Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753117AbZD0MWA (ORCPT ); Mon, 27 Apr 2009 08:22:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752175AbZD0MVv (ORCPT ); Mon, 27 Apr 2009 08:21:51 -0400 Received: from mail-ew0-f176.google.com ([209.85.219.176]:37229 "EHLO mail-ew0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152AbZD0MVu convert rfc822-to-8bit (ORCPT ); Mon, 27 Apr 2009 08:21:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=iT6eUkHCwrP65b9jJc4i3oGUQC3ktfr/xypDuPO7w+BPma5FAeqCPNSIQsMIJkt9TR feFGjvnH+ZaFMW8TQlEB4SU0NA+dl+AdO6CmP43iGzdg0UMhIjV4VW9I+LaSUaojU7JD 5MlriqjWRpgmdJUydpZe1Ot+D0Bxt/q9PzGNg= MIME-Version: 1.0 In-Reply-To: <49F59DD9.6010903@gmail.com> References: <49EDD799.8060607@gmail.com> <20090423134110.51ea8df2.akpm@linux-foundation.org> <20090423214738.GF7134@sci.fi> <49F4519F.4090003@gmail.com> <20090426131505.GG7134@sci.fi> <49F59DD9.6010903@gmail.com> Date: Mon, 27 Apr 2009 14:21:47 +0200 X-Google-Sender-Auth: 1069d9aca05c3abb Message-ID: <10f740e80904270521n48b687c5y5b7e2e7bddbad027@mail.gmail.com> Subject: Re: [Linux-fbdev-devel] fbcmap: non working tests on unsigned cmap->start From: Geert Uytterhoeven To: Roel Kluin Cc: Andrew Morton , linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, adaplas@gmail.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4233 Lines: 109 On Mon, Apr 27, 2009 at 13:58, Roel Kluin wrote: > Ville Syrjälä wrote: >> On Sun, Apr 26, 2009 at 02:20:47PM +0200, Roel Kluin wrote: >>> cmap->start is unsigned, > >>>> On Thu, Apr 23, 2009 at 01:41:10PM -0700, Andrew Morton wrote: >>>>> argh. >>>>> >>>>> - Perhaps userspace can kill the kernel by sending a "negative" >>>>>   `start'.  Removing the test will make it even less likely that we'll >>>>>   fix this bug. >>>> Shouldn't happen. 'start' is used as the starting index for the hardware >>>> palette, 'start+len-1' is the last index. All drivers should already check >>>> the passed values since the maximum index depends on the display mode. >>>> And I suppose the worst thing that could happen if the driver fails to >>>> check the values would be incorrect colors. > >> You would rather need something like >> 'if (start+len > 1 << max(red.len, green.len, blue.len, transp.len))' > > what do you mean with `red.len'? is that `info->var.red.length'? That's correct. >> and a check to make sure that start+len doesn't overflow. >> >> Oh and I guess it should also check that the visual is pseudocolor or >> directcolor. > > I am fairly new so please review carefully. > > Not yet signed off-by: Roel Kluin Looks OK, thx! > --- > diff --git a/drivers/video/fbcmap.c b/drivers/video/fbcmap.c > index f53b9f1..b34e74e 100644 > --- a/drivers/video/fbcmap.c > +++ b/drivers/video/fbcmap.c > @@ -249,6 +249,7 @@ 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; > +       __u32 rgba_max = 0; > >        memset(&umap, 0, sizeof(struct fb_cmap)); >        rc = fb_alloc_cmap(&umap, cmap->len, cmap->transp != NULL); > @@ -261,13 +262,27 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info) >                rc = -EFAULT; >                goto out; >        } > + > +       if (cmap->start + cmap->len < cmap->start) { > +               rc = -EINVAL; > +               goto out; > +       } > + >        umap.start = cmap->start; >        if (!lock_fb_info(info)) { >                rc = -ENODEV; >                goto out; >        } > -       if (cmap->start < 0 || (!info->fbops->fb_setcolreg && > -                               !info->fbops->fb_setcmap)) { > + > +       rgba_max = max(info->var.red.length, info->var.green.length); > +       rgba_max = max(rgba_max, info->var.blue.length); > +       rgba_max = max(rgba_max, info->var.transp.length); > + > +       if (cmap->start + cmap->len > 1 << rgba_max || > +                       !(info->fbops->fb_setcolreg || > +                               info->fbops->fb_setcmap) || > +                       !(info->fix.visual == FB_VISUAL_PSEUDOCOLOR || > +                               info->fix.visual == FB_VISUAL_TRUECOLOR)) { >                rc = -EINVAL; >                goto out1; >        } > > ------------------------------------------------------------------------------ > Crystal Reports - New Free Runtime and 30 Day Trial > Check out the new simplified licensign option that enables unlimited > royalty-free distribution of the report engine for externally facing > server and web deployment. > http://p.sf.net/sfu/businessobjects > _______________________________________________ > Linux-fbdev-devel mailing list > Linux-fbdev-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel > -- Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/