sysctl: allow CLONE_NEWUSER to be disabled

There continues to be many CONFIG_USER_NS related security exposures.
For admins running distro kernels with CONFIG_USER_NS, there is no way
to disable CLONE_NEWUSER. As many systems do not need CLONE_NEWUSER,
this provides a way for sysadmins to disable the feature.

Signed-off-by: Kees Cook <keescook@chromium.org>
3 files changed