From 68e8cc2a23b61862bf20ffc9b782a3fb49c65568 Mon Sep 17 00:00:00 2001 From: Yizhuo Zhai Date: Wed, 2 Feb 2022 15:58:08 -0800 Subject: [PATCH] fbdev: fbmem: Fix the implicit type casting In function do_fb_ioctl(), the "arg" is the type of unsigned long, and in "case FBIOBLANK:" this argument is casted into an int before passig to fb_blank(). In fb_blank(), the comparision if (blank > FB_BLANK_POWERDOWN) would be bypass if the original "arg" is a large number, which is possible because it comes from the user input. Fix this by adding the check before the function call. Reviewed-by: Guenter Roeck Reviewed-by: Sam Ravnborg Acked-by: Helge Deller Signed-off-by: Yizhuo Zhai Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220202235811.1621017-1-yzhai003@ucr.edu --- drivers/video/fbdev/core/fbmem.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0fa7ede94fa61..13083ad8d7515 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1160,6 +1160,8 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, ret = fbcon_set_con2fb_map_ioctl(argp); break; case FBIOBLANK: + if (arg > FB_BLANK_POWERDOWN) + return -EINVAL; console_lock(); lock_fb_info(info); ret = fb_blank(info, arg); -- 2.39.5