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SELinux Mailing ListRe: Security issues with local filesystem caching
From: David Howells <dhowells_at_redhat.com>
Date: Thu, 26 Oct 2006 10:56:08 +0100
> Hrm. How do you do DAC checks if you don't copy over the permissions without You have to remember there are two filesystem layers involved. NFS or other netfs does the DAC, MAC, whatever checks to see whether the user can access a file. NFS then asks the cache to back the netfs file and the cache creates a file in the local filesystem to do that. The cache file doesn't need the DAC/MAC/whatever attributes applied to the netfs file, and, in fact, may not be able to support what the netfs deals with.
> I'm wondering, why don't just you duplicate all the attributes of the files You're forgetting that the userspace cache manager daemon still has to access the cache.
> > (1) Do all the cache operations in their own thread (sort of like knfsd). I'm not sure exactly. Actually, I could probably deal with read/write ops inline - though I don't have a file struct to carry a security context - but getting and releasing inodes would certainly wind up being farmed off. Consider the automounter releasing an NFS share that's been heavily used...
> I'm thinking that it would be nice to combine the caching related security That's fine by me, though I want the security on a cache file to be different to that on the netfs file it's backing. David -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@tycho.nsa.gov with the words "unsubscribe selinux" without quotes as the message.Received on Thu 26 Oct 2006 - 05:57:12 EDT |
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Date Posted: Jan 15, 2009 | Last Modified: Jan 15, 2009 | Last Reviewed: Jan 15, 2009 |