2019-10-08 16:45:13

by Denis Kenzior

Subject: [PATCH] mac80211: More strictly validate .abort_scan

nl80211 requires NL80211_CMD_ABORT_SCAN to have a wdev or netdev
attribute present and checks that if netdev is provided it is UP.
However, mac80211 does not check that an ongoing scan actually belongs
to the netdev/wdev provided by the user. In other words, it is possible
for an application to cancel scans on an interface it doesn't manage.

Signed-off-by: Denis Kenzior <[email protected]>
Cc: [email protected]
---
net/mac80211/cfg.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 70739e746c13..ece344f9e9ca 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2333,7 +2333,13 @@ static int ieee80211_scan(struct wiphy *wiphy,

static void ieee80211_abort_scan(struct wiphy *wiphy, struct wireless_dev *wdev)
{
- ieee80211_scan_cancel(wiphy_priv(wiphy));
+ struct ieee80211_local *local = wiphy_priv(wiphy);
+ struct ieee80211_sub_if_data *sdata =
+ IEEE80211_WDEV_TO_SUB_IF(wdev);
+ bool cancel_scan = rcu_access_pointer(local->scan_sdata) == sdata;
+
+ if (cancel_scan)
+ ieee80211_scan_cancel(local);
}

static int
--
2.21.0

2019-10-11 08:31:50

by Johannes Berg

Subject: Re: [PATCH] mac80211: More strictly validate .abort_scan

On Tue, 2019-10-08 at 11:33 -0500, Denis Kenzior wrote:
> nl80211 requires NL80211_CMD_ABORT_SCAN to have a wdev or netdev
> attribute present and checks that if netdev is provided it is UP.
> However, mac80211 does not check that an ongoing scan actually belongs
> to the netdev/wdev provided by the user. In other words, it is possible
> for an application to cancel scans on an interface it doesn't manage.

I think you should do this in cfg80211.

johannes