fbdev: intelfb: Fix potential divide by zero

[ Upstream commit d823685486a3446d061fed7c7d2f80af984f119a ]

Variable var->pixclock is controlled by user and can be assigned
to zero. Without proper check, divide by zero would occur in
intelfbhw_validate_mode and intelfbhw_mode_to_hw.

Error out if var->pixclock is zero.

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/video/fbdev/intelfb/intelfbdrv.c b/drivers/video/fbdev/intelfb/intelfbdrv.c
index d4a2891a9a7acee21a3563529198e67961d1436c..a93dd531d00df3ffaa6fd9eafee8d70b8ed46d8b 100644 (file)
--- a/drivers/video/fbdev/intelfb/intelfbdrv.c
+++ b/drivers/video/fbdev/intelfb/intelfbdrv.c
@@ -1219,6 +1219,9 @@ static int intelfb_check_var(struct fb_var_screeninfo *var,
 
        dinfo = GET_DINFO(info);
 
+       if (!var->pixclock)
+               return -EINVAL;
+
        /* update the pitch */
        if (intelfbhw_validate_mode(dinfo, var) != 0)
                return -EINVAL;