Re: [RFC 2/2] fanotify: emit FAN_MODIFY_DIR on filesystem changes

From: J. Bruce Fields
Date: Tue Mar 21 2017 - 13:47:02 EST


On Tue, Mar 21, 2017 at 05:41:22PM +0100, Jan Kara wrote:
> On Tue 21-03-17 11:38:49, J. Bruce Fields wrote:
> > On Sun, Mar 19, 2017 at 11:19:43AM +0100, Jan Kara wrote:
> > > On Tue 14-03-17 13:18:01, Amir Goldstein wrote:
> > > > On Tue, Mar 14, 2017 at 1:03 AM, Filip ÅtÄdronskà <r.lklm@xxxxxxxxxx> wrote:
> > > > > An alternative might be to create wrapper functions like
> > > > > vfs_path_(rename|unlink|...). They could also take care of calling
> > > > > security_path_(rename|unlink|...), which is currently also up to
> > > > > the indvidual callers (possibly with a flag because it might not
> > > > > be always desired).
> > > >
> > > > That's an interesting idea. There is some duplicity between security/audit
> > > > hook and fsnotify hooks. It should be interesting to try and deduplicate
> > > > some of this code.
> > >
> > > Yeah, but ecryptfs or nfsd don't actually call these security hooks AFAICT.
> >
> > We don't? E.g. nfsd_unlink calls vfs_unlink which calls
> > security_inode_unlink().
>
> OK, I have not been specific enough :). ecryptfs or nfsd don't call *path*
> security hooks AFAICT - e.g. security_path_unlink() from nfsd_unlink().

Oh, got it, thanks.

But, no, nfsd is definitely is not meant to be invisible to security
modules, so that's just a bug.

--b.