Messages in this thread | | | Date | Tue, 9 Mar 2010 00:48:29 +0000 | From | Al Viro <> | Subject | Re: Upstream first policy |
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On Tue, Mar 09, 2010 at 12:15:54AM +0000, Al Viro wrote: > On Mon, Mar 08, 2010 at 03:37:38PM -0800, Linus Torvalds wrote: > > > Of course, you can make /etc unwritable, and that is indeed the > > traditional UNIX model of handling namespace security: by just > > implementing it as "content security" of the directory. > > > > The sgid and sticky bits can be used to further try to make it more > > fine-grained (exactly becuase it is _not_ sufficient to say "you can't > > read or write this directory" on a whole-directory basis), and obviously > > SELinux has extensions of its own too. > > But that's not what the apparmor et.al. are doing. If you want (and that's > not obviously a good thing) fine-grained access control for directory > entries, it would at least make some sense. Prohibitively pricy, probably, > but that's a separate story. But they are *NOT* protecting /foo/bar directory > entry when you want to protect /foo/bar/baz/barf; it doesn't go up towards > root. > > And if you *do* protect each ancestor and try to keep granularity, you'll > end up with complexity from hell.
BTW, if you actually look at apparmor (I'd suggest tomoyo, but I'm not _that_ sadistic), you'll see how seriously do they take pathname-based *anything*. LSM hooks for namespace operations (you know, mount, umount) are lousy, but they exist. Not used by apparmor.
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