Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Encryption Pager

On Aug 27, 2008, at 5:49 AM, Nicolas CORMIER wrote: 
Hi folks,

I would like to know if it is possible to create an external pager.
My main goal is to decrypt encrypted pages when they are accessed at run-time.

I found some interesting articles like "extending the Mach external
pager interface to accommodate user-level page replacement policies".
But I actually don't know how to exploit them.

We already have an internal pager that does this; that's how "encrypted swap" works.

The traditional UNIX way to deal with this inside a process address space is to fix up the SIGSEGV/SIGBUS signals by providing handlers, and then fixing up the faults when the signal handler fires.

An alternative method which will work on Mac OS X because of the way signals are implemented would be to obtain the task exception port for the task, and fix up the exception when it is raised before it becomes a signal. You will also need the task port, so that you other process can fix up the address space contents in the target task.

Finally, as shipped, the Leopard code still has most of the Mach external pager support intact (not ripped out). If you really want to do this, you should look at the CMU or OSF documentation on how to write external pagers.

-- Terry
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Darwin-dev mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/darwin-dev/email@hidden

This email sent to email@hidden
References: 
 >Encryption Pager (From: "Nicolas CORMIER" <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.