Messages in this thread |  | | | Date | Tue, 29 Feb 2000 13:20:23 -0500 (EST) | | From | "Mark H. Wood" <> | | Subject | Re: Capabilities |
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On Mon, 28 Feb 2000, Jesse Pollard wrote: > corbet-lk@eklektix.com (Jonathan Corbet): > >Just for the sake of discussion, I would like to toss out this idea one > >more time. VMS handled the association of privileges (i.e. "capabilities") > >via a central database. For any executable to run with privilege, it had > >to be "installed" as a "known image," with the privileges spelled out. > >Executables so installed were protected from modification thereafter. > > > >This approach eliminates the problem of finding the programs with > >capabilities - they are all listed in one place. There are no issues with > >privileged programs on remotely mounted filesystems. It works with all > >filesystem types, and should not require changes to any of them. > >Implementation should be relatively simple. > > VMS had a lot going for it.. except company support (it was overpriced). > The VMS filesystem only allowed one link to a file. If a second occured, > then it was listed as an error.
Nope, you can have zero, one, or many names for a file. One of them is special in that the file header backlinks to it, but that's the only thing the filesystem does to make one name any sort of standard. I don't recall whether INSTALL barks when handed a multilinked file, but it makes good sense.
> The central database assumed that the > only path to a program was the one it was registered with. Now if it used > the inode, maybe. But what about mountable file systems. If a mount point > moved, does that mean the registry also changed?
It means that the image(s) on that volume won't be privileged until the sysadmin changes the Known Files List. Read on.
> VMS didn't allow privleged > programs to reside anywhere except the system disk.
Hmmm, I don't recall such a restriction. There's no need: known files are held open, so you can't dismount the volume they're on. Okay, you can take the pack off without DISMOUNTing it, and screw on a new pack, but the results won't be useful.
-- Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu "Where's the kaboom? There was supposed to be an Earth-shattering kaboom!" -- Marvin Martian, 01/01/2000 00:00:00
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