Amit Singh's Challenge: Find a Decade-Old Bug

dreicodan writes "Well this has too many juicy Mac OS X nuggets in one bag! All details are on this page, but I'll summarise. Apparently Amit Singh discovered a 10+ year old serious bug in OS X. The bug started in Nextstep and is still in Panther (and apparently Tiger, too). Then Amit wrote a program to demo the bug, but also made the program capable of hiding what it does using some complicated Mach kernel voodo! He then threw a challenge open to OS X experts to figure out the bug. It turns out that a week and some 1000 downloads later, three brilliant hackers (Alexy Proskuryakov, Andrew Wellington, Graham Dennis) were able to solve the puzzle. Also looks like other than these guys, nobody got anywhere with the problem. Be ready for extremely gory details of how the program was written and how it was decoded. Its a thrilling read, and OS X hacking doesn't get any more hardcore than this! Hopefully Apple fixes this bug now at last."

Comments

Re:What's impressive

[Have Blue]

I don't see anything in TFA to indicate that Apple knew about this bug before now- he just mentions that the bug has been present with no explanation as to how this was determined. Singh even spends a good bit of text explaining how the bug is triggered by ultra-low-level routines that are not normally used by anything above the BSD layer, so I'd say there's a good chance it has never even been encountered by anyone before, if OS X's own process creation code is sufficiently solid as to never generate the inconsistency panpipes does.

Re:What's impressive

[HiredMan]

It is not impressive that NextStep and Apple have known about this panic bug for 10 years but haven't been able to fix it!

Is it clear from his write up that NextStep/Apple has known about this bug? It sounds to me like he uncovered a long standing bug but I didn't see anywhere that he says Apple knows about it. He simply says this bug has 'existed for 10 years' not that he told Steve Jobs about it 10 years ago.

=tkk

Re:A reason why there weren't 1000 submissions

[aftk2]

*sigh*

aftk2's recent submissions:
The Mac OS X Expert Challenge
Thu Apr 07, '05 01:22 PM
Rejected

Not for lack of trying, unfortunately.

Re:Funny responses

[Bastian]

They sound like typical Mac user responses.

You don't talk to many Windows users, do you? It's pretty much the same thing.

I've also heard pretty similar things from people who say they use Linux, thoug admittedly not nearly as often.

Re:10 years?

[jweatherley]

similar or worse M$ (note clever use of $) bug that they couldn't find or fix for 10 years?

This one was in the NT based OSes for a long time:

for(;;) printf("\t\t\b\b\b\b");