;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding:t -*-
-;; Copyright (C) 2019 Tim Vaughan
+;; Copyright (C) 2019-2020 Tim Vaughan
;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
;; Created: 11 April 2019
-;; Version: 2.7.11
+;; Version: 2.9.1
;; Keywords: comm gopher
;; Homepage: http://thelambdalab.xyz/elpher
-;; Package-Requires: ((emacs "26"))
+;; Package-Requires: ((emacs "26.2"))
;; This file is not part of GNU Emacs.
;;; Global constants
;;
-(defconst elpher-version "2.7.11"
+(defconst elpher-version "2.9.1"
"Current version of elpher.")
(defconst elpher-margin-width 6
;;
(defgroup elpher nil
- "A gopher client."
+ "A gopher and gemini client."
:group 'applications)
;; General appearance and customizations
sequences."
:type '(boolean))
+(defcustom elpher-certificate-directory
+ (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
+ "Specify the name of the directory where client certificates will be stored.
+These certificates may be used for establishing authenticated TLS connections."
+ :type '(directory))
+
+(defcustom elpher-openssl-command "openssl"
+ "The command used to launch openssl when generating TLS client certificates."
+ :type '(file))
+
(defcustom elpher-gemini-TLS-cert-checks nil
"If non-nil, verify gemini server TLS certs using the default security level.
Otherwise, certificate verification is disabled.
;; Gemini defaults
(if (equal (url-filename url) "")
(setf (url-filename url) "/"))))
- url)
+ (elpher-remove-redundant-ports url))
(set-match-data data))))
+(defun elpher-remove-redundant-ports (address)
+ "Remove redundant port specifiers from ADDRESS.
+Here 'redundant' means that the specified port matches the default
+for that protocol, eg 70 for gopher."
+ (if (and (not (elpher-address-special-p address))
+ (eq (url-portspec address) ; (url-port) is too slow!
+ (pcase (url-type address)
+ ("gemini" 1965)
+ ((or "gopher" "gophers") 70)
+ ("finger" 79)
+ (_ -1))))
+ (setf (url-portspec address) nil))
+ address)
+
(defun elpher-make-gopher-address (type selector host port &optional tls)
"Create an ADDRESS object using gopher directory record attributes.
The basic attributes include: TYPE, SELECTOR, HOST and PORT.
(let ((inhibit-read-only t))
(goto-char (point-min))
(if line
- (goto-line line))
+ (forward-line line))
(let ((data (match-data)))
(unwind-protect
(progn
(propertize "\n----------------\n\n" 'face 'error)
"Press 'u' to return to the previous page.")))
+
;;; General network communication
+;;
+
+(defvar elpher-network-timer nil
+ "Timer used for network connections.")
+
+(defvar elpher-use-tls nil
+ "If non-nil, use TLS to communicate with gopher servers.")
+
+(defvar elpher-client-certificate nil
+ "If non-nil, contains client certificate details to use for TLS connections.")
+
+(defun elpher-process-cleanup ()
+ "Immediately shut down any extant elpher process and timers."
+ (let ((p (get-process "elpher-process")))
+ (if p (delete-process p)))
+ (if (timerp elpher-network-timer)
+ (cancel-timer elpher-network-timer)))
(defun elpher-get-host-response (address default-port query-string response-processor
&optional use-tls force-ipv4)
+ "Generic function for retrieving data from ADDRESS.
+
+When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
+QUERY-STRING is a string sent to the host specified by ADDRESS to
+illicet a response. This response is passed as an argument to the
+function RESPONSE-PROCESSOR.
+
+If non-nil, USE-TLS specifies that the connection is to be made over
+TLS. If set to gemini, the certificate verification will be disabled
+unless `elpher-gemini-TLS-cert-checks' is non-nil.
+
+If non-nil, FORCE-IPV4 causes the network connection to be made over
+ipv4 only. (The default behaviour when this is not set depends on
+the host operating system and the local network capabilities."
(if (and use-tls (not (gnutls-available-p)))
(error "Use of TLS requires Emacs to be compiled with GNU TLS support")
(unless (< (elpher-address-port address) 65536)
(cons 'gnutls-x509pki
(gnutls-boot-parameters
:type 'gnutls-x509pki
- :hostname host)))))
+ :hostname host
+ :keylist
+ (elpher-get-current-keylist address))))))
(timer (run-at-time elpher-connection-timeout nil
(lambda ()
(elpher-process-cleanup)
(not (eq use-tls 'gemini))
(or elpher-auto-disengage-TLS
(y-or-n-p
- "TLS connetion failed. Disable TLS mode and retry? ")))
+ "TLS connetion failed. Disable TLS mode and retry? ")))
(setq elpher-use-tls nil)
(elpher-get-host-response address default-port
query-string
(let ((new-hkbytes-received (/ bytes-received 102400)))
(when (> new-hkbytes-received hkbytes-received)
(setq hkbytes-received new-hkbytes-received)
- (elpher-buffer-message
+ (elpher-buffer-message
(concat "("
(number-to-string (/ hkbytes-received 10.0))
" MB read)")
- 2)))
+ 1)))
(setq response-string-parts
(cons string response-string-parts))))
(set-process-sentinel proc
(cond
((string-prefix-p "open" event) ; request URL
(elpher-buffer-message
- (concat "Connected to " host ". Receiving data...\n"))
+ (concat "Connected to " host ". Receiving data..."))
(let ((inhibit-eol-conversion t))
(process-send-string proc query-string)))
((string-prefix-p "deleted" event)) ; do nothing
(apply #'concat (reverse response-string-parts)))
(elpher-restore-pos))
(t
- (error "No response from server.")))
+ (error "No response from server")))
(error
(elpher-network-error address the-error))))))
(error
(error "Error initiating connection to server")))))
-
-;;; Gopher selector retrieval
+;;; Client-side TLS Certificate Management
;;
-(defvar elpher-network-timer nil
- "Timer used for network connections.")
+(defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
+ "Generate a key and a self-signed client TLS certificate using openssl.
-(defun elpher-process-cleanup ()
- "Immediately shut down any extant elpher process and timers."
- (let ((p (get-process "elpher-process")))
- (if p (delete-process p)))
- (if (timerp elpher-network-timer)
- (cancel-timer elpher-network-timer)))
+The Common Name field of the certificate is set to COMMON-NAME. The
+arguments KEY-FILE and CERT-FILE should contain the absolute paths of
+the key and certificate files to write.
-(defvar elpher-use-tls nil
- "If non-nil, use TLS to communicate with gopher servers.")
+If TEMPORARY is non-nil, the certificate will be given an exporation
+period of one day, and the key and certificate files will be deleted
+when the certificate is no longer needed for the current session.
+
+Otherwise, the certificate will be given a 100 year expiration period
+and the files will not be deleted.
+
+The function returns a list containing the current host name, the
+temporary flag, and the key and cert file names in the form required
+by `gnutls-boot-parameters`."
+ (let ((exp-key-file (expand-file-name key-file))
+ (exp-cert-file (expand-file-name cert-file)))
+ (condition-case nil
+ (progn
+ (call-process elpher-openssl-command nil nil nil
+ "req" "-x509" "-newkey" "rsa:2048"
+ "-days" (if temporary "1" "36500")
+ "-nodes"
+ "-subj" (concat "/CN=" common-name)
+ "-keyout" exp-key-file
+ "-out" exp-cert-file)
+ (list (elpher-address-host (elpher-page-address elpher-current-page))
+ temporary exp-key-file exp-cert-file))
+ (error
+ (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
+ (error "Program 'openssl', required for certificate generation, not found")))))
+
+(defun elpher-generate-throwaway-certificate ()
+ "Generate and return details of a throwaway certificate.
+The key and certificate files will be deleted when they are no
+longer needed for this session."
+ (let* ((file-base (make-temp-name "elpher"))
+ (key-file (concat temporary-file-directory file-base ".key"))
+ (cert-file (concat temporary-file-directory file-base ".crt")))
+ (elpher-generate-certificate file-base key-file cert-file t)))
+
+(defun elpher-generate-permanent-certificate (file-base common-name)
+ "Generate and return details of a persistant certificate.
+The argument FILE-BASE is used as the base for the key and certificate
+files, while COMMON-NAME specifies the common name field of the
+certificate.
+
+The key and certificate files are written to in `elpher-certificate-directory'."
+ (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
+ (cert-file (concat elpher-certificate-directory file-base ".crt")))
+ (elpher-generate-certificate common-name key-file cert-file)))
+
+(defun elpher-get-existing-certificate (file-base)
+ "Return a certificate object corresponding to an existing certificate.
+It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
+the directory `elpher-certificate-directory'."
+ (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
+ (cert-file (concat elpher-certificate-directory file-base ".crt")))
+ (list (elpher-address-host (elpher-page-address elpher-current-page))
+ nil
+ (expand-file-name key-file)
+ (expand-file-name cert-file))))
+
+(defun elpher-list-existing-certificates ()
+ "Return a list of the persistant certificates in `elpher-certificate-directory'."
+ (mapcar
+ (lambda (file)
+ (file-name-sans-extension file))
+ (directory-files elpher-certificate-directory nil "\.key$")))
+
+(defun elpher-forget-current-certificate ()
+ "Causes any current certificate to be forgotten.
+In the case of throwaway certificates, the key and certificate files
+are also deleted."
+ (interactive)
+ (when elpher-client-certificate
+ (unless (and (called-interactively-p 'any)
+ (not (y-or-n-p (concat "Really forget client certificate? "
+ "(Throwaway certificates will be deleted.)"))))
+ (when (cadr elpher-client-certificate)
+ (delete-file (elt elpher-client-certificate 2))
+ (delete-file (elt elpher-client-certificate 3)))
+ (setq elpher-client-certificate nil)
+ (if (called-interactively-p 'any)
+ (message "Client certificate forgotten.")))))
+
+(defun elpher-get-current-keylist (address)
+ "Retrieve the `gnutls-boot-parameters'-compatable keylist.
+
+This is obtained from the client certificate described by
+`elpher-current-certificate', if one is available and the host for
+that certificate matches the host in ADDRESS.
+
+If `elpher-current-certificate' is non-nil, and its host name doesn't
+match that of ADDRESS, the certificate is forgotten."
+ (if elpher-client-certificate
+ (if (string= (car elpher-client-certificate)
+ (elpher-address-host address))
+ (list (cddr elpher-client-certificate))
+ (elpher-forget-current-certificate)
+ (message "Disabling client certificate for new host")
+ nil)
+ nil))
+
+
+;;; Gopher selector retrieval
+;;
(defun elpher-get-gopher-response (address renderer)
+ "Get response string from gopher server at ADDRESS and render using RENDERER."
(elpher-get-host-response address 70
(concat (elpher-gopher-address-selector address) "\r\n")
renderer
(defvar elpher-gemini-redirect-chain)
(defun elpher-get-gemini-response (address renderer)
+ "Get response string from gemini server at ADDRESS and render using RENDERER."
(elpher-get-host-response address 1965
(concat (elpher-address-to-url address) "\r\n")
(lambda (response-string)
(?1 ; Input required
(elpher-with-clean-buffer
(insert "Gemini server is requesting input."))
- (let* ((query-string (read-string (concat response-meta ": ")))
+ (let* ((query-string
+ (if (eq (elt response-code 1) ?1)
+ (read-passwd (concat response-meta ": "))
+ (read-string (concat response-meta ": "))))
(query-address (seq-copy (elpher-page-address elpher-current-page)))
(old-fname (url-filename query-address)))
(setf (url-filename query-address)
(error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
response-code response-meta))
(?6 ; Client certificate required
- (error "Gemini server requires client certificate (unsupported at this time)"))
+ (elpher-with-clean-buffer
+ (if elpher-client-certificate
+ (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
+ (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
+ (auto-fill-mode 1)
+ (elpher-gemini-insert-text response-meta))
+ (let* ((read-answer-short t))
+ (pcase (read-answer "What do you want to do? "
+ '(("throwaway" ?t
+ "generate and use throw-away certificate")
+ ("permanent" ?p
+ "generate new or use existing permanent certificate")
+ ("abort" ?a
+ "stop immediately")))
+ ("throwaway"
+ (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
+ ("permanent"
+ (let* ((existing-certificates (elpher-list-existing-certificates))
+ (file-base (completing-read
+ "Name of new or existing certificate (autocompletes, empty response aborts): "
+ existing-certificates)))
+ (if (string-empty-p (string-trim file-base))
+ (error "Gemini server requires certificate and none was provided")
+ (if (member file-base existing-certificates)
+ (setq elpher-client-certificate
+ (elpher-get-existing-certificate file-base))
+ (let ((common-name (read-string "Common Name field for new certificate: "
+ file-base)))
+ (setq elpher-client-certificate
+ (elpher-generate-permanent-certificate file-base common-name))
+ (message "New key and self-signed certificate written to %s"
+ elpher-certificate-directory))))))
+ ("abort"
+ (error "Gemini server requires a client certificate and none was provided")))
+ (elpher-with-clean-buffer)
+ (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer)))
(_other
(error "Gemini server response unknown: %s %s"
response-code response-meta))))))
(url-filename address)))))
(unless (url-type address)
(setf (url-type address) "gemini"))
- (if (equal (url-type address) "gemini")
- (setf (url-filename address)
- (elpher-collapse-dot-sequences (url-filename address)))))
- address))
+ (when (equal (url-type address) "gemini")
+ (setf (url-filename address)
+ (elpher-collapse-dot-sequences (url-filename address)))))
+ (elpher-remove-redundant-ports address)))
(defun elpher-gemini-insert-link (link-line)
"Insert link described by LINK-LINE into a text/gemini document."
(elpher-page-address elpher-current-page)
(buffer-string))))
+
;; Finger page connection
-(defun elpher-get-finger-page (renderer &optional force-ipv4)
+(defun elpher-get-finger-page (renderer)
"Opens a finger connection to the current page address.
-The result is rendered using RENDERER. When the optional argument
-FORCE-IPV4 or the variable `elpher-ipv4-always' are non-nil, the
-IPv4 address returned by a DNS lookup will be used explicitly in
-making the connection."
+The result is rendered using RENDERER."
(let* ((address (elpher-page-address elpher-current-page))
(content (elpher-get-cached-content address)))
(if (and content (funcall renderer nil))
(elpher-network-error address the-error))))))
+;; Telnet page connection
+
+(defun elpher-get-telnet-page (renderer)
+ "Opens a telnet connection to the current page address (RENDERER must be nil)."
+ (when renderer
+ (elpher-visit-previous-page)
+ (error "Command not supported for telnet URLs"))
+ (let* ((address (elpher-page-address elpher-current-page))
+ (host (elpher-address-host address))
+ (port (elpher-address-port address)))
+ (elpher-visit-previous-page)
+ (if (> port 0)
+ (telnet host port)
+ (telnet host))))
+
+
;; Other URL page opening
(defun elpher-get-other-url-page (renderer)
(browse-web url)
(browse-url url)))))
-;; Telnet page connection
-
-(defun elpher-get-telnet-page (renderer)
- "Opens a telnet connection to the current page address (RENDERER must be nil)."
- (when renderer
- (elpher-visit-previous-page)
- (error "Command not supported for telnet URLs"))
- (let* ((address (elpher-page-address elpher-current-page))
- (host (elpher-address-host address))
- (port (elpher-address-port address)))
- (elpher-visit-previous-page)
- (if (> port 0)
- (telnet host port)
- (telnet host))))
;; Start page page retrieval
" - R: reload current page (regenerates cache)\n"
" - S: set character coding system for gopher (default is to autodetect)\n"
" - T: toggle TLS gopher mode\n"
+ " - F: forget/discard current TLS client certificate\n"
" - .: display the raw server response for the current page\n"
"\n"
"Start your exploration of gopher space and gemini:\n")
(interactive "sGopher or Gemini URL: ")
(let* ((cleaned-host-or-url (string-trim host-or-url))
(address (elpher-address-from-url cleaned-host-or-url))
- (page (elpher-make-page cleaned-host-or-url address)))
+ (page (elpher-make-page cleaned-host-or-url address)))
(switch-to-buffer "*elpher*")
(elpher-visit-page page)
nil))
(define-key map (kbd "X") 'elpher-unbookmark-current)
(define-key map (kbd "B") 'elpher-bookmarks)
(define-key map (kbd "S") 'elpher-set-gopher-coding-system)
+ (define-key map (kbd "F") 'elpher-forget-current-certificate)
(when (fboundp 'evil-define-key*)
(evil-define-key* 'motion map
(kbd "TAB") 'elpher-next-link
(kbd "x") 'elpher-unbookmark-link
(kbd "X") 'elpher-unbookmark-current
(kbd "B") 'elpher-bookmarks
- (kbd "S") 'elpher-set-gopher-coding-system))
+ (kbd "S") 'elpher-set-gopher-coding-system
+ (kbd "F") 'elpher-forget-current-certificate))
map)
"Keymap for gopher client.")
The Lambda Lab / projects / elpher.git / blobdiff