Messages in this thread | | | Subject | Re: [fuse-devel] [PATCH v4 4/5] fuse: Support privileged xattrs only with a mount option | From | Michael j Theall <> | Date | Tue, 14 Oct 2014 13:12:26 -0500 |
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Seth Forshee <seth.forshee@canonical.com> wrote on 10/14/2014 09:25:55 AM:
> From: Seth Forshee <seth.forshee@canonical.com> > To: Miklos Szeredi <miklos@szeredi.hu> > Cc: fuse-devel@lists.sourceforge.net, "Serge H. Hallyn" > <serge.hallyn@ubuntu.com>, linux-kernel@vger.kernel.org, Seth > Forshee <seth.forshee@canonical.com>, "Eric W. Biederman" > <ebiederm@xmission.com>, linux-fsdevel@vger.kernel.org > Date: 10/14/2014 09:27 AM > Subject: [fuse-devel] [PATCH v4 4/5] fuse: Support privileged xattrs > only with a mount option > > Allowing unprivileged users to provide arbitrary xattrs via fuse > mounts bypasses the normal restrictions on setting xattrs. Such > mounts should be restricted to reading and writing xattrs in the > user.* namespace. >
Can you explain how the normal restrictions on setting xattrs are bypassed? My filesystem still needs security.* and system.*, and it looks like xattr_permission already prevents non-privileged users from accessing trusted.*
> It's difficult though to tell whether a mount is being performed > on behalf of an unprivileged user since fuse mounts are ususally > done via a suid root helper. Thus a new mount option, > privileged_xattrs, is added to indicated that xattrs from other > namespaces are allowed. This option can only be supplied by > system-wide root; supplying the option as an unprivileged user > will cause the mount to fail.
I can't say I'm convinced that this is the right direction to head.
Regards, Michael Theall
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