From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54496) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBJCZ-0005lV-0J for qemu-devel@nongnu.org; Mon, 28 Nov 2016 05:30:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cBJCU-0002cc-P4 for qemu-devel@nongnu.org; Mon, 28 Nov 2016 05:30:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36954) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cBJCU-0002bk-Iy for qemu-devel@nongnu.org; Mon, 28 Nov 2016 05:30:18 -0500 Message-ID: <1480329014.20061.57.camel@redhat.com> From: Gerd Hoffmann Date: Mon, 28 Nov 2016 11:30:14 +0100 In-Reply-To: <290015b23a9ec5033ee65209882dcbc0@openmailbox.org> References: <290015b23a9ec5033ee65209882dcbc0@openmailbox.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Subject: Re: [Qemu-devel] QEMU soundcards vulnerable to jack retasking? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: bancfc@openmailbox.org Cc: qemu-devel@nongnu.org On Fr, 2016-11-25 at 21:25 +0100, bancfc@openmailbox.org wrote: > Recent security research shows that soundcards support surreptitiously= =20 > switching line-out jacks into line-in by modifying the software stack.= =20 > The way modern speakers and headphones are designed makes them readily= =20 > usable as microphones. The Intel High Definition (HD) Audio standards=20 > which all modern consumer soundcards are based mandates this stupidity. >=20 > https://arxiv.org/ftp/arxiv/papers/1611/1611.07350.pdf >=20 > Does anyone know if QEMU's emulated sound devices follow this standard?= =20 No. Output line is output only and input line is input only, period. There are three qemu hda codecs available: hda-output only playback (line-out). No way the guest can record anything. hda-duplex record (line-in) and playback (line-out). Use that if you need sound recording in the guest. hda-micro record (micro) and playback (speaker). Same as hda-duplex, except that the record and playback channels are tagged differently. Use that if your guests app is picky and refuses to record from line-in. Where the data for the record channel comes from is subject to host configuration. On a typical linux system it'll probably being pulseaudio, either directly or indirectly (via spice). cheers, Gerd