grack.com

Welcome to grack.com

Get Firefox

If you're wondering: Why grack?

News

RSS Validate

Google Backlinks

Hmm… Google introduced a backlinks feature in the last few days, but it doesn’t seem to work for me on the webmaster tools page.

Does it take some time to show up on older accounts?

UPDATE: Looks like there was a bit of a bug and it was disabled for a short period of time.

Posted in Tech | no comments

Treo 680 ROM Tool

I started looking into a Treo 680 ROM tool. Unfortunately, there is no longer a recovery bootloader on the Treo, making ROM upgrades significantly riskier.

There are some possible ways to proceed, but this will take some time to investigate. I’ll keep you posted.

If you have a Treo 680, would you be willing to build/purchase a serial cable?

Posted in Tech, Palm | 2 comments

Vista's anti-consumer design

Miguel de Icaze points us at an article entitled ‘A Cost Analysis of Windows Vista Content Protection’.

In this article, you’ll discover all the wonderful ways Microsoft is making your next video card more expensive and/or less featureful, as well as removing the ability for certain functionality to continue to work in the presence of so-called “premium content”.

I find the whole thing vaguely amusing, considering that Prof. Ed Felton and others pointed out the flaws in HDCP, one of the lynchpins of the whole system. You won’t be able to get at the raw MPEG-encoded video when HDCP is cracked, but you’ll certainly be able to stream it into another high-quality encoder and get a pretty darn good approximation.

So, is this the “longest suicide note in history”?

Posted in Open Source, Politics, Tech | no comments

Hmm… when I see Jobs talking about the iPod, he’s standing on a stage in a turtleneck, confident.

When I see Ballmer talking about the Zune, I see a red-faced, sweaty, 60-year-old guy in a suit trying to sound like he is somehow in touch with what “the youth want”.

I think they need a new face for Zune PR…

Posted in Tech | no comments

OLPC has a "View Source" key

According to LinuxWorld, the OLPC is going to drop the caps-lock key in favour of a key named “view source”. The purpose of this key is to allow the children to figure out how the current webpage or application is written.

I’m not sure why this key appeals to me so much. Maybe it has something to do with typing in BASIC games on my old computers and being able to edit the source of GORILLA.BAS and other interesting programs to make them do what I wanted. I think it is a fantastic way for the children to get to know how things work. Think of it as a transparent case on an engine or an analog watch.

Posted in Open Source, Tech | 3 comments

Congratulations IE7 team

On the simultaneous release of both IE7 and its first vulnerability

Posted in Tech | no comments

Microsoft's BitLocker - mostly insecure?

Out of curiousity, I started reading about Microsoft’s BitLocker technology. This is a way of encrypting a whole hard drive that stores keys in the machine’s trusted platform module (TPM).

My conclusion (though I may be wrong) is that a laptop that uses BitLocker without either an external crypto token or a secure boot ROM is likely susceptible to some relatively easy hardware attacks. BitLocker may defend against casual snooping on random stolen laptops, but a determined attacker with a deliberate target probably won’t be thwarted unless the extra precautions mentioned above are taken.

While on the surface it appears to be a good idea, it seems to have a number of flaws that seem apparent at first glance.

Note that asking for a PIN would add some complexity to the attack, but would be vulnerable to poor PIN choices.

1. The algorithm assumes that BIOS code is immutable. Since the OpenBIOS/LinuxBIOS people have been replacing BIOS chips for a while, this seems to be something that can be easily circumvented. The replacement BIOS need only extend the base PCR with the original BIOS image, effectively inserting itself into the chain of execution.

Note that Microsoft’s document here talks about BIOS upgrades and how they can destroy keys. See this BitLocker presentation for some more information.

The solution for this problem is getting laptop manufacturers to add a secure bootloader that checks the cryptographic signature of the BIOS and embeds a secret key in the TPM. This would be a tricky operation – requiring a hidden boot ROM like what is available on the XBOX.

Difficulty: best case: replacing socketed BIOS or backup BIOS. Worst case: desoldering/resoldering chips.

2. The TPM can be transplanted. By running the TPM in a controlled environment, any software can extend the PCR registers as they would be extended on a real boot, which would then allow the TPM to unseal the keys. The solution, again, is to have a hidden boot ROM that embeds a secret key.

Diffculty: desoldering/resoldering chips.

3. The whole authentication system can be emulated after boot in a non-secure OS. It might be possible to reset the TPM without resetting the system itself. I don’t have specific facts here, but I know that the TPM does have a way to reset the PCR registers, but this doesn’t reset an internal “resets after reboot” counter. An alternative might be to cut one of the Vcc leads of the TPM and allow it to be power-cycled externally.

Once the TPM has been reset, the user may then use an x86 emulator such as QEMU to run the BIOS and boot loader and recover the decryption keys from memory or a more sophisticated attack.

Difficulty: best case: software-only attack, worst case: hardware hack to reset TPM after boot.

Posted in Tech | 2 comments

A Month with Roomba

We’ve spent an interesting month with our new Roomba Scheduler. The role it fills is a “between-vacuuming” cleanup.

It works really well on carpets. It gets pretty much every spot that it can reach, and its small, round shape lets it get a lot of spots.

How it works on tile is a different matter altogether. I don’t know if it’s because our kitchen tile is a dark color, but we’ve found that it missed pretty much all the dirt along the edges of the kitchen, and a fair bit in the middle too. I guess the Scooba is designed to excel at this part of the cleaning, but it would be nice if Roomba had better support for cleaning smooth surfaces.

It’s been good at keeping out of trouble so far. You pretty much have to pick up any rugs or mats that Roomba might encounter. I believe they claim that Roomba will just seamlessly transition over these rugs, but most of the time you’ll find it pulling the rugs over themselves and occasionally getting caught. The net result of this is us spending roughly five minutes before each Roomba run picking everything up.

For a “between-vacuuming” device, the Roomba certainly helps out a lot. The carpets look nice and clean after it finishes and there isn’t half as much stuff on them when it comes time to do the real vacuum.

We haven’t used the scheduling functionality yet because between the two of us we are home pretty much all the time. It’s easier to start it as you are heading out or run it while you are home.

For a gadget nut, this is a perfect device!

Posted in Personal, Tech | no comments

Portable PuTTy 0.58
UPDATE: The author of portaPuTTy has updated his build with the font fix as well. Excellent! I recommend going with his version - it's more likely to be supported.

I rebuilt a portable version of PuTTy using the latest 0.58 release.  It correctly saves font information (a shortcoming of the current portaPuTTy) and has all the updated security and bugfixes of 0.58.

I've also packaged up all the PuTTy executables (paegent, pscp, etc.) so that you can easily use them portably as well.  Note that all of the executables will load configuration files from $EXEPATH\.putty\configuration.

Get it here:

Portable PuTTy 0.58 (binaries)
Portable PuTTy 0.58 (source)

For those who want to know what I changed, here's a quick summary:

  • Moved the unix storage backend into the windows storage backend, since it has all the code we need
  • Added a BSD Win32 "dirent.h" and "dirent.c" implementation
  • Changed the code to look in the EXE's path (via GetModuleFilePath(NULL)) instead of $HOME
  • Added the Win32 font load/save code
  • Hacked the Makefiles manually to add dirent.obj (out of sheer laziness ;))

There's no patch available, but those instructions will reproduce the exact build I provided from the latest SVN or source packages.

Posted in Tech, Open Source | 1 comment

Billboard Clouds

I can’t believe how cool this technique is.

It takes a 3D mesh and calculates the lowest-error set of billboards that, when rendered, look very much like the object they are representing.

Take a look at this sample movie of a billboard-cloud-tree flyover.

Posted in Tech | no comments

Older posts: 1 2 3

RSS Validate

Note: If you're not sure where you are, you may have come here looking for one of my old addresses.

If you are looking for something in particular, you can search this site via Google:

Google
 
Web www.grack.com