From debbugs-submit-bounces@debbugs.gnu.org Sun Aug 30 16:41:49 2020 Received: (at 43106) by debbugs.gnu.org; 30 Aug 2020 20:41:49 +0000 Received: from localhost ([127.0.0.1]:50836 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kCU8y-0006mN-Kx for submit@debbugs.gnu.org; Sun, 30 Aug 2020 16:41:49 -0400 Received: from eggs.gnu.org ([209.51.188.92]:36754) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kCU8t-0006m7-Hy for 43106@debbugs.gnu.org; Sun, 30 Aug 2020 16:41:39 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:44866) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kCU8o-0004FD-0h; Sun, 30 Aug 2020 16:41:30 -0400 Received: from [2001:980:1b4f:1:42d2:832d:bb59:862] (port=40166 helo=dundal.janneke.lilypond.org) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1kCU8n-0007dl-CT; Sun, 30 Aug 2020 16:41:29 -0400 From: Jan Nieuwenhuizen To: Ludovic =?utf-8?Q?Court=C3=A8s?= Subject: Re: [bug#43106] [PATCH] DRAFT services: childhurd: Support for setting secrets. Organization: AvatarAcademy.nl References: <20200829215726.3910-1-janneke@gnu.org> <87h7ski6zg.fsf@gnu.org> X-Url: http://AvatarAcademy.nl Date: Sun, 30 Aug 2020 22:41:24 +0200 In-Reply-To: <87h7ski6zg.fsf@gnu.org> ("Ludovic =?utf-8?Q?Court=C3=A8s=22'?= =?utf-8?Q?s?= message of "Sun, 30 Aug 2020 15:44:03 +0200") Message-ID: <87mu2buarv.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 43106 Cc: 43106@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -1.0 (-) --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Ludovic Court=C3=A8s writes: Hi! > "Jan (janneke) Nieuwenhuizen" skribis: >> >> +@example >> +/etc/childhurd/etc/guix/signing-key.pub >> +/etc/childhurd/etc/guix/signing-key.sec >> +/etc/childhurd/etc/ssh/ssh_host_ed25519_key >> +/etc/childhurd/etc/ssh/ssh_host_ecdsa_key >> +/etc/childhurd/etc/ssh/ssh_host_ed25519_key.pub >> +/etc/childhurd/etc/ssh/ssh_host_ecdsa_key.pub >> +@end example > > Would it make sense to have a list of source/target pairs instead of a > directory: > > (("/etc/childhurd/pubkey" . "/etc/guix/signing-key.pub") > =E2=80=A6) > > ? We could do that...I'm not opposed to it and in fact I thought about something like this but then opted for the file system root idea because I didn't see the need for adding this extra indirection. If you think it's a good idea, sure. Postponed that for now, though. >> + ;; #:use-module (ssh auth) >> + ;; #:use-module (ssh channel) >> + ;; #:use-module (ssh session) >> + ;; #:use-module (ssh sftp) >> + >> + #:autoload (ssh auth) (userauth-password!) > > You could add the file to MODULES_NOT_COMPILED in gnu/local.mk to avoid > the autoload dance. Ah, right, thanks, good to know. Following another path now, so I'm leaving this for a bit. >> +(define* (hurd-vm-copy-secrets port secret-root #:key (retry 20)) >> + "Copy all files under SECRET-ROOT using ssh to childhurd at local POR= T." >> + (format (current-error-port) "hurd-vm-copy-secrets\n") >> + (let ((session (make-session #:host "127.0.0.1" #:port port >> + #:user "root"))) > > I just realized that we have a bootstrapping issue here: we have to > explicitly skip SSH host authentication because we haven=E2=80=99t instal= led the > host keys yet. Right! Hmm... > The boot sequence of the guest is actually: generate SSH host keys, > start sshd, receive host keys over SFTP. > > [...] > >> - (start #~(make-forkexec-constructor #$vm-command)) >> + (requirement '(loopback networking user-processes)) >> + (start >> + (with-imported-modules (source-module-closure '((gnu build child= hurd) >> + (guix build util= s))) >> + (with-extensions (list guile-ssh) >> + #~(let ((spawn (make-forkexec-constructor #$vm-command))) >> + (use-modules (gnu build childhurd)) > > We should use the =E2=80=98modules=E2=80=99 field of i= nstead of a > non-top-level =E2=80=98use-modules=E2=80=99. OK, done. >> + (lambda _ >> + (let ((pid (spawn)) >> + (port #$(hurd-vm-port config %hurd-vm-ssh-port)) >> + (root #$(hurd-vm-configuration-secret-root config= ))) >> + (when (and root (directory-exists? root)) >> + (catch #t >> + (lambda _ >> + (hurd-vm-copy-secrets port root)) >> + (lambda (key . args) >> + (format (current-error-port) "childhurd: ~a ~s\= n" key args)))) > > To avoid race conditions, we probably have to wait until PORT becomes > available, no? Also, the VM boots even if we=E2=80=99ve failed to inject= the > secrets, right? Yes on both...that's a problem. > As discussed on IRC, attached is my attempt at addressing this problem: > the guest would run an activation snippet early on to receive secret > files over raw unauthenticated TCP, blocking until it has received them. > What=E2=80=99s missing from this patch is the host side that actually con= nects > to the guest and sends this file. Okay. > I think it has the advantage of failing in case the secrets haven=E2=80= =99t been > installed and it avoids the SSH host key bootstrapping issue. (It has > at least the disadvantage of not being fully implemented. :-)) Also, > longer term, it would allow us to not force password-less root > authentication in the VM. > > I=E2=80=99m tempted to go the raw TCP way; WDYT? We can pair-hack on it = if you > feel like it! That would be great. I'm attaching a new iteration of our combined work Using client.scm: --8<---------------cut here---------------start------------->8--- (use-modules (gnu build secret-service)) (hurd-vm-secret-service-copy-secrets 5999 "/home/janneke/var/geert/childhur= d") --8<---------------cut here---------------end--------------->8--- and (cutting the body of secret-service-activation to) server.scm: --8<---------------cut here---------------start------------->8--- (use-modules (ice-9 match) (guix build utils) (rnrs bytevectors) (ice-9 binary-ports)) [...] (define (wait-for-client port) (let ((port (wait-for-client 5999))) (read-secrets port) (close-port port)) --8<---------------cut here---------------end--------------->8--- this actually copies files...However, the secret-service does not build: --8<---------------cut here---------------start------------->8--- $ ./pre-inst-env guix system disk-image gnu/system/examples/bare-hurd.tmpl guix system: error: reference to invalid output 'out' of derivation '/gnu/s= tore/189x9ph3piyihbs6asnjkinc5qqwfw1h-secret-service-client.drv' [1]22:40:08 janneke@dundal:~/src/guix/master [env] --8<---------------cut here---------------end--------------->8--- ...it seems we're missing something obvious. Thanks, Janneke --=-=-= Content-Type: text/x-patch; charset=utf-8 Content-Disposition: inline; filename=v2-0001-DRAFT-services-Add-secret-service-type.patch Content-Transfer-Encoding: quoted-printable From 7c2523a6b25ec28539d3476bdc57d29db85bcbae Mon Sep 17 00:00:00 2001 From: "Jan (janneke) Nieuwenhuizen" Date: Sat, 29 Aug 2020 23:14:59 +0200 Subject: [PATCH v2] DRAFT services: Add secret-service-type. MIME-Version: 1.0 Content-Type: text/plain; charset=3DUTF-8 Content-Transfer-Encoding: 8bit Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=3DUTF-8 TODO: $ ./pre-inst-env guix system disk-image gnu/system/examples/bare-hurd.tmpl guix system: error: reference to invalid output 'out' of derivation '/gnu/s= tore/189x9ph3piyihbs6asnjkinc5qqwfw1h-secret-service-client.drv' * split in two? * switch ownership/co-authorship? co-authored-by: Ludovic Court=C3=A8s * gnu/build/secret-service.scm: New file. * gnu/local.mk (GNU_SYSTEM_MODULES): Add it. * gnu/services/virtualization.scm (hurd-vm-shepherd-service): Use it to copy secrets. (hurd-vm-port): New function. (hurd-vm-net-options): Use it. (secret-service-activation): New procedure. (secret-service-type): New variable. (%hurd-vm-operating-system): Add it. * gnu/system/examples/bare-hurd.tmpl (%hurd-os): Add it. * doc/guix.texi (The Hurd in a Virtual Machine): Document it. --- doc/guix.texi | 19 ++++ gnu/build/secret-service.scm | 68 +++++++++++++ gnu/local.mk | 1 + gnu/services/virtualization.scm | 151 ++++++++++++++++++++++++++--- gnu/system/examples/bare-hurd.tmpl | 20 ++-- 5 files changed, 238 insertions(+), 21 deletions(-) create mode 100644 gnu/build/secret-service.scm diff --git a/doc/guix.texi b/doc/guix.texi index 6206a93857..f8e03242b2 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -25119,6 +25119,7 @@ Return the name of @var{platform}---a string such a= s @code{"arm"}. =20 @cindex @code{hurd} @cindex the Hurd +@cindex childhurd =20 Service @code{hurd-vm} provides support for running GNU/Hurd in a virtual machine (VM), a so-called ``Childhurd''. The virtual machine is @@ -25200,6 +25201,24 @@ with forwarded ports : @code{(+ 15900 (* 1000 @var{ID}))} @end example =20 +@item @code{secret-root} (default: @code{#f}) +If set, the root directory with out-of-band secrets to be injected into +the childhurd once it runs. Childhurds are volatile which means that on +every startup, secrets such as the SSH host keys and Guix signing key +are recreated. + +Typical use is setting @code{secret-root} to @code{"/etc/childhurd"} +pointing at a tree of non-volatile secrets like so + +@example +/etc/childhurd/etc/guix/signing-key.pub +/etc/childhurd/etc/guix/signing-key.sec +/etc/childhurd/etc/ssh/ssh_host_ed25519_key +/etc/childhurd/etc/ssh/ssh_host_ecdsa_key +/etc/childhurd/etc/ssh/ssh_host_ed25519_key.pub +/etc/childhurd/etc/ssh/ssh_host_ecdsa_key.pub +@end example + @end table @end deftp =20 diff --git a/gnu/build/secret-service.scm b/gnu/build/secret-service.scm new file mode 100644 index 0000000000..fc817f8c5c --- /dev/null +++ b/gnu/build/secret-service.scm @@ -0,0 +1,68 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright =C2=A9 2020 Jan (janneke) Nieuwenhuizen +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix is free software; you can redistribute it and/or modify it +;;; under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3 of the License, or (at +;;; your option) any later version. +;;; +;;; GNU Guix is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Guix. If not, see . + +(define-module (gnu build secret-service) + #:use-module (srfi srfi-26) + #:use-module (ice-9 rdelim) + #:use-module (guix build utils) + + #:export (hurd-vm-secret-service-copy-secrets)) + +;;; Commentary: +;;; +;;; Utility procedures for copying secrets into a VM. +;;; +;;; Code: + +(define* (hurd-vm-secret-service-copy-secrets port secret-root #:key (retr= y 20)) + "Copy all files under SECRET-ROOT using TCP to secret-service listening = at +local PORT." + + (define (file->file+size+mode file-name) + (let ((stat (stat file-name)) + (target (substring file-name (string-length secret-root)))) + (list target (stat:size stat) (stat:mode stat)))) + + (format (current-error-port) "hurd-vm-secret-service-copy-secrets\n") + + (let ((sock (socket AF_INET SOCK_STREAM 0)) + (addr (make-socket-address AF_INET INADDR_LOOPBACK port))) + ;; connect to wait for port + (let loop ((retry retry)) + (if (zero? retry) + (error "connecting to childhurd failed") + (catch 'system-error + (lambda _ + (connect sock addr)) + (lambda (key . args) + (format (current-error-port) "connect failed: ~a ~s\n" key a= rgs) + (sleep 1) + (loop (1- retry)))))) + (format (current-error-port) "connected!\n") + ;; copy tree + (let* ((files (find-files secret-root)) + (files-sizes-modes (map file->file+size+mode files)) + (secrets `(secrets + (version 0) + (files ,files-sizes-modes)))) + (write secrets sock) + (for-each (compose (cute display <> sock) + (cute with-input-from-file <> read-string)) + files)))) + +;;; secret-service.scm ends here diff --git a/gnu/local.mk b/gnu/local.mk index 8854698178..1d8022fd11 100644 --- a/gnu/local.mk +++ b/gnu/local.mk @@ -659,6 +659,7 @@ GNU_SYSTEM_MODULES =3D \ %D%/build/linux-initrd.scm \ %D%/build/linux-modules.scm \ %D%/build/marionette.scm \ + %D%/build/secret-service.scm \ %D%/build/vm.scm \ \ %D%/tests.scm \ diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.= scm index b93ed70099..aa9b06f74b 100644 --- a/gnu/services/virtualization.scm +++ b/gnu/services/virtualization.scm @@ -1,6 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright =C2=A9 2017 Ryan Moe -;;; Copyright =C2=A9 2018 Ludovic Court=C3=A8s +;;; Copyright =C2=A9 2018, 2020 Ludovic Court=C3=A8s ;;; Copyright =C2=A9 2020 Jan (janneke) Nieuwenhuizen ;;; ;;; This file is part of GNU Guix. @@ -39,6 +39,7 @@ #:use-module (gnu system) #:use-module (guix derivations) #:use-module (guix gexp) + #:use-module (guix modules) #:use-module (guix monads) #:use-module (guix packages) #:use-module (guix records) @@ -48,6 +49,7 @@ #:use-module (srfi srfi-9) #:use-module (srfi srfi-26) #:use-module (rnrs bytevectors) + #:use-module (ice-9 binary-ports) #:use-module (ice-9 match) =20 #:export (%hurd-vm-operating-system @@ -61,7 +63,10 @@ hurd-vm-configuration-options hurd-vm-configuration-id hurd-vm-configuration-net-options + hurd-vm-configuration-secrets + hurd-vm-disk-image + hurd-vm-port hurd-vm-net-options hurd-vm-service-type =20 @@ -804,6 +809,94 @@ given QEMU package." compiled for other architectures using QEMU and the @code{binfmt_misc} functionality of the kernel Linux."))) =20 + +;;; +;;; Secrets for guest VMs. +;;; + +(define (secret-service-activation port) + "Return an activation snippet that fetches sensitive material at PORT, o= ver +TCP." + (define install-secrets + (with-imported-modules '((guix build utils)) + #~(begin + (use-modules (guix build utils) + (rnrs io ports) + (rnrs bytevectors) + (ice-9 match)) + + (define (wait-for-client port) + ;; Wait for a TCP connection on PORT. Note: We cannot use the + ;; virtio-serial ports, which would be safer, because they are + ;; (presumably) unsupported on GNU/Hurd. + (let ((sock (socket AF_INET SOCK_STREAM 0))) + (bind sock AF_INET INADDR_ANY port) + (listen sock 1) + (format (current-error-port) + "waiting for secrets on port ~a...~%" + port) + (match (accept sock) + ((client . address) + (format (current-error-port) "client connection from ~a~%" + (inet-ntop (sockaddr:fam address) + (sockaddr:addr address))) + (close-port sock) + client)))) + + ;; TODO: Remove when (@ (guix build utils) dump-port) has a 'siz= e' + ;; parameter. + (define (dump in out size) + ;; Copy SIZE bytes from IN to OUT. + (define buf-size 65536) + (define buf (make-bytevector buf-size)) + + (let loop ((left size)) + (if (<=3D left 0) + 0 + (let ((read (get-bytevector-n! in buf 0 (min left buf-si= ze)))) + (if (eof-object? read) + left + (begin + (put-bytevector out buf 0 read) + (loop (- left read)))))))) + + (define (read-secrets port) + ;; Read secret files from PORT and install them. + (match (false-if-exception (read port)) + (('secrets ('version 0) + ('files ((files sizes modes) ...))) + (for-each (lambda (file size mode) + (format (current-error-port) + "installing file '~a' (~a bytes)...~%" + file size) + (mkdir-p (dirname file)) + (call-with-output-file file + (lambda (output) + (dump port output size) + (chmod file mode)))) + files sizes modes)) + (_ + (format (current-error-port) + "invalid secrets received~%") + (sleep 3) + (reboot)))) + + (let ((port (wait-for-client #$port))) + (read-secrets port) + (close-port port))))) + + (computed-file "secret-service-client" install-secrets)) + +(define secret-service-type + (service-type + (name 'secret-service) + (extensions (list (service-extension activation-service-type + secret-service-activation))) + (description + "This service fetches secret key and other sensitive material over TCP= at +boot time. This service is meant to be used by virtual machines (VMs) that +can only be accessed by their host."))) + ;;; ;;; The Hurd in VM service: a Childhurd. @@ -819,6 +912,8 @@ functionality of the kernel Linux."))) (target "/dev/vda") (timeout 0))) (services (cons* + ;; Receive secret keys on port 5999, TCP. + (service secret-service-type 5999) (service openssh-service-type (openssh-configuration (openssh openssh-sans-x) @@ -849,7 +944,9 @@ functionality of the kernel Linux."))) (default #f)) (net-options hurd-vm-configuration-net-options ;list of string (thunked) - (default (hurd-vm-net-options this-record)))) + (default (hurd-vm-net-options this-record))) + (secret-root hurd-vm-configuration-secret-root ;#f or string + (default #f))) =20 (define (hurd-vm-disk-image config) "Return a disk-image for the Hurd according to CONFIG." @@ -861,15 +958,27 @@ functionality of the kernel Linux."))) (size disk-size) (operating-system os))))) =20 -(define (hurd-vm-net-options config) +(define (hurd-vm-port config base) + "Return the forwarded vm port for this childhurd config." (let ((id (or (hurd-vm-configuration-id config) 0))) - (define (qemu-vm-port base) - (number->string (+ base (* 1000 id)))) - `("--device" "rtl8139,netdev=3Dnet0" - "--netdev" ,(string-append - "user,id=3Dnet0" - ",hostfwd=3Dtcp:127.0.0.1:" (qemu-vm-port 10022) "-:222= 2" - ",hostfwd=3Dtcp:127.0.0.1:" (qemu-vm-port 15900) "-:590= 0")))) + (+ base (* 1000 id)))) +(define %hurd-vm-secrets-port 15999) +(define %hurd-vm-ssh-port 10022) +(define %hurd-vm-vnc-port 15900) + +(define (hurd-vm-net-options config) + `("--device" "rtl8139,netdev=3Dnet0" + "--netdev" + ,(string-append "user,id=3Dnet0" + ",hostfwd=3Dtcp:127.0.0.1:" + (number->string (hurd-vm-port config %hurd-vm-secrets-= port)) + "-:5999" + ",hostfwd=3Dtcp:127.0.0.1:" + (number->string (hurd-vm-port config %hurd-vm-ssh-port= )) + "-:2222" + ",hostfwd=3Dtcp:127.0.0.1:" + (number->string (hurd-vm-port config %hurd-vm-vnc-port= )) + "-:5900"))) =20 (define (hurd-vm-shepherd-service config) "Return a for a Hurd in a Virtual Machine with CONFIG= ." @@ -900,8 +1009,26 @@ functionality of the kernel Linux."))) (string->symbol (number->string id))) provisions) provisions)) - (requirement '(networking)) - (start #~(make-forkexec-constructor #$vm-command)) + (requirement '(loopback networking user-processes)) + (start + (with-imported-modules (source-module-closure '((gnu build secret-s= ervice) + (guix build utils))) + (with-extensions (list guile-ssh) + #~(let ((spawn (make-forkexec-constructor #$vm-command))) + (lambda _ + (let ((pid (spawn)) + (port #$(hurd-vm-port config %hurd-vm-secrets-port)) + (root #$(hurd-vm-configuration-secret-root config))) + (when (and root (directory-exists? root)) + (catch #t + (lambda _ + (hurd-vm-secret-service-copy-secrets port root)) + (lambda (key . args) + (format (current-error-port) "childhurd: ~a ~s\n" = key args)))) + pid)))))) + (modules `((gnu build secret-service) + (guix build utils) + ,@%default-modules)) (stop #~(make-kill-destructor)))))) =20 (define hurd-vm-service-type diff --git a/gnu/system/examples/bare-hurd.tmpl b/gnu/system/examples/bare-= hurd.tmpl index 414a9379c8..2d00a7c8bb 100644 --- a/gnu/system/examples/bare-hurd.tmpl +++ b/gnu/system/examples/bare-hurd.tmpl @@ -41,14 +41,16 @@ (host-name "guixygnu") (timezone "Europe/Amsterdam") (packages (cons openssh-sans-x %base-packages/hurd)) - (services (cons (service openssh-service-type - (openssh-configuration - (openssh openssh-sans-x) - (use-pam? #f) - (port-number 2222) - (permit-root-login #t) - (allow-empty-passwords? #t) - (password-authentication? #t))) - %base-services/hurd)))) + (services (append (list (service openssh-service-type + (openssh-configuration + (openssh openssh-sans-x) + (use-pam? #f) + (port-number 2222) + (permit-root-login #t) + (allow-empty-passwords? #t) + (password-authentication? #t))) + (service (@@ (gnu services virtualization) + secret-service-type) 5999)) + %base-services/hurd)))) =20 %hurd-os --=20 Jan Nieuwenhuizen | GNU LilyPond http://lilypond.org Freelance IT http://JoyofSource.com | Avatar=C2=AE http://AvatarAcademy.com --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable --=20 Jan Nieuwenhuizen | GNU LilyPond http://lilypond.org Freelance IT http://JoyofSource.com | Avatar=C2=AE http://AvatarAcademy.com --=-=-=--