linux-kernel - [PATCH 5.11 13/45] mac80211: choose first enabled channel for monitor

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]

Date:   Fri,  9 Apr 2021 11:53:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Karthikeyan Kathirvel <kathirve@...eaurora.org>,
        Johannes Berg <johannes.berg@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.11 13/45] mac80211: choose first enabled channel for monitor

From: Karthikeyan Kathirvel <kathirve@...eaurora.org>

[ Upstream commit 041c881a0ba8a75f71118bd9766b78f04beed469 ]

Even if the first channel from sband channel list is invalid
or disabled mac80211 ends up choosing it as the default channel
for monitor interfaces, making them not usable.

Fix this by assigning the first available valid or enabled
channel instead.

Signed-off-by: Karthikeyan Kathirvel <kathirve@...eaurora.org>
Link: https://lore.kernel.org/r/1615440547-7661-1-git-send-email-kathirve@codeaurora.org
[reword commit message, comment, code cleanups]
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/mac80211/main.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index dee88ec566ad..d1023188ef37 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -970,8 +970,19 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 			continue;
 
 		if (!dflt_chandef.chan) {
+			/*
+			 * Assign the first enabled channel to dflt_chandef
+			 * from the list of channels
+			 */
+			for (i = 0; i < sband->n_channels; i++)
+				if (!(sband->channels[i].flags &
+						IEEE80211_CHAN_DISABLED))
+					break;
+			/* if none found then use the first anyway */
+			if (i == sband->n_channels)
+				i = 0;
 			cfg80211_chandef_create(&dflt_chandef,
-						&sband->channels[0],
+						&sband->channels[i],
 						NL80211_CHAN_NO_HT);
 			/* init channel we're on */
 			if (!local->use_chanctx && !local->_oper_chandef.chan) {
-- 
2.30.2