请教大家一下关于PAM的问题

[Guannan Ma <mythmgn gmail com>]

Hi, all,
最近才开始关注PAM验证方面的问题, 请大家帮忙解答下我的疑问.
先谢谢了 :)


[1] 第一个问题是关于PAM 里面的session的

PAM里面的session管理主要提供了两个函数,pam_open_session pam_close_session

我的疑问是, 我open session之后, 得到了什么样的环境. 在我执行过open_session之后? PAM为我做了什么?
在pam_open_session 和pam_close_session之间 我得到了什么特权? 或者说什么样的特殊环境.


[2] 第二个问题关于PAM 里的设置credential

我援引一下pam的函数介绍.

 On a Linux system 
the user's UID and GID's are credentials too. However, it has been 
decided that these properties (along with the default supplementary 
groups of which the user is a member) are credentials that should be set
 directly by the application and not by PAM. Such credentials should be 
established, by the application, prior to a call to this function. For 
example, initgroups(2) (or equivalent) should have been performed.

这句话, 也就是说我程序的组设置和uid设置, 是先于setcredential的. 那我设置这个credential 有啥用处?我用它来做什么? 


int pam_setcred(pamh,  
 flags); 
pam_handle_t *pamh;
int flags;
 

3.1.8.1. DESCRIPTION

The pam_setcred function is used to establish, maintain and delete the credentials of a user. It should be called to set the credentials after a user has been authenticated and before a session is opened for the user (with pam_open_session(3)). The credentials should be deleted after the session has been closed (with pam_close_session(3)).

A credential is something that the user possesses. It is some property, such as a Kerberos ticket, or a supplementary group membership that make up the uniqueness of a given user. On a Linux system the user's UID and GID's are credentials too. However, it has been decided that these properties (along with the default supplementary groups of which the user is a member) are credentials that should be set directly by the application and not by PAM. Such credentials should be established, by the application, prior to a call to this function. For example, initgroups(2) (or equivalent) should have been performed.



PAM的文档搜索起来很费劲.. 大部分的实例都是关于auth方面的..  这个session方面的比较少.
请懂这方面的朋友给我示意下 这个session到底能做些什么?

我现在在做C/S server端的开发.. 想引入pam做用户管理 最近在想这个用户对话的保存, 不知道pam是否能满足条件.


再次致谢.

--
Regards,
Guannan