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Diffstat (limited to 'guix/gnupg.scm')
| -rw-r--r-- | guix/gnupg.scm | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/guix/gnupg.scm b/guix/gnupg.scm new file mode 100644 index 0000000000..ee67bea91b --- /dev/null +++ b/guix/gnupg.scm @@ -0,0 +1,152 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2010, 2011, 2013 Ludovic Courtès <ludo@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 (guix gnupg) + #:use-module (ice-9 popen) + #:use-module (ice-9 match) + #:use-module (ice-9 regex) + #:use-module (ice-9 rdelim) + #:use-module (srfi srfi-1) + #:export (gnupg-verify + gnupg-verify* + gnupg-status-good-signature? + gnupg-status-missing-key?)) + +;;; Commentary: +;;; +;;; GnuPG interface. +;;; +;;; Code: + +(define %gpg-command "gpg2") +(define %openpgp-key-server "keys.gnupg.net") + +(define (gnupg-verify sig file) + "Verify signature SIG for FILE. Return a status s-exp if GnuPG failed." + + (define (status-line->sexp line) + ;; See file `doc/DETAILS' in GnuPG. + (define sigid-rx + (make-regexp + "^\\[GNUPG:\\] SIG_ID ([A-Za-z0-9/]+) ([[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}) ([[:digit:]]+)")) + (define goodsig-rx + (make-regexp "^\\[GNUPG:\\] GOODSIG ([[:xdigit:]]+) (.+)$")) + (define validsig-rx + (make-regexp + "^\\[GNUPG:\\] VALIDSIG ([[:xdigit:]]+) ([[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}) ([[:digit:]]+) .*$")) + (define expkeysig-rx ; good signature, but expired key + (make-regexp "^\\[GNUPG:\\] EXPKEYSIG ([[:xdigit:]]+) (.*)$")) + (define errsig-rx + (make-regexp + "^\\[GNUPG:\\] ERRSIG ([[:xdigit:]]+) ([^ ]+) ([^ ]+) ([^ ]+) ([[:digit:]]+) ([[:digit:]]+)")) + + (cond ((regexp-exec sigid-rx line) + => + (lambda (match) + `(signature-id ,(match:substring match 1) ; sig id + ,(match:substring match 2) ; date + ,(string->number ; timestamp + (match:substring match 3))))) + ((regexp-exec goodsig-rx line) + => + (lambda (match) + `(good-signature ,(match:substring match 1) ; key id + ,(match:substring match 2)))) ; user name + ((regexp-exec validsig-rx line) + => + (lambda (match) + `(valid-signature ,(match:substring match 1) ; fingerprint + ,(match:substring match 2) ; sig creation date + ,(string->number ; timestamp + (match:substring match 3))))) + ((regexp-exec expkeysig-rx line) + => + (lambda (match) + `(expired-key-signature ,(match:substring match 1) ; fingerprint + ,(match:substring match 2)))) ; user name + ((regexp-exec errsig-rx line) + => + (lambda (match) + `(signature-error ,(match:substring match 1) ; key id or fingerprint + ,(match:substring match 2) ; pubkey algo + ,(match:substring match 3) ; hash algo + ,(match:substring match 4) ; sig class + ,(string->number ; timestamp + (match:substring match 5)) + ,(let ((rc + (string->number ; return code + (match:substring match 6)))) + (case rc + ((9) 'missing-key) + ((4) 'unknown-algorithm) + (else rc)))))) + (else + `(unparsed-line ,line)))) + + (define (parse-status input) + (let loop ((line (read-line input)) + (result '())) + (if (eof-object? line) + (reverse result) + (loop (read-line input) + (cons (status-line->sexp line) result))))) + + (let* ((pipe (open-pipe* OPEN_READ %gpg-command "--status-fd=1" + "--verify" sig file)) + (status (parse-status pipe))) + ;; Ignore PIPE's exit status since STATUS above should contain all the + ;; info we need. + (close-pipe pipe) + status)) + +(define (gnupg-status-good-signature? status) + "If STATUS, as returned by `gnupg-verify', denotes a good signature, return +a key-id/user pair; return #f otherwise." + (any (lambda (sexp) + (match sexp + (((or 'good-signature 'expired-key-signature) key-id user) + (cons key-id user)) + (_ #f))) + status)) + +(define (gnupg-status-missing-key? status) + "If STATUS denotes a missing-key error, then return the key-id of the +missing key." + (any (lambda (sexp) + (match sexp + (('signature-error key-id _ ...) + key-id) + (_ #f))) + status)) + +(define (gnupg-receive-keys key-id server) + (system* %gpg-command "--keyserver" server "--recv-keys" key-id)) + +(define* (gnupg-verify* sig file #:optional (server %openpgp-key-server)) + "Like `gnupg-verify', but try downloading the public key if it's missing. +Return #t if the signature was good, #f otherwise." + (let ((status (gnupg-verify sig file))) + (or (gnupg-status-good-signature? status) + (let ((missing (gnupg-status-missing-key? status))) + (and missing + (begin + ;; Download the missing key and try again. + (gnupg-receive-keys missing server) + (gnupg-status-good-signature? (gnupg-verify sig file)))))))) + +;;; gnupg.scm ends here |