netdev - [PATCH][net-next] net: check extack.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Fri,  3 Aug 2018 15:45:21 +0800
From:   Li RongQing <lirongqing@...du.com>
To:     netdev@...r.kernel.org
Subject: [PATCH][net-next] net: check extack._msg before print

dev_set_mtu_ext is able to fail with a valid mtu value, at that
condition, extack._msg is not set and random since it is in stack,
then kernel will crash when print it.

Fixes: 7a4c53bee3324a ("net: report invalid mtu value via netlink extack")
Signed-off-by: Zhang Yu <zhangyu31@...du.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
---
 net/core/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 36e994519488..f68122f0ab02 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7583,8 +7583,9 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
 	struct netlink_ext_ack extack;
 	int err;
 
+	memset(&extack, 0, sizeof(extack));
 	err = dev_set_mtu_ext(dev, new_mtu, &extack);
-	if (err)
+	if (err && extack._msg)
 		net_err_ratelimited("%s: %s\n", dev->name, extack._msg);
 	return err;
 }
-- 
2.16.2