Re: SE-PgSQL patch review - Mailing list pgsql-hackers

From KaiGai Kohei
Subject Re: SE-PgSQL patch review
Date
Msg-id 4B0B85CC.8000107@ak.jp.nec.com
Whole thread Raw
In response to Re: SE-PgSQL patch review  (KaiGai Kohei <kaigai@ak.jp.nec.com>)
List pgsql-hackers
>> * Can we use error messages that looks like existing privilege errors?
>>    ERRCODE_INSUFFICIENT_PRIVILEGE:
>>      => permission denied to rename database
> 
> Here is a point that we should provide users a hint which enables
> to make clear the reason of access violations. So, I think we should
> contains a mark to show it come from SE-PgSQL.
> 
> Currently, it raises an error on access violation in sepgsql_compute_perms().
> It always prints out "SELinux: security policy violation".

It is just for your information.

SELinux allows end-users to confirm what accesses are violated using audit logs.
In operating system, it is written on the /var/log/audit/audit.log.

See the result of: % grep ^type=AVC /var/log/audit/audit.log           : type=AVC msg=audit(1258412043.107:81): avc:
denied { search } for  pid=1750 comm="httpd" name="root" dev=sda5 ino=1062881 scontext=system_u:system_r:httpd_t:s0
tcontext=system_u:object_r:admin_home_t:s0tclass=dir           :
 

In SE-PgSQL, it writes out detailed information about access violations
on log files. Then, it can be used to revise security policy.

For example: postgres=# UPDATE t1 SET a = 1; ERROR:  SELinux: security policy violation

It shall be logged as follows: LOG:  SELinux: denied { update }
scontext=unconfined_u:unconfined_r:sepgsql_test_t:Unclassifiedtcontext=system_u:object_r:sepgsql_ro_table_t:Classified
tclass=db_tablename=t1 STATEMENT:  UPDATE t1 SET a = 1; ERROR:  SELinux: security policy violation STATEMENT:  UPDATE
t1SET a = 1;
 

We can also provide these logs to analyzer programs to pop-up a hint for
trouble-shooting (setroubleshoot), to generate policy module automatically
from access violation logs (audit2allow), and so on.

Thanks,
-- 
OSS Platform Development Division, NEC
KaiGai Kohei <kaigai@ak.jp.nec.com>


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