- The context in which devpts is mounted has no effect on the creation
of ptys as the /dev/ptmx interface has been used by unprivileged
users for many years.
- Only support unprivileged mounts in combination with the newinstance
option to ensure that mounting of /dev/pts in a user namespace will
not allow the options of an existing mount of devpts to be modified.
- Create /dev/pts/ptmx as the root user in the user namespace that
mounts devpts so that it's permissions to be changed.
Acked-by: Serge Hallyn <email@example.com>
Signed-off-by: "Eric W. Biederman" <firstname.lastname@example.org>