linux-kernel - Re: [PATCH 7/7][v8] SI_USER: Masquerade si

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:	Thu, 19 Feb 2009 19:51:59 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...l.org>, roland@...hat.com,
	daniel@...ac.com, Containers <containers@...ts.osdl.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/7][v8] SI_USER: Masquerade si_pid when crossing pid
	ns boundary

On 02/19, Eric W. Biederman wrote:
>
> Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com> writes:
>
> > From: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
> > Date: Wed, 24 Dec 2008 14:14:18 -0800
> > Subject: [PATCH 7/7][v8] SI_USER: Masquerade si_pid when crossing pid ns
> > boundary
> >
> > When sending a signal to a descendant namespace, set ->si_pid to 0 since
> > the sender does not have a pid in the receiver's namespace.
> >
> > Note:
> > 	- If rt_sigqueueinfo() sets si_code to SI_USER when sending a
> > 	  signal across a pid namespace boundary, the value in ->si_pid
> > 	  will be cleared to 0.
> >
> > Changelog[v5]:
> > 	- (Oleg Nesterov) Address both sys_kill() and sys_tkill() cases
> > 	  in send_signal() to simplify code (this drops patch 7/7 from
> > 	  earlier version of patchset).
> >
> > Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
> > ---
> >  kernel/signal.c |    2 ++
> >  1 files changed, 2 insertions(+), 0 deletions(-)
> >
> > diff --git a/kernel/signal.c b/kernel/signal.c
> > index c94355b..a416d77 100644
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -883,6 +883,8 @@ static int __send_signal(int sig, struct siginfo *info,
> > struct task_struct *t,
> >  			break;
> >  		default:
> >  			copy_siginfo(&q->info, info);
> > +			if (from_ancestor_ns)
> > +				q->info.si_pid = 0;
>
> This is wrong.  siginfo is a union and you need to inspect
> code to see if si_pid is present in the current union.

SI_FROMUSER() == T, unless we have more (hopefully not) in-kernel
users which send SI_FROMUSER() signals, .si_pid must be valid?

kill_pid_info_as_uid() was the only known sender of SI_FROMUSER
signal, it was converted to use __send_signal(from_ancestor_ns => 0).

Oleg.

--
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/