原 PostgreSQL下如何修改用户权限的介绍以及hook机制对超级用户的权限修改

rolename=xxxx -- privileges granted to a role
        =xxxx -- privileges granted to PUBLIC
 
            r -- SELECT ("read")
            w -- UPDATE ("write")
            a -- INSERT ("append")
            d -- DELETE
            D -- TRUNCATE
            x -- REFERENCES
            t -- TRIGGER
            X -- EXECUTE
            U -- USAGE
            C -- CREATE
            c -- CONNECT
            T -- TEMPORARY
      arwdDxt -- ALL PRIVILEGES (for tables, varies for other objects)
            * -- grant option for preceding privilege
 
        /yyyy -- role that granted this privilege

typedef struct AclItem
{
	Oid			ai_grantee;		/* ID that this item grants privs to */
	Oid			ai_grantor;		/* grantor of privs */
	AclMode		ai_privs;		/* privilege bits */
} AclItem;

typedef uint32 AclMode;

/*
 * The upper 16 bits of the ai_privs field of an AclItem are the grant option
 * bits, and the lower 16 bits are the actual privileges.  We use "rights"
 * to mean the combined grant option and privilege bits fields.
 */

#define ACL_INSERT		(1<<0)	/* for relations */
#define ACL_SELECT		(1<<1)
#define ACL_UPDATE		(1<<2)
#define ACL_DELETE		(1<<3)
#define ACL_TRUNCATE	   (1<<4)
#define ACL_REFERENCES	(1<<5)
#define ACL_TRIGGER		(1<<6)
#define ACL_EXECUTE		(1<<7)	/* for functions */
#define ACL_USAGE		(1<<8)	/* for languages, namespaces, FDWs, and
								 * servers */
#define ACL_CREATE		(1<<9)	/* for namespaces and databases */
#define ACL_CREATE_TEMP (1<<10) /* for databases */
#define ACL_CONNECT		(1<<11) /* for databases */
#define N_ACL_RIGHTS	12		/* 1 plus the last 1<<x */
#define ACL_NO_RIGHTS	0
/* Currently, SELECT ... FOR [KEY] UPDATE/SHARE requires UPDATE privileges */
#define ACL_SELECT_FOR_UPDATE	ACL_UPDATE

#define ACL_INSERT_CHR			'a'		/* formerly known as "append" */
#define ACL_SELECT_CHR			'r'		/* formerly known as "read" */
#define ACL_UPDATE_CHR			'w'		/* formerly known as "write" */
#define ACL_DELETE_CHR			'd'
#define ACL_TRUNCATE_CHR		'D'		/* super-delete, as it were */
#define ACL_REFERENCES_CHR		'x'
#define ACL_TRIGGER_CHR			't'
#define ACL_EXECUTE_CHR			'X'
#define ACL_USAGE_CHR			'U'
#define ACL_CREATE_CHR			'C'
#define ACL_CREATE_TEMP_CHR		'T'
#define ACL_CONNECT_CHR			'c'

create user ff createdb;
\c test ff
create database tain;
select * from pg_database where datname = 'tain';
  datname  | datdba | encoding | datcollate  |  datctype   | datistemplate | datallowconn | datconnlimit | datlastsysoid | da
tfrozenxid | datminmxid | dattablespace |                         datacl                         
-----------+--------+----------+-------------+-------------+---------------+--------------+--------------+---------------+---
-----------+------------+---------------+--------------------------------------------------------
 tain      |  16438 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12917 |   
      1674 |          1 |          1663 | 
(5 rows)

grant all on database tain to ss; select * from pg_database where datname = 'tain';  datname  | datdba | encoding | datcollate  |  datctype   | datistemplate | datallowconn | datconnlimit | datlastsysoid | da
tfrozenxid | datminmxid | dattablespace |                         datacl                         
-----------+--------+----------+-------------+-------------+---------------+--------------+--------------+---------------+---
-----------+------------+---------------+--------------------------------------------------------
 tain      |  16438 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12917 |   
      1674 |          1 |          1663 | {=Tc/ff,ff=CTc/ff,ss=CTc/ff}
(5 rows)

\c postgres postgres
alter database tain owner to postgres;
select * from pg_database where datname = 'tain';
  datname  | datdba | encoding | datcollate  |  datctype   | datistemplate | datallowconn | datconnlimit | datlastsysoid | da
tfrozenxid | datminmxid | dattablespace |                         datacl                         
-----------+--------+----------+-------------+-------------+---------------+--------------+--------------+---------------+---
-----------+------------+---------------+--------------------------------------------------------
 tain      |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12917 |   
      1674 |          1 |          1663 | {=Tc/postgres,postgres=CTc/postgres,ss=CTc/postgres}
(5 rows)

postgres=# \help grant
Command:     GRANT
Description: define access privileges
Syntax:
GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { [ TABLE ] table_name [, ...]
         | ALL TABLES IN SCHEMA schema_name [, ...] }
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { { SELECT | INSERT | UPDATE | REFERENCES } ( column_name [, ...] )
    [, ...] | ALL [ PRIVILEGES ] ( column_name [, ...] ) }
    ON [ TABLE ] table_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { { USAGE | SELECT | UPDATE }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { SEQUENCE sequence_name [, ...]
         | ALL SEQUENCES IN SCHEMA schema_name [, ...] }
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { { CREATE | CONNECT | TEMPORARY | TEMP } [, ...] | ALL [ PRIVILEGES ] }
    ON DATABASE database_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON DOMAIN domain_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN DATA WRAPPER fdw_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN SERVER server_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { EXECUTE | ALL [ PRIVILEGES ] }
    ON { FUNCTION function_name ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) [, ...]
         | ALL FUNCTIONS IN SCHEMA schema_name [, ...] }
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON LANGUAGE lang_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { { SELECT | UPDATE } [, ...] | ALL [ PRIVILEGES ] }
    ON LARGE OBJECT loid [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { { CREATE | USAGE } [, ...] | ALL [ PRIVILEGES ] }
    ON SCHEMA schema_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { CREATE | ALL [ PRIVILEGES ] }
    ON TABLESPACE tablespace_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON TYPE type_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT role_name [, ...] TO role_name [, ...] [ WITH ADMIN OPTION ]

\help revoke
Command:     REVOKE
Description: remove access privileges
Syntax:
REVOKE [ GRANT OPTION FOR ]
    { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { [ TABLE ] table_name [, ...]
         | ALL TABLES IN SCHEMA schema_name [, ...] }
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { { SELECT | INSERT | UPDATE | REFERENCES } ( column_name [, ...] )
    [, ...] | ALL [ PRIVILEGES ] ( column_name [, ...] ) }
    ON [ TABLE ] table_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { { USAGE | SELECT | UPDATE }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { SEQUENCE sequence_name [, ...]
         | ALL SEQUENCES IN SCHEMA schema_name [, ...] }
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { { CREATE | CONNECT | TEMPORARY | TEMP } [, ...] | ALL [ PRIVILEGES ] }
    ON DATABASE database_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON DOMAIN domain_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN DATA WRAPPER fdw_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN SERVER server_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { EXECUTE | ALL [ PRIVILEGES ] }
    ON { FUNCTION function_name ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) [, ...]
         | ALL FUNCTIONS IN SCHEMA schema_name [, ...] }
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON LANGUAGE lang_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { { SELECT | UPDATE } [, ...] | ALL [ PRIVILEGES ] }
    ON LARGE OBJECT loid [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { { CREATE | USAGE } [, ...] | ALL [ PRIVILEGES ] }
    ON SCHEMA schema_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { CREATE | ALL [ PRIVILEGES ] }
    ON TABLESPACE tablespace_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON TYPE type_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]

REVOKE [ ADMIN OPTION FOR ]
    role_name [, ...] FROM role_name [, ...]
    [ CASCADE | RESTRICT ]

bool
superuser(void)
{
	return superuser_arg(GetUserId());
}

Oid
GetUserId(void)
{
	AssertState(OidIsValid(CurrentUserId));
	return CurrentUserId;
}

[root@localhost contrib]# mkdir acl_super;
[root@localhost contrib]#

/*
 * acl_super.c
 * the super user sure can not have not permission to operate the 
 * ordinary table.
 */
#include "postgres.h"
#include "miscadmin.h"
#include "nodes/parsenodes.h"
#include "nodes/pg_list.h"
#include "catalog/pg_class.h"
#include "executor/executor.h"

PG_MODULE_MAGIC;

void _PG_init(void);
void _PG_fini(void);

static ExecutorCheckPerms_hook_type prev_ExecutorCheckPerms_hook = NULL;

static void myExecCheckRTPerms(List *rangeTable, bool ereport_on_violation);

/*
 * Stop the super user sure from operating the ordinary table  */

static
void myExecCheckRTPerms(List *rangeTable, bool ereport_on_violation)
{
        ListCell   *l;
        Oid        cuser = InvalidOid;
        char*      cusername = NULL;

        cuser = GetSessionUserId();
        cusername = GetUserNameFromId(cuser);

        if(strcmp("sure", cusername) == 0)
        {
                foreach(l, rangeTable)
                {
                        RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
                        if(rte->relkind == RELKIND_RELATION)      //                                      ereport(ERROR,
                                                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                                                 errmsg("permission denied to table")));
                }
        }

        return true;
}

/*
 * _PG_init
 * Install the hook.
 */
void
_PG_init(void)
{
        prev_ExecutorCheckPerms_hook = ExecutorCheckPerms_hook;
        ExecutorCheckPerms_hook = myExecCheckRTPerms;
}

/*
 * _PG_fini
 * Uninstall the hook.
 */
void
_PG_fini(void)
{
        ExecutorCheckPerms_hook = prev_ExecutorCheckPerms_hook;
}

# contrib/dbrestrict/Makefile

MODULES = acl_super
OBJS = acl_super.so

ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)
else
subdir = contrib/acl_super
top_builddir = ../..
include $(top_builddir)/src/Makefile.global
include $(top_srcdir)/contrib/contrib-global.mk
endif

[root@localhost acl_super]# ls
acl_super.c  Makefile
[root@localhost acl_super]#

[root@localhost acl_super]# make
gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fpic -I. -I. -I../../src/include -D_GNU_SOURCE   -c -o acl_super.o acl_super.c
gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fpic -L../../src/port -L../../src/common  -Wl,-rpath,'/opt/pgdbdevel/lib',--enable-new-dtags  -shared -o acl_super.so acl_super.o
[root@localhost acl_super]# make install
/bin/mkdir -p '/opt/pgdbdevel/lib/postgresql'
/usr/bin/install -c -m 755  acl_super.so '/opt/pgdbdevel/lib/postgresql/'
[root@localhost acl_super]#

#shared_preload_libraries = ''		# (change requires restart)

shared_preload_libraries = 'acl_super'	# (change requires restart)

[postgres@localhost bin]$  ./pg_ctl -D ../data restart
waiting for server to shut down....LOG:  received smart shutdown request
LOG:  autovacuum launcher shutting down
LOG:  shutting down
LOG:  database system is shut down
 done
server stopped
server starting
[postgres@localhost bin]$ LOG:  database system was shut down at 2014-09-12 00:21:22 PDT
LOG:  autovacuum launcher started
LOG:  database system is ready to accept connections

[postgres@localhost bin]$ ./psql 
psql (9.5devel)
Type "help" for help.

postgres=#

postgres=# create table sure_test(s1 int);
insert into sure_test values (1),(2),(3);
select * from sure_test;
 s1 
----
  1
  2
  3
(3 rows)

\c postgres sure
You are now connected to database "postgres" as user "sure".
postgres=# select * from sure_test;
ERROR:  permission denied to table
STATEMENT:  select * from sure_test;
ERROR:  permission denied to table
postgres=#