From: Taehee Yoo <ap420073@gmail.com>
Date: Wed, 24 Oct 2018 20:15:17 +0900
Subject: bpf: devmap: fix wrong interface selection in notifier_call
Patch-mainline: v4.20-rc1
Git-commit: f592f804831f1cf9d1f9966f58c80f150e6829b5
References: bsc#1109837

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 kernel/bpf/devmap.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -511,8 +511,7 @@ static int dev_map_notification(struct n
 				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)