1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
;;; Consfigurator -- Lisp declarative configuration management system
;;; Copyright (C) 2021 Sean Whitton <spwhitton@spwhitton.name>
;;; This file 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, or (at your option)
;;; any later version.
;;; This file 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 this program. If not, see <http://www.gnu.org/licenses/>.
(in-package :consfigurator.connection.setuid)
(named-readtables:in-readtable :consfigurator)
(defclass setuid-connection (rehome-connection fork-connection) ())
(defmethod establish-connection ((type (eql :setuid)) remaining &key to)
(unless (and (lisp-connection-p) (zerop (nix:geteuid)))
(error "~&SETUIDing requires a Lisp image running as root"))
(informat 1 "~&SETUIDing to ~A" to)
(multiple-value-bind (match groups)
(re:scan-to-strings #?/uid=([0-9]+).+gid=([0-9]+)/ (run "id" to))
(unless match
(error "Could not determine UID and GID of ~A" to))
(let* ((uid (parse-integer (elt groups 0)))
(gid (parse-integer (elt groups 1)))
(home
;; tilde expansion is POSIX
(ensure-directory-pathname (stripln (run (strcat "echo ~" to)))))
(xdg-cache-home
(ensure-directory-pathname
(stripln
;; su(1) is not POSIX but very likely to be present. Note that
;; the -c argument here is to the user's login shell, not the
;; -c argument to su(1) on, e.g., FreeBSD. So should be fairly
;; portable.
(mrun "su" to "-c" "echo ${XDG_CACHE_HOME:-$HOME/.cache}")))))
(continue-connection
(make-instance
'setuid-connection
:datadir (merge-pathnames "consfigurator/data/" xdg-cache-home)
:connattrs `(:remote-uid ,uid :remote-gid ,gid
:remote-user ,to :remote-home ,home
:XDG-CACHE-HOME ,xdg-cache-home))
remaining))))
(defmethod post-fork ((connection setuid-connection))
(let ((uid (connection-connattr connection :remote-uid))
(gid (connection-connattr connection :remote-gid))
(user (connection-connattr connection :remote-user)))
(run-program (list "chown" "-R"
(format nil "~A:~A" uid gid)
(unix-namestring (slot-value connection 'datadir))))
(posix-login-environment
user (connection-connattr connection :remote-home))
;; We are privileged, so this sets the real, effective and saved IDs.
(nix:setgid gid) (nix:initgroups user gid) (nix:setuid uid)))
|
