linux-kernel - Re: [tip:x86/cpu] x86/cpu: Strip any /proc/ cpuinfo model name field whitespace

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Date:	Wed, 27 May 2015 10:07:34 -0700
From:	Joe Perches <joe@...ches.com>
To:	luto@...capital.net, bp@...en8.de, peterz@...radead.org,
	dvlasenk@...hat.com, torvalds@...ux-foundation.org,
	imammedo@...hat.com, brgerst@...il.com, mingo@...nel.org,
	prarit@...hat.com, dave.hansen@...ux.intel.com,
	fenghua.yu@...el.com, hpa@...or.com, linux-kernel@...r.kernel.org,
	tglx@...utronix.de, bp@...e.de
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/cpu] x86/cpu: Strip any /proc/ cpuinfo model name
 field whitespace

On Wed, 2015-05-27 at 07:16 -0700, tip-bot for Prarit Bhargava wrote:

> x86/cpu: Strip any /proc/cpuinfo model name field whitespace
[]
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> @@ -431,18 +430,10 @@ static void get_model_name(struct cpuinfo_x86 *c)
>  	c->x86_model_id[48] = 0;
>  
>  	/*
> -	 * Intel chips right-justify this string for some dumb reason;
> -	 * undo that brain damage:
> +	 * Remove leading whitespace on Intel processors and trailing
> +	 * whitespace on AMD processors.
>  	 */
> -	p = q = &c->x86_model_id[0];
> -	while (*p == ' ')
> -		p++;
> -	if (p != q) {
> -		while (*p)
> -			*q++ = *p++;
> -		while (q <= &c->x86_model_id[48])
> -			*q++ = '\0';	/* Zero-pad the rest */
> -	}
> +	memmove(c->x86_model_id, strim(c->x86_model_id), 48);

This code can memmove from beyond the x86_model_id field.

If the id was a single right justified char, to avoid overrunning
the field, it'd be safer moving only the actual string and
terminating 0 though this code is sub-optimal:

	memmove(c->x86_model_id, strim(c->x86_model_id),
		strlen(strim(c->x86_model_id) + 1);

Maybe:
	char *model = strim(c->x86_model_id);
	memmove(c->x86_model_id, model, strlen(model) + 1);

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