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Message-Id: <20180528100058.298836991@linuxfoundation.org>
Date: Mon, 28 May 2018 12:02:10 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Peter Malone <peter.malone@...il.com>,
Mathieu Malaterre <malat@...ian.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 3.18 089/185] fbdev: Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper().
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Malone <peter.malone@...il.com>
[ Upstream commit 250c6c49e3b68756b14983c076183568636e2bde ]
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.
This patch fixes CVE-2018-6412.
Signed-off-by: Peter Malone <peter.malone@...il.com>
Acked-by: Mathieu Malaterre <malat@...ian.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/video/fbdev/sbuslib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/video/fbdev/sbuslib.c
+++ b/drivers/video/fbdev/sbuslib.c
@@ -121,7 +121,7 @@ int sbusfb_ioctl_helper(unsigned long cm
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) ||
@@ -160,7 +160,7 @@ int sbusfb_ioctl_helper(unsigned long cm
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) ||
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