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NCSU's Fingernail-Size Chip Can Hold 1TB

peter ROM or EEPROM/flash? (227 comments)

I wasn't sure at first if they were setting the data by doping the material, but on closer reading
"The engineers manipulated the nanomaterial so the electrons' spin within the material could be controlled, ..."
makes it sound electrically re-writeable. Which is probably the only thing anyone's really interested in,
unless it was super-cheap. (i.e. cheap enough to replace pressed optical discs with ROM USB-storage.)

As bobjr94 hopes, it would be nice if it is that cheap, though, and optical discs are replaced by a standard flash storage standard.

more than 5 years ago

What Desktop Search Engine For a Shared Volume?

peter Re:the god-awful truth (232 comments)

FYI, GNU find has xargs built in these days:

find -name '*.php*' -exec grep func {} +

the + instead of ';' makes it collect up multiple arguments to grep
like xargs instead of the traditional find -exec behaviour which is like xargs -n1. I use -exec {} + all the time, because it's less typing, and safe with
filenames with punctuation or whitespace, so you don't have to type -print0 | xargs -0 either. (BTW, if you have a list of filenames that you processes with something line oriented, you can use xargs -d'\n')

more than 5 years ago

CFLs Causing Utility Woes

peter Re:Summary is wrong. (859 comments)

> No loads in real life are linear

except electric heaters, stoves, and incandescent lights. They're all just resistors that get hot. Power factor = 1.0.

> then 50% of the power you're using isn't being measured by the power company's basic meters.

  The "extra" power (Apparent power (Volts * Amps) - real power (actual Watts accounting for phase) is only wasted by the inefficiency of your transmission lines.

  Other people have already explained this in detail in this thread.

  Other than that, good try at explaining this for people who don't already know.

more than 5 years ago

Locking Down Linux Desktops In an Enterprise?

peter Re:What are you trying to do? (904 comments)

> Mount users' home directories noexec, don't give users root access.

  noexec doesn't stop you from running /lib/ld.so on an ELF binary, or /bin/bash on a shell script. Or whatever interpreter you want, if it's installed.

  Most people who know how to do that also know enough to avoid breaking things. But they might not have the self-discipline to stop playing games. Other than that, yeah, use firewalls and network policy.

more than 5 years ago

The Backstory of the Kaminsky Bug

peter Re:Do I not understand? (122 comments)

I was as confused as you were by all this, since the article didn't say what the actual attack is. I eventually found something that explains it.
http://www.doxpara.com/DMK_BO2K8.ppt linked from http://www.isp-planet.com/equipment/2008/nominum+vantio.html

  See slide 17 in the presentation. But the trick is, your forged reply to a query for 83.foo.com is:

83.foo.com IN NS www.foo.com (83.foo.com is a subdomain, whose name server is www.foo.com)
www.foo.com IN A (glue)

  So I guess I still agree with you, that BIND must be trusting more than it needs to. Caches could distrust any glue except when it has to. (I think the glue is only necessary when the name server is part of the domain it's serving. e.g. The glue would be needed if the name server was ns1.83.foo.com. Otherwise why not ask the .foo.com server for www.foo.com's A record, or use a cached one, instead of trusting the glue?)

  IIRC, djbdns is skeptical of glue. I remember reading a big rant about glue on DJB's web site years ago. I'm not sure if that's why it's not vulnerable, or if it's because it already did source-port randomization.

  Anyway, that presentation seems to cover a lot of what I wanted to know. In the worst case, you have a cache that trusts glue, and you can poison it by guessing a 16bit ID. In the even worse case, multiple requests for the same name leave the cache willing to accept more than 1 ID for a single response, leading to a birthday attack.

    The trick is to generate lots of DNS queries for names you choose when the server isn't run by idiots (accepting recursive queries from the whole Internet). Web log analyzers are one possible vector. Otherwise if you can feed HTML to something that will resolve names for IMG tags, or presumably javascript could go nuts...

about 6 years ago

The Backstory of the Kaminsky Bug

peter Re:Do I not understand? (122 comments)

So, the dirty fix is to always request a random bogus sub-domain before making the real request?

No, cache misses for A records don't make a recursive resolver go back to the parent domain for an updated NS record. If a cache was poisoned so it thought .bank.com queries were handled by w.x.y.z (the attackers IP), a request for nonexistant.bank.com would cause it to send an A request for the name to w.x.y.z, but not go back to the .com servers to find out which server is authoritative for .bank.com. (It will do that once the cached NS record for .bank.com expires, which could be weeks. Or until another black hat re-poisons that cache.).

about 6 years ago

The Backstory of the Kaminsky Bug

peter Re:Slashdotted (122 comments)

ArsenneLupin, this topic must be right up your alley, since you've stolen your name from a master thief. :)

  I was going to say, don't browsers have copies of the root certificates locally, and require a chain of signatures from them to anything they're going to accept without complaint. But I didn't realize that one could potentially get another cert for a domain without anyone checking with the people who have the first cert.

  Now I understand how the pieces could fit together to play man-in-the-middle with a bank. Otherwise I couldn't see how you could get a valid SSL certificate for yourtarget.com. Which you _need_ if people are going to access your fake site with SSL, and you're not just proxying the traffic to the real yourtarget.com without decrypting it.

  Even with the low-validation certs you mentioned, where you just need to be able to receive mail at the domain, and have a phone, I would have hoped they wouldn't issue certificates for domains that they (or another cert authority) have already issued or signed a previous cert for.

  BTW, the article makes this sound way easier than this, esp. since it's talking about the cert vendors selling encryption, when they actually sell trust. The encryption is free (and easy). Trust is hard, and can be worth paying for. The article was a real mixed bag: painfully bad technical sections, but I loved reading about Vixie's response, calling people and telling them to fly to the west coast without telling them why. That's serious paranoia about even traffic analysis of email (assuming you could trust PGP).

about 6 years ago

The Backstory of the Kaminsky Bug

peter painfully non-technical (122 comments)

I wasn't familiar with the attack, and this article isn't really helping much. I guess I'll just look it up elsewhere. I know its not for a technical audience, but I wish people wouldn't say things that are more or less wrong. Since when is a hostname = a web page? This is so wrong that it makes the article painful to read. (Which is unfortunate, because the personal story is somewhat interesting.) And the article has a few more-technical bits later, so why stoop to being so wrong at the start?

a couple examples from the main article:

... He used a software program called Scapy to fire random queries at the system. He liked to see how it would respond and decided to ask for the location of a series of nonexistent Web pages at a Fortune 500 company. Then he tried to trick his DNS server in San Diego into thinking that he knew the location of the bogus pages.

If I didn't understand DNS and HTTP, I might be thinking this had something to do with HTTP 404 errors. Most people have seen the difference between a bad page on a good server and a server that doesn't exist at all.

Suddenly it worked. The server accepted one of the fake pages as real. But so what? He could now supply fake information for a page nobody would ever visit. Then he realized that the server was willing to accept more information from him. Since he had supplied data about one of the company's Web pages, it believed that he was an authoritative source for general information about the company's domain. The server didn't know that the Web page didn't existâ"it was listening to Kaminsky now, as if it had been hypnotized.

Hypnotized? WTF? This sounds like hollywood-hacking to me. Just a case of misplaced trust. Otherwise this paragraph isn't so bad. (except for saying pages instead of names. He already made a directory assistance analogy, why not continue with DNS = phonebook metaphors. e.g. computers need a number to call another computer, but people like to use names... Or don't people understand that web servers are just computers like their own?)

about 6 years ago

Perfecting a Tron Game

peter Re:Excellent game (63 comments)

glxgears is such a simple scene (no textures, for one thing) that even software rendering is not slow. Way back in the day on a P200MMX, maybe HW 3D was needed for a fast glxgears...

  These days a core2 can run glxgears _really_ fast. e.g. 3GHz Harpertown gets > 500fps, IIRC.

more than 6 years ago


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