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: <20120328170401.GB18944@redhat.com>
Date:	Wed, 28 Mar 2012 19:04:01 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Boaz Harrosh <bharrosh@...asas.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
	linux-security-module@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Turner <pjt@...gle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	NFS list <linux-nfs@...r.kernel.org>,
	Trond Myklebust <Trond.Myklebust@...app.com>,
	"Bhamare, Sachin" <sbhamare@...asas.com>,
	David Howells <dhowells@...hat.com>,
	Eric Paris <eparis@...hat.com>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	Kay Sievers <kay.sievers@...y.org>,
	James Morris <jmorris@...ei.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Greg KH <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"keyrings@...ux-nfs.org" <keyrings@...ux-nfs.org>
Subject: Re: [PATCH 5/6] kmod: Add new call_usermodehelper_timeout() API

On 03/27, Oleg Nesterov wrote:
>
> On 03/26, Boaz Harrosh wrote:
> >
> >  int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
> >  {
> >  	DECLARE_COMPLETION_ONSTACK(done);
> > +	int wait_state;
> >  	int retval = 0;
> >
> >  	helper_lock();
> > @@ -540,19 +541,15 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
> >  	if (wait == UMH_NO_WAIT)	/* task has freed sub_info */
> >  		goto unlock;
> >
> > -	if (wait & UMH_KILLABLE) {
> > -		retval = wait_for_completion_killable(&done);
> > -		if (!retval)
> > -			goto wait_done;
> > -
> > +	wait_state = (wait & UMH_KILLABLE) ? TASK_KILLABLE : 0;
> > +	retval = wait_for_completion_timeout_state(&done, sub_info->timeout,
> > +						   wait_state);
> > +	if (unlikely(retval)) {
> >  		/* umh_complete() will see NULL and free sub_info */
> >  		if (xchg(&sub_info->complete, NULL))
> >  			goto unlock;
> > -		/* fallthrough, umh_complete() was already called */
> >  	}
> >
> > -	wait_for_completion(&done);
>
> at first glance this looks certainly wrong, or I misread the patch.
>
> We can't remove the "fallback to wait_for_completion" logic until
> you move the completion into subprocess_info (the next patch seems
> to do this).

Yes, I think this is true after I re-checked the code.



One more nit. With this patch call_usermodehelper_fns() does

	info = call_usermodehelper_setup(path, argv, envp, gfp_mask);

	call_usermodehelper_setfns(info, init, cleanup, data);

	info->timeout = timeout;

We have 2 (static!) helpers to initialize info, yet we initialize
->timeout by hand. Of course I do not blame this patch, but imho
this looks a bit messy and deserves another minor cleanup.

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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ