Messages in this thread | | | Subject | Re: [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning | From | Eric Paris <> | Date | Mon, 18 Aug 2008 19:07:04 -0400 |
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On Tue, 2008-08-19 at 00:40 +0200, Pavel Machek wrote: > Hi! > > > > On Mon, Aug 18, 2008 at 02:15:24PM +0100, tvrtko.ursulin@sophos.com > > wrote: > > > > Then there is still a question of who allows some binary to declare > > itself > > > > exempt. If that decision was a mistake, or it gets compromised > > security > > > > will be off. A very powerful mechanism which must not be easily > > > > accessible. With a good cache your worries go away even without a > > scheme > > > > like this. > > > > > > I have one word for you --- bittorrent. If you are downloading a very > > > large torrent (say approximately a gigabyte), and it contains many > > > pdf's that are say a few megabytes a piece, and things are coming in > > > tribbles, having either a indexing scanner or an AV scanner wake up > > > and rescan the file from scratch each time a tiny piece of the pdf > > > comes in is going to eat your machine alive.... > > > > 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 > > Why do you think non-malicious applications won't write after close / > keep file open forever?
If you ask this one more time without reading the many times I've answered these questions I think I'm going to explode.
Permissions checks are done on open/read. Decisions are invalidated at mtime update, which INCLUDES mmap after close! I don't care if you keep your file open forever, if you wrote to it, we are just going to scan it next time a process decided to open/read it. Please stop confusing this already long and almost pointless thread with implementation details that have repeatedly been explained.
-Eric
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