* gnu/build/chromium-extension.scm: New file. * gnu/local.mk (GNU_SYSTEM_MODULES): Adjust accordingly.
		
			
				
	
	
		
			192 lines
		
	
	
	
		
			8.1 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
			
		
		
	
	
			192 lines
		
	
	
	
		
			8.1 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
| ;;; GNU Guix --- Functional package management for GNU
 | |
| ;;; Copyright © 2020 Marius Bakke <marius@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 chromium-extension)
 | |
|   #:use-module (gcrypt base16)
 | |
|   #:use-module ((gcrypt hash) #:prefix hash:)
 | |
|   #:use-module (ice-9 iconv)
 | |
|   #:use-module (guix gexp)
 | |
|   #:use-module (guix packages)
 | |
|   #:use-module (gnu packages base)
 | |
|   #:use-module (gnu packages check)
 | |
|   #:use-module (gnu packages chromium)
 | |
|   #:use-module (gnu packages gnupg)
 | |
|   #:use-module (gnu packages tls)
 | |
|   #:use-module (gnu packages xorg)
 | |
|   #:use-module (guix build-system trivial)
 | |
|   #:export (make-chromium-extension))
 | |
| 
 | |
| ;;; Commentary:
 | |
| ;;;
 | |
| ;;; Tools to deal with Chromium extensions.
 | |
| ;;;
 | |
| ;;; Code:
 | |
| 
 | |
| (define (make-signing-key seed)
 | |
|   "Return a derivation for a deterministic PKCS #8 private key using SEED."
 | |
| 
 | |
|   (define sha256sum
 | |
|     (bytevector->base16-string (hash:sha256 (string->bytevector seed "UTF-8"))))
 | |
| 
 | |
|   ;; certtool.c wants a 56 byte seed for a 2048 bit key.
 | |
|   (define size 2048)
 | |
|   (define normalized-seed (string-take sha256sum 56))
 | |
| 
 | |
|   (computed-file (string-append seed "-signing-key.pem")
 | |
|                  #~(system* #$(file-append gnutls "/bin/certtool")
 | |
|                             "--generate-privkey"
 | |
|                             "--key-type=rsa"
 | |
|                             "--pkcs8"
 | |
|                             ;; Use the provable FIPS-PUB186-4 algorithm for
 | |
|                             ;; deterministic results.
 | |
|                             "--provable"
 | |
|                             "--password="
 | |
|                             "--no-text"
 | |
|                             (string-append "--bits=" #$(number->string size))
 | |
|                             (string-append "--seed=" #$normalized-seed)
 | |
|                             "--outfile" #$output)
 | |
|                  #:local-build? #t))
 | |
| 
 | |
| (define* (make-crx signing-key package #:optional (package-output "out"))
 | |
|   "Create a signed \".crx\" file from the unpacked Chromium extension residing
 | |
| in PACKAGE-OUTPUT of PACKAGE.  The extension will be signed with SIGNING-KEY."
 | |
|   (define name (package-name package))
 | |
|   (define version (package-version package))
 | |
| 
 | |
|   (with-imported-modules '((guix build utils))
 | |
|     (computed-file
 | |
|      (string-append name "-" version ".crx")
 | |
|      #~(begin
 | |
|          ;; This is not great.  We pull Xorg and Chromium just to Zip and
 | |
|          ;; sign an extension.  This should be implemented with something
 | |
|          ;; lighter.  (TODO: where is the CRXv3 documentation..?)
 | |
|          (use-modules (guix build utils))
 | |
|          (let ((chromium #$(file-append ungoogled-chromium "/bin/chromium"))
 | |
|                (xvfb #$(file-append xorg-server "/bin/Xvfb"))
 | |
|                (packdir "/tmp/extension"))
 | |
|            (mkdir-p (dirname packdir))
 | |
|            (copy-recursively (ungexp package package-output) packdir)
 | |
|            (system (string-append xvfb " :1 &"))
 | |
|            (setenv "DISPLAY" ":1")
 | |
|            (sleep 2)                    ;give Xorg some time to initialize...
 | |
|            ;; Chromium stores the current time in the .crx Zip archive.
 | |
|            ;; Use a fixed timestamp for deterministic behavior.
 | |
|            ;; FIXME (core-updates): faketime is missing an absolute reference
 | |
|            ;; to 'date', hence the need to set PATH.
 | |
|            (setenv "PATH" #$(file-append coreutils "/bin"))
 | |
|            (invoke #$(file-append libfaketime "/bin/faketime")
 | |
|                    "2000-01-01 00:00:00"
 | |
|                    chromium
 | |
|                    "--user-data-dir=/tmp/signing-profile"
 | |
|                    (string-append "--pack-extension=" packdir)
 | |
|                    (string-append "--pack-extension-key=" #$signing-key))
 | |
|            (copy-file (string-append packdir ".crx") #$output)))
 | |
|      #:local-build? #t)))
 | |
| 
 | |
| (define* (crx->chromium-json crx version)
 | |
|   "Return a derivation that creates a Chromium JSON settings file for the
 | |
| extension given as CRX.  VERSION is used to signify the CRX version, and
 | |
| must match the version listed in the extension manifest.json."
 | |
|   ;; See chrome/browser/extensions/external_provider_impl.cc and
 | |
|   ;; extensions/common/extension.h for documentation on the JSON format.
 | |
|   (computed-file "extension.json"
 | |
|                  #~(call-with-output-file #$output
 | |
|                      (lambda (port)
 | |
|                        (format port "{
 | |
|   \"external_crx\": \"~a\",
 | |
|   \"external_version\": \"~a\"
 | |
| }
 | |
| "
 | |
|                                #$crx #$version)))
 | |
|                  #:local-build? #t))
 | |
| 
 | |
| 
 | |
| (define (signing-key->public-der key)
 | |
|   "Return a derivation for a file containing the public key of KEY in DER
 | |
| format."
 | |
|   (computed-file "der"
 | |
|                  #~(system* #$(file-append gnutls "/bin/certtool")
 | |
|                             "--load-privkey" #$key
 | |
|                             "--pubkey-info"
 | |
|                             "--outfile" #$output
 | |
|                             "--outder")
 | |
|                  #:local-build? #t))
 | |
| 
 | |
| (define (chromium-json->profile-object json signing-key)
 | |
|   "Return a derivation that installs JSON to the directory searched by
 | |
| Chromium, using a file name (aka extension ID) derived from SIGNING-KEY."
 | |
|   (define der (signing-key->public-der signing-key))
 | |
| 
 | |
|   (with-extensions (list guile-gcrypt)
 | |
|     (with-imported-modules '((guix build utils))
 | |
|       (computed-file
 | |
|        "chromium-extension"
 | |
|        #~(begin
 | |
|            (use-modules (guix build utils)
 | |
|                         (gcrypt base16)
 | |
|                         (gcrypt hash))
 | |
|            (define (base16-string->chromium-base16 str)
 | |
|              ;; Translate STR, a hexadecimal string, to a Chromium-style
 | |
|              ;; representation using the letters a-p (where a=0, p=15).
 | |
|              (define s1 "0123456789abcdef")
 | |
|              (define s2 "abcdefghijklmnop")
 | |
|              (let loop ((chars (string->list str))
 | |
|                         (converted '()))
 | |
|                (if (null? chars)
 | |
|                    (list->string (reverse converted))
 | |
|                    (loop (cdr chars)
 | |
|                          (cons (string-ref s2 (string-index s1 (car chars)))
 | |
|                                converted)))))
 | |
| 
 | |
|            (let* ((checksum (bytevector->base16-string (file-sha256 #$der)))
 | |
|                   (file-name (base16-string->chromium-base16
 | |
|                               (string-take checksum 32)))
 | |
|                   (extension-directory (string-append #$output
 | |
|                                                       "/share/chromium/extensions")))
 | |
|              (mkdir-p extension-directory)
 | |
|              (symlink #$json (string-append extension-directory "/"
 | |
|                                             file-name ".json"))))
 | |
|        #:local-build? #t))))
 | |
| 
 | |
| (define* (make-chromium-extension p #:optional (output "out"))
 | |
|   "Create a Chromium extension from package P and return a package that,
 | |
| when installed, will make the extension contained in P available as a
 | |
| Chromium browser extension.  OUTPUT specifies which output of P to use."
 | |
|   (let* ((pname (package-name p))
 | |
|          (version (package-version p))
 | |
|          (signing-key (make-signing-key pname)))
 | |
|     (package
 | |
|       (inherit p)
 | |
|       (name (string-append pname "-chromium"))
 | |
|       (source #f)
 | |
|       (build-system trivial-build-system)
 | |
|       (native-inputs '())
 | |
|       (inputs
 | |
|        `(("extension" ,(chromium-json->profile-object
 | |
|                         (crx->chromium-json (make-crx signing-key p output)
 | |
|                                             version)
 | |
|                         signing-key))))
 | |
|       (propagated-inputs '())
 | |
|       (outputs '("out"))
 | |
|       (arguments
 | |
|        '(#:modules ((guix build utils))
 | |
|          #:builder
 | |
|          (begin
 | |
|            (use-modules (guix build utils))
 | |
|            (copy-recursively (assoc-ref %build-inputs "extension")
 | |
|                              (assoc-ref %outputs "out"))))))))
 |