Re: [TOMOYO #7 30/30] Hooks for SAKURA and TOMOYO.

From: Stephen Smalley
Date: Wed Apr 09 2008 - 09:37:41 EST



On Wed, 2008-04-09 at 07:11 -0600, Matthew Wilcox wrote:
> On Wed, Apr 09, 2008 at 05:37:38PM +0900, Toshiharu Harada wrote:
> > LWN article 239962 says, "At the 2006 summit, Linus took a clear
> > position that the use of pathnames for security policies seemed
> > reasonable to him". Current LSM implementation is sufficient for SELinux
> > and other label based MACs but not for pathname-based MACs.
> > This has been argued in the AppAmor thread for quite a long time.
> > Though proposals had been posted by AppArmor and TOMOYO Linux project,
> > none has been merged until now.
>
> How about an approach which doesn't require the vfsmount to be passed
> down?
>
> When the rule is put in place, say "No modifications to /etc/passwd",
> look up the inode and major:minor of /etc/passwd. If there's a rename,
> look up the new inode number. If it's mounted elsewhere, it doesn't
> matter, they still can't modify it because it has the same
> major:minor:inode.
>
> Is this workable?

Sounds similar to audit watches, e.g. see audit_add_watch() and
audit_handle_ievent(). That leverages inotify internally.

--
Stephen Smalley
National Security Agency

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