This is a note to let you know that I've just added the patch titled
fbdev: color map copying bounds checking
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fbdev-color-map-copying-bounds-checking.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2dc705a9930b4806250fbf5a76e55266e59389f2 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@xxxxxxxxxxxx>
Date: Tue, 24 Jan 2017 15:18:24 -0800
Subject: fbdev: color map copying bounds checking
From: Kees Cook <keescook@xxxxxxxxxxxx>
commit 2dc705a9930b4806250fbf5a76e55266e59389f2 upstream.
Copying color maps to userspace doesn't check the value of to->start,
which will cause kernel heap buffer OOB read due to signedness wraps.
CVE-2016-8405
Link: http://lkml.kernel.org/r/20170105224249.GA50925@beast
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reported-by: Peter Pi (@heisecode) of Trend Micro
Cc: Min Chong <mchong@xxxxxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fbcmap.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
--- a/drivers/video/fbdev/core/fbcmap.c
+++ b/drivers/video/fbdev/core/fbcmap.c
@@ -163,17 +163,18 @@ void fb_dealloc_cmap(struct fb_cmap *cma
int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to)
{
- int tooff = 0, fromoff = 0;
- int size;
+ unsigned int tooff = 0, fromoff = 0;
+ size_t size;
if (to->start > from->start)
fromoff = to->start - from->start;
else
tooff = from->start - to->start;
- size = to->len - tooff;
- if (size > (int) (from->len - fromoff))
- size = from->len - fromoff;
- if (size <= 0)
+ if (fromoff >= from->len || tooff >= to->len)
+ return -EINVAL;
+
+ size = min_t(size_t, to->len - tooff, from->len - fromoff);
+ if (size == 0)
return -EINVAL;
size *= sizeof(u16);
@@ -187,17 +188,18 @@ int fb_copy_cmap(const struct fb_cmap *f
int fb_cmap_to_user(const struct fb_cmap *from, struct fb_cmap_user *to)
{
- int tooff = 0, fromoff = 0;
- int size;
+ unsigned int tooff = 0, fromoff = 0;
+ size_t size;
if (to->start > from->start)
fromoff = to->start - from->start;
else
tooff = from->start - to->start;
- size = to->len - tooff;
- if (size > (int) (from->len - fromoff))
- size = from->len - fromoff;
- if (size <= 0)
+ if (fromoff >= from->len || tooff >= to->len)
+ return -EINVAL;
+
+ size = min_t(size_t, to->len - tooff, from->len - fromoff);
+ if (size == 0)
return -EINVAL;
size *= sizeof(u16);
Patches currently in stable-queue which might be from keescook@xxxxxxxxxxxx are
queue-4.9/fbdev-color-map-copying-bounds-checking.patch
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