linux-kernel - Re: [patch 2/2] fbcmap: integer overflow bug

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Message-ID: <20101115072014.GB21614@bicker>
Date:	Mon, 15 Nov 2010 10:20:15 +0300
From:	Dan Carpenter <error27@...il.com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:	Paul Mundt <lethal@...ux-sh.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: Re: [patch 2/2] fbcmap: integer overflow bug

On Mon, Nov 15, 2010 at 07:56:05AM +0100, Geert Uytterhoeven wrote:
> On Mon, Nov 15, 2010 at 05:48, Paul Mundt <lethal@...ux-sh.org> wrote:
> > On Sat, Nov 13, 2010 at 01:07:18PM +0300, Dan Carpenter wrote:
> >> @@ -256,8 +264,12 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
> >>       int rc, size = cmap->len * sizeof(u16);
> >>       struct fb_cmap umap;
> >>
> >> +     if (cmap->len * 2 > INT_MAX)
> 
> Isn't that another integer overflow? I.e. should be "if (cmap->len >
> INT_MAX / sizeof(u16))" instead?
> 

Yeah it is.  :/

I'll change it to:
	if (size < 0 || size < cmap->len)
like Paul asked.

regards,
dan carpenter

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