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
| ||
|
Date: Thu, 23 Sep 2010 09:00:31 -0700 From: ebiederm@...ssion.com (Eric W. Biederman) To: linux-kernel@...r.kernel.org Cc: Linux Containers <containers@...ts.osdl.org>, netdev@...r.kernel.org, netfilter-devel@...r.kernel.org, linux-fsdevel@...r.kernel.org, jamal <hadi@...erus.ca>, Daniel Lezcano <daniel.lezcano@...e.fr>, Linus Torvalds <torvalds@...ux-foundation.org>, Michael Kerrisk <mtk.manpages@...il.com>, Ulrich Drepper <drepper@...il.com>, Al Viro <viro@...IV.linux.org.uk>, David Miller <davem@...emloft.net>, "Serge E. Hallyn" <serge@...lyn.com>, Pavel Emelyanov <xemul@...nvz.org>, Pavel Emelyanov <xemul@...allels.com>, Ben Greear <greearb@...delatech.com>, Matt Helsley <matthltc@...ibm.com>, Jonathan Corbet <corbet@....net>, Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>, Jan Engelhardt <jengelh@...ozas.de>, Patrick McHardy <kaber@...sh.net> Subject: Re: [PATCH 3/8] ns proc: Add support for the network namespace. Louis Rilling <Louis.Rilling@...labs.com> writes: > On 23/09/10 1:47 -0700, Eric W. Biederman wrote: >> >> Implementing file descriptors for the network namespace is simple and >> straight forward. >> >> Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com> > > [...] > >> diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c >> index c988e68..581a088 100644 >> --- a/net/core/net_namespace.c >> +++ b/net/core/net_namespace.c >> @@ -571,3 +571,33 @@ void unregister_pernet_device(struct pernet_operations *ops) >> mutex_unlock(&net_mutex); >> } >> EXPORT_SYMBOL_GPL(unregister_pernet_device); >> + >> +#ifdef CONFIG_NET_NS >> +static void *netns_get(struct task_struct *task) >> +{ >> + struct net *net; >> + rcu_read_lock(); >> + net = get_net(task->nsproxy->net_ns); > > task could be exiting, so task->nsproxy could be NULL, right? > Maybe make proc_ns_instantiate() rcu_dereference task->nsproxy, check for it > being not NULL, and pass task->nsproxy to ns_ops->get()? Ugh. Thanks. fixed. Somehow I forgot /proc shows zombies which means nsproxy will definitely be NULL in those cases. It is easy enough to handle once my brain gets out of park. I don't hold any locks at that point so I don't think I want to do anything in proc_ns_instantiate() except handle a NULL return when the ns_ops->get() fails. > That could be an issue for the user namespace since it is not in nsproxy, but > maybe no reasonable usage of ns_ops with user namespaces is > envisioned. It is also a issue for the pid namespace. > Otherwise, checking that task is alive with RCU locked in proc_ns_instantiate() should be enough to be > rely on task->cred when calling ns_ops->get(). That sounds about right. I keep conveniently forgetting the user namespace. It doesn't support unshare right now so there isn't anything I can reasonably do with it at the moment. It wouldn't surprise me if I don't wind up handling the user namespace like the pid namespace, where unsharing it changes the properties for the children and not the parent. Bleh. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists