linux-kernel - [PATCH 4.2.y-ckt 094/305] mac80211: do not actively scan DFS channels

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1452902519-2754-95-git-send-email-kamal@canonical.com>
Date:	Fri, 15 Jan 2016 15:58:28 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Antonio Quartulli <antonio@...n-mesh.com>,
	Johannes Berg <johannes.berg@...el.com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 094/305] mac80211: do not actively scan DFS channels

4.2.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Antonio Quartulli <antonio@...hcoding.com>

commit 4e39ccac0d678eacb5dd6ffc5057531af33c12d6 upstream.

DFS channels should not be actively scanned as we can't be sure
if we are allowed or not.

If the current channel is in the DFS band, active scan might be
performed after CSA, but we have no guarantee about other channels,
therefore it is safer to prevent active scanning at all.

Signed-off-by: Antonio Quartulli <antonio@...n-mesh.com>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 net/mac80211/scan.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 11d0901..9c1cccd 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -599,8 +599,8 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 		/* We need to ensure power level is at max for scanning. */
 		ieee80211_hw_config(local, 0);
 
-		if ((req->channels[0]->flags &
-		     IEEE80211_CHAN_NO_IR) ||
+		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
+						IEEE80211_CHAN_RADAR)) ||
 		    !req->n_ssids) {
 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 		} else {
@@ -647,7 +647,7 @@ ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 	 * TODO: channel switching also consumes quite some time,
 	 * add that delay as well to get a better estimation
 	 */
-	if (chan->flags & IEEE80211_CHAN_NO_IR)
+	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 		return IEEE80211_PASSIVE_CHANNEL_TIME;
 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 }
@@ -779,7 +779,8 @@ static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 	 *
 	 * In any case, it is not necessary for a passive scan.
 	 */
-	if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
+	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
+	    !scan_req->n_ssids) {
 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 		local->next_scan_state = SCAN_DECISION;
 		return;
-- 
1.9.1