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| | ;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; 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 <http://www.gnu.org/licenses/>.
(define-module (gnu build secret-service)
#:use-module (guix build utils)
#:use-module (srfi srfi-26)
#:use-module (rnrs bytevectors)
#:use-module (ice-9 binary-ports)
#:use-module (ice-9 match)
#:use-module (ice-9 rdelim)
#:export (secret-service-receive-secrets
secret-service-send-secrets))
;;; Commentary:
;;;
;;; Utility procedures for copying secrets into a VM.
;;;
;;; Code:
(define* (secret-service-send-secrets port secret-root #:key (retry 60))
"Copy all files under SECRET-ROOT using TCP to secret-service listening at
local PORT. If connect fails, sleep 1s and retry RETRY times."
(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) "sending secrets to ~a~%" port)
(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))
(catch 'system-error
(cute connect sock addr)
(lambda (key . args)
(when (zero? retry)
(apply throw key args))
(format (current-error-port)
"secret service: retrying connection [~a attempts left]~%"
(- retry 1))
(sleep 1)
(loop (1- retry)))))
(format (current-error-port)
"secret service: connected; sending files in ~s~%"
secret-root)
(let* ((files (if secret-root (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 dump-port <> sock)
(cute open-input-file <>))
files))))
(define (secret-service-receive-secrets port)
"Listen to local PORT and wait for a secret service client to send secrets.
Write them to the file system. Return the list of files installed on success,
and #f otherwise."
(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)
"secret service: waiting for secrets on port ~a...~%"
port)
(match (select (list sock) '() '() 60)
(((_) () ())
(match (accept sock)
((client . address)
(format (current-error-port)
"secret service: client connection from ~a~%"
(inet-ntop (sockaddr:fam address)
(sockaddr:addr address)))
(close-port sock)
client)))
((() () ())
(format (current-error-port)
"secret service: did not receive any secrets; time out~%")
#f))))
;; TODO: Remove when (@ (guix build utils) dump-port) has a 'size'
;; 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 (<= left 0)
0
(let ((read (get-bytevector-n! in buf 0 (min left buf-size))))
(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)
"secret service: \
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)
files)
(_
(format (current-error-port)
"secret service: invalid secrets received~%")
#f)))
(let* ((port (wait-for-client port))
(result (and=> port read-secrets)))
(when port
(close-port port))
result))
;;; secret-service.scm ends here
|