From patchwork Wed Aug 12 09:41:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?C=C3=A9sar_Belley?= X-Patchwork-Id: 276708 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76569C433DF for ; Wed, 12 Aug 2020 09:43:54 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FC0C2076B for ; Wed, 12 Aug 2020 09:43:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=lse.epita.fr header.i=@lse.epita.fr header.b="Xlvk/cTH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FC0C2076B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lse.epita.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58928 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k5nIX-0003V1-Dq for qemu-devel@archiver.kernel.org; Wed, 12 Aug 2020 05:43:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42258) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5nHS-00022d-EK for qemu-devel@nongnu.org; Wed, 12 Aug 2020 05:42:46 -0400 Received: from gate-2.cri.epita.net ([163.5.55.20]:40864 helo=mail-2.srv.cri.epita.fr) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5nHQ-0006kH-BE for qemu-devel@nongnu.org; Wed, 12 Aug 2020 05:42:46 -0400 Received: from MattGorko-Laptop.localdomain (unknown [78.194.154.81]) (Authenticated sender: cesar.belley) by mail-2.srv.cri.epita.fr (Postfix) with ESMTPSA id 2C5DB4150B; Wed, 12 Aug 2020 11:42:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=lse.epita.fr; s=cri; t=1597225363; bh=mXjkHDuBA2Pelp7FvLqsvotpGAVI+Oj+eqQ5xB79ZVs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xlvk/cTHYNzxQP3ZauXx6odIb4WJK1dEADQYWb2ITyIx/IFc5D4ykBSfsvlDiCVW9 oVwhyNA36YMPx2C6hP5DgyD+zt+vB34o89QnPUByTIbKC3D7etpB+CFRN14WQVb5td 7T3XiDtAgCBFcqD984xK7idOaQiEco/ZlRiXWWT8= From: =?utf-8?q?C=C3=A9sar_Belley?= To: qemu-devel@nongnu.org Subject: [PATCH 02/13] docs: Add USB U2F key device documentation Date: Wed, 12 Aug 2020 11:41:24 +0200 Message-Id: <20200812094135.20550-3-cesar.belley@lse.epita.fr> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200812094135.20550-1-cesar.belley@lse.epita.fr> References: <20200812094135.20550-1-cesar.belley@lse.epita.fr> MIME-Version: 1.0 Received-SPF: pass client-ip=163.5.55.20; envelope-from=srs0=nna4=bw=lse.epita.fr=cesar.belley@cri.epita.fr; helo=mail-2.srv.cri.epita.fr X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/12 05:42:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?q?C=C3=A9sar_Belley?= , kraxel@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add USB U2F key device documentation: - USB U2F key device - Building - Using u2f-emulated - Using u2f-passthru - Libu2f-emu Signed-off-by: César Belley --- docs/u2f.txt | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 docs/u2f.txt diff --git a/docs/u2f.txt b/docs/u2f.txt new file mode 100644 index 0000000000..f60052882e --- /dev/null +++ b/docs/u2f.txt @@ -0,0 +1,101 @@ +QEMU U2F Key Device Documentation. + +Contents +1. USB U2F key device +2. Building +3. Using u2f-emulated +4. Using u2f-passthru +5. Libu2f-emu + +1. USB U2F key device + +U2F is an open authentication standard that enables relying parties +exposed to the internet to offer a strong second factor option for end +user authentication. + +The standard brings many advantages to both parties, client and server, +allowing to reduce over-reliance on passwords, it increases authentication +security and simplifies passwords. + +The second factor is materialized by a device implementing the U2F +protocol. In case of a USB U2F security key, it is a USB HID device +that implements the U2F protocol. + +In Qemu, the USB U2F key device offers a dedicated support of U2F, allowing +guest USB FIDO/U2F security keys operating in two possible modes: +pass-through and emulated. + +The pass-through mode consists of passing all requests made from the guest +to the physical security key connected to the host machine and vice versa. +In addition, the dedicated pass-through allows to have a U2F security key +shared on several guests which is not possible with a simple host device +assignment pass-through. + +The emulated mode consists of completely emulating the behavior of an +U2F device through software part. Libu2f-emu is used for that. + + +2. Building + +To ensure the build of the u2f-emulated device variant which depends +on libu2f-emu: configuring and building: + + ./configure --enable-u2f && make + + +3. Using u2f-emulated + +To work, an emulated U2F device must have four elements: + * ec x509 certificate + * ec private key + * counter (four bytes value) + * 48 bytes of entropy (random bits) + +To use this type of device, this one has to be configured, and these +four elements must be passed one way or another. + +Assuming that you have a working libu2f-emu installed on the host. +There are three possible ways of configurations: + * ephemeral + * setup directory + * manual + +Ephemeral is the simplest way to configure, it lets the device generate +all the elements it needs for a single use of the lifetime of the device. + + qemu -usb -device u2f-emulated + +Setup directory allows to configure the device from a directory containing +four files: + * certificate.pem: ec x509 certificate + * private-key.pem: ec private key + * counter: counter value + * entropy: 48 bytes of entropy + + qemu -usb -device u2f-emulated,dir=$dir + +Manual allows to configure the device more finely by specifying each +of the elements necessary for the device: + * cert + * priv + * counter + * entropy + + qemu -usb -device u2f-emulated,cert=$DIR1/$FILE1,priv=$DIR2/$FILE2,counter=$DIR3/$FILE3,entropy=$DIR4/$FILE4 + + +4. Using u2f-passthru + +On the host specify the u2f-passthru device with a suitable hidraw: + + qemu -usb -device u2f-passthru,hidraw=/dev/hidraw0 + + +5. Libu2f-emu + +The u2f-emulated device uses libu2f-emu for the U2F key emulation. Libu2f-emu +implements completely the U2F protocol device part for all specified +transport given by the FIDO Alliance. + +For more information about libu2f-emu see this page: +https://github.com/MattGorko/libu2f-emu.