linux-kernel - Re: [PATCH 3/5] x86: simplify early command line parsing

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Message-ID: <20160106171044.GB20321@pd.tnic>
Date:	Wed, 6 Jan 2016 18:10:44 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Dave Hansen <dave@...1.net>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	dave.hansen@...ux.intel.com, hpa@...or.com, fenghua.yu@...el.com,
	yu-cheng.yu@...el.com
Subject: Re: [PATCH 3/5] x86: simplify early command line parsing

On Tue, Dec 22, 2015 at 02:52:41PM -0800, Dave Hansen wrote:
> 
> From: Dave Hansen <dave.hansen@...ux.intel.com>
> 
> __cmdline_find_option_bool() tries to account for both
> NULL-terminated and non-NULL-terminated strings.  It keeps 'pos'
> to look for the end of the buffer and also looks for '!c' in a
> bunch of places to look for NULL termination.
> 
> But, it also calls strlen().  You can't call strlen on a
> non-NULL-terminated string.
> 
> If !strlen(cmdline), then cmdline[0]=='\0'.  In that case, we
> will go in to the while() loop, set c='\0', hit st_wordstart,
> notice !c, and will immediately return 0.
> 
> So, remove the strlen().  It is unnecessary and unsafe.
> 
> Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Borislav Petkov <bp@...e.de>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: linux-kernel@...r.kernel.org
> Cc: fenghua.yu@...el.com
> Cc: yu-cheng.yu@...el.com
> ---
> 
>  b/arch/x86/lib/cmdline.c |    3 ---
>  1 file changed, 3 deletions(-)
> 
> diff -puN arch/x86/lib/cmdline.c~x86-early-command-line-non-term arch/x86/lib/cmdline.c
> --- a/arch/x86/lib/cmdline.c~x86-early-command-line-non-term	2015-12-22 11:56:59.454186167 -0800
> +++ b/arch/x86/lib/cmdline.c	2015-12-22 11:56:59.457186302 -0800
> @@ -39,9 +39,6 @@ int cmdline_find_option_bool(const char
>  	if (!cmdline)
>  		return -1;      /* No command line */
>  
> -	if (!strlen(cmdline))
> -		return 0;
> -

Patch 1 adds the strlen(), this patch removes it. Please merge both patches.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 
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