Re: [malware-list] scanner interface proposal was: [TALPA] Intro toa linux interface for on access scanning

[Alan Cox]

> Huh? I was never advocating re-scan after each modification and I even 
> explicitly said it does not make sense for AV not only for performance but 
> because it will be useless most of the time. I thought sending out 
> modified notification on close makes sense because it is a natural point, 
> unless someone is trying to subvert which is out of scope. Other have 
> suggested time delay and lumping up.

You need a bit more than close I imagine, otherwise I can simply keep the
file open forever. There are lots of cases where that would be natural
behaviour - eg if I was to attack some kind of web forum and insert a
windows worm into the forum which was database backed the file would
probably never be closed. That seems to be one of the more common attack
vectors nowdays.

> 
> Also, just to double-check, you don't think AV scanning would read the 
> whole file on every write?

So you need the system to accumulate some kind of complete in memory set
of 'dirty' range lists on all I/O ? That is going to have pretty bad
performance impacts and serialization.
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