selinux: Fix user namespace creation after breaking kernel change

Kernel commit ed5d44d42c95 ("selinux: Implement userns_create hook")
seems to just introduce a new functionality, but given that SELinux
implements a form of mandatory access control, introducing the new
permission breaks any application (shipping with SELinux policies)
that needs to create user namespaces, such as passt and pasta for
sandboxing purposes.

Add the new 'allow' rules. They appear to be backward compatible,
kernel-wise, and the policy now requires the new 'user_namespace'
class to build, but that's something distributions already ship.

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/contrib/selinux/passt.te b/contrib/selinux/passt.te
index 687ae40..5868a41 100644
--- a/contrib/selinux/passt.te
+++ b/contrib/selinux/passt.te
@@ -51,6 +51,7 @@ require {
 
 	class capability sys_tty_config;
 	class cap_userns { setpcap sys_admin sys_ptrace };
+	class user_namespace create;
 }
 
 type passt_t;
@@ -90,6 +91,7 @@ allow syslogd_t self:cap_userns sys_ptrace;
 allow passt_t self:process setcap;
 allow passt_t self:capability { sys_tty_config setpcap net_bind_service };
 allow passt_t self:cap_userns { setpcap sys_admin sys_ptrace };
+allow passt_t self:user_namespace create;
 
 allow passt_t proc_net_t:file read;
 allow passt_t net_conf_t:file { open read };