fbdev: sm501fb: Add some geometry checks.

[ Upstream commit aee50bd88ea5fde1ff4cc021385598f81a65830c ]

Added checks for xoffset, yoffset settings.
Incorrect settings of these parameters can lead to errors
in sm501fb_pan_ functions.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 5fc404e47bdf ("[PATCH] fb: SM501 framebuffer driver")
Signed-off-by: Danila Chernetsov <listdansp@mail.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
index 86ecbb2d86db8d99a1d2c3b8f23e157a52992db5..2eb27ebf822e804d798da9701321b0e218b487c2 100644 (file)
--- a/drivers/video/fbdev/sm501fb.c
+++ b/drivers/video/fbdev/sm501fb.c
@@ -326,6 +326,13 @@ static int sm501fb_check_var(struct fb_var_screeninfo *var,
        if (var->xres_virtual > 4096 || var->yres_virtual > 2048)
                return -EINVAL;
 
+       /* geometry sanity checks */
+       if (var->xres + var->xoffset > var->xres_virtual)
+               return -EINVAL;
+
+       if (var->yres + var->yoffset > var->yres_virtual)
+               return -EINVAL;
+
        /* can cope with 8,16 or 32bpp */
 
        if (var->bits_per_pixel <= 8)