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emacs/lisp/epa-ks.el
2023-01-01 05:31:12 -05:00

340 lines
12 KiB
EmacsLisp

;;; epa-ks.el --- EasyPG Key Server Client -*- lexical-binding: t -*-
;; Copyright (C) 2021-2023 Free Software Foundation, Inc.
;; Author: Philip K. <philipk@posteo.net>
;; Keywords: PGP, GnuPG
;; This file is part of GNU Emacs.
;; GNU Emacs 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 Emacs 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 Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Keyserver client in Emacs.
;;; Code:
(require 'cl-lib)
(require 'epa)
(require 'subr-x)
(require 'tabulated-list)
(require 'url)
(require 'url-http)
(defgroup epa-ks nil
"The EasyPG Assistant Keyserver client."
:version "28.1"
:group 'epa)
(defcustom epa-keyserver "pgp.mit.edu"
"Domain of keyserver.
This is used by `epa-search-keys', for looking up public keys."
:type '(choice :tag "Keyserver"
(repeat :tag "Random pool"
(string :tag "Keyserver address"))
(const "keyring.debian.org")
(const "keys.gnupg.net")
(const "keyserver.ubuntu.com")
(const "pgp.mit.edu")
(const "pool.sks-keyservers.net")
(const "zimmermann.mayfirst.org")
(string :tag "Custom keyserver"))
:version "28.1")
(cl-defstruct epa-ks-key
"Structure to hold key data."
id algo len created expires names flags)
(cl-defstruct epa-ks-name
"Structure to hold user associated with keys data."
uid created expires flags)
(defvar epa-ks-last-query nil
"List of arguments to pass to `epa-search-keys'.
This is used when reverting a buffer to restart search.")
(defvar-keymap epa-ks-search-mode-map
:suppress t
"f" #'epa-ks-mark-key-to-fetch
"i" #'epa-ks-inspect-key-to-fetch
"u" #'epa-ks-unmark-key-to-fetch
"x" #'epa-ks-do-key-to-fetch)
(define-derived-mode epa-ks-search-mode tabulated-list-mode "Keyserver"
"Major mode for listing public key search results."
(buffer-disable-undo)
(setq tabulated-list-format [("ID" 8 t)
("Algo." 5 nil)
("Created" 10 t)
("Expires" 10 t)
("User" 0 t)]
tabulated-list-sort-key '("User" . nil)
tabulated-list-padding 2)
(add-hook 'tabulated-list-revert-hook
#'epa-ks--restart-search
nil t)
(tabulated-list-init-header))
(defun epa-ks-inspect-key-to-fetch ()
"Display full ID of key under point in the minibuffer."
(interactive)
(message "Full ID: %s" (epa-ks-key-id (car (tabulated-list-get-id)))))
(defun epa-ks-unmark-key-to-fetch ()
"Remove fetch mark for key under point.
If a region is active, unmark all keys in active region."
(interactive)
(epa-ks-mark-key-to-fetch ""))
(defun epa-ks-mark-key-to-fetch (tag)
"Add fetch-mark to key under point.
If a region is active, mark all keys in active region.
When all keys have been selected, use \\[epa-ks-do-key-to-fetch] to
actually import the keys.
When called interactively, `epa-ks-mark-key-to-fetch' will always
add a \"F\" tag. Non-interactively the tag must be specified by
setting the TAG parameter."
(interactive (list "F"))
(if (region-active-p)
(save-mark-and-excursion
(save-restriction
(narrow-to-region (region-beginning) (1- (region-end)))
(goto-char (point-min))
(while (not (eobp))
(tabulated-list-put-tag tag t))))
(tabulated-list-put-tag tag t)))
(defun epa-ks-do-key-to-fetch ()
"Fetch all marked keys from keyserver and import them.
Keys are marked using `epa-ks-mark-key-to-fetch'."
(interactive)
(save-excursion
(let (keys)
(goto-char (point-min))
(while (not (eobp))
(when (looking-at-p (rx bol "F"))
(push (epa-ks-key-id (car (tabulated-list-get-id)))
keys))
(forward-line))
(when (yes-or-no-p (format "Proceed with fetching all %d key(s)? "
(length keys)))
(dolist (id keys)
(epa-ks--fetch-key id)))))
(tabulated-list-clear-all-tags))
(defun epa-ks--query-url (query exact)
"Return URL for QUERY.
If EXACT is non-nil, don't accept approximate matches."
(format "https://%s/pks/lookup?%s"
(cond ((null epa-keyserver)
(user-error "Empty keyserver pool"))
((listp epa-keyserver)
(seq-random-elt epa-keyserver))
((stringp epa-keyserver)
epa-keyserver)
((error "Invalid type for `epa-keyserver'")))
(url-build-query-string
(append `(("search" ,query)
("options" "mr")
("op" "index"))
(and exact '(("exact" "on")))))))
(defun epa-ks--fetch-key (id)
"Send request to import key with specified ID."
(url-retrieve
(epa-ks--query-url (concat "0x" (url-hexify-string id)) t)
(lambda (status)
(when (plist-get status :error)
(error "Request failed: %s"
(caddr (assq (caddr (plist-get status :error))
url-http-codes))))
(forward-paragraph)
(save-excursion
(goto-char (point-max))
(while (memq (char-before) '(?\s ?\t ?\n))
(forward-char -1))
(delete-region (point) (point-max)))
(let ((epa-popup-info-window nil))
(epa-import-armor-in-region (point) (point-max)))
(kill-buffer))))
(defun epa-ks--display-keys (buf keys)
"Prepare KEYS for `tabulated-list-mode', for buffer BUF.
KEYS is a list of `epa-ks-key' structures, as parsed by
`epa-ks--parse-buffer'."
(when (buffer-live-p buf)
(let (entries)
(dolist (key keys)
(dolist (name (epa-ks-key-names key))
(push (list (cons key name)
(vector
(substring (epa-ks-key-id key) -8)
(cdr (epa-ks-key-algo key))
(if (epa-ks-key-created key)
(format-time-string "%F" (epa-ks-key-created key))
"N/A")
(if (epa-ks-key-expires key)
(let* ((date (epa-ks-key-expires key))
(str (format-time-string "%F" date)))
(when (< 0 (time-to-seconds (time-since date)))
(setq str (propertize str 'face
'font-lock-warning-face)))
str)
(propertize "N/A" 'face 'shadow))
(decode-coding-string
(epa-ks-name-uid name)
(select-safe-coding-system (epa-ks-name-uid name)
nil 'utf-8))))
entries)))
(with-current-buffer buf
(setq tabulated-list-entries entries)
(tabulated-list-print t t))
(message (substitute-command-keys
"Press \\`f' to mark a key, \\`x' to fetch all marked keys.")))))
(defun epa-ks--restart-search ()
(when epa-ks-last-query
(apply #'epa-search-keys epa-ks-last-query)))
;;;###autoload
(defun epa-search-keys (query exact)
"Ask a keyserver for all keys matching QUERY.
The keyserver to be used is specified by `epa-keyserver'.
If EXACT is non-nil (interactively, prefix argument), require
exact matches.
Note that the request may fail if the query is not specific
enough, since keyservers have strict timeout settings."
(interactive (list (read-string "Search for: ")
current-prefix-arg))
(when (string-empty-p query)
(user-error "No query"))
(let ((buf (get-buffer-create "*Key search*")))
(with-current-buffer buf
(let ((inhibit-read-only t))
(erase-buffer))
(epa-ks-search-mode))
(url-retrieve
(epa-ks--query-url query exact)
(lambda (status)
(when (plist-get status :error)
(when buf
(kill-buffer buf))
(error "Request failed: %s"
(caddr (assq (caddr (plist-get status :error))
url-http-codes))))
(goto-char (point-min))
(while (search-forward "\r\n" nil t)
(replace-match "\n" t t))
(goto-char (point-min))
(re-search-forward "\n\n")
(let (keys)
(save-match-data
(setq keys (epa-ks--parse-buffer))
(kill-buffer (current-buffer)))
(when buf
(epa-ks--display-keys buf keys) keys))))
(pop-to-buffer buf)
(setq epa-ks-last-query (list query exact)))
(message "Searching keys..."))
(defun epa-ks--parse-buffer ()
;; parse machine readable response according to
;; https://tools.ietf.org/html/draft-shaw-openpgp-hkp-00#section-5.2
(when (looking-at (rx bol "info:" (group (+ digit))
":" (* digit) eol))
(unless (string= (match-string 1) "1")
(error "Unsupported keyserver version")))
(forward-line 1)
(let (key keys)
(while (and (not (eobp))
(not (looking-at "[ \t]*\n")))
(cond
((looking-at (rx bol "pub:" (group (+ alnum))
":" (group (* digit))
":" (group (* digit))
":" (group (* digit))
":" (group (* digit))
":" (group (* (any ?r ?d ?e)))
eol))
(setq key
(make-epa-ks-key
:id (match-string 1)
:algo
(and (match-string 2)
(not (string-empty-p (match-string 2)))
(assoc (string-to-number (match-string 2))
epg-pubkey-algorithm-alist))
:len
(and (match-string 3)
(not (string-empty-p (match-string 3)))
(string-to-number (match-string 3)))
:created
(and (match-string 4)
(not (string-empty-p (match-string 4)))
(time-convert (string-to-number (match-string 4)) t))
:expires
(and (match-string 5)
(not (string-empty-p (match-string 5)))
(time-convert (string-to-number (match-string 5)) t))
:flags
(mapcar (lambda (flag)
(cdr (assq flag '((?r revoked)
(?d disabled)
(?e expired)))))
(match-string 6))))
(push key keys))
((looking-at (rx bol "uid:" (group (+ (not ":")))
":" (group (* digit))
":" (group (* digit))
":" (group (* (any ?r ?d ?e)))
eol))
(push (make-epa-ks-name
:uid (url-unhex-string (match-string 1) t)
:created
(and (match-string 2)
(not (string-empty-p (match-string 2)))
(decode-time (string-to-number (match-string 2))))
:expires
(and (match-string 3)
(not (string-empty-p (match-string 3)))
(decode-time (string-to-number (match-string 3))))
:flags
(mapcar (lambda (flag)
(cdr (assq flag '((?r revoked)
(?d disabled)
(?e expired)))))
(match-string 4)))
(epa-ks-key-names key)))
((looking-at-p (rx bol "uat:"))
;; user attribute fields are ignored
nil)
(t (error "Invalid server response")))
(forward-line))
keys))
(provide 'epa-ks)
;;; epa-ks.el ends here