* [PATCH] fbdev: fbmon: fix potential divide error in fb_validate_mode
@ 2023-10-14 12:14 Zhang Shurong
2023-10-16 21:15 ` Helge Deller
0 siblings, 1 reply; 2+ messages in thread
From: Zhang Shurong @ 2023-10-14 12:14 UTC (permalink / raw)
To: daniel; +Cc: deller, linux-fbdev, dri-devel, linux-kernel, Zhang Shurong
We can easily use FBIOPUT_VSCREENINFO set fb_var_screeninfo, so
it's possible for a divide by zero error to occur.
Fix this by making sure the divisor is non-zero before the computation.
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
drivers/video/fbdev/core/fbmon.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
index 79e5bfbdd34c..bdd15b8e3a71 100644
--- a/drivers/video/fbdev/core/fbmon.c
+++ b/drivers/video/fbdev/core/fbmon.c
@@ -1470,6 +1470,9 @@ int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
if (var->vmode & FB_VMODE_DOUBLE)
vtotal *= 2;
+ if (!htotal || !vtotal)
+ return -EINVAL;
+
hfreq = pixclock/htotal;
hfreq = (hfreq + 500) / 1000 * 1000;
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] fbdev: fbmon: fix potential divide error in fb_validate_mode
2023-10-14 12:14 [PATCH] fbdev: fbmon: fix potential divide error in fb_validate_mode Zhang Shurong
@ 2023-10-16 21:15 ` Helge Deller
0 siblings, 0 replies; 2+ messages in thread
From: Helge Deller @ 2023-10-16 21:15 UTC (permalink / raw)
To: Zhang Shurong, daniel; +Cc: linux-fbdev, dri-devel, linux-kernel
On 10/14/23 14:14, Zhang Shurong wrote:
> We can easily use FBIOPUT_VSCREENINFO set fb_var_screeninfo, so
> it's possible for a divide by zero error to occur.
>
> Fix this by making sure the divisor is non-zero before the computation.
>
> Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> ---
> drivers/video/fbdev/core/fbmon.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
> index 79e5bfbdd34c..bdd15b8e3a71 100644
> --- a/drivers/video/fbdev/core/fbmon.c
> +++ b/drivers/video/fbdev/core/fbmon.c
> @@ -1470,6 +1470,9 @@ int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
> if (var->vmode & FB_VMODE_DOUBLE)
> vtotal *= 2;
>
> + if (!htotal || !vtotal)
> + return -EINVAL;
This is above here:
htotal = var->xres + var->right_margin + var->hsync_len +
var->left_margin;
vtotal = var->yres + var->lower_margin + var->vsync_len +
var->upper_margin;
I don't see how htotal and vtotal can become zero...
Helge
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2023-10-16 21:15 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-10-14 12:14 [PATCH] fbdev: fbmon: fix potential divide error in fb_validate_mode Zhang Shurong
2023-10-16 21:15 ` Helge Deller
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).