This is a note to let you know that I've just added the patch titled
fbmem: add margin check to fb_check_caps()
to the 4.4-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:
fbmem-add-margin-check-to-fb_check_caps.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a49145acfb975d921464b84fe00279f99827d816 Mon Sep 17 00:00:00 2001
From: George Kennedy <george.kennedy@xxxxxxxxxx>
Date: Tue, 7 Jul 2020 15:26:03 -0400
Subject: fbmem: add margin check to fb_check_caps()
From: George Kennedy <george.kennedy@xxxxxxxxxx>
commit a49145acfb975d921464b84fe00279f99827d816 upstream.
A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting
or yres setting in struct fb_var_screeninfo will result in a
KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as
the margins are being cleared. The margins are cleared in
chunks and if the xres setting or yres setting is a value of
zero upto the chunk size, the failure will occur.
Add a margin check to validate xres and yres settings.
Signed-off-by: George Kennedy <george.kennedy@xxxxxxxxxx>
Reported-by: syzbot+e5fd3e65515b48c02a30@xxxxxxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Dhaval Giani <dhaval.giani@xxxxxxxxxx>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-email-george.kennedy@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fbmem.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1001,6 +1001,10 @@ fb_set_var(struct fb_info *info, struct
goto done;
}
+ /* bitfill_aligned() assumes that it's at least 8x8 */
+ if (var->xres < 8 || var->yres < 8)
+ return -EINVAL;
+
ret = info->fbops->fb_check_var(var, info);
if (ret)
Patches currently in stable-queue which might be from george.kennedy@xxxxxxxxxx are
queue-4.4/fbmem-add-margin-check-to-fb_check_caps.patch
