linux-kernel - Re: [PATCH 0/3] Fix bugs in *_set

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Date:   Thu, 4 Aug 2022 16:43:47 +0200
From:   Ondrej Zajicek <santiago@...reenet.org>
To:     Zheyu Ma <zheyuma97@...il.com>
Cc:     deller@....de, adaplas@...il.com, akpm@...ux-foundation.org,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] Fix bugs in *_set_par() caused by user input

On Thu, Aug 04, 2022 at 08:41:22PM +0800, Zheyu Ma wrote:
> In the function *_set_par(), the value of 'screen_size' is
> calculated by the user input. If the user provides the improper value,
> the value of 'screen_size' may larger than 'info->screen_size', which
> may cause a bug in the memset_io().

Hi

I did not saw fbdev code in years, but should not this be already checked
by *_check_var() ?

arkfb_check_var():

	...
	/* Check whether have enough memory */
	mem = ((var->bits_per_pixel * var->xres_virtual) >> 3) * var->yres_virtual;
	if (mem > info->screen_size)
	...

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago@...reenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."