From: Samuel Thibault <samuel.thibault@ens-lyon.org>
To: gregkh@linuxfoundation.org, Daniel Vetter <daniel@ffwll.ch>,
Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Sanan Hasanov <sanan.hasanov@Knights.ucf.edu>,
Samuel Thibault <samuel.thibault@ens-lyon.org>
Subject: [PATCH] fbcon: Check font dimension limits
Date: Thu, 26 Jan 2023 01:49:12 +0100 [thread overview]
Message-ID: <20230126004921.616264824@ens-lyon.org> (raw)
In-Reply-To: 20230126004911.869923511@ens-lyon.org
blit_x and blit_y are uint32_t, 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@IA1PR07MB9830.namprd07.prod.outlook.com
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@Knights.ucf.edu>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Index: linux-6.0/drivers/video/fbdev/core/fbcon.c
===================================================================
--- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c
+++ linux-6.0/drivers/video/fbdev/core/fbcon.c
@@ -2489,9 +2489,12 @@ 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 & (1U << (font->width - 1))) ||
+ !(info->pixmap.blit_y & (1U << (font->height - 1))))
return -EINVAL;
/* Make sure driver can handle the font length */
WARNING: multiple messages have this Message-ID (diff)
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
To: gregkh@linuxfoundation.org, Daniel Vetter <daniel@ffwll.ch>,
Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, dri-devel@lists.freedesktop.org,
Sanan Hasanov <sanan.hasanov@Knights.ucf.edu>,
Samuel Thibault <samuel.thibault@ens-lyon.org>
Subject: [PATCH] fbcon: Check font dimension limits
Date: Thu, 26 Jan 2023 01:49:12 +0100 [thread overview]
Message-ID: <20230126004921.616264824@ens-lyon.org> (raw)
In-Reply-To: 20230126004911.869923511@ens-lyon.org
blit_x and blit_y are uint32_t, 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@IA1PR07MB9830.namprd07.prod.outlook.com
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@Knights.ucf.edu>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Index: linux-6.0/drivers/video/fbdev/core/fbcon.c
===================================================================
--- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c
+++ linux-6.0/drivers/video/fbdev/core/fbcon.c
@@ -2489,9 +2489,12 @@ 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 & (1U << (font->width - 1))) ||
+ !(info->pixmap.blit_y & (1U << (font->height - 1))))
return -EINVAL;
/* Make sure driver can handle the font length */
next parent reply other threads:[~2023-01-26 0:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230126004911.869923511@ens-lyon.org>
2023-01-26 0:49 ` Samuel Thibault [this message]
2023-01-26 0:49 ` [PATCH] fbcon: Check font dimension limits Samuel Thibault
2023-01-26 0:51 ` Samuel Thibault
2023-01-26 0:51 ` Samuel Thibault
2023-01-26 7:43 ` Greg KH
2023-01-26 7:43 ` Greg KH
2023-01-26 9:08 ` Jiri Slaby
2023-01-26 9:08 ` Jiri Slaby
2023-01-29 15:13 ` Samuel Thibault
2023-01-29 15:13 ` Samuel Thibault
2023-01-26 9:02 ` Jiri Slaby
2023-01-26 9:02 ` Jiri Slaby
2023-01-29 15:04 ` Samuel Thibault
2023-01-29 15:04 ` Samuel Thibault
2023-01-28 1:32 ` kernel test robot
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