[Emacs-diffs] Changes to emacs/lisp/server.el

[Stefan Monnier]

Index: emacs/lisp/server.el
diff -c emacs/lisp/server.el:1.90 emacs/lisp/server.el:1.91
*** emacs/lisp/server.el:1.90   Mon Feb 10 16:44:24 2003
--- emacs/lisp/server.el        Sat Apr 12 15:04:11 2003
***************
*** 1,6 ****
  ;;; server.el --- Lisp code for GNU Emacs running as server process
  
! ;; Copyright (C) 1986, 87, 92, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002
  ;;     Free Software Foundation, Inc.
  
  ;; Author: William Sommerfeld <address@hidden>
--- 1,6 ----
  ;;; server.el --- Lisp code for GNU Emacs running as server process
  
! ;; Copyright (C) 1986,87,92,94,95,96,97,98,99,2000,01,02,2003
  ;;     Free Software Foundation, Inc.
  
  ;; Author: William Sommerfeld <address@hidden>
***************
*** 159,169 ****
  are done with it in the server.")
  (make-variable-buffer-local 'server-existing-buffer)
  
- ;; Fixme: This doesn't look secure.  If it really is, it deserves a
- ;; comment, but I'd expect it to be created in a protected subdir as
- ;; normal.  -- fx
  (defvar server-socket-name
!   (format "/tmp/esrv%d-%s" (user-uid)
          (substring (system-name) 0 (string-match "\\." (system-name)))))
  
  (defun server-log (string &optional client)
--- 159,166 ----
  are done with it in the server.")
  (make-variable-buffer-local 'server-existing-buffer)
  
  (defvar server-socket-name
!   (format "/tmp/emacs%d-%s/server" (user-uid)
          (substring (system-name) 0 (string-match "\\." (system-name)))))
  
  (defun server-log (string &optional client)
***************
*** 223,228 ****
--- 220,241 ----
            (t " ")))
     arg t t))
  
+ (defun server-ensure-safe-dir (dir)
+   "Make sure DIR is a directory with no race-condition issues.
+ Creates the directory if necessary and makes sure:
+ - there's no symlink involved
+ - it's owned by us
+ - it's not readable/writable by anybody else."
+   (setq dir (directory-file-name dir))
+   (let ((attrs (file-attributes dir)))
+     (unless attrs
+       (letf (((default-file-modes) ?\700)) (make-directory dir))
+       (setq attrs (file-attributes dir)))
+     ;; Check that it's safe for use.
+     (unless (and (eq t (car attrs)) (eq (nth 2 attrs) (user-uid))
+                (zerop (logand ?\077 (file-modes dir))))
+       (error "The directory %s is unsafe" dir))))
+ 
  ;;;###autoload
  (defun server-start (&optional leave-dead)
    "Allow this Emacs process to be a server for client processes.
***************
*** 233,238 ****
--- 246,253 ----
  
  Prefix arg means just kill any existing server communications subprocess."
    (interactive "P")
+   ;; Make sure there is a safe directory in which to place the socket.
+   (server-ensure-safe-dir (file-name-directory server-socket-name))
    ;; kill it dead!
    (condition-case () (delete-process server-process) (error nil))
    ;; Delete the socket files made by previous server invocations.
***************
*** 271,277 ****
    ;; Fixme: Should this check for an existing server socket and do
    ;; nothing if there is one (for multiple Emacs sessions)?
    (server-start (not server-mode)))
- (custom-add-version 'server-mode "21.4")
  
  (defun server-process-filter (proc string)
    "Process a request from the server to edit some files.
--- 286,291 ----
***************
*** 296,308 ****
        (setq string (substring string (match-end 0)))
        (setq client (cons proc nil))
        (while (string-match "[^ ]* " request)
!       (let ((arg (substring request (match-beginning 0) (1- (match-end 0))))
!             (pos 0))
          (setq request (substring request (match-end 0)))
          (cond
           ((equal "-nowait" arg) (setq nowait t))
! ;;; This is not safe unless we make sure other users can't send commands.
! ;;;      ((equal "-eval" arg) (setq eval t))
           ((and (equal "-display" arg) (string-match "\\([^ ]*\\) " request))
            (let ((display (server-unquote-arg (match-string 1 request))))
              (setq request (substring request (match-end 0)))
--- 310,320 ----
        (setq string (substring string (match-end 0)))
        (setq client (cons proc nil))
        (while (string-match "[^ ]* " request)
!       (let ((arg (substring request (match-beginning 0) (1- (match-end 0)))))
          (setq request (substring request (match-end 0)))
          (cond
           ((equal "-nowait" arg) (setq nowait t))
!          ((equal "-eval" arg) (setq eval t))
           ((and (equal "-display" arg) (string-match "\\([^ ]*\\) " request))
            (let ((display (server-unquote-arg (match-string 1 request))))
              (setq request (substring request (match-end 0)))