linux-kernel - Re: [PATCH] pid: change task

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: <20140123192403.GA5823@madcap2.tricolour.ca>
Date:	Thu, 23 Jan 2014 14:24:03 -0500
From:	Richard Guy Briggs <rgb@...hat.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	akpm@...ux-foundation.org, Peter Zijlstra <peterz@...radead.org>,
	linux-audit@...hat.com, linux-kernel@...r.kernel.org,
	Eric Paris <eparis@...hat.com>
Subject: Re: [PATCH] pid: change task_struct::pid to read-only

On 13/12/22, Oleg Nesterov wrote:
> On 12/20, Peter Zijlstra wrote:
> >
> > On Fri, Dec 20, 2013 at 08:01:57PM +0100, Oleg Nesterov wrote:
> > > The only problem is that
> > >
> > > 	#define ASSIGN_CONST(l, r)      (*(typeof(r) *)&(l) = (r))
> > >
> > > obviously can't work in this case ;) We need something more clever.
> >
> > Hmm indeed, C++ has both the const_cast<>() thingy and the template
> > system is powerful enough to actually implement const_cast<>() inside
> > the language.
> 
> So, how about
> 
> 	#define CONST_CAST(type, lval)	\
> 		(*({					\
> 			(void)((type *)0 == &(lval));	\
> 			(type *)&(lval);		\
> 		}))					\
> 
> de_thread/copy_process can do
> 
> 	CONST_CAST(pid_t, tsk->pid) = leader->pid;
> 
> and if "type" is wrong we have a warning.

Cool.  This works very nicely.  Thanks for the ideas Oleg!

> Oleg.

- RGB

--
Richard Guy Briggs <rbriggs@...hat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
--
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/