linux-kernel - Re: [PATCH v2 2/5] string_helpers: add kstrdup_quotable

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Message-ID: <1459336290.5907.39.camel@linux.intel.com>
Date:	Wed, 30 Mar 2016 14:11:30 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Kees Cook <keescook@...omium.org>, James Morris <jmorris@...ei.org>
Cc:	"Serge E. Hallyn" <serge@...lyn.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Kalle Valo <kvalo@...eaurora.org>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	Joe Perches <joe@...ches.com>,
	Guenter Roeck <linux@...ck-us.net>,
	Jiri Slaby <jslaby@...e.com>, Paul Moore <pmoore@...hat.com>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Casey Schaufler <casey@...aufler-ca.com>,
	Andreas Gruenbacher <agruenba@...hat.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] string_helpers: add kstrdup_quotable_cmdline

On Wed, 2016-03-30 at 14:07 +0300, Andy Shevchenko wrote:
> On Mon, 2016-03-28 at 14:14 -0700, Kees Cook wrote:


> > +	res = get_cmdline(task, buffer, PAGE_SIZE - 1);
> > +	buffer[res] = '\0';
> > +
> > +	/* Collapse trailing NULLs. */
> > +	for (; res > 0; res--)
> > +		if (buffer[res-1] != '\0')
> > +			break;
> /* buffer[res] is '\0', so, predecrement is safe here */
> while (buffer[--res] == '\0')
>  /* nothing */;
> 
> ?
> 

Oops, no, the following should be better

while (--res >= 0 && buffer[res] == '\0') ;

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy