On Thu, Apr 10, 2014 at 12:14:27PM -0700, Andy Lutomirski wrote:
>
> This is the second time in a week that someone has asked for a way to
> have a struct file (or struct inode or whatever) that can't be reopened
> through /proc/pid/fd. This should be quite easy to implement as a
> separate feature.
What I suggested on a different thread was to add the following new
file descriptor flags, to join FD_CLOEXEC, which would be maniuplated
using the F_GETFD and F_SETFD fcntl commands:
FD_NOPROCFS disallow being able to open the inode via /proc/<pid>/fd
FD_NOPASSFD disallow being able to pass the fd via a unix domain socket
FD_LOCKFLAGS if this bit is set, disallow any further changes of FD_CLOEXEC,
FD_NOPROCFS, FD_NOPASSFD, and FD_LOCKFLAGS flags.
Regardless of what else we might need to meet the use case for the
proposed File Sealing API, I think this is a useful feature that could
be used in many other contexts besides just the proposed
memfd_create() use case.
Cheers,
- Ted
