oracle的一些tips技巧

最近群裡好多人討論oracle安全問題,今天找了些資料學習了下

擷取Oracle當前會話的一些屬性 (對於sql注射的環境判斷很有用哦)

SYS_CONTEXT 函數返回是與上下文名稱空間相關的屬性值。這個函數可以用在SQL和PL/SQL語句中。
注意: SYS_CONTEXT 返回的是使用者會話期間的屬性，所以，你無法使用它在並行的查詢或即時應用叢集環境。

對於名稱空間和變數, 你可以定義它（們）為常量字串，也可以定義一個變數，來代替名稱空間或屬性的字串。名稱空間必須是已經在資料庫中定義好的, 並且相關的參數和值已經被指定到DBMS_SESSION中。名稱空間必須是一個合法的SQL標識符。變數名字可以是任意的字串。它們不區分大小寫, 但是長度不能超出30個位元組。

函數返回的資料類型是VARCHAR2，迴歸值的預設最大長度是256個位元組。你也可以通過設定函數參數length來修改這個預設長度值。值的合法的長度範圍是1到4000位元組。(如果你指定的值不在這個範圍內, Oracle將使用預設長度。)

Oracle9i 提供了一個內建的"USERENV"名稱空間, 用來表示當前的會話資訊。該名稱空間預定義的參數如表1, 表的最後一列標識了傳回值的長度。

文法：
SYS_CONTEXT(namespace, attribute[, length])

例子：
select SYS_CONTEXT ('USERENV', 'TERMINAL') TERMINAL,
SYS_CONTEXT ('USERENV', 'LANGUAGE') LANGUAGE,
SYS_CONTEXT ('USERENV', 'SESSIONID') SESSIONID,
SYS_CONTEXT ('USERENV', 'INSTANCE') INSTANCE,
SYS_CONTEXT ('USERENV', 'ENTRYID') ENTRYID,
SYS_CONTEXT ('USERENV', 'ISDBA') ISDBA,
SYS_CONTEXT ('USERENV', 'NLS_TERRITORY') NLS_TERRITORY,
SYS_CONTEXT ('USERENV', 'NLS_CURRENCY') NLS_CURRENCY,
SYS_CONTEXT ('USERENV', 'NLS_CALENDAR') NLS_CALENDAR,
SYS_CONTEXT ('USERENV', 'NLS_DATE_FORMAT') NLS_DATE_FORMAT,
SYS_CONTEXT ('USERENV', 'NLS_DATE_LANGUAGE') NLS_DATE_LANGUAGE,
SYS_CONTEXT ('USERENV', 'NLS_SORT') NLS_SORT,
SYS_CONTEXT ('USERENV', 'CURRENT_USER') CURRENT_USER,
SYS_CONTEXT ('USERENV', 'CURRENT_USERID') CURRENT_USERID,
SYS_CONTEXT ('USERENV', 'SESSION_USER') SESSION_USER,
SYS_CONTEXT ('USERENV', 'SESSION_USERID') SESSION_USERID,
SYS_CONTEXT ('USERENV', 'PROXY_USER') PROXY_USER,
SYS_CONTEXT ('USERENV', 'PROXY_USERID') PROXY_USERID,
SYS_CONTEXT ('USERENV', 'DB_DOMAIN') DB_DOMAIN,
SYS_CONTEXT ('USERENV', 'DB_NAME') DB_NAME,
SYS_CONTEXT ('USERENV', 'HOST') HOST,
SYS_CONTEXT ('USERENV', 'OS_USER') OS_USER,
SYS_CONTEXT ('USERENV', 'EXTERNAL_NAME') EXTERNAL_NAME,
SYS_CONTEXT ('USERENV', 'IP_ADDRESS') IP_ADDRESS,
SYS_CONTEXT ('USERENV', 'NETWORK_PROTOCOL') NETWORK_PROTOCOL,
SYS_CONTEXT ('USERENV', 'BG_JOB_ID') BG_JOB_ID,
SYS_CONTEXT ('USERENV', 'FG_JOB_ID') FG_JOB_ID,
SYS_CONTEXT ('USERENV', 'AUTHENTICATION_TYPE') AUTHENTICATION_TYPE,
SYS_CONTEXT ('USERENV', 'AUTHENTICATION_DATA') AUTHENTICATION_DATA
FROM DUAL;

下面的語句返回登入使用者的名字:

CONNECT OE/OE
select SYS_CONTEXT ('USERENV', 'SESSION_USER')
FROM DUAL;
SYS_CONTEXT ('USERENV', 'SESSION_USER')

網上找的
[code]AUTHENTICATION_DATA
Data being used to authenticate the login user. For X.503 certificate authenticated sessions, this field returns the context of the certificate in HEX2 format.
256

Note: You can change the return value of the AUTHENTICATION_DATA attribute using the length parameter of the syntax. Values of up to 4000 are accepted. This is the only attribute of USERENV for which Oracle implements such a change.

AUTHENTICATION_TYPE
How the user was authenticated:

DATABASE: username/password authentication

OS: operating system external user authentication

NETWORK: network protocol or ANO authentication

PROXY: OCI proxy connection authentication

30

BG_JOB_ID
Job ID of the current session if it was established by an Oracle background process. Null if the session was not established by a background process.
30

CLIENT_INFO
Returns up to 64 bytes of user session information that can be stored by an application using the DBMS_APPLICATION_INFO package.
64

CURRENT_SCHEMA
Name of the default schema being used in the current schema. This value can be changed during the session with an alter SESSION SET CURRENT_SCHEMA statement.
30

CURRENT_SCHEMAID
Identifier of the default schema being used in the current session.
30

CURRENT_USER
The name of the user whose privilege the current session is under.
30

CURRENT_USERID
User ID of the user whose privilege the current session is under
30

DB_DOMAIN
Domain of the database as specified in the DB_DOMAIN initialization parameter.
256

DB_NAME
Name of the database as specified in the DB_NAME initialization parameter
30

ENTRYID
The available auditing entry identifier. You cannot use this option in distributed SQL statements. To use this keyword in USERENV, the initialization parameter AUDIT_TRAIL must be set to true.
30

EXTERNAL_NAME
External name of the database user. For SSL authenticated sessions using v.503 certificates, this field returns the distinguished name (DN) stored in the user certificate.
256

FG_JOB_ID
Job ID of the current session if it was established by a client foreground process. Null if the session was not established by a foreground process.
30

HOST
Name of the host machine from which the client has connected.
54

INSTANCE
The instance identification number of the current instance.
30

IP_ADDRESS
IP address of the machine from which the client is connected.
30

ISDBA
TRUE if you currently have the DBA role enabled and FALSE if you do not.
30

LANG
The ISO abbreviation for the language name, a shorter form than the existing 'LANGUAGE' parameter.
62

LANGUAGE
The language and territory currently used by your session, along with the database character set, in this form:

language_territory.characterset
52

NETWORK_PROTOCOL
Network protocol being used for communication, as specified in the 'PROTOCOL=protocol' portion of the connect string.
256

NLS_CALENDAR
The current calendar of the current session.
62

NLS_CURRENCY
The currency of the current session.
62

NLS_DATE_FORMAT
The date format for the session.
62

NLS_DATE_LANGUAGE
The language used for expressing dates.
62

NLS_SORT
BINARY or the linguistic sort basis.
62

NLS_TERRITORY
The territory of the current session.
62

OS_USER
Operating system username of the client process that initiated the database session
30

PROXY_USER
Name of the database user who opened the current session on behalf of SESSION_USER.
30

PROXY_USERID
Identifier of the database user who opened the current session on behalf of SESSION_USER.
30

SESSION_USER
Database user name by which the current user is authenticated. This value remains the same throughout the duration of the session.
30

SESSION_USERID
Identifier of the database user name by which the current user is authenticated.
30

SESSIONID
The auditing session identifier. You cannot use this option in distributed SQL statements.
30

TERMINAL
The operating system identifier for the client of the current session. In distributed SQL statements, this option returns the identifier for your local session. In a distributed environment, this is supported only for remote select statements, not for remote insert, update, or delete operations. (The return length of this parameter may vary by operating system.)