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authorSven Eckelmann <sven@narfation.org>2018-12-30 12:46:01 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-20 10:13:20 +0100
commit8fe161469f1847d14068aec829d77e428cb653d1 (patch)
parentca6fd8df6f737e0a108e6b77486d6d6ea8a0897e (diff)
batman-adv: Avoid WARN on net_device without parent in netns
commit 955d3411a17f590364238bd0d3329b61f20c1cd2 upstream. It is not allowed to use WARN* helpers on potential incorrect input from the user or transient problems because systems configured as panic_on_warn will reboot due to such a problem. A NULL return value of __dev_get_by_index can be caused by various problems which can either be related to the system configuration or problems (incorrectly returned network namespaces) in other (virtual) net_device drivers. batman-adv should not cause a (harmful) WARN in this situation and instead only report it via a simple message. Fixes: b7eddd0b3950 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 2 deletions
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index f11345e163d7..3c8d8142e8c6 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -18,7 +18,6 @@
#include "hard-interface.h"
#include "main.h"
-#include <linux/bug.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/fs.h>
@@ -104,8 +103,10 @@ static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
/* recurse over the parent device */
parent_dev = __dev_get_by_index(&init_net, dev_get_iflink(net_dev));
/* if we got a NULL parent_dev there is something broken.. */
- if (WARN(!parent_dev, "Cannot find parent device"))
+ if (!parent_dev) {
+ pr_err("Cannot find parent device\n");
return false;
+ }
ret = batadv_is_on_batman_iface(parent_dev);