The memset() got moved out of the check for _IOC_NONE, so passing a
made-up command number with a size but no direction would allow clearing
data on user-provided pointers.
Move video_get_user() back into the _IOC_NONE check where it belongs.
Reported-by: syzbot+54fd8cca4b7226c94b8e@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 6c625c01c7a6 ("media: v4l2-core: split out data copy from video_usercopy")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index b0d670715c27..0f11fc6b5447 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -3208,12 +3208,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg,
parg = mbuf;
}
+ err = video_get_user((void __user *)arg, parg, orig_cmd,
+ &always_copy);
+ if (err)
+ goto out;
}
- err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy);
- if (err)
- goto out;
-
err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr);
if (err < 0)
goto out;
--
2.20.0
