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Message-ID: <1460548402.6620.128.camel@linux.intel.com>
Subject: Re: [PATCH v4 2/6] string_helpers: add kstrdup_quotable_cmdline
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Serge E. Hallyn" <serge@hallyn.com>, Kees Cook <keescook@chromium.org>
Cc: James Morris <jmorris@namei.org>, Joe Perches <joe@perches.com>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>, Kalle Valo <kvalo@codeaurora.org>,
        Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
        Guenter Roeck <linux@roeck-us.net>, Jiri Slaby <jslaby@suse.com>,
        Paul Moore <pmoore@redhat.com>, Stephen Smalley <sds@tycho.nsa.gov>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org
Date: Wed, 13 Apr 2016 14:53:22 +0300
In-Reply-To: <20160412211942.GB12324@mail.hallyn.com>
References: <1460480085-32263-1-git-send-email-keescook@chromium.org>
	 <1460480085-32263-3-git-send-email-keescook@chromium.org>
	 <20160412211942.GB12324@mail.hallyn.com>
Organization: Intel Finland Oy
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On Tue, 2016-04-12 at 16:19 -0500, Serge E. Hallyn wrote:
> Quoting Kees Cook (keescook@chromium.org):
> > 
> > Provide an escaped (but readable: no inter-argument NULLs)
> > commandline
> > safe for logging.
> > 

Sorry, have no access to the original mail right now.

>> +char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
> > +{
> > +	char *buffer, *quoted;
> > +	int i, res;
> > +
> > +	buffer = kmalloc(PAGE_SIZE, GFP_TEMPORARY);
> > +	if (!buffer)
> > +		return NULL;
> > +
> > +	res = get_cmdline(task, buffer, PAGE_SIZE - 1);
> > +	buffer[res] = '\0';
> > +
> > +	/* Collapse trailing NULLs, leave res pointing to last non-
> > NULL. */
> > +	while (--res >= 0 && buffer[res] == '\0')
> > +		;

Nitpick: perhaps leave comment that make more visible
/* nothing */ ;

(up to you)?

> > +
> > +	/* Replace inter-argument NULLs. */
> > +	for (i = 0; i <= res; i++)

But why do you need to check = res? It's already checked by previous
condition and undoubtfully it's non-'\0'.

Forgot to mention this earlier.

> > +		if (buffer[i] == '\0')
> > +			buffer[i] = ' ';

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