kern/40490: 5.0: linux futex cas stuff is a security hole

[ad%netbsd.org@localhost]

>Number:         40490
>Category:       kern
>Synopsis:       5.0: linux futex cas stuff is a security hole
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jan 26 23:45:00 +0000 2009
>Originator:     Andrew Doran
>Release:        5.0_BETA
>Organization:
ad%netbsd.org@localhost
>Environment:
n/a
>Description:
The CAS stuff added for linux futexes is a security hole that could
either leak memory cross process or crash the kernel.

>How-To-Repeat:
Code inspection.

>Fix:
Add ucasptr() and move to copy.S, build linux ops on it.