allowlist new Linux close_range() system call, use it in posix_spawn()

Linux kernel's close_range() system call (currently) allows:
  close() unshare() fcntl(F_SETFD, FD_CLOEXEC)
to be performed on ranges of fds.

All 3 of these are already allowed by seccomp bpf:
as such this doesn't allow you to do anything you can't already do.

We can't add close_range() properly to bionic because we'd need to
fiddle about with ltp and it's too late to add new T API anyway,
so let's just make the direct syscall() call.

We'll add proper support in U.

See also:
  https://man7.org/linux/man-pages/man2/close_range.2.html

Test: TreeHugger
Bug: 229913920
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I85586d544fc23bed6aee59f00bdb79ee7a8150d1
Merged-In: I85586d544fc23bed6aee59f00bdb79ee7a8150d1

0 files changed, 0 insertions, 0 deletions