userdom_unpriv_user_template use errors and creating new roles

Andy Warner warner at rubix.com
Mon Mar 22 19:14:09 UTC 2010


Using FC12, fully updated. I have two basic, but possibly related 
questions. The first is regarding a change to the targeted policy that 
resulted in an install error for our Trusted RUBIX policy when using the 
userdom_unpriv_user_template interface, as off the last targeted policy 
update. The second are denials I now receive after changing our policy 
to use a different interface.

First issue:

Our policy had been declaring a custom role (rubix_dbadm_r in this case) 
using the following:
userdom_unpriv_user_template(rubix_dbadm)
corecmd_exec_shell(rubix_dbadm_t)

Originally, this worked for its intended purposes with no selinux 
denials. As of installing policy update:
Name       : selinux-policy-targeted
Arch       : noarch
Version    : 3.6.32
Release    : 103.fc12

When we build our policy we received the following errors:
rubix-dev.te:175: Warning: xserver_user_client() has been deprecated, 
please use xserver_user_x_domain_template instead.
Installing rubix-dev-targeted policy
libsepol.print_missing_requirements: rubix-dev's global requirements 
were not met: type/attribute xdrawable_type (No such file or directory).
libsemanage.semanage_link_sandbox: Link packages failed (No such file or 
directory).
semodule:  Failed!

I had been receiving the depreciated warning a while (ignoring at my own 
peril), the link error was new to this targeted policy version. I also 
received errors while installing selinux-policy-targeted rpm itself, 
stating a different requirement not being met in the then installed 
rubix-dev policy. I do not recall the exact error message, but remember 
it was an X related type that was missing.

Noting the X connection between the depreciated function and the link 
error, I traced the reference to the depreciated 'xserver_user_client' 
interface to 'userdom_unpriv_user_template'. I did not call 
'xserver_user_client' directly. I replaced the call to 
'userdom_unpriv_user_template' with a call to 
'userdom_restricted_user_template' and my then policy installed properly.

But using the 'userdom_restricted_user_template ' interface, now I 
notice some selinux denials during a call to newrole, which is my second 
question below. I am not sure that the change to the new interface is 
the cause of the denials, I am just now noticing them.

Should the 'userdom_unpriv_user_template' interface either be fixed or 
removed from the userdom *.if file?

Second issue:

The rubix_dbadm_r role is now created with:
userdom_restricted_user_template(rubix_dbadm)
corecmd_exec_shell(rubix_dbadm_t)

When I perform a newrole, I receive denials as follows (note, I am in 
permissive mode so the newrole succeeds):

$ id -Z
rxdev_u:staff_r:staff_t:s0-s0:c0.c1023
$ ls -Z `tty`
crw--w----. warner tty rxdev_u:object_r:user_devpts_t:s0 /dev/pts/4
$ newrole -r rubix_dbadm_r
Password:
$

Note: I am a bit surprised that the tty type is user_devpts_t and not 
staff_devpts_t, though I am very unfamiliar with this.

Mar 22 11:04:03 localhost setroubleshoot: SELinux is preventing 
/usr/bin/newrole "write" access on /var/run/dbus/system_bus_socket. For 
complete SELinux messages. run sealert -l 
95fc56ee-8711-460c-874b-6ddb91cc9add
Mar 22 11:04:03 localhost setroubleshoot: SELinux is preventing 
/usr/bin/newrole "write" access on /var/run/dbus/system_bus_socket. For 
complete SELinux messages. run sealert -l 
95fc56ee-8711-460c-874b-6ddb91cc9add

# more securetty_types
sysadm_tty_device_t
user_tty_device_t
staff_tty_device_t
user_devpts_t
devpts_t
#

Are these denials related to how I create the rubix_dbadm_r role? Is 
there a proper way to create a role suitable for  auser to transition 
into and as a potential default logon user role?

I fully admit my choice of creating a role was through observation of 
other policy code and trail and error. It would be nice to have a 
definitive word on it.

Thanks,

Andy

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