linux-kernel - Re: [CRED bug?] 2.6.29-rc3 don't survive on stress workload

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: <20090212143932.GA10101@us.ibm.com>
Date:	Thu, 12 Feb 2009 08:39:32 -0600
From:	"Serge E. Hallyn" <serue@...ibm.com>
To:	David Howells <dhowells@...hat.com>
Cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Lee Schermerhorn <Lee.Schermerhorn@...com>
Subject: Re: [CRED bug?] 2.6.29-rc3 don't survive on stress workload

Quoting David Howells (dhowells@...hat.com):
> KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> wrote:
> 
> > but perhaps I am merely lucky guy.
> 
> Or perhaps Serge's patch fixes it - as I said I don't have it applied - though
> I don't see exactly why it should fix this problem...

I believe it was because

	1. put_user_ns() was being called before the uid (which
	   was in the init_user_ns) was unhashed

	2. alloc_uid would race in before the unhash, find
	   the hashed uid, and reuse it - without doing
	   another get_user_ns().

so a reference was lost.

-serge
--
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/