Hello Mark, Our security team was very concerned about the old ALSA FD. It provided too much access to the guts of ALSA. I assume they will not like anything other than a plain "anon_inode:dmabuf". If it is a new FD, then the code would have to be reviewed. Even if it looked OK there might be some holes that we don't find. So it would probably be rejected. I cannot speak for our security team so I am working on setting up a meeting or conversation between Mark and Zach, our security expert. Adding the anon_inode:snd-pcm might be great for ALSA. That could be used by the HAL for STATUS and CONTROL. But it is likely that we will need an additional anon_inode:dmabuf FD that is only associated with the PCM buffer. It can then be safely passed to an Android app. Thanks, Phil Burk On Wed, Jan 30, 2019 at 2:32 PM Mark Brown <broonie@xxxxxxxxxx> wrote: > On Wed, Jan 30, 2019 at 01:41:37PM +0100, Jaroslav Kysela wrote: > > This patchset contains the anonymous dup implementation with permissions > > checking for the ALSA's PCM interface in kernel to enable the restricted > > DMA sound buffer sharing for the restricted tasks. > > > > The code was tested through qemu and it seems to be pretty stable. > > > > The initial tinyalsa implementation can be found here: > > > > https://github.com/perexg/tinyalsa/commits/anondup > > > > The filtering might be refined. It depends on the real requirements. > > Perhaps, we may create more ioctl groups. Any comments are more than > > welcome. > > My understanding based on some off-list discussion is that the Android > security people are going to see anything that involves passing more > than a block of memory (and in particular anything that gives access to > the sound APIs) as a problem. That's obviously going to be an issue for > anything O_APPEND based. My understanding is that this is fundamentally > a risk mitigation thing - by not having any of the sound kernel > interfaces available to the applications affected there's no possibility > that any problems in the sound code can cause security issues. > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
