netdev - [PATCH net-2.6] netns: assign NULL after pernet memory is freed

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: <20100426111806.GB2941@psychotron.lab.eng.brq.redhat.com>
Date:	Mon, 26 Apr 2010 13:18:07 +0200
From:	Jiri Pirko <jpirko@...hat.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, ebiederm@...ssion.com
Subject: [PATCH net-2.6] netns: assign NULL after pernet memory is freed

This is needed to let know appropriate code (driver) know that pernet memory
chunk  was freed already. For example when driver has also registered netdev
notifier, it can be called after memory is freed which could eventually lead
to panic. Also a null check should be present in these notifiers.

For example, previously, when drivers were responsible for pernet memory
allocation/freeing, in pppoe this assign was done in pppoe_exit_net() right
after pernet memory was freed. The check in notifier stayed (in pppoe_flush_dev
called from pppoe_device_event) but makes no sense now without this patch.

I already know about several notifiers where the check should be present,
patches will follow up.

Signed-off-by: Jiri Pirko <jpirko@...hat.com>

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index bd8c471..29f622c 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -51,6 +51,7 @@ static void ops_free(const struct pernet_operations *ops, struct net *net)
 	if (ops->id && ops->size) {
 		int id = *ops->id;
 		kfree(net_generic(net, id));
+		net_assign_generic(net, id, NULL);
 	}
 }

--
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