Re: [RFC PATCH] ALSA: core: Add DMA share buffer support

[Mark Brown <broonie@kernel.org>]

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On Fri, Jan 18, 2019 at 08:39:32PM +0100, Takashi Iwai wrote:
> Mark Brown wrote:

> > > multiple tasks). I would probably go in this way and add more extended
> > > permission control for the PCM device, so permissions can be restricted
> > > for the passed descriptor to the producer or the consumer task. In this

> > One concern I have with doing some ALSA-specific custom permissions
> > thing is integration with frameworks like SELinux (they'd presumably
> > need to learn about the ALSA specific stuff to manage it).  It also

> Well, I wonder what makes it more difficult by the approach Jaroslav
> suggested.  With O_APPEND, you can just call mmap() normally, and
> that's all. What's the merit of dma-buf approach wrt the security?

It was the bit about adding more extended permission control that I was
worried about there, not the initial O_APPEND bit.  Indeed the O_APPEND
bit sounds like it might also work from the base buffer sharing point of
view, I have to confess I'd not heard of that feature before (it didn't
come up in the discussion when Eric raised this in Prague).

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