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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 5 +++++
1 file changed, 5 insertions(+)
@@ -1162,6 +1162,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,caseFBIOBLANK:console_lock();lock_fb_info(info);+if(arg>FB_BLANK_POWERDOWN){+unlock_fb_info(info);+console_unlock();+return-EINVAL;+}ret=fb_blank(info,arg);/* might again call into fb_blank */fbcon_fb_blanked(info,arg);
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 5 +++++
1 file changed, 5 insertions(+)
@@ -1162,6 +1162,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,caseFBIOBLANK:console_lock();lock_fb_info(info);+if(arg>FB_BLANK_POWERDOWN){+unlock_fb_info(info);+console_unlock();+return-EINVAL;+}ret=fb_blank(info,arg);/* might again call into fb_blank */fbcon_fb_blanked(info,arg);
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 5 +++++
1 file changed, 5 insertions(+)
@@ -1162,6 +1162,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,caseFBIOBLANK:console_lock();lock_fb_info(info);+if(arg>FB_BLANK_POWERDOWN){+unlock_fb_info(info);+console_unlock();+return-EINVAL;+}
Is it really necessary to perform this check within the lock ?
arg is a passed in value, and FB_BLANK_POWERDOWN.
It seems to me that
case FBIOBLANK:
if (arg > FB_BLANK_POWERDOWN)
return -EINVAL;
console_lock();
...
should be sufficient.
Sorry if I missed some previous discussion; this is the first time
I looked at this patch.
Guenter
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)
On Wed, Feb 02, 2022 at 03:58:09PM -0800, Yizhuo Zhai wrote:
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 <redacted>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
On a side note, change logs would be useful.
Guenter
From: Sam Ravnborg <hidden> Date: 2022-02-06 00:56:10
Hi Daniel,
I assume you will take this.
Patch is:
Reviewed-by: Sam Ravnborg <redacted>
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -0800, Yizhuo Zhai wrote:
quoted hunk
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)
Hi Daniel,
I assume you will take this.
Patch is:
Reviewed-by: Sam Ravnborg <redacted>
Acked-by: Helge Deller <deller@gmx.de>
Helge
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -0800, Yizhuo Zhai wrote:
quoted
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)
From: Daniel Vetter <hidden> Date: 2022-02-03 12:52:02
On Thu, Feb 03, 2022 at 09:18:30AM +0100, Helge Deller wrote:
On 2/3/22 07:39, Sam Ravnborg wrote:
quoted
Hi Daniel,
I assume you will take this.
Patch is:
Reviewed-by: Sam Ravnborg <redacted>
Acked-by: Helge Deller <deller@gmx.de>
Pushed to drm-misc-fixes, thanks for patch&review.
-Daniel
Helge
quoted
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -0800, Yizhuo Zhai wrote:
quoted
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 <redacted>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)