Messages in this thread | | | Date | Fri, 11 Dec 2009 13:25:49 +0200 | From | Ivan Zahariev <> | Subject | EUID != root + EGID = root, and CAP_SETGID |
| |
Hi guys,
Currently, if a process is started with EUID which is non-root, and EGID which IS root (for example by set-group-ID file permission + file group owner "root", or an account in /etc/passwd with group=0), then the processes is not granted CAP_SETGID.
As a result, such a process cannot change its EGID to an arbitrary one, even though the current EGID is the super-user "root" one. Therefore, such a process cannot easily drop its EGID "root" privileges to non-root ones, for security reasons.
This is not the case if the process starts with EUID=0. Then the processes is granted *both* CAP_SETUID and CAP_SETGID.
Is this an intended behavior? Shouldn't a process which is started with EGID=0 get CAP_SETGID too?
Thank you.
Best regads, Ivan Zahariev
P.S. For more detailed info: http://blog.famzah.net/2009/12/11/linux-non-root-user-processes-which-run-with-group-root-cannot-change-their-process-group-to-an-arbitrary-one/
| |