From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Malone Subject: Re: [PATCH v2] Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper(). Date: Sun, 4 Feb 2018 09:12:42 -0500 Message-ID: References: <20180130203042.4797-1-peter.malone@gmail.com> <20180131145755.26109-1-peter.malone@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0626205550==" Return-path: Received: from mail-oi0-x241.google.com (mail-oi0-x241.google.com [IPv6:2607:f8b0:4003:c06::241]) by gabe.freedesktop.org (Postfix) with ESMTPS id AD3BB6E0BE for ; Sun, 4 Feb 2018 14:12:45 +0000 (UTC) Received: by mail-oi0-x241.google.com with SMTP id c8so19434506oiy.9 for ; Sun, 04 Feb 2018 06:12:45 -0800 (PST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Mathieu Malaterre Cc: Linux Fbdev development list , linux-kernel@vger.kernel.org, dri-devel , Bartlomiej Zolnierkiewicz List-Id: dri-devel@lists.freedesktop.org --===============0626205550== Content-Type: multipart/alternative; boundary="f403043697e00118ef0564638a4f" --f403043697e00118ef0564638a4f Content-Type: text/plain; charset="UTF-8" Hi folks, CVE-2018-6412 has been created for this. Is it possible for you to add a note indicating the CVE number when merging the patch? I received the CVE number after the patch was created and ack'd, which is why I didn't include it in the commit message. On Jan 31, 2018 10:49, "Mathieu Malaterre" wrote: > Hi Peter, > > On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone > wrote: > > Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in > > sbusfb_ioctl_helper(). > > > > 'index' is defined as an int in sbusfb_ioctl_helper(). > > We retrieve this from the user: > > if (get_user(index, &c->index) || > > __get_user(count, &c->count) || > > __get_user(ured, &c->red) || > > __get_user(ugreen, &c->green) || > > __get_user(ublue, &c->blue)) > > return -EFAULT; > > > > and then we use 'index' in the following way: > > red = cmap->red[index + i] >> 8; > > green = cmap->green[index + i] >> 8; > > blue = cmap->blue[index + i] >> 8; > > > > This is a classic information leak vulnerability. 'index' should be > > an unsigned int, given its usage above. > > > > This patch is straight-forward; it changes 'index' to unsigned int > > in two switch-cases: FBIOGETCMAP_SPARC && FBIOPUTCMAP_SPARC. > > > > Signed-off-by: Peter Malone > > --- > > much better :) > > > v2: fixed formatting > > > > drivers/video/fbdev/sbuslib.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/video/fbdev/sbuslib.c > b/drivers/video/fbdev/sbuslib.c > > index af6fc97f4ba4..a436d44f1b7f 100644 > > --- a/drivers/video/fbdev/sbuslib.c > > +++ b/drivers/video/fbdev/sbuslib.c > > @@ -122,7 +122,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned > long arg, > > unsigned char __user *ured; > > unsigned char __user *ugreen; > > unsigned char __user *ublue; > > - int index, count, i; > > + unsigned int index, count, i; > > > > if (get_user(index, &c->index) || > > __get_user(count, &c->count) || > > @@ -161,7 +161,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned > long arg, > > unsigned char __user *ugreen; > > unsigned char __user *ublue; > > struct fb_cmap *cmap = &info->cmap; > > - int index, count, i; > > + unsigned int index, count, i; > > u8 red, green, blue; > > > > if (get_user(index, &c->index) || > > -- > > 2.14.3 > > > > By just looking at the code and commit message: > > Acked-by: Mathieu Malaterre > --f403043697e00118ef0564638a4f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi folks,

CV= E-2018-6412 has been created for this. Is it possible for you to add a note= indicating the CVE number when merging the patch?
<= br>
I received the CVE number after the patch was cr= eated and ack'd, which is why I didn't include it in the commit mes= sage.



On Jan 31, 2018 10:= 49, "Mathieu Malaterre" <m= alat@debian.org> wrote:
Hi Peter,

On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone <peter.malone@gmail.com> wrote:
> Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in
> sbusfb_ioctl_helper().
>
> 'index' is defined as an int in sbusfb_ioctl_helper().
> We retrieve this from the user:
> if (get_user(index, &c->index) ||
>=C2=A0 =C2=A0 =C2=A0__get_user(count, &c->count) ||
>=C2=A0 =C2=A0 =C2=A0__get_user(ured, &c->red) ||
>=C2=A0 =C2=A0 =C2=A0__get_user(ugreen, &c->green) ||
>=C2=A0 =C2=A0 =C2=A0__get_user(ublue, &c->blue))
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 return -EFAULT;
>
> and then we use 'index' in the following way:
> red =3D cmap->red[index + i] >> 8;
> green =3D cmap->green[index + i] >> 8;
> blue =3D cmap->blue[index + i] >> 8;
>
> This is a classic information leak vulnerability. 'index' shou= ld be
> an unsigned int, given its usage above.
>
> This patch is straight-forward; it changes 'index' to unsigned= int
> in two switch-cases: FBIOGETCMAP_SPARC && FBIOPUTCMAP_SPARC. >
> Signed-off-by: Peter Malone <peter.malone@gmail.com>
> ---

much better :)

> v2: fixed formatting
>
>=C2=A0 drivers/video/fbdev/sbuslib.c | 4 ++--
>=C2=A0 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/= sbuslib.c
> index af6fc97f4ba4..a436d44f1b7f 100644
> --- a/drivers/video/fbdev/sbuslib.c
> +++ b/drivers/video/fbdev/sbuslib.c
> @@ -122,7 +122,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigne= d long arg,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned = char __user *ured;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned = char __user *ugreen;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned = char __user *ublue;
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0int index, cou= nt, i;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned int i= ndex, count, i;
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (get_u= ser(index, &c->index) ||
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0__get_user(count, &c->count) ||
> @@ -161,7 +161,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigne= d long arg,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned = char __user *ugreen;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned = char __user *ublue;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0struct fb= _cmap *cmap =3D &info->cmap;
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0int index, cou= nt, i;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned int i= ndex, count, i;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0u8 red, g= reen, blue;
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (get_u= ser(index, &c->index) ||
> --
> 2.14.3
>

By just looking at the code and commit message:

Acked-by: Mathieu Malaterre <malat@d= ebian.org>
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