Description of problem:

When dblink is used with no host specified, PostgreSQL server tries to connect to itself over the socket in /tmp. It leads to AVC denial.

Version-Release number of selected component (if applicable):

# rpm -q selinux-policy postgresql-server postgresql-contrib
selinux-policy-3.10.0-75.fc16.noarch
postgresql-server-9.1.2-2.fc16.i686
postgresql-contrib-9.1.2-2.fc16.i686

How reproducible:

Deterministic.

Steps to Reproduce:
1. # yum install -y postgresql-server postgresql-contrib
2. # postgresql-setup initdb
3. # service postgresql start
4. # su - postgres
5. $ psql
6. postgres=# create extension dblink;
7. postgres=# select * from dblink('dbname=' || current_database(), 'select 1') as x(i numeric);
8. # grep AVC /var/log/audit/audit.log
  
Actual results:

postgres=# select * from dblink('dbname=' || current_database(), 'select 1') as x(i numeric);;
ERROR:  could not establish connection
DETAIL:  could not connect to server: Permission denied
	Is the server running locally and accepting
	connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

type=AVC msg=audit(1330672651.814:210): avc:  denied  { connectto } for  pid=7075 comm="postgres" path="/tmp/.s.PGSQL.5432" scontext=system_u:system_r:postgresql_t:s0 tcontext=system_u:system_r:postgresql_t:s0 tclass=unix_stream_socket

Expected results:

postgres=# select * from dblink('dbname=' || current_database(), 'select 1') as x(i numeric);
 i 
---
 1
(1 row)

which you get when you switch to permissive, and no AVC denial.

Additional info:

In Spacewalk SELinux policy, adding

optional_policy(`
        gen_require(`
                type postgresql_t;
        ')
        allow postgresql_t self:unix_stream_socket { connectto };
')

fixed the problem for us on RHEL 5, 6, Fedora 15, 16.