Understanding Mac OS X Kernel

An anonymous reader writes "Kernelthread.com has published a flash presentation overview of the Mac OS X kernel. Its title is 'A Tour of the Mac OS X Kernel' and it also covers Tiger features. Maybe interesting to note is that the slides are from a talk given to the NSA. Well, there is a nice security architecture diagram towards the end of the presentation."

Comments

Re:AES encryption under the hood?

[zhiwenchong]

Apparently not:
http://en.wikipedia.org/wiki/AES#Security

Re:AES encryption under the hood?

[Anonymous Coward]

You're wrong.

Maybe you're thinking of the old DES standard.

http://en.wikipedia.org/wiki/Data_Encryption_Stand ard

Eek, a presentation in flash!

[Psychic Burrito]

There is no way to step back (at least I found none), to get an overview, to jump to a certain frame (like the mentioned security architecture diagram) - why do people make presentations in flash, instead of pdf or css (example)?

Keynote

[TimmyDee]

I'm willing to bet it's in Flash because he did the presentation in Keynote. While the SWF export in Keynote isn't great, at least it preserves transitions, fonts, and other formatting options and doesn't look like shit (like the HTML export of another presentation software).

Plus, it takes one step to export. I haven't seen anything that will do that with CSS.

Re:AES encryption under the hood?

[Anonymous Coward]

FS and swap encryption is used to encrypt user's home directories. This is the "File Vault" functionality of OS X. Tiger adds the ability to optionally encrypt the users swap space also (only on file vaulted home folders) to secure the users memory space as well. A file vaulted home folder becomes a sparse disk image file (a disk image that can grow in size as it's written too) that uses the users account password to open. If the user losses their account password then the admin can use the master file vault (set separately) to restore the users home directory. That scenario only really applies for multi-user systems.

I am not sure what bit of AES is used though. I would guess 128 bit at least.

For explanatory purposes

[Anonymous Coward]

"Largest file size is 2^63 bytes"

Pedantic note:

• 2^63 bytes == 9007199254740992 KiB

• 9007199254740992 KiB == 8796093022208 MB

• 8796093022208 MB == 8589934592 GB

• 8 exabytes == 8*(1,024*1,024*1,024) GB == 8*1073741824 GB == 8589934592 GB

____

Now my head hurts

Re:* Encrypted swap (optional, uses AES)

[kerry-buckley]

Wow.. So it looks like they finally fixed this security bug where the password could be discovered in the swap. Anyone know how to turn this feature on?

There's a "use secure virtual memory" checkbox in the security preference pane.

Re:So, HFS+ can be case-sensitive...

[ahknight]

Like this: http://www.codepoetry.net/archives/2003/10/26/case sensitive_hfs_for_the_masses.php

Re:So, HFS+ can be case-sensitive...

[macshome]

Just use diskutil on 10.3 or Disk Utility in the GUI on 10.4. Josh

Re:NSA deciding how to break into Mac computers?

[noewun]

Sorry to dint your tinfoil body suit, but the reason the NSA is interested in OS X is because they use OS X. I have a very interesting, very thorough PDF authored by the NSA (report #I331-009R-2004) on how to secure an OS X box, from install through end use. Very interesting, and I learned a bit.

Re:NSA deciding how to break into Mac computers?

[wirelessbuzzers]

The NSA is not allowed to break US laws. Of course, they spy on other countries, so they're probably allowed to break other countries' laws.

As for the other nasty stuff, it sounds an awful lot like your tinfoil hat is on too tight.

Also, if you want to hack a computer, you probably care more about the services running on it than the guts of the kernel, at least up to the point where you install a rootkit. They probably care more because they want to use MacOS X in a highly secure environment. SEDarwin anyone?