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From: Ira Weiny <ira.weiny@intel.com>
To: Paul Moore <paul@paul-moore.com>, Mike Rapoport <rppt@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>,
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Subject: Re: [PATCH 1/2] fs: Provide function that allocates a secure anonymous inode
Date: Fri, 6 Jun 2025 10:09:11 -0500	[thread overview]
Message-ID: <68430497a6fbf_19ff672943@iweiny-mobl.notmuch> (raw)
In-Reply-To: <CAHC9VhR3dKsXYAxY+1Ujr4weO=iBHMPHsJ3-8f=wM5q_oo81wA@mail.gmail.com>

Paul Moore wrote:
> On Thu, Jun 5, 2025 at 1:50 AM Mike Rapoport <rppt@kernel.org> wrote:
> >
> > secretmem always had S_PRIVATE set because alloc_anon_inode() clears it
> > anyway and this patch does not change it.
> 
> Yes, my apologies, I didn't look closely enough at the code.
> 
> > I'm just thinking that it makes sense to actually allow LSM/SELinux
> > controls that S_PRIVATE bypasses for both secretmem and guest_memfd.
> 
> It's been a while since we added the anon_inode hooks so I'd have to
> go dig through the old thread to understand the logic behind marking
> secretmem S_PRIVATE, especially when the
> anon_inode_make_secure_inode() function cleared it.  It's entirely
> possible it may have just been an oversight.

I'm jumping in where I don't know what I'm talking about...

But my reading of the S_PRIVATE flag is that the memory can't be mapped by
user space.  So for guest_memfd() we need !S_PRIVATE because it is
intended to be mapped by user space.  So we want the secure checks.

I think secretmem is the same.

Do I have that right?

Ira

[snip]

  reply	other threads:[~2025-06-06 15:09 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-02 19:17 [PATCH 0/2] Use guest mem inodes instead of anonymous inodes Ackerley Tng
2025-06-02 19:17 ` [PATCH 1/2] fs: Provide function that allocates a secure anonymous inode Ackerley Tng
2025-06-02 20:02   ` David Hildenbrand
2025-06-03  4:52   ` Christoph Hellwig
2025-06-03 10:40     ` Shivank Garg
2025-06-04  7:59   ` Mike Rapoport
2025-06-04 21:13     ` Paul Moore
2025-06-05  5:49       ` Mike Rapoport
2025-06-05 18:23         ` Paul Moore
2025-06-06 15:09           ` Ira Weiny [this message]
2025-06-16 13:00             ` Shivank Garg
2025-06-19  5:36               ` Mike Rapoport
2025-06-04  8:02   ` Christian Brauner
2025-06-02 19:17 ` [PATCH 2/2] KVM: guest_memfd: Use guest mem inodes instead of anonymous inodes Ackerley Tng
2025-06-02 20:13   ` David Hildenbrand

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