From: Miko Larsson <mikoxyzzz@gmail.com>
To: Samuel Thibault <samuel.thibault@ens-lyon.org>,
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>
Subject: Re: [PATCHv2] fbcon: Check font dimension limits
Date: Sun, 29 Jan 2023 18:09:03 +0100 [thread overview]
Message-ID: <727b87ec3e93c6cfd9524d3947ca6e272cdf1a38.camel@gmail.com> (raw)
In-Reply-To: <20230129151740.x5p7jj2pbuilpzzt@begin>
On Sun, 2023-01-29 at 16:17 +0100, Samuel Thibault wrote:
> 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@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>
> Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of
> driver")
> Cc: stable@vger.kernel.org
>
> ---
> v1 -> v2:
> - Use BIT macro instead of fixing bit test by hand.
> - Add Fixes and Cc: stable headers.
>
> 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 & BIT(font->width - 1)) ||
> + !(info->pixmap.blit_y & BIT(font->height - 1)))
> return -EINVAL;
>
> /* Make sure driver can handle the font length */
Tested-by: Miko Larsson <mikoxyzzz@gmail.com>
--
~miko
WARNING: multiple messages have this Message-ID (diff)
From: Miko Larsson <mikoxyzzz@gmail.com>
To: Samuel Thibault <samuel.thibault@ens-lyon.org>,
gregkh@linuxfoundation.org, Daniel Vetter <daniel@ffwll.ch>,
Helge Deller <deller@gmx.de>
Cc: Sanan Hasanov <sanan.hasanov@Knights.ucf.edu>,
stable@vger.kernel.org, linux-fbdev@vger.kernel.org,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCHv2] fbcon: Check font dimension limits
Date: Sun, 29 Jan 2023 18:09:03 +0100 [thread overview]
Message-ID: <727b87ec3e93c6cfd9524d3947ca6e272cdf1a38.camel@gmail.com> (raw)
In-Reply-To: <20230129151740.x5p7jj2pbuilpzzt@begin>
On Sun, 2023-01-29 at 16:17 +0100, Samuel Thibault wrote:
> 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@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>
> Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of
> driver")
> Cc: stable@vger.kernel.org
>
> ---
> v1 -> v2:
> - Use BIT macro instead of fixing bit test by hand.
> - Add Fixes and Cc: stable headers.
>
> 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 & BIT(font->width - 1)) ||
> + !(info->pixmap.blit_y & BIT(font->height - 1)))
> return -EINVAL;
>
> /* Make sure driver can handle the font length */
Tested-by: Miko Larsson <mikoxyzzz@gmail.com>
--
~miko
next prev parent reply other threads:[~2023-01-29 17:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-29 15:17 [PATCHv2] fbcon: Check font dimension limits Samuel Thibault
2023-01-29 15:17 ` Samuel Thibault
2023-01-29 17:09 ` Miko Larsson [this message]
2023-01-29 17:09 ` Miko Larsson
2023-01-31 14:51 ` Greg KH
2023-02-04 13:31 ` Helge Deller
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