 5 SS: Not Supported (0x0003) .... 11.. .... .... = Rx 6 SS: Not Supported (0x0003) ..11 .... .... .... = Rx 7 SS: Not Supported (0x0003) 11.. .... .... .... = Rx 8 SS: Not Supported (0x0003) ...0 0000 0000 0000 = Rx Highest Long GI Data Rate (in Mb/s, 0 = subfield not in use): 0x0000 Tx MCS Map: 0xffff ...0 0000 0000 0000 = Tx Highest Long GI Data Rate (in Mb/s, 0 = subfield not in use): 0x0000 Signed-off-by: Filip Matusiak Signed-off-by: Johannes Berg --- net/mac80211/vht.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c index ee715764a828..6832bf6ab69f 100644 --- a/net/mac80211/vht.c +++ b/net/mac80211/vht.c @@ -270,6 +270,22 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata, vht_cap->vht_mcs.tx_mcs_map |= cpu_to_le16(peer_tx << i * 2); } + /* + * This is a workaround for VHT-enabled STAs which break the spec + * and have the VHT-MCS Rx map filled in with value 3 for all eight + * spacial streams, an example is AR9462. + * + * As per spec, in section 22.1.1 Introduction to the VHT PHY + * A VHT STA shall support at least single spactial stream VHT-MCSs + * 0 to 7 (transmit and receive) in all supported channel widths. + */ + if (vht_cap->vht_mcs.rx_mcs_map == cpu_to_le16(0xFFFF)) { + vht_cap->vht_supported = false; + sdata_info(sdata, "Ignoring VHT IE from %pM due to invalid rx_mcs_map\n", + sta->addr); + return; + } + /* finally set up the bandwidth */ switch (vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK) { case IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ: -- 2.20.1