[PATCH wireless-next] wifi: nl80211: re-check wiphy netns in testmode and vendor dump continuations

[Maoyi Xie <maoyixie.tju@gmail.com>]

Commit 79240f3f6d76 ("wifi: nl80211: re-check wiphy netns in
nl80211_prepare_wdev_dump() continuation") fixed one dumpit path that
looked the wiphy up by index on a later call without confirming it was
still in the caller's netns. Two more dumpit paths have the same gap.

nl80211_testmode_dump() and nl80211_prepare_vendor_dump() both keep the
wiphy index in cb->args[] and look it up again on later calls, through
cfg80211_rdev_by_wiphy_idx() and wiphy_idx_to_wiphy(). The first call
binds to the caller's netns. A later call does not check it again. In
between, the wiphy can move to another netns via
NL80211_CMD_SET_WIPHY_NETNS.

Add the same net_eq() check to both. On a mismatch, return -ENODEV and
the dump ends.

No mainline driver registers .testmode_dump or
wiphy_vendor_command.dumpit, so these paths are not reachable today.
Drivers outside the tree can register either.

Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
---
 net/wireless/nl80211.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index f334cdef8958..d462e0b784ad 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -13420,6 +13420,16 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 			err = -ENOENT;
 			goto out_err;
 		}
+
+		/*
+		 * The wiphy may have moved netns between dumpit
+		 * invocations (via NL80211_CMD_SET_WIPHY_NETNS), so
+		 * re-check that it still matches the caller's netns.
+		 */
+		if (!net_eq(wiphy_net(&rdev->wiphy), sock_net(skb->sk))) {
+			err = -ENODEV;
+			goto out_err;
+		}
 	} else {
 		attrbuf = kzalloc_objs(*attrbuf, NUM_NL80211_ATTR);
 		if (!attrbuf) {
@@ -17382,6 +17392,15 @@ static int nl80211_prepare_vendor_dump(struct sk_buff *skb,
 
 		if (!wiphy)
 			return -ENODEV;
+
+		/*
+		 * The wiphy may have moved netns between dumpit
+		 * invocations (via NL80211_CMD_SET_WIPHY_NETNS), so
+		 * re-check that it still matches the caller's netns.
+		 */
+		if (!net_eq(wiphy_net(wiphy), sock_net(skb->sk)))
+			return -ENODEV;
+
 		*rdev = wiphy_to_rdev(wiphy);
 		*wdev = NULL;
 
-- 
2.34.1