sepgsql_setcon().

This is intended as infrastructure to allow sepgsql to cooperate with
connection pooling software, by allowing the effective security label
to be set for each new connection.

KaiGai Kohei, reviewed by Yeb Havinga.

contrib/sepgsql/sql/label.sql

@@ -31,8 +31,39 @@ CREATE FUNCTION f4 () RETURNS text
     AS 'SELECT sepgsql_getcon()'
     LANGUAGE sql;
 SECURITY LABEL ON FUNCTION f4()
+    IS 'system_u:object_r:sepgsql_nosuch_trusted_proc_exec_t:s0';
+
+CREATE FUNCTION f5 (text) RETURNS bool
+	AS 'SELECT sepgsql_setcon($1)'
+    LANGUAGE sql;
+SECURITY LABEL ON FUNCTION f5(text)
     IS 'system_u:object_r:sepgsql_regtest_trusted_proc_exec_t:s0';
 
+CREATE TABLE auth_tbl(uname text, credential text, label text);
+INSERT INTO auth_tbl
+    VALUES ('foo', 'acbd18db4cc2f85cedef654fccc4a4d8', 'sepgsql_regtest_foo_t:s0'),
+           ('var', 'b2145aac704ce76dbe1ac7adac535b23', 'sepgsql_regtest_var_t:s0'),
+           ('baz', 'b2145aac704ce76dbe1ac7adac535b23', 'sepgsql_regtest_baz_t:s0');
+SECURITY LABEL ON TABLE auth_tbl
+    IS 'system_u:object_r:sepgsql_secret_table_t:s0';
+
+CREATE FUNCTION auth_func(text, text) RETURNS bool
+    LANGUAGE sql
+    AS 'SELECT sepgsql_setcon(regexp_replace(sepgsql_getcon(), ''_r:.*$'', ''_r:'' || label))
+        FROM auth_tbl WHERE uname = $1 AND credential = $2';
+SECURITY LABEL ON FUNCTION auth_func(text,text)
+    IS 'system_u:object_r:sepgsql_regtest_trusted_proc_exec_t:s0';
+
+CREATE TABLE foo_tbl(a int, b text);
+INSERT INTO foo_tbl VALUES (1, 'aaa'), (2,'bbb'), (3,'ccc'), (4,'ddd');
+SECURITY LABEL ON TABLE foo_tbl
+	IS 'system_u:object_r:sepgsql_regtest_foo_table_t:s0';
+
+CREATE TABLE var_tbl(x int, y text);
+INSERT INTO var_tbl VALUES (2,'xxx'), (3,'yyy'), (4,'zzz'), (5,'xyz');
+SECURITY LABEL ON TABLE var_tbl
+	IS 'system_u:object_r:sepgsql_regtest_var_table_t:s0';
+
 --
 -- Tests for default labeling behavior
 --
@@ -68,6 +99,129 @@ SELECT f3();			-- trusted procedure that raises an error
 SELECT f4();			-- failed on domain transition
 SELECT sepgsql_getcon();	-- client's label must be restored
 
+--
+-- Test for Dynamic Domain Transition
+--
+
+-- validation of transaction aware dynamic-transition
+-- @SECURITY-CONTEXT=unconfined_u:unconfined_r:unconfined_t:s0:c0.c25
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c15');
+SELECT sepgsql_getcon();
+
+SELECT sepgsql_setcon(NULL);	-- failed to reset
+SELECT sepgsql_getcon();
+
+BEGIN;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c12');
+SELECT sepgsql_getcon();
+
+SAVEPOINT svpt_1;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c9');
+SELECT sepgsql_getcon();
+
+SAVEPOINT svpt_2;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c6');
+SELECT sepgsql_getcon();
+
+SAVEPOINT svpt_3;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c3');
+SELECT sepgsql_getcon();
+
+ROLLBACK TO SAVEPOINT svpt_2;
+SELECT sepgsql_getcon();		-- should be 's0:c0.c9'
+
+ROLLBACK TO SAVEPOINT svpt_1;
+SELECT sepgsql_getcon();		-- should be 's0:c0.c12'
+
+ABORT;
+SELECT sepgsql_getcon();		-- should be 's0:c0.c15'
+
+BEGIN;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c8');
+SELECT sepgsql_getcon();
+
+SAVEPOINT svpt_1;
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c4');
+SELECT sepgsql_getcon();
+
+ROLLBACK TO SAVEPOINT svpt_1;
+SELECT sepgsql_getcon();		-- should be 's0:c0.c8'
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:unconfined_t:s0:c0.c6');
+
+COMMIT;
+SELECT sepgsql_getcon();		-- should be 's0:c0.c6'
+
+-- sepgsql_regtest_user_t is not available dynamic-transition,
+-- unless sepgsql_setcon() is called inside of trusted-procedure
+-- @SECURITY-CONTEXT=unconfined_u:unconfined_r:sepgsql_regtest_user_t:s0:c0.c15
+
+-- sepgsql_regtest_user_t has no permission to switch current label
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:sepgsql_regtest_user_t:s0');	-- failed
+SELECT sepgsql_getcon();
+
+-- trusted procedure allows to switch, but unavailable to override MCS rules
+SELECT f5('unconfined_u:unconfined_r:sepgsql_regtest_user_t:s0:c0.c7');	-- OK
+SELECT sepgsql_getcon();
+
+SELECT f5('unconfined_u:unconfined_r:sepgsql_regtest_user_t:s0:c0.c31');	-- Failed
+SELECT sepgsql_getcon();
+
+SELECT f5(NULL);	-- Failed
+SELECT sepgsql_getcon();
+
+BEGIN;
+SELECT f5('unconfined_u:unconfined_r:sepgsql_regtest_user_t:s0:c0.c3');	-- OK
+SELECT sepgsql_getcon();
+
+ABORT;
+SELECT sepgsql_getcon();
+
+--
+-- Test for simulation of typical connection pooling server
+--
+-- @SECURITY-CONTEXT=unconfined_u:unconfined_r:sepgsql_regtest_pool_t:s0
+
+-- we shouldn't allow to switch client label without trusted procedure
+SELECT sepgsql_setcon('unconfined_u:unconfined_r:sepgsql_regtest_foo_t:s0');
+
+SELECT * FROM auth_tbl;	-- failed, no permission to reference
+
+-- switch to "foo"
+SELECT auth_func('foo', 'acbd18db4cc2f85cedef654fccc4a4d8');
+
+SELECT sepgsql_getcon();
+
+SELECT * FROM foo_tbl;	-- OK
+
+SELECT * FROM var_tbl;	-- failed
+
+SELECT * FROM auth_tbl;	-- failed
+
+SELECT sepgsql_setcon(NULL);	-- end of session
+SELECT sepgsql_getcon();
+
+-- the pooler cannot touch these tables directry
+SELECT * FROM foo_tbl;	-- failed
+
+SELECT * FROM var_tbl;	-- failed
+
+-- switch to "var"
+SELECT auth_func('var', 'b2145aac704ce76dbe1ac7adac535b23');
+
+SELECT sepgsql_getcon();
+
+SELECT * FROM foo_tbl;  -- failed
+
+SELECT * FROM var_tbl;  -- OK
+
+SELECT * FROM auth_tbl;	-- failed
+
+SELECT sepgsql_setcon(NULL);    -- end of session
+
+-- misc checks
+SELECT auth_func('var', 'invalid credential');	-- not works
+SELECT sepgsql_getcon();
+
 --
 -- Clean up
 --
@@ -79,3 +233,4 @@ DROP FUNCTION IF EXISTS f1() CASCADE;
 DROP FUNCTION IF EXISTS f2() CASCADE;
 DROP FUNCTION IF EXISTS f3() CASCADE;
 DROP FUNCTION IF EXISTS f4() CASCADE;
+DROP FUNCTION IF EXISTS f5(text) CASCADE;