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Bug #37823 posix_setgid fails to logout of groups, or call initgroups()
Submitted: 2006-06-16 01:07 UTC Modified: 2006-06-19 02:20 UTC
From: james-php at bytehosting dot com Assigned:
Status: Closed Package: POSIX related
PHP Version: 5.1.4 OS: mandriva2006.0 - linux 2.6.12-22
Private report: No CVE-ID: None
 [2006-06-16 01:07 UTC] james-php at bytehosting dot com
Description:
------------
When calling posix_get[e]gid() to drop root privledges, it does NOT logout of group=0(root).

Please look VERY closely at the 'id' output from the script, you will see that the third section "groups=" shows that i am effectively still logged into group "0".

It indeed sets the current process group id to 0, however, it does NOT completely DROP all group memeberships, as well PHP provides no "posix_initgroups()" so there is no way to call initgroups() on linux to re-init the group memeberships from /etc/group, which would effectively, or should, drop the group=0(root) membership.

Reproduce code:
---------------
<?
 system("id");
 posix_setgid(500);
 posix_setegid(500);
 posix_setuid(500);
 posix_seteuid(500);
 system("id");
?>

Expected result:
----------------
[root@admin cluster]# php test.php
uid=0(root) gid=0(root) groups=0(root)
uid=500(cluster) gid=500(cluster) groups=500(cluster)
[root@admin cluster]#

Actual result:
--------------
[root@admin cluster]# php test.php
uid=0(root) gid=0(root) groups=0(root)
uid=500(cluster) gid=500(cluster) groups=0(root)
[root@admin cluster]#

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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2006-06-19 02:20 UTC] iliaa@php.net
This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

The posix_initgroups() was added in CVS.
 
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