From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 485CE2D9499; Tue, 3 Feb 2026 08:32:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770107537; cv=none; b=LB/arjcce2oUa4E8MiHWRJ44aXvHJEuloTJWK7mp9nnhIboANJN9KoNx0Mq9bZntBCje2ADbd0yjDG0LEO7bL5lnewR4VAlPZ1HrHAnfFgyQMDq+LiXmSvYZLEFkjHsA4iJEZUYo8gZl3OUlL9UHda+INmMAIZXep52Zlp3rLb4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770107537; c=relaxed/simple; bh=AaGvZ6MNlA5k2IKQAdwa/l89TAkY8OiHHDWQNGJqX7I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OUC39fU6bLI4rK8vpEQoqWmprNDhRmgxf3pnL8H56H9UHyuNZI7MJxyAK0yXOE+Iy/rJlDVVxkUn2qinN6ONLX48B5XyHiGa4TS98eW8AI7diQAXVI3wtAzNYQe1W2WTqiPfFmoo4k4/Qp7xyJidV8LkVLTUaEfT+b8rruuhNuI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QyXvwaCP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QyXvwaCP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2ABAFC116D0; Tue, 3 Feb 2026 08:32:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770107536; bh=AaGvZ6MNlA5k2IKQAdwa/l89TAkY8OiHHDWQNGJqX7I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QyXvwaCP/7sk7pWDMaymAVGUrldlKJTszeoHZ/hWPQz+6Z0VXYu9Kv8Cqa8hXA5uL bLnGiBl4gjVX9HDs/+N9O0dEkEn2rz9ij9HSMH6dRWOk+EJRQzaggf6/GC8Arkx8F3 jidlSYKpXpy+GjnWnSB0SKpovh37tvdKLJtzH+FEc6Ef5lDCZQZyJau7+j+b1u0fLD ECoXIPoRRFbBglffufP8QQWA4uZnYSdFi8uE5C2YflPWL5ae2eQpnkSzkf78PVAFte kaK5Urgrf2qxyjCIgmCaaKlxQIYiDSHzY62exYnAqwhqh4MtBGUaLriT5rpfxewb+U /T0PTTw9D7wKA== Date: Tue, 3 Feb 2026 10:32:12 +0200 From: Jarkko Sakkinen To: linux-media@vger.kernel.org Cc: jani.nikula@linux.intel.com, anisse@astier.eu, oleksandr@natalenko.name, linux-integrity@vger.kernel.org, Mauro Carvalho Chehab , Hans Verkuil , Laurent Pinchart , Sakari Ailus , Jacopo Mondi , Ricardo Ribalda , open list Subject: Re: [RFC PATCH v2] media: Virtual camera driver Message-ID: References: <20260202204425.2614054-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Feb 03, 2026 at 10:09:25AM +0200, Jarkko Sakkinen wrote: > On Mon, Feb 02, 2026 at 10:44:21PM +0200, Jarkko Sakkinen wrote: > > Already a quick Google survey backs strongly that OOT drivers (e.g., > > v4l2loopback) are the defacto solution for streaming phone cameras in > > video conference calls, which puts confidential discussions at risk. > > > > It can be also claimed that there's enough OOT usage in the wild that > > possible security bugs could be considered as potential zerodays for the > > benefit of malicious actors. > > > > The situation has been stagnated for however many years, which is > > unsastainable situation, and it further factors potential security > > risks. Therefore, a driver is needed to address the popular use case. > > > > vcam is a DMA-BUF backed virtual camera driver capable of creating video > > capture devices to which data can be streamed through /dev/vcam after > > calling VCAM_IOC_CREATE. Frames are pushed with VCAM_IOC_QUEUE and recycled > > with VCAM_IOC_DEQUEUE. Zero-copy semantics are supported for shared DMA-BUF > > between capture and output. > > > > This enables efficient implementation of software, which can manage network > > video streams from phone cameras, and map those streams to video devices. > > > > PipeWire or any other specific pick of userspace software cannot really > > address the issue at scale, as e.g., the use of v4l2loopback is both wide > > and scattered. > > > > Signed-off-by: Jarkko Sakkinen > > After learning a bit more about the topic and for future updates I will > drop YUYV. NV12, MJPEG, and additionally RGBX32 and XRGB32 for testing > and GPUs define pretty well the requirements for a software define device, > and limit the applicability of "proprietary risk" (as that was the main > concern raised). I honestly did not have idea what would be an > appropriate subset of formats to constraint the driver initially. > > In addition, a better name for this module would probably be swcam as it > does not mix up with those pre-existing devices starting with the > letter 'v'. In addition to phones, there's also category of devices called IP cameras, and managing them ubiquitos to other camera device is a convenience to say the least. And when it comes to pure testing, not all testing where V4L2 is involved is neither about simulating V4L2 hardware nor centered around V4L2 as a topic. It could be e.g., embedded system testing where you want to mock the cameras with simulated content in software only testing (QEMU has V4L2 passthrough) BR, Jarkko