From bfffc2c3f56b462cdf5eeea639d898a69b323001 Mon Sep 17 00:00:00 2001
From: Peter Malone <peter.malone@gmail.com>
Date: Wed, 7 Mar 2018 14:00:34 +0100
Subject: [PATCH] fbdev: Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC
in sbusfb_ioctl_helper().
[ 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@gmail.com>
Acked-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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 a350209ffbd3..31c301d6be62 100644
--- a/drivers/video/fbdev/sbuslib.c
+++ b/drivers/video/fbdev/sbuslib.c
@@ -121,7 +121,7 @@ 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) ||
@@ -160,7 +160,7 @@ 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) ||