[refpolicy] What is security_file_type and auth_file_type?

[dwalsh@redhat.com (Daniel J Walsh)]

On 12/23/2014 12:14 PM, Sven Vermeulen wrote:
> On Mon, Dec 22, 2014 at 09:23:42AM -0500, Daniel J Walsh wrote:
>> I see security_file_type as being the type associated with types that
>> should not be READ, not written.
>> /etc/shadow and friends. 
>>
>>  seinfo -asecurity_file_type  -x
>>    security_file_type
>>       selinux_config_t
>>       default_context_t
>>       dnssec_t
>>       shadow_t
>>       krb5_keytab_t
>>       selinux_login_config_t
>>       file_context_t
>>       audit_spool_t
>>       semanage_store_t
>>       auditd_etc_t
>>       auditd_log_t
>>       random_seed_t
>>
>> Although a couple of these (selinux config types) should probably not be
>> included.  
> So things like private keys and passwords (or password containing files) I
> can understand. Why would auditd related files be considered to be "not
> readable"? What leaks/problems do you see with access to those files that
> are so severe?
I can see the audit_log_t files and perhaps files that MLS folks
classify as SystemHigh.  The audit config, should not be considered a
security_file_type.  Bottom line is we should define this type.  I think
files that potentially contain system secrets would be appropriate and
then remove the type from other files.
> Wkr,
> 	Sven Vermeulen
>
> PS At least you can still query which types have security_file_type set.
>    With the 2.4 userspace if the attribute is not directly used in rules,
>    then it is no longer part of the policy:
>
>    ~# seinfo -asecurity_file_type -x
>    ERROR: Provided attribute (security_file_type) is not a valid attribute
>    name.
>
>    This is because the security_file_type is used for /excluding/ those
>    types from rules (like "{ file_type -security_file_type }").