From: Helge Deller <deller@gmx.de>
To: harperchen <harperchen1110@gmail.com>
Cc: javierm@redhat.com, tzimmermann@suse.de,
wsa+renesas@sang-engineering.com, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fbdev: tgafb: Fix potential divide by zero
Date: Wed, 8 Mar 2023 23:05:54 +0100 [thread overview]
Message-ID: <123a52d8-baf0-e32b-3262-1e8619b1c3ad@gmx.de> (raw)
In-Reply-To: <20230307130856.2295182-1-harperchen1110@gmail.com>
On 3/7/23 14:08, harperchen wrote:
> fb_set_var would by called when user invokes ioctl with cmd
> FBIOPUT_VSCREENINFO. User-provided data would finally reach
> tgafb_check_var. In case var->pixclock is assigned to zero,
> divide by zero would occur when checking whether reciprocal
> of var->pixclock is too high.
>
> Similar crashes have happened in other fbdev drivers. There
> is no check and modification on var->pixclock along the call
> chain to tgafb_check_var. We believe it could also be triggered
> in driver tgafb from user site.
>
> Signed-off-by: harperchen <harperchen1110@gmail.com>
Could you provide a real name?
Otherwise applied to fbdev git tree.
Thanks!
Helge
> ---
> drivers/video/fbdev/tgafb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/video/fbdev/tgafb.c b/drivers/video/fbdev/tgafb.c
> index 14d37c49633c..b44004880f0d 100644
> --- a/drivers/video/fbdev/tgafb.c
> +++ b/drivers/video/fbdev/tgafb.c
> @@ -173,6 +173,9 @@ tgafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
> {
> struct tga_par *par = (struct tga_par *)info->par;
>
> + if (!var->pixclock)
> + return -EINVAL;
> +
> if (par->tga_type == TGA_TYPE_8PLANE) {
> if (var->bits_per_pixel != 8)
> return -EINVAL;
next prev parent reply other threads:[~2023-03-08 22:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 13:08 [PATCH] fbdev: tgafb: Fix potential divide by zero harperchen
2023-03-08 22:05 ` Helge Deller [this message]
2023-03-09 6:11 ` Wei Chen
2023-03-09 7:53 ` Jani Nikula
2023-03-09 8:15 ` Helge Deller
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