Re: [PATCH 10/29] selinux: implement set acl hook

[Christian Brauner <brauner@kernel.org>]

On Fri, Sep 23, 2022 at 10:26:35AM -0400, Paul Moore wrote:
> On Fri, Sep 23, 2022 at 3:57 AM Christian Brauner <brauner@kernel.org> wrote:
> > On Fri, Sep 23, 2022 at 08:47:07AM +0200, Christoph Hellwig wrote:
> > > On Thu, Sep 22, 2022 at 01:16:57PM -0400, Paul Moore wrote:
> > > > properly review the changes, but one thing immediately jumped out at
> > > > me when looking at this: why is the LSM hook
> > > > "security_inode_set_acl()" when we are passing a dentry instead of an
> > > > inode?  We don't have a lot of them, but there are
> > > > `security_dentry_*()` LSM hooks in the existing kernel code.
> > >
> > > I'm no LSM expert, but isn't the inode vs dentry for if it is
> > > related to an inode operation or dentry operation, not about that
> > > the first argument is?
> >
> > Indeed. For example ...
> 
> If the goal is for this LSM hook to operate on an inode and not a
> dentry, let's pass it an inode instead.  This should help prevent

I would be ok with that but EVM requires a dentry being passed and as
evm is called from security_inode_set_acl() exactly like it is from
security_inode_setxattr() and similar the hook has to take a dentry.

And I want to minimize - ideally get rid of at some point - separate
calls to security_*() and evm_*() or ima_() in the vfs. So the evm hook
should please stay in there.