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 | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0fa7ede94fa6..d5dec24c4d16 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1162,6 +1162,11 @@ 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) { + 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 yzhai003@ucr.edu --- drivers/video/fbdev/core/fbmem.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0fa7ede94fa6..d5dec24c4d16 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1162,6 +1162,11 @@ 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) { + unlock_fb_info(info); + console_unlock(); + return -EINVAL; + } ret = fb_blank(info, arg); /* might again call into fb_blank */ fbcon_fb_blanked(info, arg);
On 2/2/22 15:33, 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 yzhai003@ucr.edu
drivers/video/fbdev/core/fbmem.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0fa7ede94fa6..d5dec24c4d16 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1162,6 +1162,11 @@ 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) {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 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..13083ad8d751 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);
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..13083ad8d751 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);
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 yzhai003@ucr.edu
Reviewed-by: Guenter Roeck linux@roeck-us.net
On a side note, change logs would be useful.
Guenter
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..13083ad8d751 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;-- 2.25.1
Hi Daniel,
I assume you will take this.
Patch is: Reviewed-by: Sam Ravnborg sam@ravnborg.org
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -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 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..13083ad8d751 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;-- 2.25.1
On 2/3/22 07:39, Sam Ravnborg wrote:
Hi Daniel,
I assume you will take this.
Patch is: Reviewed-by: Sam Ravnborg sam@ravnborg.org
Acked-by: Helge Deller deller@gmx.de
Helge
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -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 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..13083ad8d751 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;-- 2.25.1
On Thu, Feb 03, 2022 at 09:18:30AM +0100, Helge Deller wrote:
On 2/3/22 07:39, Sam Ravnborg wrote:
Hi Daniel,
I assume you will take this.
Patch is: Reviewed-by: Sam Ravnborg sam@ravnborg.org
Acked-by: Helge Deller deller@gmx.de
Pushed to drm-misc-fixes, thanks for patch&review. -Daniel
Helge
Sam
On Wed, Feb 02, 2022 at 03:58:08PM -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 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..13083ad8d751 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;-- 2.25.1
dri-devel@lists.freedesktop.org
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Daniel Vetter -
Guenter Roeck -
Helge Deller -
Sam Ravnborg -
Yizhuo Zhai