[sudo-users] pam session

[Karel Zak]

On Tue, 2005-05-24 at 10:12 -0600, Todd C. Miller wrote: 
> In message <1116926417.4053.14.camel at petra>
> 	so spake Karel Zak (kzak):
> 
> > is there any real reason why 'sudo' doesn't use PAM session? It means
> > the code doesn't call pam_open_session() and pam_close_sesssion(). 
> 
> This would require that the sudo process spawn a command and wait
> until it finishes instead of just exec()ing the command as it does
> now.

Yes and no :-) It depends on PAM session modules.

An example system limits (by pam_limits) are persistent after
pam_close_session(). It means you can use code like:

	pam_open_session(pamh, 0);
	pam_close_session(pamh, 0);

and now you have set all system limits for actual process and all
children processes.

I think it better support at least some PAM session modules that ignore
everything.

	Karel


--- sudo-1.6.8p8/auth/pam.c.sess	2005-05-24 16:38:35.976866872 +0200
+++ sudo-1.6.8p8/auth/pam.c	2005-05-24 16:39:50.061604280 +0200
@@ -175,6 +175,8 @@
 pam_prep_user(pw)
     struct passwd *pw;
 {
+    int error;
+
     if (pamh == NULL)
 	pam_init(pw, NULL, NULL);
 
@@ -195,6 +197,20 @@
      */
     (void) pam_setcred(pamh, PAM_ESTABLISH_CRED);
 
+    /*
+     * That's enough initialize PAM session in this function, because
+     * sudo calls it before exec()
+     */
+    if ((error = pam_open_session(pamh, 0))!=PAM_SUCCESS) {
+	    pam_end(pamh, error);
+	    return(AUTH_FAILURE);
+    }
+    /*
+     * For example settings from pam_limits are persistent after
pam_session_close() and
+     * it's probably more clean call pam_close_session() than omit it.
+     */
+    pam_close_session(pamh, 0);
+   
     if (pam_end(pamh, PAM_SUCCESS | PAM_DATA_SILENT) == PAM_SUCCESS)
 	return(AUTH_SUCCESS);
     else


-- 
Karel Zak <kzak at redhat.com>