Idea: fuse-kvm filesystem

Currently when you mount a filesystem, you face two issues:
- you have to be root
- if the media is untrusted, it can exploit your kernel

With kvm and fuse, we can have a virtualized kernel mount the filesystem, and re-export to the host, which mounts it using a fuse interface. This solves both problems, at the expense of speed and simplicity. In theory this can be used for mounting untrusted USB sticks (perhaps only for the less well tested filesystems).

Quoted 9 lines · Avi Kivity

Currently when you mount a filesystem, you face two issues:
- you have to be root
- if the media is untrusted, it can exploit your kernel

With kvm and fuse, we can have a virtualized kernel mount the filesystem, and re-export to the host, which mounts it using a fuse interface. This solves both problems, at the expense of speed and simplicity. In theory this can be used for mounting untrusted USB sticks (perhaps only for the less well tested filesystems).

I guess you CC'd me so I could point out guestmount :-?

http://libguestfs.org/guestmount.1.html

guestmount does the above already, and you can point it directly at USB sticks, hard drives and the like, although most people use it for mounting VM filesystems on the host.

On my local machine I'm a member of the "disk" group so I can do all this as non-root:

  $ guestmount --ro -a /dev/vg_pin/F16x64 -i /tmp/mnt
  $ cat /tmp/mnt/etc/redhat-release 
  Fedora release 16 (Verne)
  $ ls /tmp/mnt
  bin   dev  home  lib64       media  opt   root  sbin     srv  tmp  var
  boot  etc  lib   lost+found  mnt    proc  run   selinux  sys  usr

One problem you'll find is that FUSE is pretty slow. I recommend if you're looking for performance that you use the libguestfs API calls directly instead of POSIX-over-FUSE.

Currently when you mount a filesystem, you face two issues:
- you have to be root
- if the media is untrusted, it can exploit your kernel

With kvm and fuse, we can have a virtualized kernel mount the filesystem, and re-export to the host, which mounts it using a fuse interface.  This solves both problems, at the expense of speed and simplicity.  In theory this can be used for mounting untrusted USB sticks (perhaps only for the less well tested filesystems).

Quoted 9 lines · Avi Kivity

Currently when you mount a filesystem, you face two issues:
- you have to be root
- if the media is untrusted, it can exploit your kernel

With kvm and fuse, we can have a virtualized kernel mount the filesystem, and re-export to the host, which mounts it using a fuse interface. This solves both problems, at the expense of speed and simplicity. In theory this can be used for mounting untrusted USB sticks (perhaps only for the less well tested filesystems).

Is this not one of the many features of guestfs? At least, I'm not sure I understand from your description how it's different.

http://libguestfs.org/guestmount.1.html

Currently when you mount a filesystem, you face two issues:
- you have to be root
- if the media is untrusted, it can exploit your kernel

With kvm and fuse, we can have a virtualized kernel mount the filesystem, and re-export to the host, which mounts it using a fuse interface. This solves both problems, at the expense of speed and simplicity. In theory this can be used for mounting untrusted USB sticks (perhaps only for the less well tested filesystems).