[PATCH 5.10 51/77] cfg80211: correct bridge/4addr mode check

Greg Kroah-Hartman
2021-11-01T09:36:20Z

From: Janusz Dziedzic <janusz.dziedzic@gmail.com>

commit 689a0a9f505f7bffdefe6f17fddb41c8ab6344f6 upstream.

Without the patch we fail:

$ sudo brctl addbr br0
$ sudo brctl addif br0 wlp1s0
$ sudo iw wlp1s0 set 4addr on
command failed: Device or resource busy (-16)

Last command failed but iface was already in 4addr mode.

Fixes: ad4bb6f8883a ("cfg80211: disallow bridging managed/adhoc interfaces")
Signed-off-by: Janusz Dziedzic <janusz.dziedzic@gmail.com>
Link: https://lore.kernel.org/r/20211024201546.614379-1-janusz.dziedzic@gmail.com
[add fixes tag, fix indentation, edit commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/wireless/util.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1028,14 +1028,14 @@ int cfg80211_change_iface(struct cfg8021
!(rdev->wiphy.interface_modes & (1 << ntype)))
return -EOPNOTSUPP;

- /* if it's part of a bridge, reject changing type to station/ibss */
- if (netif_is_bridge_port(dev) &&
- (ntype == NL80211_IFTYPE_ADHOC ||
- ntype == NL80211_IFTYPE_STATION ||
- ntype == NL80211_IFTYPE_P2P_CLIENT))
- return -EBUSY;
-
if (ntype != otype) {
+ /* if it's part of a bridge, reject changing type to station/ibss */
+ if (netif_is_bridge_port(dev) &&
+ (ntype == NL80211_IFTYPE_ADHOC ||
+ ntype == NL80211_IFTYPE_STATION ||
+ ntype == NL80211_IFTYPE_P2P_CLIENT))
+ return -EBUSY;
+
dev->ieee80211_ptr->use_4addr = false;
dev->ieee80211_ptr->mesh_id_up_len = 0;
wdev_lock(dev->ieee80211_ptr);