fbdev: color map copying bounds checking

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

Change-Id: Iac32fe0cffcdc91b136bef474b05e9b1a4a9d7dc
Link: http://lkml.kernel.org/r/20170105224249.GA50925@beast
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Peter Pi (@heisecode) of Trend Micro
Cc: Min Chong <mchong@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Kevin F. Haggerty <haggertk@lineageos.org>
This commit is contained in:
Kees Cook
2019-08-06 12:24:21 +02:00
committed by Francescodario Cuzzocrea
parent 473b3eecf3
commit d6574165ad
+14 -12
View File
@@ -163,8 +163,8 @@ void fb_dealloc_cmap(struct fb_cmap *cmap)
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 || !from)
return -EINVAL;
@@ -173,10 +173,11 @@ int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to)
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);
@@ -193,8 +194,8 @@ int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to)
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 || !from || (int)(to->start) < 0)
return -EINVAL;
@@ -203,10 +204,11 @@ int fb_cmap_to_user(const struct fb_cmap *from, struct fb_cmap_user *to)
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);