[Fwd: Fwd: RE: [AG-TECH] ddvic error]

Robert Olson olson at mcs.anl.gov
Tue Nov 12 06:57:09 CST 2002

That machine was reflecting multicast streams back into the multicast 
group, so that the same source was being received by vic from multiple 
hosts. When the source went away, vic receieved the BYE twice. In the 
processing of the second BYE, it crashed due to a memory error (I'm 
guessing perhaps a multiple free, or something similar). Its data 
structures were likely confused as the streams receieved were clearly not 
RTP-compliant, and it didn't have the code in place to prevent this confusion.

Ideally we'd get vic fixed to not crash in this case (it should never 
crash); however, I don't have the time right now to chase it down. I can 
give more details to anyone who's interested in chasing this down.


At 04:23 PM 11/12/2002 +1100, Markus Buchhorn wrote:
>Uhm - is anybody going/able to explain what happened? i.e. why did we get 
>this error, and why did ddvic die because of it? I know there are other 
>(more or less) imaginative ways to DoS the AG, so I'd like to understand 
>what to watch out for in this case.

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