This is a note to let you know that I've just added the patch titled
fbcon: Check font dimension limits
to the 4.19-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:
fbcon-check-font-dimension-limits.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2b09d5d364986f724f17001ccfe4126b9b43a0be Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
Date: Sun, 29 Jan 2023 16:17:40 +0100
Subject: fbcon: Check font dimension limits
From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
commit 2b09d5d364986f724f17001ccfe4126b9b43a0be upstream.
blit_x and blit_y are u32, so fbcon currently cannot support fonts
larger than 32x32.
The 32x32 case also needs shifting an unsigned int, to properly set bit
31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font",
as reported on:
http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Kernel Branch: 6.2.0-rc5-next-20230124
Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing
Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing
Reported-by: Sanan Hasanov <sanan.hasanov@xxxxxxxxxxxxxxx>
Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of driver")
Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Miko Larsson <mikoxyzzz@xxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fbcon.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2475,9 +2475,12 @@ static int fbcon_set_font(struct vc_data
h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres))
return -EINVAL;
+ if (font->width > 32 || font->height > 32)
+ return -EINVAL;
+
/* Make sure drawing engine can handle the font */
- if (!(info->pixmap.blit_x & (1 << (font->width - 1))) ||
- !(info->pixmap.blit_y & (1 << (font->height - 1))))
+ if (!(info->pixmap.blit_x & BIT(font->width - 1)) ||
+ !(info->pixmap.blit_y & BIT(font->height - 1)))
return -EINVAL;
/* Make sure driver can handle the font length */
Patches currently in stable-queue which might be from samuel.thibault@xxxxxxxxxxxx are
queue-4.19/fbcon-check-font-dimension-limits.patch
