Re: [PATCH RFC v2 1/2] selinux: Fix selinux_sb_mnt_opts_compat()

From: Paul Moore
Date: Tue Feb 01 2022 - 11:19:52 EST


On Tue, Feb 1, 2022 at 9:38 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
> On Mon, Jan 31, 2022 at 5:16 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> > On Mon, Jan 31, 2022 at 7:46 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
> > > On Fri, Jan 28, 2022 at 3:28 AM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> > > > On Thu, Jan 27, 2022 at 4:54 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
> > > > > I wonder if we could make this all much simpler by *always* doing the
> > > > > label parsing in selinux_add_opt() and just returning an error when
> > > > > !selinux_initialized(&selinux_state). Before the new mount API, mount
> > > > > options were always passed directly to the mount(2) syscall, so it
> > > > > wasn't possible to pass any SELinux mount options before the SELinux
> > > > > policy was loaded. I don't see why we need to jump through hoops here
> > > > > just to support this pseudo-feature of stashing an unparsed label into
> > > > > an fs_context before policy is loaded... Userspace should never need
> > > > > to do that.
> > > >
> > > > I could agree with that, although part of my mind is a little nervous
> > > > about the "userspace should *never* ..." because that always seems to
> > > > bite us. Although I'm struggling to think of a case where userspace
> > > > would need to set explicit SELinux mount options without having a
> > > > policy loaded.
> > >
> > > I get that, but IMO this is enough of an odd "use case" that I
> > > wouldn't worry too much ...
> >
> > I understand, but seeing as I'm the only one that defends these things
> > with Linus and others lets do this:
>
> It's not all black and white:
> https://lore.kernel.org/lkml/Pine.LNX.4.64.0512291322560.3298@xxxxxxxxxxx/

I made my statement above not to ask your opinion, but rather to make a point.

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