触发器限制指定IP访问oracle数据库

---------------------来自德哥的BLOG，觉着很有用，记录一下-------------------<wbr style="line-height:25px"></wbr>

最近有个项目需要限制某些数据库用户的访问来源IP，在PG中比较好实现，但是ORACLE没有比较简便的操作。
如果不管用户的话，仅仅限制来源IP对监听的访问是比较容易实现的，通过配置数据库服务器的sqlnet.ora文件或者修改数据库服务器的IPTABLES等手段实现。
sqlnet.ora范例:
tcp.validnode_checking=yes
tcp.invited_nodes=(172.16.33.11,172.16.34.89)

iptables范例:
[root@kefu ~]# cat /etc/sysconfig/iptables
# Firewall configuration written by system-config-securitylevel
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
# 允许访问1521的服务器
-A RH-Firewall-1-INPUT -s 172.16.3.68/32 -m state --state NEW -m tcp -p tcp --dport 1521 -j ACCEPT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 5353 -d 224.0.0.251 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT

下面来看看如何限制特定用户和特定IP：

1. 创建ACL表 (本例将ACL表建立在dsm用户下,随便建哪里都可以)
create table dsm.tbl_iplimit (logonuser varchar2(32),ip_address varchar2(15),remark varchar2(64),create_time date default sysdate);
insert into dsm.tbl_iplimit values ('DSM','172.16.18.81','digoal''s host.',sysdate);
insert into dsm.tbl_iplimit values ('DSM','local','本地',sysdate);
commit;
这里限制了DSM用户只能从172.16.18.81和ORACLE所在服务器登录.其他用户不受限制.

2. 创建触发器
conn / as sysdba
create or replace trigger "logon_audit" after
logon on database
declare
record_num number;
userip varchar2(15);
isforbidden boolean:=true;
begin
userip:=nvl(sys_context ('userenv','ip_address'),'local');
select count(*) into record_num from dsm.tbl_iplimit where logonuser=user;
if (record_num>0) then
select count(*) into record_num from dsm.tbl_iplimit where logonuser=user and ip_address=userip;
if (record_num=0) then
raise_application_error(-20003,'ip :'||userip||' is forbided');
end if;
end if;
exception
when value_error then
sys.dbms_output.put_line('exception handed');
when others then
raise;
end logon_audit;
/

3. 测试
在本地登录
SQL> conn dsm/pwd
正常
delete from tbl_iplimit where ip_address='local';
commit;
exit;
再在本地登录,已经受阻了.
SQL> conn dsm/pwd
ERROR:
ORA-00604: error occurred at recursive SQL level 1
ORA-20003: ip :local is forbided
ORA-06512: at line 18

换台机器(172.16.3.67)登录:
SQL> conn dsm/pwd@//172.16.3.13:1521/sid
ERROR:
ORA-00604: error occurred at recursive SQL level 1
ORA-20003: ip :local is forbided
ORA-06512: at line 18
受阻

换台机器(172.16.3.81)登录:
SQL> conn dsm/pwd@//172.16.3.13:1521/sid
正常

如果IP范围比较宽，可以写一个IP比较的函数加入到上面的判断中,避免写很多条记录