> > +   /*
> > +    * For unprivileged mounts use current uid/gid.  Still allow
> > +    * "user_id" and "group_id" options for compatibility, but
> > +    * only if they match these values.
> > +    */
> > +   if (!capable(CAP_SYS_ADMIN)) {
> > +           d->user_id = current->uid;
> > +           d->user_id_present = 1;
> > +           d->group_id = current->gid;
> > +           d->group_id_present = 1;
> > +
> > +   }
> 
> CAP_SETUID is the appropriate capability...
> 
> This is not a dimension we have not fully explored.
> What is the problem with a user controlled mount having different
> uid and gid values.
> 
> Yes they map into different users but how is this a problem.
> The only problem that I can recall is the historic chown problem
> where you could give files to other users and mess up their quotas.
> 
> Or is the problem other users writing to this user controlled
> filesystem?

Yes.  Or even just a suid process trying to access the user controlled
filesystem.  See Documentation/filesystems/fuse.txt for the gory
details.

Eric, thanks for the detailed review :)

Miklos
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to