;;; sieve-manage.el --- Implementation of the managesieve protocol in elisp -*- lexical-binding:t -*- ;; Copyright (C) 2001-2023 Free Software Foundation, Inc. ;; Author: Simon Josefsson ;; Albert Krewinkel ;; 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 . ;;; Commentary: ;; This library provides an elisp API for the managesieve network ;; protocol. ;; ;; It uses the SASL library for authentication, which means it ;; supports DIGEST-MD5, CRAM-MD5, SCRAM-MD5, NTLM, PLAIN and LOGIN ;; methods. STARTTLS is not well tested, but should be easy to get to ;; work if someone wants. ;; ;; The API should be fairly obvious for anyone familiar with the ;; managesieve protocol, interface functions include: ;; ;; `sieve-manage-open' ;; open connection to managesieve server, returning a buffer to be ;; used by all other API functions. ;; ;; `sieve-manage-opened' ;; check if a server is open or not ;; ;; `sieve-manage-close' ;; close a server connection. ;; ;; `sieve-manage-listscripts' ;; `sieve-manage-deletescript' ;; `sieve-manage-getscript' ;; performs managesieve protocol actions ;; ;; and that's it. Example of a managesieve session in *scratch*: ;; ;; (with-current-buffer (sieve-manage-open "mail.example.com") ;; (sieve-manage-authenticate) ;; (sieve-manage-listscripts)) ;; ;; => ((active . "main") "vacation") ;; ;; References: ;; ;; RFC5804, ;; "A Protocol for Remotely Managing Sieve Scripts", ;; by Tim Martin. ;; ;; Release history: ;; ;; 2001-10-31 Committed to Oort Gnus. ;; 2002-07-27 Added DELETESCRIPT. Suggested by Ned Ludd. ;; 2002-08-03 Use SASL library. ;; 2013-06-05 Enabled STARTTLS support, fixed bit rot. ;;; Code: (if (locate-library "password-cache") (require 'password-cache) (require 'password)) (eval-when-compile (require 'cl-lib)) (require 'sasl) (autoload 'sasl-find-mechanism "sasl") (autoload 'auth-source-search "auth-source") (autoload 'auth-info-password "auth-source") ;; User customizable variables: (defgroup sieve-manage nil "Low-level Managesieve protocol issues." :group 'mail :prefix "sieve-") (defcustom sieve-manage-log "*sieve-manage-log*" "Name of buffer for managesieve session trace." :type 'string) (defcustom sieve-manage-server-eol "\r\n" "The EOL string sent from the server." :type 'string) (defcustom sieve-manage-client-eol "\r\n" "The EOL string we send to the server." :type 'string) (defcustom sieve-manage-authenticators '(digest-md5 cram-md5 scram-md5 ntlm plain login) "Priority of authenticators to consider when authenticating to server." ;; FIXME Improve this. It's not `set'. ;; It's like (repeat (choice (const ...))), where each choice can ;; only appear once. :type '(repeat symbol)) (defcustom sieve-manage-authenticator-alist '((cram-md5 sieve-manage-cram-md5-p sieve-manage-cram-md5-auth) (digest-md5 sieve-manage-digest-md5-p sieve-manage-digest-md5-auth) (scram-md5 sieve-manage-scram-md5-p sieve-manage-scram-md5-auth) (ntlm sieve-manage-ntlm-p sieve-manage-ntlm-auth) (plain sieve-manage-plain-p sieve-manage-plain-auth) (login sieve-manage-login-p sieve-manage-login-auth)) "Definition of authenticators. \(NAME CHECK AUTHENTICATE) NAME names the authenticator. CHECK is a function returning non-nil if the server support the authenticator and AUTHENTICATE is a function for doing the actual authentication." :type '(repeat (list (symbol :tag "Name") (function :tag "Check function") (function :tag "Authentication function")))) (defcustom sieve-manage-default-port "sieve" "Default port number or service name for managesieve protocol." :type '(choice natnum string) :version "24.4") (defcustom sieve-manage-default-stream 'network "Default stream type to use for `sieve-manage'." :version "24.1" :type 'symbol) (defcustom sieve-manage-ignore-starttls nil "Ignore STARTTLS even if STARTTLS capability is provided." :version "26.1" :type 'boolean) ;; Internal variables: (defconst sieve-manage--coding-system 'utf-8-unix "Use \\='utf-8-unix coding system for (network) communication. Defines the coding system used for the internal (process, log) buffers and the network stream created to communicate with the managesieve server. Using \\='utf-8-unix encoding corresponds to the use of UTF-8 in RFC5804 (managesieve). The explicit use of \\='-unix\\=' avoids EOL conversions (and thus keeps CRLF (\"\\r\\n\") sequences intact).") (defconst sieve-manage-local-variables '(sieve-manage-server sieve-manage-port sieve-manage-auth sieve-manage-stream sieve-manage-process sieve-manage-client-eol sieve-manage-server-eol sieve-manage-capability)) (defvar sieve-manage-stream nil) (defvar sieve-manage-auth nil) (defvar sieve-manage-server nil) (defvar sieve-manage-port nil) (defvar sieve-manage-state 'closed "Managesieve state. Valid states are `closed', `initial', `nonauth', and `auth'.") (defvar sieve-manage-process nil) (defvar sieve-manage-capability nil) ;; Internal utility functions (defun sieve-manage--set-buffer-maybe-append-text (buffer-name &rest args) "Append ARGS to buffer named BUFFER-NAME and return buffer. To be used with process and log buffers. When the buffer doesn't exist, it gets created and configure as follows: - set coding system to 'sieve-manage--coding-system', - set buffer to single-byte mode, - set `after-change-functions' to nil to avoid those functions messing with buffer content, - disable undo (to save a bit of memory and improve performance). ARGS can be a nil, a string or a list of strings. If no ARGS are provided, the content of buffer will not be modified." (let* ((existing-buffer (get-buffer buffer-name)) (buffer (or existing-buffer (get-buffer-create buffer-name)))) (with-current-buffer buffer (unless existing-buffer (set-buffer-file-coding-system sieve-manage--coding-system) (set-buffer-multibyte nil) (setq-local after-change-functions nil) (buffer-disable-undo)) (when args (goto-char (point-max)) (apply #'insert args))) buffer)) (defun sieve-manage--append-to-log (&rest args) "Append ARGS to `sieve-manage-log' buffer. If `sieve-manage-log' is nil, logging is disabled. See also `sieve-manage--set-buffer-maybe-append-text'." (when sieve-manage-log (apply #'sieve-manage--set-buffer-maybe-append-text sieve-manage-log args))) (defun sieve-manage--message (format-string &rest args) "Wrapper around `message' which also logs to sieve manage log. See `sieve-manage--append-to-log'." (let ((ret (apply #'message (concat "sieve-manage: " format-string) args))) (sieve-manage--append-to-log ret "\n") ret)) (defun sieve-manage--error (format-string &rest args) "Wrapper around `error' which also logs to sieve manage log. See `sieve-manage--append-to-log'." (let ((msg (apply #'format (concat "sieve-manage/ERROR: " format-string) args))) (sieve-manage--append-to-log msg "\n") (error msg))) (defun sieve-manage-encode (str) "Convert STR to managesieve protocol octets." (encode-coding-string str sieve-manage--coding-system t)) (defun sieve-manage-decode (octets &optional buffer) "Convert managesieve protocol OCTETS to UTF-8 string. If optional BUFFER is non-nil, insert decoded string into BUFFER." (when octets ;; eol type unix is required to preserve "\r\n" (decode-coding-string octets sieve-manage--coding-system t buffer))) (defun sieve-manage-make-process-buffer () (let ((buffer (sieve-manage--set-buffer-maybe-append-text (format " *sieve %s:%s*" sieve-manage-server sieve-manage-port)))) (with-current-buffer buffer (mapc #'make-local-variable sieve-manage-local-variables)) buffer)) (defun sieve-manage-erase (&optional p buffer) (with-current-buffer (or buffer (current-buffer)) (let* ((start (point-min)) (end (or p (point-max))) (logdata (buffer-substring-no-properties start end))) (sieve-manage--append-to-log logdata) (delete-region start end) logdata))) (defun sieve-manage-open-server (server port &optional stream buffer) "Open network connection to SERVER on PORT. Return the buffer associated with the connection." (with-current-buffer buffer (sieve-manage-erase) (setq sieve-manage-state 'initial) (pcase-let ((`(,proc . ,props) (open-network-stream "SIEVE" buffer server port :type stream :coding 'binary :capability-command "CAPABILITY\r\n" :end-of-command "^\\(OK\\|NO\\|BYE\\).*\r\n" :success "^OK.*\r\n" :return-list t :starttls-function (lambda (capabilities) (when (and (not sieve-manage-ignore-starttls) (string-match "\\bSTARTTLS\\b" capabilities)) "STARTTLS\r\n"))))) (setq sieve-manage-process proc) (setq sieve-manage-capability (sieve-manage-parse-capability (plist-get props :capabilities))) ;; Ignore new capabilities issues after successful STARTTLS (when (or sieve-manage-ignore-starttls (and (memq stream '(nil network starttls)) (eq (plist-get props :type) 'tls))) (sieve-manage-drop-next-answer)) (current-buffer)))) ;; Authenticators (defun sieve-sasl-auth (buffer mech) "Login to server using the SASL MECH method." (sieve-manage--message "Authenticating using %s..." mech) (with-current-buffer buffer (let* ((auth-info (auth-source-search :host sieve-manage-server :port "sieve" :max 1 :create t)) (user-name (or (plist-get (nth 0 auth-info) :user) "")) (user-password (or (auth-info-password (nth 0 auth-info)) "")) (client (sasl-make-client (sasl-find-mechanism (list mech)) user-name "sieve" sieve-manage-server)) (sasl-read-passphrase ;; We *need* to copy the password, because sasl will modify it ;; somehow. (lambda (_prompt) (copy-sequence user-password))) (step (sasl-next-step client nil)) (_tag (sieve-manage-send (concat "AUTHENTICATE \"" mech "\"" (and (sasl-step-data step) (concat " \"" (base64-encode-string (sasl-step-data step) 'no-line-break) "\""))))) data rsp) (catch 'done (while t (setq rsp nil) (goto-char (point-min)) (while (null (or (progn (setq rsp (sieve-manage-is-string)) (if (not (and rsp (looking-at sieve-manage-server-eol))) (setq rsp nil) (goto-char (match-end 0)) rsp)) (setq rsp (sieve-manage-is-oknobye)))) (accept-process-output sieve-manage-process 1) (goto-char (point-min))) (sieve-manage-erase) (when (sieve-manage-ok-p rsp) (when (and (cadr rsp) (string-match "^SASL \"\\([^\"]+\\)\"" (cadr rsp))) (sasl-step-set-data step (base64-decode-string (match-string 1 (cadr rsp))))) (if (and (setq step (sasl-next-step client step)) (setq data (sasl-step-data step))) ;; We got data for server but it's finished (sieve-manage--error "Server not ready for SASL data: %s" data) ;; The authentication process is finished. (sieve-manage--message "Logged in as %s using %s" user-name mech) (throw 'done t))) (unless (stringp rsp) (sieve-manage--error "Server aborted SASL authentication: %s" (caddr rsp))) (sasl-step-set-data step (base64-decode-string rsp)) (setq step (sasl-next-step client step)) (sieve-manage-send (if (sasl-step-data step) (concat "\"" (base64-encode-string (sasl-step-data step) 'no-line-break) "\"") ""))))))) (defun sieve-manage-cram-md5-p (buffer) (sieve-manage-capability "SASL" "CRAM-MD5" buffer)) (defun sieve-manage-cram-md5-auth (buffer) "Login to managesieve server using the CRAM-MD5 SASL method." (sieve-sasl-auth buffer "CRAM-MD5")) (defun sieve-manage-digest-md5-p (buffer) (sieve-manage-capability "SASL" "DIGEST-MD5" buffer)) (defun sieve-manage-digest-md5-auth (buffer) "Login to managesieve server using the DIGEST-MD5 SASL method." (sieve-sasl-auth buffer "DIGEST-MD5")) (defun sieve-manage-scram-md5-p (buffer) (sieve-manage-capability "SASL" "SCRAM-MD5" buffer)) (defun sieve-manage-scram-md5-auth (buffer) "Login to managesieve server using the SCRAM-MD5 SASL method." (sieve-sasl-auth buffer "SCRAM-MD5")) (defun sieve-manage-ntlm-p (buffer) (sieve-manage-capability "SASL" "NTLM" buffer)) (defun sieve-manage-ntlm-auth (buffer) "Login to managesieve server using the NTLM SASL method." (sieve-sasl-auth buffer "NTLM")) (defun sieve-manage-plain-p (buffer) (sieve-manage-capability "SASL" "PLAIN" buffer)) (defun sieve-manage-plain-auth (buffer) "Login to managesieve server using the PLAIN SASL method." (sieve-sasl-auth buffer "PLAIN")) (defun sieve-manage-login-p (buffer) (sieve-manage-capability "SASL" "LOGIN" buffer)) (defun sieve-manage-login-auth (buffer) "Login to managesieve server using the LOGIN SASL method." (sieve-sasl-auth buffer "LOGIN")) ;; Managesieve API (defun sieve-manage-open (server &optional port stream auth buffer) "Open a network connection to a managesieve SERVER (string). Optional argument PORT is port number (integer) on remote server. Optional argument STREAM is any of `sieve-manage-stream' (a symbol). Optional argument AUTH indicates authenticator to use, see `sieve-manage-authenticators' for available authenticators. If nil, chooses the best stream the server is capable of. Optional argument BUFFER is buffer (buffer, or string naming buffer) to work in." (setq sieve-manage-port (or port sieve-manage-default-port)) (with-current-buffer (or buffer (sieve-manage-make-process-buffer)) (setq sieve-manage-server (or server sieve-manage-server) sieve-manage-stream (or stream sieve-manage-stream sieve-manage-default-stream) sieve-manage-auth (or auth sieve-manage-auth)) (sieve-manage--message "Connecting to %s..." sieve-manage-server) (sieve-manage-open-server sieve-manage-server sieve-manage-port sieve-manage-stream (current-buffer)) (when (sieve-manage-opened (current-buffer)) ;; Choose authenticator (when (and (null sieve-manage-auth) (not (eq sieve-manage-state 'auth))) (cl-dolist (auth sieve-manage-authenticators) (when (funcall (nth 1 (assq auth sieve-manage-authenticator-alist)) buffer) (setq sieve-manage-auth auth) (cl-return))) (unless sieve-manage-auth (sieve-manage--error "Couldn't figure out authenticator for server"))) (sieve-manage-erase) (current-buffer)))) (defun sieve-manage-authenticate (&optional buffer) "Authenticate on server in BUFFER. Return `sieve-manage-state' value." (with-current-buffer (or buffer (current-buffer)) (if (eq sieve-manage-state 'nonauth) (when (funcall (nth 2 (assq sieve-manage-auth sieve-manage-authenticator-alist)) (current-buffer)) (setq sieve-manage-state 'auth)) sieve-manage-state))) (defun sieve-manage-opened (&optional buffer) "Return non-nil if connection to managesieve server in BUFFER is open. If BUFFER is nil then the current buffer is used." (and (setq buffer (get-buffer (or buffer (current-buffer)))) (buffer-live-p buffer) (with-current-buffer buffer (and sieve-manage-process (memq (process-status sieve-manage-process) '(open run)))))) (defun sieve-manage-close (&optional buffer) "Close connection to managesieve server in BUFFER. If BUFFER is nil, the current buffer is used." (with-current-buffer (or buffer (current-buffer)) (when (sieve-manage-opened) (sieve-manage-send "LOGOUT") (sit-for 1)) (when (and sieve-manage-process (memq (process-status sieve-manage-process) '(open run))) (delete-process sieve-manage-process)) (setq sieve-manage-process nil) (sieve-manage-erase) t)) (defun sieve-manage-capability (&optional name value buffer) "Check if capability NAME of server BUFFER match VALUE. If it does, return the server value of NAME. If not return nil. If VALUE is nil, do not check VALUE and return server value. If NAME is nil, return the full server list of capabilities." (with-current-buffer (or buffer (current-buffer)) (if (null name) sieve-manage-capability (let ((server-value (cadr (assoc name sieve-manage-capability)))) (when (or (null value) (and server-value (string-match value server-value))) server-value))))) (defun sieve-manage-listscripts (&optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send "LISTSCRIPTS") (sieve-manage-parse-listscripts))) (defun sieve-manage-havespace (name size &optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send (format "HAVESPACE \"%s\" %s" name size)) (sieve-manage-parse-oknobye))) (defun sieve-manage-putscript (name content &optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send (format "PUTSCRIPT \"%s\"" name) content) (sieve-manage-parse-oknobye))) (defun sieve-manage-deletescript (name &optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send (format "DELETESCRIPT \"%s\"" name)) (sieve-manage-parse-oknobye))) (defun sieve-manage-getscript (name output-buffer &optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send (format "GETSCRIPT \"%s\"" name)) (sieve-manage-decode (sieve-manage-parse-string) output-buffer) (sieve-manage-parse-crlf) (sieve-manage-parse-oknobye))) (defun sieve-manage-setactive (name &optional buffer) (with-current-buffer (or buffer (current-buffer)) (sieve-manage-send (format "SETACTIVE \"%s\"" name)) (sieve-manage-parse-oknobye))) ;; Protocol parsing routines (defun sieve-manage-regexp-oknobye () "Return regexp for managesieve 'response-oknobye'." (concat "^\\(OK\\|NO\\|BYE\\)\\( (\\([^)]+\\))\\)?\\( \\(.*\\)\\)?" sieve-manage-server-eol)) (defun sieve-manage-wait-for-answer () (let ((pattern (sieve-manage-regexp-oknobye)) pos) (while (not pos) (setq pos (search-forward-regexp pattern nil t)) (goto-char (point-min)) (sleep-for 0 50)) pos)) (defun sieve-manage-drop-next-answer () (sieve-manage-wait-for-answer) (sieve-manage-erase)) (defun sieve-manage-ok-p (rsp) (string= (downcase (or (car-safe rsp) "")) "ok")) (defun sieve-manage-no-p (rsp) (string= (downcase (or (car-safe rsp) "")) "no")) (defun sieve-manage-is-oknobye () (when (looking-at (sieve-manage-regexp-oknobye)) (let ((status (match-string 1)) (resp-code (match-string 3)) (response (match-string 5))) (when response (goto-char (match-beginning 5)) (setq response (sieve-manage-is-string))) (list status resp-code response)))) (defun sieve-manage-parse-oknobye () (let (rsp) (while (null rsp) (accept-process-output (get-buffer-process (current-buffer)) 1) (goto-char (point-min)) (setq rsp (sieve-manage-is-oknobye))) (sieve-manage-erase) rsp)) (defun sieve-manage-parse-capability (str) "Parse managesieve capability string `STR'. Return alist of capabilities, suitable for assignment to local variable `sieve-manage-capability'." (let ((capas (delq nil (mapcar #'split-string-and-unquote (split-string str "\n"))))) (when (string= "OK" (caar (last capas))) (setq sieve-manage-state 'nonauth)) capas)) (defun sieve-manage-is-string () (cond ((looking-at "\"\\([^\"]+\\)\"") (prog1 (match-string 1) (goto-char (match-end 0)))) ((looking-at (concat "{\\([0-9]+\\+?\\)}" sieve-manage-server-eol)) (let ((pos (match-end 0)) (len (string-to-number (match-string 1)))) (if (< (point-max) (+ pos len)) nil (goto-char (+ pos len)) (buffer-substring pos (+ pos len))))))) (defun sieve-manage-parse-string () (let (rsp) (while (null rsp) (accept-process-output (get-buffer-process (current-buffer)) 1) (goto-char (point-min)) (unless (setq rsp (sieve-manage-is-string)) (when (sieve-manage-no-p (sieve-manage-is-oknobye)) ;; simple `error' is enough since `sieve-manage-erase' ;; already adds the server response to the log (error (sieve-manage-erase))))) (sieve-manage-erase (point)) rsp)) (defun sieve-manage-parse-crlf () (when (looking-at sieve-manage-server-eol) (sieve-manage-erase (match-end 0)))) (defun sieve-manage-parse-listscripts () (let (tmp rsp data) (while (null rsp) (while (null (or (setq rsp (sieve-manage-is-oknobye)) (setq tmp (sieve-manage-decode (sieve-manage-is-string))))) (accept-process-output (get-buffer-process (current-buffer)) 1) (goto-char (point-min))) (when tmp (while (not (looking-at (concat "\\( ACTIVE\\)?" sieve-manage-server-eol))) (accept-process-output (get-buffer-process (current-buffer)) 1) (goto-char (point-min))) (if (match-string 1) (push (cons 'active tmp) data) (push tmp data)) (goto-char (match-end 0)) (setq tmp nil))) (sieve-manage-erase) (if (sieve-manage-ok-p rsp) data rsp))) (defun sieve-manage-send (command &optional payload-str) "Send COMMAND with optional PAYLOAD-STR. If non-nil, PAYLOAD-STR will be appended to COMMAND using the \\='literal-s2c\\' representation according to RFC5804." (let ((encoded (when payload-str (sieve-manage-encode payload-str))) literal-c2s cmdstr) (when encoded (setq literal-c2s (format " {%d+}%s%s" (length encoded) sieve-manage-client-eol encoded))) (setq cmdstr (concat (sieve-manage-encode command) literal-c2s sieve-manage-client-eol)) (sieve-manage--append-to-log cmdstr) (process-send-string sieve-manage-process cmdstr))) (provide 'sieve-manage) ;;; sieve-manage.el ends here