Messages in this thread | | | Date | Tue, 15 Jan 2008 08:21:15 -0600 | From | "Serge E. Hallyn" <> | Subject | Re: [patch 8/9] unprivileged mounts: propagation: inherit owner from parent |
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Quoting Miklos Szeredi (miklos@szeredi.hu): > > Quoting Miklos Szeredi (miklos@szeredi.hu): > > > From: Miklos Szeredi <mszeredi@suse.cz> > > > > > > On mount propagation, let the owner of the clone be inherited from the > > > parent into which it has been propagated. Also if the parent has the > > > "nosuid" flag, set this flag for the child as well. > > > > What about nodev? > > Hmm, I think the nosuid thing is meant to prevent suid mounts being > introduced into a "suidless" namespace. This doesn't apply to dev > mounts, which are quite safe in a suidless environment, as long as the > user is not able to create devices. But that should be taken care of > by capability tests. > > I'll update the description.
Hmm,
Part of me wants to say the safest thing for now would be to refuse mounts propagation from non-user mounts to user mounts.
I assume you're thinking about a fully user-mounted chroot, where the user woudl still want to be able to stick in a cdrom and have it automounted under /mnt/cdrom, propagated from the root mounts ns?
But then are there no devices which the user could create on a floppy while inserted into his own laptop, owned by his own uid, then insert into this machine, and use the device under the auto-mounted /dev/floppy to gain inappropriate access?
-serge
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