;;; url-http-ntlm.el --- NTLM authentication for the url library
-;; Copyright (C) 2008 Tom Schutzer-Weissmann
+;; Copyright (C) 2008, 2016 Free Software Foundation, Inc.
-;; Author: Tom Schutzer-Weissmann <tom@schutzer-weissmann.net>
+;; Author: Tom Schutzer-Weissmann <tom.weissmann@gmail.com>
+;; Maintainer: Thomas Fitzsimmons <fitzsim@fitzsim.org>
+;; Version: 2.0.2
;; Keywords: comm, data, processes, hypermedia
+;; Homepage: https://code.google.com/p/url-http-ntlm/
+;; Package-Requires: ((cl-lib "0.5") (ntlm "2.0.0"))
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;;; Commentary:
;;
;; This package provides a NTLM handler for the URL package.
-;; It supports one username and password per server.
;;
;; Installation:
;;
-;; Add the directory containing this file to the load path and then load the url-http-ntlm
-;; package. One way would be to add something like the lines below to your .emacs file:
-;;
-;; (add-to-list 'load-path ".emacs.d/url-http-ntlm")
-;; (require 'url-http-ntlm)
+;; M-x package-install RET url-http-ntlm RET
;;
;; Acknowledgements:
;;
-;; Taro Kawagishi <tarok@transpulse.org> wrote ntlm.el and md4.el, which are parts of FLIM
-;; (Faithful Library about Internet Message).
+;; Taro Kawagishi <tarok@transpulse.org> wrote ntlm.el and md4.el,
+;; which are parts of FLIM (Faithful Library about Internet Message).
;;
;; http://stuff.mit.edu/afs/sipb/contrib/emacs/packages/flim-1.14.7/ntlm.el
;; http://stuff.mit.edu/afs/sipb/contrib/emacs/packages/flim-1.14.7/md4.el
;;; Code:
(require 'url-auth)
(require 'url-http)
+(require 'url-util)
(require 'mail-parse)
-(require 'cl)
+(require 'cl-lib)
(require 'ntlm)
-(defvar url-http-ntlm-auth-storage nil
- "Authentication storage. An alist that maps a server name
-to a pair of \(<username> <ntlm hashes>\).
-
-The hashes are built using `ntlm-get-password-hashes'.
-The username can contain the domain name, in the form \"user@domain\".
-
-Note that for any server, only one user and password is ever stored.")
-
-(defun url-ntlm-auth (url &optional prompt overwrite realm args)
- "Get the contents of the Authorization header for a HTTP
- response using NTLM authentication, to access URL. Because
- NTLM is a two-step process, this function expects to be called
- twice, first to generate the NTLM type 1 message (request),
- then to respond to the server's type 2 message (challenge) with
- a suitable response.
-
- PROMPT, OVERWRITE, and REALM are ignored.
-
- ARGS is expected to contain the WWW-Authentication header from
- the server's last response. These are used by
- `url-http-get-stage' to determine what stage we are at."
- (url-ntlm-ensure-keepalive)
- (let ((stage (url-ntlm-get-stage args)))
- (case stage
- ;;
- ;; NTLM Type 1 message: the request
- (:request
- (destructuring-bind (&optional server user hash)
- (url-http-ntlm-authorisation url)
- (when server
- (url-http-ntlm-string (ntlm-build-auth-request user server)))))
- ;;
- ;; NTLM Type 3 message: the response
- (:response
- (let ((challenge (url-http-ntlm-get-challenge)))
- (destructuring-bind (server user hash)
- (url-http-ntlm-authorisation url)
- (url-http-ntlm-string (ntlm-build-auth-response challenge
- user
- hash)))))
- (:error
- (url-http-ntlm-authorisation url :clear)))))
-
-
-(defun url-ntlm-ensure-keepalive ()
- (assert url-http-attempt-keepalives
- nil
- "NTLM authentication won't work unless `url-http-attempt-keepalives' is set!"))
-
-
-(defun url-ntlm-clean-headers ()
+;; Remove authorization after redirect.
+(when (and (boundp 'emacs-major-version)
+ (< emacs-major-version 25))
+ (defvar url-http-ntlm--parsing-headers nil)
+ (defadvice url-http-parse-headers (around clear-authorization activate)
+ (let ((url-http-ntlm--parsing-headers t))
+ ad-do-it))
+ (defadvice url-http-handle-authentication (around clear-authorization
+ activate)
+ (let ((url-http-ntlm--parsing-headers nil))
+ ad-do-it))
+ (defadvice url-retrieve-internal (before clear-authorization activate)
+ (when (and url-http-ntlm--parsing-headers
+ (eq url-request-extra-headers url-http-extra-headers))
+ ;; This retrieval is presumably in response to a redirect.
+ ;; Do not automatically include an authorization header in the
+ ;; redirect. If needed it will be regenerated by the relevant
+ ;; auth scheme when the new request happens.
+ (setq url-http-extra-headers
+ (cl-remove "Authorization"
+ url-http-extra-headers :key #'car :test #'equal))
+ (setq url-request-extra-headers url-http-extra-headers))))
+
+\f
+;;; Private variables.
+(defvar url-http-ntlm--auth-storage nil
+ "Authentication storage.
+An alist that maps a server name to a pair of \(<username> <ntlm
+hashes>\).
+
+The hashes are built using `ntlm-get-password-hashes'.")
+
+(defvar url-http-ntlm--last-args nil
+ "The last `url-http-ntlm--get-stage' arguments and result.
+This is used to detect multiple calls.")
+(make-variable-buffer-local 'url-http-ntlm--last-args)
+
+(defvar url-http-ntlm--loop-timer-counter nil
+ "A hash table used to detect NTLM negotiation errors.
+Keys are urls, entries are (START-TIME . COUNTER).")
+
+(defvar url-http-ntlm--default-users nil
+ "An alist that stores one default username per server.")
+
+\f
+;;; Private functions.
+(defun url-http-ntlm--detect-loop (url)
+ "Detect potential infinite loop when NTLM fails on URL."
+ (when (not url-http-ntlm--loop-timer-counter)
+ (setq url-http-ntlm--loop-timer-counter (make-hash-table :test 'equal)))
+ (let* ((url-string (url-recreate-url url))
+ (last-entry (gethash url-string url-http-ntlm--loop-timer-counter))
+ (start-time (car last-entry))
+ (counter (cdr last-entry)))
+ (if last-entry
+ (progn
+ (if (< (- (float-time) start-time) 10.0)
+ (if (< counter 20)
+ ;; Still within time window, so increment count.
+ (puthash url-string (cons start-time (1+ counter))
+ url-http-ntlm--loop-timer-counter)
+ ;; Error detected, so remove entry and clear.
+ (url-http-ntlm--authorization url-string :clear)
+ (remhash url-string url-http-ntlm--loop-timer-counter)
+ (error
+ (format (concat "Access rate to %s is too high,"
+ " indicating an NTLM failure;"
+ " to debug, re-run with url-debug set to 1")
+ url-string)))
+ ;; Timeout expired, so reset counter.
+ (puthash url-string (cons (float-time) 0)
+ url-http-ntlm--loop-timer-counter)))
+ ;; New access, so initialize counter to 0.
+ (puthash url-string (cons (float-time) 0)
+ url-http-ntlm--loop-timer-counter))))
+
+(defun url-http-ntlm--ensure-user (url)
+ "Return URL with its user slot set.
+If URL's user slot is nil, set it to the last user that made a
+request to the host in URL's server slot."
+ (let ((new-url url))
+ (if (url-user new-url)
+ new-url
+ (setf (url-user new-url)
+ (cdr (assoc (url-host new-url) url-http-ntlm--default-users)))
+ new-url)))
+
+(defun url-http-ntlm--ensure-keepalive ()
+ "Report an error if `url-http-attempt-keepalives' is not set."
+ (cl-assert url-http-attempt-keepalives
+ nil
+ (concat "NTLM authentication won't work unless"
+ " `url-http-attempt-keepalives' is set!")))
+
+(defun url-http-ntlm--clean-headers ()
+ "Remove Authorization element from `url-http-extra-headers' alist."
+ (cl-declare (special url-http-extra-headers))
(setq url-http-extra-headers
- (url-http-ntlm-rmssoc "Authorization" url-http-extra-headers)))
+ (url-http-ntlm--rmssoc "Authorization" url-http-extra-headers)))
-
-(defvar url-ntlm-last-args nil
- "Stores the last ARGS argument to `url-ntlm-get-stage' and the return value. This is
- used to detect multiple calls.")
-(make-variable-buffer-local 'url-ntlm-last-args)
-
-
-(defun url-ntlm-get-stage (args)
+(defun url-http-ntlm--get-stage (args)
"Determine what stage of the NTLM handshake we are at.
+PROMPT and ARGS come from `url-ntlm-auth''s caller,
+`url-get-authentication'. Their meaning depends on the current
+implementation - this function is well and truly coupled.
+
+`url-get-authentication' calls `url-ntlm-auth' once when checking
+what authentication schemes are supported (PROMPT and ARGS are
+nil), and then twice for every stage of the handshake: the first
+time PROMPT is nil, the second, t; ARGS contains the server
+response's \"WWW-Authenticate\" header, munged by
+`url-parse-args'."
+ (cl-declare (special url-http-extra-headers))
+ (let* ((response-rxp "^NTLM TlRMTVNTUAADAAA")
+ (challenge-rxp "^TLRMTVNTUAACAAA")
+ (auth-header (assoc "Authorization" url-http-extra-headers))
+ (case-fold-search t)
+ stage)
+ (url-debug 'url-http-ntlm "Buffer: %s" (current-buffer))
+ (url-debug 'url-http-ntlm "Arguments: %s" args)
+ (url-debug 'url-http-ntlm "Previous arguments: %s" url-http-ntlm--last-args)
+ (if (eq args (car url-http-ntlm--last-args))
+ ;; multiple calls, return the same argument we returned last time
+ (progn
+ (url-debug 'url-http-ntlm "Returning previous result: %s"
+ (cdr url-http-ntlm--last-args))
+ (cdr url-http-ntlm--last-args))
+ (let ((stage
+ (cond ((and auth-header (string-match response-rxp
+ (cdr auth-header)))
+ :error)
+ ((and (= (length args) 2)
+ (cl-destructuring-bind (challenge ntlm) args
+ (and (string-equal "ntlm" (car ntlm))
+ (string-match challenge-rxp
+ (car challenge)))))
+ :response)
+ (t
+ :request))))
+ (url-http-ntlm--clean-headers)
+ (setq url-http-ntlm--last-args (cons args stage))
+ stage))))
+
+(defun url-http-ntlm--authorization (url &optional clear realm)
+ "Get or clear NTLM authentication details for URL.
+If CLEAR is non-nil, clear any saved credentials for server.
+Otherwise, return the credentials, prompting the user if
+necessary. REALM appears in the prompt.
-PROMPT and ARGS come from `url-ntlm-auth''s caller, `url-get-authentication'. Their
-meaning depends on the current implementation - this function is well and truly coupled...
-
-url-get-authentication' calls `url-ntlm-auth' once when checking what authentication
-schemes are supported (PROMPT and ARGS are nil), and then twice for every stage of the
-handshake: the first time PROMPT is nil, the second, t; ARGS contains the server
-response's \"WWW-Authenticate\" header, munged by `url-parse-args'."
- (let* ((response-rxp "^NTLM TlRMTVNTUAADAAA")
- (challenge-rxp "^TLRMTVNTUAACAAA")
- (auth-header (assoc "Authorization" url-http-extra-headers))
- (case-fold-search t)
- stage)
- (if (eq args (car url-ntlm-last-args))
- ;; multiple calls, return the same argument we returned last time
- (cdr url-ntlm-last-args)
- ;;
- (let ((stage
- (cond ((and auth-header (string-match response-rxp (cdr auth-header)))
- :error)
- ((and (= (length args) 2)
- (destructuring-bind (challenge ntlm) args
- (and (string-equal "ntlm" (car ntlm))
- (string-match challenge-rxp (car challenge)))))
- :response)
- (t
- :request))))
- (url-ntlm-clean-headers)
- (setq url-ntlm-last-args (cons args stage))
- stage))))
-
-
-(defun url-http-ntlm-authorisation (url &optional clear)
- "Get or clear NTLM authentication details for URL. If CLEAR is
- non-nil, clear any saved credentials for server. Otherwise,
- return the credentials, prompting the user if necessary.
-
If URL contains a username and a password, they are used and
-stored credentials are not affected.
-
-Note that for any server, only one user and password is ever
-stored."
+stored credentials are not affected."
(let* ((href (if (stringp url)
- (url-generic-parse-url url)
- url))
- (server (url-host href))
- (user (url-user href))
- (pass (url-password href))
- (stored (assoc server url-http-ntlm-auth-storage))
- (both (and user pass)))
+ (url-generic-parse-url url)
+ url))
+ (type (url-type href))
+ (user (url-user href))
+ (server (url-host href))
+ (port (url-portspec href))
+ (pass (url-password href))
+ (stored (assoc (list type user server port)
+ url-http-ntlm--auth-storage))
+ (both (and user pass)))
(if clear
- ;; clear
- (unless both
- (setq url-http-ntlm-auth-storage
- (url-http-ntlm-rmssoc server url-http-ntlm-auth-storage))
- nil)
- ;; get
- (if (or both
- (and stored user (not (equal user (second stored))))
- (not stored))
- (let* ((user* (if both
- user
- (read-string (url-auth-user-prompt url realm)
- (or user (user-real-login-name)))))
- (pass* (if both
- pass
- (read-passwd "Password: ")))
- (entry `(,server . (,user* ,(ntlm-get-password-hashes pass*)))))
- (unless both
- (setq url-http-ntlm-auth-storage
- (cons entry
- (url-http-ntlm-rmssoc server url-http-ntlm-auth-storage))))
- entry)
- ;;
- stored))))
-
-
-(defun url-http-ntlm-get-challenge ()
- "Return the NTLM Type-2 message in the WWW-Authenticate header,
-if it is there."
+ ;; clear
+ (unless both
+ (setq url-http-ntlm--default-users
+ (url-http-ntlm--rmssoc server url-http-ntlm--default-users))
+ (setq url-http-ntlm--auth-storage
+ (url-http-ntlm--rmssoc '(type user* server port)
+ url-http-ntlm--auth-storage))
+ nil)
+ ;; get
+ (if (or both
+ (and stored user (not (equal user (cl-second (car stored)))))
+ (not stored))
+ (let* ((user* (or user
+ (url-do-auth-source-search server type :user)
+ (read-string (url-auth-user-prompt url realm)
+ (or user (user-real-login-name)))))
+ (pass* (if both
+ pass
+ (or (url-do-auth-source-search server type :secret)
+ (read-passwd (format "Password [for %s]: "
+ (url-recreate-url url))))))
+ (key (list type user* server port))
+ (entry `(,key . (,(ntlm-get-password-hashes pass*)))))
+ (unless both
+ (setq url-http-ntlm--default-users
+ (cons
+ `(,server . ,user*)
+ (url-http-ntlm--rmssoc server
+ url-http-ntlm--default-users)))
+ (setq url-http-ntlm--auth-storage
+ (cons entry
+ (url-http-ntlm--rmssoc
+ key
+ url-http-ntlm--auth-storage))))
+ entry)
+ stored))))
+
+(defun url-http-ntlm--get-challenge ()
+ "Return the NTLM Type-2 message in the WWW-Authenticate header.
+Return nil if the NTLM Type-2 message is not present."
(save-restriction
(mail-narrow-to-head)
(let ((www-authenticate (mail-fetch-field "www-authenticate")))
(when (string-match "NTLM\\s-+\\(\\S-+\\)"
- www-authenticate)
- (base64-decode-string (match-string 1 www-authenticate))))))
+ www-authenticate)
+ (base64-decode-string (match-string 1 www-authenticate))))))
+(defun url-http-ntlm--rmssoc (key alist)
+ "Remove all elements whose `car' match KEY from ALIST."
+ (cl-remove key alist :key 'car :test 'equal))
-(defun url-http-ntlm-rmssoc (key alist)
- (remove* key alist :key 'car :test 'equal))
-
-
-(defun url-http-ntlm-string (data)
+(defun url-http-ntlm--string (data)
+ "Return DATA encoded as an NTLM string."
(concat "NTLM " (base64-encode-string data :nobreak)))
+\f
+;;; Public function called by `url-get-authentication'.
+;;;###autoload
+(defun url-ntlm-auth (url &optional prompt overwrite realm args)
+ "Return an NTLM HTTP authorization header.
+Get the contents of the Authorization header for a HTTP response
+using NTLM authentication, to access URL. Because NTLM is a
+two-step process, this function expects to be called twice, first
+to generate the NTLM type 1 message (request), then to respond to
+the server's type 2 message (challenge) with a suitable response.
+
+PROMPT, OVERWRITE, and REALM are ignored.
+
+ARGS is expected to contain the WWW-Authentication header from
+the server's last response. These are used by
+`url-http-get-stage' to determine what stage we are at."
+ (url-http-ntlm--ensure-keepalive)
+ (let* ((user-url (url-http-ntlm--ensure-user url))
+ (stage (url-http-ntlm--get-stage args)))
+ (url-debug 'url-http-ntlm "Stage: %s" stage)
+ (cl-case stage
+ ;; NTLM Type 1 message: the request
+ (:request
+ (url-http-ntlm--detect-loop user-url)
+ (cl-destructuring-bind (&optional key hash)
+ (url-http-ntlm--authorization user-url nil realm)
+ (when (cl-third key)
+ (url-http-ntlm--string
+ (ntlm-build-auth-request (cl-second key) (cl-third key))))))
+ ;; NTLM Type 3 message: the response
+ (:response
+ (url-http-ntlm--detect-loop user-url)
+ (let ((challenge (url-http-ntlm--get-challenge)))
+ (cl-destructuring-bind (key hash)
+ (url-http-ntlm--authorization user-url nil realm)
+ (url-http-ntlm--string
+ (ntlm-build-auth-response challenge
+ (cl-second key)
+ hash)))))
+ (:error
+ (url-http-ntlm--authorization user-url :clear)))))
+\f
+;;; Register `url-ntlm-auth' HTTP authentication method.
+;;;###autoload
(url-register-auth-scheme "ntlm" nil 8)
-
(provide 'url-http-ntlm)
+
;;; url-http-ntlm.el ends here