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From: Yizhuo Zhai <yzhai003@ucr.edu>
To: unlisted-recipients:; (no To-header on input)
Cc: Yizhuo Zhai <yzhai003@ucr.edu>, Helge Deller <deller@gmx.de>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Matthew Wilcox <willy@infradead.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	Alex Deucher <alexander.deucher@amd.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Zheyu Ma <zheyuma97@gmail.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Zhen Lei <thunder.leizhen@huawei.com>,
	Xiyu Yang <xiyuyang19@fudan.edu.cn>,
	linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4] fbdev: fbmem: Fix the implicit type casting
Date: Wed,  2 Feb 2022 15:16:34 -0800	[thread overview]
Message-ID: <20220202231636.1433050-2-yzhai003@ucr.edu> (raw)
In-Reply-To: <20220202231636.1433050-1-yzhai003@ucr.edu>

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.

Signed-off-by: Yizhuo Zhai <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 0fa7ede94fa6..b3352e23caaa 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1162,6 +1162,8 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 	case FBIOBLANK:
 		console_lock();
 		lock_fb_info(info);
+		if (arg > FB_BLANK_POWERDOWN)
+			return -EINVAL;
 		ret = fb_blank(info, arg);
 		/* might again call into fb_blank */
 		fbcon_fb_blanked(info, arg);
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Yizhuo Zhai <yzhai003@ucr.edu>
Cc: linux-fbdev@vger.kernel.org, Xiyu Yang <xiyuyang19@fudan.edu.cn>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Helge Deller <deller@gmx.de>, Zheyu Ma <zheyuma97@gmail.com>,
	linux-kernel@vger.kernel.org,
	Matthew Wilcox <willy@infradead.org>,
	Yizhuo Zhai <yzhai003@ucr.edu>,
	dri-devel@lists.freedesktop.org,
	Zhen Lei <thunder.leizhen@huawei.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Sam Ravnborg <sam@ravnborg.org>,
	Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH v4] fbdev: fbmem: Fix the implicit type casting
Date: Wed,  2 Feb 2022 15:16:34 -0800	[thread overview]
Message-ID: <20220202231636.1433050-2-yzhai003@ucr.edu> (raw)
In-Reply-To: <20220202231636.1433050-1-yzhai003@ucr.edu>

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.

Signed-off-by: Yizhuo Zhai <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 0fa7ede94fa6..b3352e23caaa 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1162,6 +1162,8 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 	case FBIOBLANK:
 		console_lock();
 		lock_fb_info(info);
+		if (arg > FB_BLANK_POWERDOWN)
+			return -EINVAL;
 		ret = fb_blank(info, arg);
 		/* might again call into fb_blank */
 		fbcon_fb_blanked(info, arg);
-- 
2.25.1


  reply	other threads:[~2022-02-02 23:17 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-31  6:57 [PATCH] fbdev: fbmem: Fix the implicit type casting Yizhuo Zhai
2022-01-31  6:57 ` Yizhuo Zhai
2022-01-31 10:55 ` kernel test robot
2022-01-31 10:55   ` kernel test robot
2022-01-31 10:55   ` kernel test robot
2022-01-31 11:36 ` kernel test robot
2022-01-31 11:36   ` kernel test robot
2022-01-31 11:36   ` kernel test robot
2022-01-31 12:27 ` kernel test robot
2022-01-31 12:27   ` kernel test robot
2022-01-31 12:27   ` kernel test robot
2022-02-01  2:35   ` [PATCH v2] " Yizhuo Zhai
2022-02-01  2:35     ` Yizhuo Zhai
2022-02-02  9:02     ` David Laight
2022-02-02  9:02       ` David Laight
2022-02-01 15:02 ` [PATCH] " Helge Deller
2022-02-01 15:02   ` Helge Deller
2022-02-01 22:37   ` Yizhuo Zhai
2022-02-02 17:27   ` Sam Ravnborg
2022-02-02 17:27     ` Sam Ravnborg
2022-02-02 17:36     ` Helge Deller
2022-02-02 17:36       ` Helge Deller
2022-02-02 22:58       ` Yizhuo Zhai
2022-02-02 23:16       ` [PATCH v4] " Yizhuo Zhai
2022-02-02 23:16         ` Yizhuo Zhai
2022-02-02 23:16         ` Yizhuo Zhai [this message]
2022-02-02 23:16           ` Yizhuo Zhai

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