tree 7dd5e7c8288d08e47108692664294be27f9b6b8f
parent e9f238c3041e2582a710e75910c8cbf2a98e51b2
author Eric W. Biederman <ebiederm@xmission.com> 1345004713 -0700
committer Eric W. Biederman <ebiederm@xmission.com> 1353413935 -0800

userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file

To keep things sane in the context of file descriptor passing derive the
user namespace that uids are mapped into from the opener of the file
instead of from current.

When writing to the maps file the lower user namespace must always
be the parent user namespace, or setting the mapping simply does
not make sense.  Enforce that the opener of the file was in
the parent user namespace or the user namespace whose mapping
is being set.

Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>