Re: [PATCH] fbdev: fbmon: fix potential divide error in fb_validate_mode
From: Helge Deller <deller@gmx.de>
Date: 2023-10-16 21:15:45
Also in:
dri-devel, lkml
On 10/14/23 14:14, Zhang Shurong wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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