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authorKees Cook <keescook@chromium.org>2017-01-24 15:18:24 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-01 08:33:02 +0100
commit544160b6ea18670196d1173c099f2cced5075132 (patch)
tree00d7e6913b506d6c1ee873a110a20350e9f9473d /drivers/video
parent09f886dc5a6945679ed35e6acfbc746f472f0f34 (diff)
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 Link: http://lkml.kernel.org/r/20170105224249.GA50925@beast Fixes: 1da177e4c3f4 ("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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/core/fbcmap.c26
1 files changed, 14 insertions, 12 deletions
diff --git a/drivers/video/fbdev/core/fbcmap.c b/drivers/video/fbdev/core/fbcmap.c
index f89245b8ba8e..68a113594808 100644
--- 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 *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->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 *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->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);