netdev - [Patch] rtnetlink: call ->dellink on failure when ->newlink exists

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]

Message-Id: <1423864613-29637-1-git-send-email-xiyou.wangcong@gmail.com>
Date:	Fri, 13 Feb 2015 13:56:53 -0800
From:	Cong Wang <xiyou.wangcong@...il.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, ignacy.gawedzki@...en-communications.fr,
	Cong Wang <xiyou.wangcong@...il.com>
Subject: [Patch] rtnetlink: call ->dellink on failure when ->newlink exists

Ignacy reported that when eth0 is down and add a vlan device
on top of it like:

  ip link add link eth0 name eth0.1 up type vlan id 1

We will get a refcount leak:

  unregister_netdevice: waiting for eth0.1 to become free. Usage count = 2

The problem is when rtnl_configure_link() fails in rtnl_newlink(),
we simply call unregister_device(), but for stacked device like vlan,
we almost do nothing when we unregister the upper device, more work
is done when we unregister the lower device, so call its ->dellink().

Reported-by: Ignacy Gawedzki <ignacy.gawedzki@...en-communications.fr>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 net/core/rtnetlink.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 5be499b..ab293a3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2162,7 +2162,14 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh)
 		}
 		err = rtnl_configure_link(dev, ifm);
 		if (err < 0) {
-			unregister_netdevice(dev);
+			if (ops->newlink) {
+				LIST_HEAD(list_kill);
+
+				ops->dellink(dev, &list_kill);
+				unregister_netdevice_many(&list_kill);
+			} else {
+				unregister_netdevice(dev);
+			}
 			goto out;
 		}
 
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html