bpf: devmap: fix wrong interface selection in notifier_call

[ Upstream commit f592f804831f1cf9d1f9966f58c80f150e6829b5 ]

The dev_map_notification() removes interface in devmap if
unregistering interface's ifindex is same.
But only checking ifindex is not enough because other netns can have
same ifindex. so that wrong interface selection could occurred.
Hence netdev pointer comparison code is added.

v2: compare netdev pointer instead of using net_eq() (Daniel Borkmann)
v1: Initial patch

Fixes: 2ddf71e23cc2 ("net: add notifier hooks for devmap bpf map")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 0f00b4fd20b56bf07a9f9b2dde98e2eb01beedfd..1a846a636ae1d4be886d8ac0ba9499cd929d3ddc 100644 (file)
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -391,8 +391,7 @@ static int dev_map_notification(struct notifier_block *notifier,
                                struct bpf_dtab_netdev *dev, *odev;
 
                                dev = READ_ONCE(dtab->netdev_map[i]);
-                               if (!dev ||
-                                   dev->dev->ifindex != netdev->ifindex)
+                               if (!dev || netdev != dev->dev)
                                        continue;
                                odev = cmpxchg(&dtab->netdev_map[i], dev, NULL);
                                if (dev == odev)