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/pasta.te b/contrib/selinux/pasta.te
index 367d09f..645ccee 100644
--- a/contrib/selinux/pasta.te
+++ b/contrib/selinux/pasta.te
@@ -80,6 +80,7 @@ require {
 	type init_t;
 
 	class cap_userns { setpcap sys_admin sys_ptrace net_bind_service net_admin };
+	class user_namespace create;
 }
 
 type pasta_t;
@@ -104,6 +105,7 @@ init_daemon_domain(pasta_t, pasta_exec_t)
 
 allow pasta_t self:capability { setpcap net_bind_service sys_tty_config dac_read_search net_admin sys_resource };
 allow pasta_t self:cap_userns { setpcap sys_admin sys_ptrace net_admin net_bind_service };
+allow pasta_t self:user_namespace create;
 
 allow pasta_t bin_t:file { execute execute_no_trans map };
 allow pasta_t nsfs_t:file { open read };