3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kees Cook <redacted>

commit 12176503366885edd542389eed3aaf94be163fdb upstream.

The compat ioctl for VIDEO_SET_SPU_PALETTE was missing an error check
while converting ioctl arguments.  This could lead to leaking kernel
stack contents into userspace.

Patch extracted from existing fix in grsecurity.

Signed-off-by: Kees Cook <redacted>
Cc: David Miller <davem@davemloft.net>
Cc: Brad Spengler <redacted>
Cc: PaX Team <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/compat_ioctl.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c

@@ -208,6 +208,8 @@ static int do_video_set_spu_palette(unsi
 
 	err  = get_user(palp, &up->palette);
 	err |= get_user(length, &up->length);
+	if (err)
+		return -EFAULT;
 
 	up_native = compat_alloc_user_space(sizeof(struct video_spu_palette));
 	err  = put_user(compat_ptr(palp), &up_native->palette);