Release 2 (9.2)
Part Number A96521-01
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| Oracle9i Database Administrator's Guide Release 2 (9.2) Part Number A96521-01 |
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This chapter explains how to use privileges and roles to control access to schema objects and to control the ability to execute system operations. The following topics are discussed:
See Also:
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A user privilege is a right to execute a particular type of SQL statement, or a right to access another user's object. The types of privileges are defined by Oracle.
Roles, on the other hand, are created by users (usually administrators) and are used to group together privileges or other roles. They are a means of facilitating the granting of multiple privileges or roles to users.
This section describes Oracle user privileges, and contains the following topics:
| See Also:
Oracle9i Database Concepts for additional information about privileges and roles |
There are over 100 distinct system privileges. Each system privilege allows a user to perform a particular database operation or class of database operations.
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Caution: System privileges can be very powerful, and should be granted only when necessary to roles and trusted users of the database. |
| See Also:
Oracle9i SQL Reference. for the complete list of system privileges and their descriptions |
Because system privileges are so powerful, Oracle recommends that you configure your database to prevent regular (non-DBA) users exercising ANY system privileges (such as UPDATE ANY TABLE) on the data dictionary. In order to secure the data dictionary, ensure that the O7_DICTIONARY_ACCESSIBILITY initialization parameter is set to FALSE. This feature is called the dictionary protection mechanism.
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Note: The When this parameter is not set to See the Oracle9i Database Reference for more information on the |
If you enable dictionary protection (O7_DICTIONARY_ACCESSIBILITY is FALSE), access to objects in the SYS schema (dictionary objects) is restricted to users with the SYS schema. These users are SYS and those who connect as SYSDBA. System privileges providing access to objects in other schemas do not give other users access to objects in the SYS schema. For example, the SELECT ANY TABLE privilege allows users to access views and tables in other schemas, but does not enable them to select dictionary objects (base tables of dynamic performance views, views, packages, and synonyms). These users can, however, be granted explicit object privileges to access objects in the SYS schema.
Users with explicit object privileges or those who connect with administrative privileges (SYSDBA) can access objects in the SYS schema. Another means of allowing access to objects in the SYS schema is by granting users any of the following roles:
SELECT_CATALOG_ROLE
This role can be granted to users to allow SELECT privileges on all data dictionary views.
EXECUTE_CATALOG_ROLE
This role can be granted to users to allow EXECUTE privileges for packages and procedures in the data dictionary.
DELETE_CATALOG_ROLE
This role can be granted to users to allow them to delete records from the system audit table (AUD$).
Additionally, the following system privilege can be granted to users who require access to tables created in the SYS schema:
SELECT ANY DICTIONARY
This system privilege allows query access to any object in the SYS schema, including tables created in that schema. It must be granted individually to each user requiring the privilege. It is not included in GRANT ALL PRIVILEGES, nor can it be granted through a role.
Each type of object has different privileges associated with it.
You can specify ALL [PRIVILEGES] to grant or revoke all available object privileges for an object. ALL is not a privilege; rather, it is a shortcut, or a way of granting or revoking all object privileges with one word in GRANT and REVOKE statements. Note that if all object privileges are granted using the ALL shortcut, individual privileges can still be revoked.
Likewise, all individually granted privileges can be revoked by specifying ALL. However, if you REVOKE ALL, and revoking causes integrity constraints to be deleted (because they depend on a REFERENCES privilege that you are revoking), you must include the CASCADE CONSTRAINTS option in the REVOKE statement.
| See Also:
Oracle9i SQL Reference. for the complete list of object privileges |
A role groups several privileges and roles, so that they can be granted to and revoked from users simultaneously. A role must be enabled for a user before it can be used by the user.
Oracle provides some predefined roles to help in database administration. These roles, listed in Table 25-1, are automatically defined for Oracle databases when you run the standard scripts that are part of database creation. You can grant privileges and roles to, and revoke privileges and roles from, these predefined roles in the same way as you do with any role you define.
If you install other options or products, other predefined roles may be created.
This section describes aspects of managing roles, and contains the following topics:
You can create a role using the CREATE ROLE statement, but you must have the CREATE ROLE system privilege to do so. Typically, only security administrators have this system privilege.
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Note: Immediately after creation, a role has no privileges associated with it. To associate privileges with a new role, you must grant privileges or other roles to the new role. |
You must give each role you create a unique name among existing usernames and role names of the database. Roles are not contained in the schema of any user. In a database that uses a multibyte character set, Oracle recommends that each role name contain at least one single-byte character. If a role name contains only multibyte characters, the encrypted role name/password combination is considerably less secure.
The following statement creates the clerk role, which is authorized by the database using the password bicentennial:
CREATE ROLE clerk IDENTIFIED BY bicentennial;
The IDENTIFIED BY clause specifies how the user must be authorized before the role can be enabled for use by a specific user to which it has been granted. If this clause is not specified, or NOT IDENTIFIED is specified, then no authorization is required when the role is enabled. Roles can be specified to be authorized by:
These authorizations are discussed in following sections.
Later, you can set or change the authorization method for a role using the ALTER ROLE statement. The following statement alters the clerk role to specify that the user must have been authorized by an external source before enabling the role:
ALTER ROLE clerk IDENTIFIED EXTERNALLY;
To alter the authorization method for a role, you must have the ALTER ANY ROLE system privilege or have been granted the role with the ADMIN OPTION.
| See Also:
Oracle9i SQL Reference for syntax, restrictions, and authorization information about the SQL statements used to manage roles and privileges |
The methods of authorizing roles are presented in this section. A role must be enabled for you to use it.
| See Also:
"When Do Grants and Revokes Take Effect?" for a discussion about enabling roles |
The use of a role authorized by the database can be protected by an associated password. If you are granted a role protected by a password, you can enable or disable the role by supplying the proper password for the role in a SET ROLE statement. However, if the role is made a default role and enabled at connect time, the user is not required to enter a password.
The following statement creates a role manager. When it is enabled, the password morework must be supplied.
CREATE ROLE manager IDENTIFIED BY morework;
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Note: In a database that uses a multibyte character set, passwords for roles must include only singlebyte characters. Multibyte characters are not accepted in passwords. See the Oracle9i SQL Reference for information about specifying valid passwords. |
The INDENTIFIED USING package_name clause lets you create an application role, which is a role that can be enabled only by applications using an authorized package. Application developers do not need to secure a role by embedding passwords inside applications. Instead, they can create an application role and specify which PL/SQL package is authorized to enable the role.
The following example indicates that the role admin_role is an application role and the role can only be enabled by any module defined inside the PL/SQL package hr.admin.
CREATE ROLE admin_role IDENTIFIED USING hr.admin;
When enabling the user's default roles at login as specified in the user's profile, no checking is performed for application roles.
The following statement creates a role named accts_rec and requires that the user be authorized by an external source before it can be enabled:
CREATE ROLE accts_rec IDENTIFIED EXTERNALLY;
Role authentication through the operating system is useful only when the operating system is able to dynamically link operating system privileges with applications. When a user starts an application, the operating system grants an operating system privilege to the user. The granted operating system privilege corresponds to the role associated with the application. At this point, the application can enable the application role. When the application is terminated, the previously granted operating system privilege is revoked from the user's operating system account.
If a role is authorized by the operating system, you must configure information for each user at the operating system level. This operation is operating system dependent.
If roles are granted by the operating system, you do not need to have the operating system authorize them also; this is redundant.
| See Also:
"Granting Roles Using the Operating System or Network" for more information about roles granted by the operating system |
If users connect to the database over Oracle Net, by default their roles cannot be authenticated by the operating system. This includes connections through a shared server configuration, as this connection requires Oracle Net. This restriction is the default because a remote user could impersonate another operating system user over a network connection.
If you are not concerned with this security risk and want to use operating system role authentication for network clients, set the initialization parameter REMOTE_OS_ROLES in the database's initialization parameter file to TRUE. The change will take effect the next time you start the instance and mount the database. The parameter is FALSE by default.
A role can be defined as a global role, whereby a (global) user can only be authorized to use the role by an enterprise directory service. You define the global role locally in the database by granting privileges and roles to it, but you cannot grant the global role itself to any user or other role in the database. When a global user attempts to connect to the database, the enterprise directory is queried to obtain any global roles associated with the user.
The following statement creates a global role:
CREATE ROLE supervisor IDENTIFIED GLOBALLY;
Global roles are one component of enterprise user management. A global role only applies to one database, but it can be granted to an enterprise role defined in the enterprise directory. An enterprise role is a directory structure which contains global roles on multiple databases, and which can be granted to enterprise users.
A general discussion of global authentication and authorization of users, and its role in enterprise user management, was presented earlier in "Global Authentication and Authorization".
| See Also:
Oracle Advanced Security Administrator's Guide and Oracle Internet Directory Administrator's Guide for information about enterprise user management and how to implement it |
In some cases, it may be appropriate to drop a role from the database. The security domains of all users and roles granted a dropped role are immediately changed to reflect the absence of the dropped role's privileges. All indirectly granted roles of the dropped role are also removed from affected security domains. Dropping a role automatically removes the role from all users' default role lists.
Because the creation of objects is not dependent on the privileges received through a role, tables and other objects are not dropped when a role is dropped.
You can drop a role using the SQL statement DROP ROLE. To drop a role, you must have the DROP ANY ROLE system privilege or have been granted the role with the ADMIN OPTION.
The following statement drops the role CLERK:
DROP ROLE clerk;
This section describes the granting of privileges and roles, and contains the following topics:
It is also possible to grant roles to a user connected through a middle tier or proxy. This is discussed in "Proxy Authentication and Authorization".
You can grant system privileges and roles to other users and roles using the GRANT statement. The following privileges are required:
ADMIN OPTION or have been granted the GRANT ANY PRIVILEGE system privilege.ADMIN OPTION or have been granted the GRANT ANY ROLE system privilege.
The following statement grants the system privilege CREATE SESSION and the accts_pay role to the user jward:
GRANT CREATE SESSION, accts_pay TO jward;
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Note: Object privileges cannot be granted along with system privileges and roles in the same |
A user or role that is granted a privilege or role specifying the WITH ADMIN OPTION clause has several expanded capabilities:
ADMIN OPTION.In the following statement, the security administrator grants the new_dba role to michael:
GRANT new_dba TO michael WITH ADMIN OPTION;
The user michael cannot only use all of the privileges implicit in the new_dba role, but can grant, revoke, or drop the new_dba role as deemed necessary. Because of these powerful capabilities, exercise caution when granting system privileges or roles with the ADMIN OPTION. Such privileges are usually reserved for a security administrator and rarely granted to other administrators or users of the system.
When a user creates a role, the role is automatically granted to the creator with the ADMIN OPTION
Oracle allows you to create a new user with the GRANT statement. If you specify a password using the IDENTIFIED BY clause, and the username/password does not exist in the database, a new user with that username and password is created. The following example creates ssmith as a new user while granting ssmith the CONNECT system privilege:
GRANT CONNECT TO ssmith IDENTIFIED BY p1q2r3;
You also use the GRANT statement to grant object privileges to roles and users. To grant an object privilege, you must fulfill one of the following conditions:
GRANT ANY OBJECT PRIVILEGE system privilege that enables you to grant and revoke privileges on behalf of the object owner.WITH GRANT OPTION clause was specified when you were granted the object privilege by its owner.
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Note: System privileges and roles cannot be granted along with object privileges in the same |
The following statement grants the SELECT, INSERT, and DELETE object privileges for all columns of the emp table to the users jfee and tsmith:
GRANT SELECT, INSERT, DELETE ON emp TO jfee, tsmith;
To grant all object privileges on the salary view to the user jfee, use the ALL keyword, as shown in the following example:
GRANT ALL ON salary TO jfee;
Specify WITH GRANT OPTION to enable the grantee to grant the object privileges to other users and roles. The user whose schema contains an object is automatically granted all associated object privileges with the GRANT OPTION. This special privilege allows the grantee several expanded privileges:
GRANT OPTION, or to any role in the database.The GRANT OPTION is not valid when granting an object privilege to a role. Oracle prevents the propagation of object privileges through roles so that grantees of a role cannot propagate object privileges received by means of roles.
The GRANT ANY OBJECT PRIVILEGE system privilege allows users to grant and revoke any object privilege on behalf of the object owner. This provides a convenient means for database and application administrators to grant access to objects in any schema without requiring that they connect to the schema. This eliminates the need to maintain login credentials for schema owners so that they can grant access to objects, and it reduces the number of connections required during configuration.
This system privilege is part of the Oracle supplied DBA role and is thus granted (with the ADMIN OPTION) to any user connecting AS SYSDBA (user SYS). As with other system privileges, the GRANT ANY OBJECT PRIVILEGE system privilege can only be granted by a user who possesses the ADMIN OPTION.
When you exercise the GRANT ANY OBJECT PRIVILEGE system privilege to grant an object privilege to a user, if you already possess the object privilege with the GRANT OPTION, then the grant is performed in the usual way. In this case, you become the grantor of the grant. If you do not possess the object privilege, then the object owner is shown as the grantor, even though you, with the GRANT ANY OBJECTPRIVILEGE system privilege, actually performed the grant.
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Note: The audit record generated by the GRANT statement will always show the real user who performed the grant. |
For example, consider the following. User adams possesses the GRANT ANY OBJECT PRIVILEGE system privilege. He does not possess any other grant privileges. He issues the following statement:
GRANT SELECT ON hr.employees TO blake WITH GRANT OPTION;
If you examine the DBA_TAB_PRIVS view, you will see that hr is shown as being the grantor of the privilege:
SQL> SELECT GRANTEE, OWNER, GRANTOR, PRIVILEGE, GRANTABLE 2> FROM DBA_TAB_PRIVS 3> WHERE TABLE_NAME = 'EMPLOYEES' and OWNER = 'HR'; GRANTEE OWNER GRANTOR PRIVILEGE GRANTABLE -------- ----- ------- ----------- ---------- BLAKE HR HR SELECT YES
Now assume that blake also has the GRANT ANY OBJECT PRIVILEGE system. He, issues the following statement:
GRANT SELECT ON hr.employees TO clark;
In this case, when you again query the DBA_TAB_PRIVS view, you see that blake is shown as being the grantor of the privilege:
GRANTEE OWNER GRANTOR PRIVILEGE GRANTABLE -------- ----- -------- -------- ---------- BLAKE HR HR SELECT YES CLARK HR BLAKE SELECT NO
This is because blake already possesses the SELECT privilege on hr.employees with the GRANT OPTION.
You can grant INSERT, UPDATE, or REFERENCES privileges on individual columns in a table.
The following statement grants INSERT privilege on the acct_no column of the accounts table to scott:
GRANT INSERT (acct_no) ON accounts TO scott;
In another example, object privilege for the ename and job columns of the emp table are granter to the users jfee and tsmith:
GRANT INSERT(ename, job) ON emp TO jfee, tsmith;
This section describes aspects of revoking user privileges and roles, and contains the following topics:
You can revoke system privileges and roles using the SQL statement REVOKE.
Any user with the ADMIN OPTION for a system privilege or role can revoke the privilege or role from any other database user or role. The revoker does not have to be the user that originally granted the privilege or role. Users with GRANT ANY ROLE can revoke any role.
The following statement revokes the CREATE TABLE system privilege and the accts_rec role from tsmith:
REVOKE CREATE TABLE, accts_rec FROM tsmith;
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Note: The |
The REVOKE statement is used to revoke object privileges. To revoke an object privilege, you must fulfill one of the following conditions:
GRANT ANY OBJECT PRIVILEGE system privilege that enables you to grant and revoke privileges on behalf of the object owner.You can only revoke the privileges that you, the grantor, directly authorized, not the grants made by other users to whom you granted the GRANT OPTION. However, there is a cascading effect. The object privilege grants propagated using the GRANT OPTION are revoked if a grantor's object privilege is revoked.
Assuming you are the original grantor, the following statement revokes the SELECT and INSERT privileges on the emp table from the users jfee and tsmith:
REVOKE SELECT, insert ON emp FROM jfee, tsmith;
The following statement revokes all object privileges for the dept table that you originally granted to the human_resource role
REVOKE ALL ON dept FROM human_resources;
The GRANT ANY OBJECT PRIVILEGE system privilege allows you to revoke any specified object privilege where the object owner is the grantor. This occurs when the object privilege is granted by the object owner, or on behalf of the owner by any user holding the GRANT ANY OBJECT PRIVILEGE system privilege.
In a situation where the object privilege has been granted by both the owner of the object and the user executing the REVOKE statement (who has both the specific object privilege and the GRANT ANY OBJECT PRIVILEGE system privilege), Oracle only revokes the object privilege granted by the user issuing the REVOKE. This can be illustrated by continuing the example started in "Granting Object Privileges on Behalf of the Object Owner".
At this point, blake has granted the SELECT privilege on hr.employees to clark. Even though blake possesses the GRANT ANY OBJECT PRIVILEGE system privilege, he also holds the specific object privilege, thus this grant is attributed to him. Assume that hr also grants the SELECT privilege on hr.employees to clark. A query of the DBA_TAB_PRIVS view shows that the following grants are in effect for the hr.employees table:
GRANTEE OWNER GRANTOR PRIVILEGE GRANTABLE -------- ----- ------- ----------- ---------- BLAKE HR HR SELECT YES CLARK HR BLAKE SELECT NO CLARK HR HR SELECT NO
User blake now issues the following REVOKE statement:
REVOKE SELECT ON hr.employees FROM clark;
Only the object privilege for clark granted by blake is removed. The grant by the object owner, hr, remains.
GRANTEE OWNER GRANTOR PRIVILEGE GRANTABLE -------- ----- ------- ----------- ---------- BLAKE HR HR SELECT YES CLARK HR HR SELECT NO
If blake issues the REVOKE statement again, this time the effect will be to remove the object privilege granted by hr.
Although users can grant column-selective INSERT, UPDATE, and REFERENCES privileges for tables and views, they cannot selectively revoke column specific privileges with a similar REVOKE statement. Instead, the grantor must first revoke the object privilege for all columns of a table or view, and then selectively re-grant the column-specific privileges that should remain.
For example, assume that role human_resources has been granted the UPDATE privilege on the deptno and dname columns of the table dept. To revoke the UPDATE privilege on just the deptno column, issue the following two statements:
REVOKE UPDATE ON dept FROM human_resources; GRANT UPDATE (dname) ON dept TO human_resources;
The REVOKE statement revokes UPDATE privilege on all columns of the dept table from the role human_resources. The GRANT statement re-grants UPDATE privilege on the dname column to the role human_resources.
If the grantee of the REFERENCES object privilege has used the privilege to create a foreign key constraint (that currently exists), the grantor can revoke the privilege only by specifying the CASCADE CONSTRAINTS option in the REVOKE statement:
REVOKE REFERENCES ON dept FROM jward CASCADE CONSTRAINTS;
Any foreign key constraints currently defined that use the revoked REFERENCES privilege are dropped when the CASCADE CONSTRAINTS clause is specified.
Depending on the type of privilege, there may be cascading effects when a privilege is revoked.
There are no cascading effects when revoking a system privilege related to DDL operations, regardless of whether the privilege was granted with or without the ADMIN OPTION. For example, assume the following:
CREATE TABLE system privilege to jfee with the ADMIN OPTION.jfee creates a table.jfee grants the CREATE TABLE system privilege to tsmith.tsmith creates a table.CREATE TABLE system privilege from jfee.jfee's table continues to exist. tsmith still has the table and the CREATE TABLE system privilege.Cascading effects can be observed when revoking a system privilege related to a DML operation. If SELECT ANY TABLE is revoked from a user, then all procedures contained in the users schema relying on this privilege will fail until the privilege is reauthorized.
Revoking an object privilege can have cascading effects that should be investigated before issuing a REVOKE statement.
test procedure includes a SQL statement that queries data from the emp table. If the SELECT privilege on the emp table is revoked from the owner of the test procedure, the procedure can no longer be executed successfully.REFERENCES privilege for a table is revoked from a user, any foreign key integrity constraints defined by the user that require the dropped REFERENCES privilege are automatically dropped. For example, assume that the user jward is granted the REFERENCES privilege for the deptno column of the dept table and creates a foreign key on the deptno column in the emp table that references the deptno column. If the references privilege on the deptno column of the dept table is revoked, the foreign key constraint on the deptno column of the emp table is dropped in the same operation.GRANT OPTION are revoked if a grantor's object privilege is revoked. For example, assume that user1 is granted the SELECT object privilege with the GRANT OPTION, and grants the SELECT privilege on emp to user2. Subsequently, the SELECT privilege is revoked from user1. This REVOKE is cascaded to user2 as well. Any objects that depended on user1's and user2's revoked SELECT privilege can also be affected, as described in previous bullet items.Object definitions that require the ALTER and INDEX DDL object privileges are not affected if the ALTER or INDEX object privilege is revoked. For example, if the INDEX privilege is revoked from a user that created an index on someone else's table, the index continues to exist after the privilege is revoked.
Privileges and roles can also be granted to and revoked from the user group PUBLIC. Because PUBLIC is accessible to every database user, all privileges and roles granted to PUBLIC are accessible to every database user.
Security administrators and database users should grant a privilege or role to PUBLIC only if every database user requires the privilege or role. This recommendation reinforces the general rule that at any given time, each database user should only have the privileges required to accomplish the group's current tasks successfully.
Revoking a privilege from PUBLIC can cause significant cascading effects. If any privilege related to a DML operation is revoked from PUBLIC (for example, SELECT ANY TABLE, UPDATE ON emp), all procedures in the database, including functions and packages, must be reauthorized before they can be used again. Therefore, exercise caution when granting and revoking DML-related privileges to PUBLIC.
| See Also:
"Managing Object Dependencies" for more information about object dependencies |
Depending on what is granted or revoked, a grant or revoke takes effect at different times:
PUBLIC) are immediately observed.PUBLIC) are only observed when a current user session issues a SET ROLE statement to re-enable the role after the grant/revoke, or when a new user session is created after the grant/revoke.You can see which roles are currently enabled by examining the SESSION_ROLES data dictionary view.
During the session, the user or an application can use the SET ROLE statement any number of times to change the roles currently enabled for the session. You must already have been granted the roles that you name in the SET ROLE statement.The number of roles that can be concurrently enabled is limited by the initialization parameter MAX_ENABLED_ROLES.
This example enables the role clerk, which you have already been granted, and specifies the password.
SET ROLE clerk IDENTIFIED BY bicentennial;
You can disable all roles with the following statement:
SET ROLE NONE;
When a user logs on, Oracle enables all privileges granted explicitly to the user and all privileges in the user's default roles.
A user's list of default roles can be set and altered using the ALTER USER statement. The ALTER USER statement allows you to specify roles that are to be enabled when a user connects to the database, without requiring the user to specify the roles' passwords. The user must have already been directly granted the roles with a GRANT statement. You cannot specify as a default role any role managed by an external service including a directory service (external roles or global roles).
The following example establishes default roles for user jane:
ALTER USER jane DEFAULT ROLE payclerk, pettycash;
You cannot set a user's default roles in the CREATE USER statement. When you first create a user, the user's default role setting is ALL, which causes all roles subsequently granted to the user to be default roles. Use the ALTER USER statement to limit the user's default roles.
A user can enable as many roles as specified by the initialization parameter MAX_ENABLED_ROLES. All indirectly granted roles enabled as a result of enabling a primary role are included in this count. The database administrator can alter this limitation by modifying the value for this parameter. Higher values permit each user session to have more concurrently enabled roles. However, the larger the value for this parameter, the more memory space is required on behalf of each user session; this is because the PGA size is affected for each user session, and requires four bytes for each role. Determine the highest number of roles that will be concurrently enabled by any one user and use this value for the MAX_ENABLED_ROLES parameter.
This section describes aspects of granting roles through your operating system or network, and contains the following topics:
Instead of a security administrator explicitly granting and revoking database roles to and from users using GRANT and REVOKE statements, the operating system that operates Oracle can grant roles to users at connect time. Roles can be administered using the operating system and passed to Oracle when a user creates a session. As part of this mechanism, each user's default roles and the roles granted to a user with the ADMIN OPTION can be identified. Even if the operating system is used to authorize users for roles, all roles must be created in the database and privileges assigned to the role with GRANT statements.
Roles can also be granted through a network service.
The advantage of using the operating system to identify a user's database roles is that privilege management for an Oracle database can be externalized. The security facilities offered by the operating system control a user's privileges. This option may offer advantages of centralizing security for a number of system activities, such as the following situation:
The main disadvantage of using the operating system to identify a user's database roles is that privilege management can only be performed at the role level. Individual privileges cannot be granted using the operating system, but can still be granted inside the database using GRANT statements.
A secondary disadvantage of using this feature is that by default users cannot connect to the database through the shared server, or any other network connection, if the operating system is managing roles. However, you can change this default; see "Using Network Connections with Operating System Role Management".
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Note: The features described in this section are available only on some operating systems. See your operating system specific Oracle documentation to determine if you can use these features. |
To operate a database so that it uses the operating system to identify each user's database roles when a session is created, set the initialization parameter OS_ROLES to TRUE (and restart the instance, if it is currently running). When a user attempts to create a session with the database, Oracle initializes the user's security domain using the database roles identified by the operating system.
To identify database roles for a user, each Oracle user's operating system account must have operating system identifiers (these may be called groups, rights identifiers, or other similar names) that indicate which database roles are to be available for the user. Role specification can also indicate which roles are the default roles of a user and which roles are available with the ADMIN OPTION. No matter which operating system is used, the role specification at the operating system level follows the format:
ora_ID_ROLE[_[d][a]]
where:
ID has a definition that varies on different operating systems. For example, on VMS, ID is the instance identifier of the database; on MVS, it is the machine type; on UNIX, it is the system ID.
ROLE is the name of the database role.d is an optional character that indicates this role is to be a default role of the database user.a is an optional character that indicates this role is to be granted to the user with the ADMIN OPTION. This allows the user to grant the role to other roles only. Roles cannot be granted to users if the operating system is used to manage roles.
For example, an operating system account might have the following roles identified in its profile:
ora_PAYROLL_ROLE1 ora_PAYROLL_ROLE2_a ora_PAYROLL_ROLE3_d ora_PAYROLL_ROLE4_da
When the corresponding user connects to the payroll instance of Oracle, role3 and role4 are defaults, while role2 and role4 are available with the ADMIN OPTION.
When you use operating system managed roles, it is important to note that database roles are being granted to an operating system user. Any database user to which the OS user is able to connect will have the authorized database roles enabled. For this reason, you should consider defining all Oracle users as IDENTIFIED EXTERNALLY if you are using OS_ROLES = TRUE, so that the database accounts are tied to the OS account that was granted privileges.
If OS_ROLES is set to TRUE, the operating system completely manages the grants and revokes of roles to users. Any previous grants of roles to users using GRANT statements do not apply; however, they are still listed in the data dictionary. Only the role grants made at the operating system level to users apply. Users can still grant privileges to roles and users.
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Note: If the operating system grants a role to a user with the |
If OS_ROLES is set to TRUE, any role granted by the operating system can be dynamically enabled using the SET ROLE statement. This still applies, even if the role was defined to require a password or operating system authorization. However, any role not identified in a user's operating system account cannot be specified in a SET ROLE statement, even if a role has been granted using a GRANT statement when OS_ROLES = FALSE. (If you specify such a role, Oracle ignores it.)
When OS_ROLES = TRUE, a user can enable as many roles as specified by the initialization parameter MAX_ENABLED_ROLES.
If you choose to have the operating system to manage roles, by default users cannot connect to the database through the shared server. This restriction is the default because a remote user could impersonate another operating system user over a non-secure connection.
If you are not concerned with this security risk and want to use operating system role management with the shared server, or any other network connection, set the initialization parameter REMOTE_OS_ROLES in the database's initialization parameter file to TRUE. The change will take effect the next time you start the instance and mount the database. The default setting of this parameter is FALSE.
To access information about grants of privileges and roles, you can query the following data dictionary views:
Some examples of using these views follow. For these examples, assume the following statements have been issued:
CREATE ROLE security_admin IDENTIFIED BY honcho; GRANT CREATE PROFILE, ALTER PROFILE, DROP PROFILE, CREATE ROLE, DROP ANY ROLE, GRANT ANY ROLE, AUDIT ANY, AUDIT SYSTEM, CREATE USER, BECOME USER, ALTER USER, DROP USER TO security_admin WITH ADMIN OPTION; GRANT SELECT, DELETE ON SYS.AUD$ TO security_admin; GRANT security_admin, CREATE SESSION TO swilliams; GRANT security_admin TO system_administrator; GRANT CREATE SESSION TO jward; GRANT SELECT, DELETE ON emp TO jward; GRANT INSERT (ename, job) ON emp TO swilliams, jward;
| See Also:
Oracle9i Database Reference for a detailed description of these data dictionary views |
The following query returns all system privilege grants made to roles and users:
SELECT * FROM DBA_SYS_PRIVS; GRANTEE PRIVILEGE ADM -------------- --------------------------------- --- SECURITY_ADMIN ALTER PROFILE YES SECURITY_ADMIN ALTER USER YES SECURITY_ADMIN AUDIT ANY YES SECURITY_ADMIN AUDIT SYSTEM YES SECURITY_ADMIN BECOME USER YES SECURITY_ADMIN CREATE PROFILE YES SECURITY_ADMIN CREATE ROLE YES SECURITY_ADMIN CREATE USER YES SECURITY_ADMIN DROP ANY ROLE YES SECURITY_ADMIN DROP PROFILE YES SECURITY_ADMIN DROP USER YES SECURITY_ADMIN GRANT ANY ROLE YES SWILLIAMS CREATE SESSION NO JWARD CREATE SESSION NO
The following query returns all the roles granted to users and other roles:
SELECT * FROM DBA_ROLE_PRIVS; GRANTEE GRANTED_ROLE ADM ------------------ ------------------------------------ --- SWILLIAMS SECURITY_ADMIN NO
The following query returns all object privileges (not including column-specific privileges) granted to the specified user:
SELECT TABLE_NAME, PRIVILEGE, GRANTABLE FROM DBA_TAB_PRIVS WHERE GRANTEE = 'JWARD'; TABLE_NAME PRIVILEGE GRANTABLE ----------- ------------ ---------- EMP SELECT NO EMP DELETE NO
To list all the column-specific privileges that have been granted, use the following query:
SELECT GRANTEE, TABLE_NAME, COLUMN_NAME, PRIVILEGE FROM DBA_COL_PRIVS; GRANTEE TABLE_NAME COLUMN_NAME PRIVILEGE ----------- ------------ ------------- -------------- SWILLIAMS EMP ENAME INSERT SWILLIAMS EMP JOB INSERT JWARD EMP NAME INSERT JWARD EMP JOB INSERT
The following query lists all roles currently enabled for the issuer:
SELECT * FROM SESSION_ROLES;
If swilliams has enabled the security_admin role and issues this query, Oracle returns the following information:
ROLE ------------------------------ SECURITY_ADMIN
The following query lists all system privileges currently available in the issuer's security domain, both from explicit privilege grants and from enabled roles:
SELECT * FROM SESSION_PRIVS;
If swilliams has the security_admin role enabled and issues this query, Oracle returns the following results:
PRIVILEGE ---------------------------------------- AUDIT SYSTEM CREATE SESSION CREATE USER BECOME USER ALTER USER DROP USER CREATE ROLE DROP ANY ROLE GRANT ANY ROLE AUDIT ANY CREATE PROFILE ALTER PROFILE DROP PROFILE
If the security_admin role is disabled for swilliams, the first query would have returned no rows, while the second query would only return a row for the CREATE SESSION privilege grant.
The DBA_ROLES data dictionary view can be used to list all roles of a database and the authentication used for each role. For example, the following query lists all the roles in the database:
SELECT * FROM DBA_ROLES; ROLE PASSWORD ---------------- -------- CONNECT NO RESOURCE NO DBA NO SECURITY_ADMIN YES
The ROLE_ROLE_PRIVS, ROLE_SYS_PRIVS, and ROLE_TAB_PRIVS data dictionary views contain information on the privilege domains of roles.
For example, the following query lists all the roles granted to the system_admin role:
SELECT GRANTED_ROLE, ADMIN_OPTION FROM ROLE_ROLE_PRIVS WHERE ROLE = 'SYSTEM_ADMIN'; GRANTED_ROLE ADM ---------------- ---- SECURITY_ADMIN NO
The following query lists all the system privileges granted to the security_admin role:
SELECT * FROM ROLE_SYS_PRIVS WHERE ROLE = 'SECURITY_ADMIN'; ROLE PRIVILEGE ADM ----------------------- ----------------------------- --- SECURITY_ADMIN ALTER PROFILE YES SECURITY_ADMIN ALTER USER YES SECURITY_ADMIN AUDIT ANY YES SECURITY_ADMIN AUDIT SYSTEM YES SECURITY_ADMIN BECOME USER YES SECURITY_ADMIN CREATE PROFILE YES SECURITY_ADMIN CREATE ROLE YES SECURITY_ADMIN CREATE USER YES SECURITY_ADMIN DROP ANY ROLE YES SECURITY_ADMIN DROP PROFILE YES SECURITY_ADMIN DROP USER YES SECURITY_ADMIN GRANT ANY ROLE YES
The following query lists all the object privileges granted to the security_admin role:
SELECT TABLE_NAME, PRIVILEGE FROM ROLE_TAB_PRIVS WHERE ROLE = 'SECURITY_ADMIN'; TABLE_NAME PRIVILEGE --------------------------- ---------------- AUD$ DELETE AUD$ SELECT
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