linux-kernel - Re: [patch 14/23] x86 microcode: dont check the size

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Date:	Sat, 2 Dec 2006 07:44:54 +0100
From:	Willy Tarreau <w@....eu>
To:	shaohua.li@...el.com
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [patch 14/23] x86 microcode: dont check the size

Shaohua,

this one seems appropriate for 2.4 too. It is OK for you if I merge it ?

Thanks,
Willy

On Wed, Nov 29, 2006 at 02:00:25PM -0800, Chris Wright wrote:
> -stable review patch.  If anyone has any objections, please let us know.
> ------------------
> 
> From: Shaohua Li <shaohua.li@...el.com>
> 
> IA32 manual says if micorcode update's size is 0, then the size is
> default size (2048 bytes). But this doesn't suggest all microcode
> update's size should be above 2048 bytes to me. We actually had a
> microcode update whose size is 1024 bytes. The patch just removed the
> check.
> 
> Backported to 2.6.18 by Daniel Drake.
> 
> Signed-off-by: Daniel Drake <dsd@...too.org>
> Signed-off-by: Chris Wright <chrisw@...s-sol.org>
> ---
>  arch/i386/kernel/microcode.c |    9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> --- linux-2.6.18.4.orig/arch/i386/kernel/microcode.c
> +++ linux-2.6.18.4/arch/i386/kernel/microcode.c
> @@ -250,14 +250,14 @@ static int find_matching_ucodes (void) 
>  		}
>  
>  		total_size = get_totalsize(&mc_header);
> -		if ((cursor + total_size > user_buffer_size) || (total_size < DEFAULT_UCODE_TOTALSIZE)) {
> +		if (cursor + total_size > user_buffer_size) {
>  			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
>  			error = -EINVAL;
>  			goto out;
>  		}
>  
>  		data_size = get_datasize(&mc_header);
> -		if ((data_size + MC_HEADER_SIZE > total_size) || (data_size < DEFAULT_UCODE_DATASIZE)) {
> +		if (data_size + MC_HEADER_SIZE > total_size) {
>  			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
>  			error = -EINVAL;
>  			goto out;
> @@ -460,11 +460,6 @@ static ssize_t microcode_write (struct f
>  {
>  	ssize_t ret;
>  
> -	if (len < DEFAULT_UCODE_TOTALSIZE) {
> -		printk(KERN_ERR "microcode: not enough data\n"); 
> -		return -EINVAL;
> -	}
> -
>  	if ((len >> PAGE_SHIFT) > num_physpages) {
>  		printk(KERN_ERR "microcode: too much data (max %ld pages)\n", num_physpages);
>  		return -EINVAL;
> 
> --
> -
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