| Message ID | tencent_C816151C508524D86E346A69B706C0D03C09@qq.com |
|---|---|
| State | New |
| Headers | show |
| Series | fbdev: fbmon: fix potential divide error in fb_validate_mode | expand |
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
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;
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(+)