From 9e478066eae41211c92a8f63cc69aafc391bd6ab Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 13 Apr 2017 14:23:49 +0200 Subject: [PATCH] mac80211: fix MU-MIMO follow-MAC mode There are two bugs in the follow-MAC code: * it treats the radiotap header as the 802.11 header (therefore it can't possibly work) * it doesn't verify that the skb data it accesses is actually present in the header, which is mitigated by the first point Fix this by moving all of this out into a separate function. This function copies the data it needs using skb_copy_bits() to make sure it can be accessed if it's paged, and offsets that by the possibly present vendor radiotap header. This also makes all those conditions more readable. Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg --- net/mac80211/rx.c | 65 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 18 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index e48724a6725e..4b12c70c85f0 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -208,6 +208,51 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local, return len; } +static void ieee80211_handle_mu_mimo_mon(struct ieee80211_sub_if_data *sdata, + struct sk_buff *skb, + int rtap_vendor_space) +{ + struct { + struct ieee80211_hdr_3addr hdr; + u8 category; + u8 action_code; + } __packed action; + + if (!sdata) + return; + + BUILD_BUG_ON(sizeof(action) != IEEE80211_MIN_ACTION_SIZE + 1); + + if (skb->len < rtap_vendor_space + sizeof(action) + + VHT_MUMIMO_GROUPS_DATA_LEN) + return; + + if (!is_valid_ether_addr(sdata->u.mntr.mu_follow_addr)) + return; + + skb_copy_bits(skb, rtap_vendor_space, &action, sizeof(action)); + + if (!ieee80211_is_action(action.hdr.frame_control)) + return; + + if (action.category != WLAN_CATEGORY_VHT) + return; + + if (action.action_code != WLAN_VHT_ACTION_GROUPID_MGMT) + return; + + if (!ether_addr_equal(action.hdr.addr1, sdata->u.mntr.mu_follow_addr)) + return; + + skb = skb_copy(skb, GFP_ATOMIC); + if (!skb) + return; + + skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME; + skb_queue_tail(&sdata->skb_queue, skb); + ieee80211_queue_work(&sdata->local->hw, &sdata->work); +} + /* * ieee80211_add_rx_radiotap_header - add radiotap header * @@ -515,7 +560,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, struct net_device *prev_dev = NULL; int present_fcs_len = 0; unsigned int rtap_vendor_space = 0; - struct ieee80211_mgmt *mgmt; struct ieee80211_sub_if_data *monitor_sdata = rcu_dereference(local->monitor_sdata); @@ -553,6 +597,8 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, return remove_monitor_info(local, origskb, rtap_vendor_space); } + ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_vendor_space); + /* room for the radiotap header based on driver features */ rt_hdrlen = ieee80211_rx_radiotap_hdrlen(local, status, origskb); needed_headroom = rt_hdrlen - rtap_vendor_space; @@ -618,23 +664,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, ieee80211_rx_stats(sdata->dev, skb->len); } - mgmt = (void *)skb->data; - if (monitor_sdata && - skb->len >= IEEE80211_MIN_ACTION_SIZE + 1 + VHT_MUMIMO_GROUPS_DATA_LEN && - ieee80211_is_action(mgmt->frame_control) && - mgmt->u.action.category == WLAN_CATEGORY_VHT && - mgmt->u.action.u.vht_group_notif.action_code == WLAN_VHT_ACTION_GROUPID_MGMT && - is_valid_ether_addr(monitor_sdata->u.mntr.mu_follow_addr) && - ether_addr_equal(mgmt->da, monitor_sdata->u.mntr.mu_follow_addr)) { - struct sk_buff *mu_skb = skb_copy(skb, GFP_ATOMIC); - - if (mu_skb) { - mu_skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME; - skb_queue_tail(&monitor_sdata->skb_queue, mu_skb); - ieee80211_queue_work(&local->hw, &monitor_sdata->work); - } - } - if (prev_dev) { skb->dev = prev_dev; netif_receive_skb(skb); -- 2.30.2