Commit 66d2f338 authored Dec 05, 2014 by Eric W. Biederman

userns: Allow setting gid_maps without privilege when setgroups is disabled



Now that setgroups can be disabled and not reenabled, setting gid_map
without privielge can now be enabled when setgroups is disabled.

This restores most of the functionality that was lost when unprivileged
setting of gid_map was removed.  Applications that use this functionality
will need to check to see if they use setgroups or init_groups, and if they
don't they can be fixed by simply disabling setgroups before writing to
gid_map.

Cc: stable@vger.kernel.org
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent 9cc46516

kernel/user_namespace.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -826,6 +826,11 @@ static bool new_idmap_permitted(const struct file *file,
		kuid_t uid = make_kuid(ns->parent, id);
		if (uid_eq(uid, cred->euid))
		return true;
		} else if (cap_setid == CAP_SETGID) {
		kgid_t gid = make_kgid(ns->parent, id);
		if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) &&
		gid_eq(gid, cred->egid))
		return true;
		}
		}