Commit 15994bb0 authored May 06, 2026 by Maoyi Xie Committed by Johannes Berg May 06, 2026

wifi: nl80211: require CAP_NET_ADMIN over the target netns in SET_WIPHY_NETNS



NL80211_CMD_SET_WIPHY_NETNS dispatches with GENL_UNS_ADMIN_PERM, which
verifies that the caller has CAP_NET_ADMIN for the source netns. It
doesn't verify that the caller has CAP_NET_ADMIN over the target netns
selected by NL80211_ATTR_NETNS_FD or NL80211_ATTR_PID.

This diverges from the convention enforced in
net/core/rtnetlink.c::rtnl_get_net_ns_capable():

    /* For now, the caller is required to have CAP_NET_ADMIN in
     * the user namespace owning the target net ns.
     */
    if (!sk_ns_capable(sk, net->user_ns, CAP_NET_ADMIN))
        return ERR_PTR(-EACCES);

A user with CAP_NET_ADMIN in their own user namespace can therefore
push a wiphy into an arbitrary netns (including init_net) over which
they have no privilege.

Mirror the rtnetlink convention by requiring CAP_NET_ADMIN in the
target netns before calling cfg80211_switch_netns().

Signed-off-by: Maoyi Xie <maoyi.xie@ntu.edu.sg>
Link: https://patch.msgid.link/20260506064854.2207105-2-maoyixie.tju@gmail.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent 0f3c0a19

net/wireless/nl80211.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -13867,6 +13867,19 @@ static int nl80211_wiphy_netns(struct sk_buff skb, struct genl_info info)
		if (IS_ERR(net))
		return PTR_ERR(net);

		/*
		* The caller already has CAP_NET_ADMIN over the source netns
		* (enforced by GENL_UNS_ADMIN_PERM on the genl op). Mirror the
		* convention used by net/core/rtnetlink.c::rtnl_get_net_ns_capable()
		* and require CAP_NET_ADMIN over the target netns as well, so that
		* a caller that is privileged in their own user namespace cannot
		* push a wiphy into a netns where they have no privilege.
		*/
		if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) {
		put_net(net);
		return -EPERM;
		}

		err = 0;

		/* check if anything to do */