netdev - Re: xfrm_state locking regression...

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]

Message-ID: <20080923130709.GA29902@gondor.apana.org.au>
Date:	Tue, 23 Sep 2008 21:07:09 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Timo Teräs <timo.teras@....fi>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: xfrm_state locking regression...

On Tue, Sep 23, 2008 at 04:01:29PM +0300, Timo Teräs wrote:
>
> So, what to do?
> 1. Go back to: list_del_rcu, xfrm_state_hold(all.next) on delete and
>    xfrm_state_put(all.next) on destruct.
> 2. Add per-entry hlist of walkers currently referencing it.
> 3. Use the global walker list.
> 
> 1 can keep memory allocated until userland wakes up. 2 & 3 can make
> the delete of that entry slow if there's many walkers suspended.

I'd cross 3 off the list because 2 is just so much better :)

I'd slightly lean towards 2 but now that you mention it yes even
that is vulnerable to loads of dumpers sitting on the same entry.
So SELINUX folks wouldn't like that :)

> Btw. the current stuff in net-next is broken. There's no locking
> for xfrm_state_walkers list handling.

What about xfrm_cfg_mutex?

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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