linux-kernel - Re: Multitude of dst obsolescense race conditions

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

Date:	Fri, 06 Jun 2014 11:57:10 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	paulmck@...ux.vnet.ibm.com
Cc:	dormando <dormando@...ia.net>, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: Multitude of dst obsolescense race conditions

On Fri, 2014-06-06 at 11:12 -0700, Paul E. McKenney wrote:

> It is probably just be me getting lost in the code, but I am not seeing
> a synchronize_rcu(), call_rcu(), or synchronize_net() anywhere in
> dst_release() or the things that it calls.  If there really isn't such
> a call, then I don't see how the above code is safe in the case where
> __sk_dst_set() is invoked on one CPU just after sk_dst_get() executes
> the rcu_dereference() on some other CPU.

Well, this part is fine, dst_release() do not free dst that are
potentially stored in sk_dst_cache

Only the refcount is decremented.

The bug is elsewhere, we had another thread raising this issue on netdev
this morning.

I am cooking a patch to clear the mess.

Thanks


--
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/