linux-kernel - Re: [PATCH v1 1/1] vsprintf: Move space out of string literals in fourcc

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]

Date:   Tue, 11 Jan 2022 16:10:25 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
Subject: Re: [PATCH v1 1/1] vsprintf: Move space out of string literals in
 fourcc_string()

On Tue 2022-01-11 13:28:21, Andy Shevchenko wrote:
> On Tue, Jan 11, 2022 at 11:26:21AM +0100, Rasmus Villemoes wrote:
> > On 10/01/2022 21.55, Andy Shevchenko wrote:
> > > The literals "big-endian" and "little-endian" may be potentially
> > > occurred in other places. Dropping space allows compiler to
> > > "compress" them by using only a single copy.
> > 
> > Nit: it's not the compiler which does that, but the linker.
> 
> Ah, I stand corrected, thanks!
> 
> > > -	strcpy(p, orig & BIT(31) ? " big-endian" : " little-endian");
> > > +	*p++ = ' ';
> > > +	strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian");
> > >  	p += strlen(p);
> > 
> > Hm, ok, those two strings do occur a lot with of_property_read_bool()
> > and friends. But if you're micro-optimizing anyway, why not drop the
> > strlen() and say p = stpcpy(...) instead?
> 
> Why not? I'll do it for v2.

It is safe here. I just hope that it will not trigger reports from
some tools looking for potential security issues ;-)

> Any thoughts / comments on the
> https://lore.kernel.org/lkml/20220110205049.11696-1-andriy.shevchenko@linux.intel.com/T/#u?
> I'm asking since dependency and I would like to know if we still want that
> fix or not.

Just commented there. It looks fine to me.

Best Regards,
Petr