linux-kernel - Re: [PATCH 1/2] RAS/CEC: Use the right length for "cec

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Date:   Tue, 3 Oct 2017 11:04:06 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Nicolas Iooss <nicolas.iooss_linux@....org>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] RAS/CEC: Use the right length for "cec_disable"

On Mon, Oct 02, 2017 at 05:42:56PM +0200, Thomas Gleixner wrote:
> On Mon, 2 Oct 2017, Borislav Petkov wrote:
> > From: Nicolas Iooss <nicolas.iooss_linux@....org>
> > 
> > parse_cec_param() compares a string with "cec_disable" using only 7
> > characters of the 11-character-long string. Fix the length.
> > 
> > Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@....org>
> > Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector")
> > Link: http://lkml.kernel.org/r/20170903075440.30250-1-nicolas.iooss_linux@m4x.org
> > Signed-off-by: Borislav Petkov <bp@...e.de>
> > ---
> >  drivers/ras/cec.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
> > index d0e5d6ee882c..586c296d1538 100644
> > --- a/drivers/ras/cec.c
> > +++ b/drivers/ras/cec.c
> > @@ -523,7 +523,7 @@ int __init parse_cec_param(char *str)
> >  	if (*str == '=')
> >  		str++;
> >  
> > -	if (!strncmp(str, "cec_disable", 7))
> > +	if (!strncmp(str, "cec_disable", 11))
> 
> This kind of issue happens over and over. So if you really want to use
> strncmp() then this should be:
> 
> #define	CEC_DISABLE	"cec_disable"
> 
> 	if (!strncmp(str, CEC_DISABLE, strlen(CEC_DISABLE))
> 
> or we get a proper helper for that. Though in case of comparing some string
> against a constant string strncmp() has no real advantage over strcmp() as
> the comparison is guaranteed to be bound by the string constant.

Right.

Nicolas, wanna address that?

Thx.

-- 
Regards/Gruss,
    Boris.

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