CVE-2008-2931 kernel: missing check before setting mount propagation

[Eugene Teo <eteo () redhat com>]

The do_change_type routine in the Linux kernel has a missing check for
capable(CAP_SYS_ADMIN). Even though the mount command restricts the
changing of mountpoint type to only root users, it is possible for local
unprivileged users to bypass and abuse this problem. More details can be
found at: https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2008-2931

This affects kernel versions from 2.6.15-rc1 up to 2.6.22-rc1. The
proposed upstream commit is: ee6f958291e2a768fd727e7a67badfff0b67711a.

I have allocated this CVE-2008-2931.

Thanks,
Eugene
-- 
Eugene Teo / Red Hat Security Response Team