fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check

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 <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: PaX Team <pageexec@freemail.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
static int sg_grt_trans(unsigned int fd, unsigned int cmd, struct
			compat_sg_req_info __user *o)
{
	int err, i;
	sg_req_info_t __user *r;
	r = compat_alloc_user_space(sizeof(sg_req_info_t)*SG_MAX_QUEUE);
	err = sys_ioctl(fd,cmd,(unsigned long)r);
	if (err < 0)
		return err;
	for (i = 0; i < SG_MAX_QUEUE; i++) {
		void __user *ptr;
		int d;

		if (copy_in_user(o + i, r + i, offsetof(sg_req_info_t, usr_ptr)) ||
		    get_user(ptr, &r[i].usr_ptr) ||
		    get_user(d, &r[i].duration) ||
		    put_user((u32)(unsigned long)(ptr), &o[i].usr_ptr) ||
		    put_user(d, &o[i].duration))
			return -EFAULT;
	}
	return err;
}

static int sg_grt_trans(unsigned int fd, unsigned int cmd, struct
			compat_sg_req_info __user *o)
{
	int err, i;
	sg_req_info_t __user *r;
	r = compat_alloc_user_space(sizeof(sg_req_info_t)*SG_MAX_QUEUE);
	err = sys_ioctl(fd,cmd,(unsigned long)r);
	if (err < 0)
		return err;
	for (i = 0; i < SG_MAX_QUEUE; i++) {
		void __user *ptr;
		int d;

		if (copy_in_user(o + i, r + i, offsetof(sg_req_info_t, usr_ptr)) ||
		    get_user(ptr, &r[i].usr_ptr) ||
		    get_user(d, &r[i].duration) ||
		    put_user((u32)(unsigned long)(ptr), &o[i].usr_ptr) ||
		    put_user(d, &o[i].duration))
			return -EFAULT;
	}
	return err;
}
