Messages in this thread | | | Date | Sat, 31 Dec 2011 11:51:02 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [patch 1/4] Add routine for generating an ID for kernel pointer |
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On Fri, Dec 30, 2011 at 06:51:37PM -0500, KOSAKI Motohiro wrote: ... > > > >Guys, this become more and more complex, finally I fear someone > >propose to do ideal hashing run-time ;) Maybe we can step back and > >live with root-only and plain pointers here? I'm not sure who else > >might need such facility except us, and if once there will be a candidate > >-- we could take a look on hashing again and provide safe hashes there. No? > > But recently kernel security fashion are, we don't expose a kernel > pointer at all even though the file is root only. I'm not sure how > much effective such fashion. but you seems run opposite way. > > I doubt user land can implement good comparison way. Why you gave up > Andrew's sys_are_these_files_the_same() idea? >
Because of speed, as Pavel mentioned | | With this the complexity of determining sharing for N files scattered across | several tasks would be N^2, since we'll have to compare each file to each file. | | On the other hand having just N IDs at hands would allow us to use more | efficient algorithms resulting in e.g. N*log(N) complexity. |
Cyrill
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