Re: [PATCH 0/2] turn on force option for FUSE in builtin policies

[Christoph Hellwig]

On Thu, Jan 11, 2018 at 08:51:48PM +0100, Dongsu Park wrote:
> In case of FUSE filesystem, cached integrity results in IMA could be
> reused, when the userspace FUSE process has changed the
> underlying files. To be able to avoid such cases, we need to turn on
> the force option in builtin policies, for actions of measure and
> appraise. Then integrity values become re-measured and re-appraised.
> In that way, cached integrity results won't be used.

The same is true for any distributed file system.  Checking for magic
numbers is always the wrong thing.  You'll need flags for specific
behavior in struct file_system_type instead.