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From: "Serge E. Hallyn" <serge@hallyn.com>
To: Christian Brauner <christian.brauner@canonical.com>
Cc: Jann Horn <jannh@google.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	kernel list <linux-kernel@vger.kernel.org>,
	security@kernel.org, Andy Lutomirski <luto@amacapital.net>,
	Kees Cook <keescook@chromium.org>,
	"Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH] userns: move user access out of the mutex
Date: Wed, 27 Jun 2018 11:32:09 -0500	[thread overview]
Message-ID: <20180627163209.GA23160@mail.hallyn.com> (raw)
In-Reply-To: <20180627142315.GC31443@gmail.com>

Quoting Christian Brauner (christian.brauner@canonical.com):
> On Tue, Jun 26, 2018 at 04:06:45PM +0200, Jann Horn wrote:
> > On Tue, Jun 26, 2018 at 3:08 PM Christian Brauner
> > <christian.brauner@canonical.com> wrote:
> > >
> > > On Mon, Jun 25, 2018 at 06:34:19PM +0200, Jann Horn wrote:
> > > > The old code would hold the userns_state_mutex indefinitely if
> > > > memdup_user_nul stalled due to e.g. a userfault region. Prevent that by
> > > > moving the memdup_user_nul in front of the mutex_lock().
> > > >
> > > > Note: This changes the error precedence of invalid buf/count/*ppos vs
> > > > map already written / capabilities missing.
> > > >
> > > > Fixes: 22d917d80e84 ("userns: Rework the user_namespace adding uid/gid...")
> > > > Cc: stable@vger.kernel.org
> > > > Signed-off-by: Jann Horn <jannh@google.com>
> 
> Acked-by: Christian Brauner <christian@brauner.io>

Acked-by: Serge Hallyn <serge@hallyn.com>

thanks.

-serge

      reply	other threads:[~2018-06-27 16:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-25 16:34 [PATCH] userns: move user access out of the mutex Jann Horn
2018-06-26 13:07 ` Christian Brauner
2018-06-26 14:06   ` Jann Horn
2018-06-27 14:23     ` Christian Brauner
2018-06-27 16:32       ` Serge E. Hallyn [this message]

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