From 930e826962d9f01dcd2220176134427358d112f2 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 14 Feb 2024 20:08:35 +0100 Subject: [PATCH] wifi: nl80211: reject iftype change with mesh ID change commit f78c1375339a291cba492a70eaf12ec501d28a8e upstream. It's currently possible to change the mesh ID when the interface isn't yet in mesh mode, at the same time as changing it into mesh mode. This leads to an overwrite of data in the wdev->u union for the interface type it currently has, causing cfg80211_change_iface() to do wrong things when switching. We could probably allow setting an interface to mesh while setting the mesh ID at the same time by doing a different order of operations here, but realistically there's no userspace that's going to do this, so just disallow changes in iftype when setting mesh ID. Cc: stable@vger.kernel.org Fixes: 29cbe68c516a ("cfg80211/mac80211: add mesh join/leave commands") Reported-by: syzbot+dd4779978217b1973180@syzkaller.appspotmail.com Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/nl80211.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index c259d3227a9e..1a3bd554e258 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -4137,6 +4137,8 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info) if (ntype != NL80211_IFTYPE_MESH_POINT) return -EINVAL; + if (otype != NL80211_IFTYPE_MESH_POINT) + return -EINVAL; if (netif_running(dev)) return -EBUSY;