fs: Expand __receive_fd() to accept existing fd

Expand __receive_fd() with support for replace_fd() for the coming seccomp
"addfd" ioctl(). Add new wrapper receive_fd_replace() for the new behavior
and update existing wrappers to retain old behavior.

Thanks to Colin Ian King <[email protected]> for pointing out an
uninitialized variable exposure in an earlier version of this patch.

Cc: Alexander Viro <[email protected]>
Cc: Dmitry Kadashev <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: [email protected]
Reviewed-by: Sargun Dhillon <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

0 files changed, 0 insertions, 0 deletions