From: Kees Cook <[email protected]>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

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 <[email protected]>
Cc: David Miller <[email protected]>
Cc: Brad Spengler <[email protected]>
Cc: PaX Team <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Paul Gortmaker <[email protected]>
---
 fs/compat_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 641640dc7ae5..7a00d9b155bf 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -227,6 +227,8 @@ static int do_video_set_spu_palette(unsigned int fd, 
unsigned int cmd,
 
        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);
-- 
1.8.5.2

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