Johnny Cache Breaks Silence On Wi-Fi Exploit

Joe Barr writes, "Johnny Cache — aka Jon Ellch — is chafing under the cone of silence placed over him and co-presenter Dave Maynor about the Wi-Fi exploit they presented at Black Hat and DEFCON last month. So he has finally broken his silence on NewsForge in hopes of ending the personal attacks coming from what he implies is a smear campaign started by Apple." (Newsforge and Slashdot are both owned by OSTG.)

Johhny Cache writes, "If you're going to post a news story that is a rehash of my post to a mailing list, I would much prefer it if people actaully just read the post in its entirety."

Comments

Re:Honestly weird

[Inoshiro]

"- how can a driver have the same bug on windows and macos x?"

Quite simply; the Intel card is, in both cases, doing things like UDP and TCP offload from the main system. This means the card and driver together have an internal state in software to manage it, and (due to the asynchronus nature of networking) you can get the hardware and driver software's core into a situation where they don't agree on the state.

The small glue layer that deals with the OS hooks is a static translation layer that wouldn't be involved. The SB Live! and Audigy drivers in Linux are the same driver as the Windows Creative driver (well, they were about 6 years ago when they contributed the code). nVidia uses the same driver code on all platforms as well. For anyone who's written a driver, this is easy to understand.

"- why use this stupid external card? what are the chances it did have the same chipset as the internal one?"

He uses it because it's a timing race, and because it's easier to demonstrate with 2 cards in the system. With a 4000 microsecond delay, this means it's likely taking a bit longer for the OS to service the interrupts between the two cards; enough that the driver bug can show itself. There are likely other ways to tickle this bug that don't require multiple cards, but then you'd have to have something running on the OS. Still, If you setup a machine to throw packets around, you could make an intermittent crash bug appear on an OS -- that's not cool.

"- and odds are the bug is a buffer overrun... does it take a SO LONG for apple to fix a stupid memory overrun?"

A stupid memory overrun? Man, you haven't programmed ever, have you? A timing related bug in device driver code is probably the second hardest bug you'll ever encounter to debug (the first would be the core of the OS itself). Concurrent programming is difficult.

It's responses like these that show why this person had been light on detail. Most people lack the technical background in OS design to understand this issue.