;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 Guix 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 Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu system pam)
  #:use-module (guix records)
  #:use-module (guix derivations)
  #:use-module (guix gexp)
  #:use-module (gnu services)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module </td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>refs</a><a href='/guix/log/gnu/build/shepherd.scm'>log</a><a href='/guix/tree/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>tree</a><a class='active' href='/guix/commit/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>commit</a><a href='/guix/diff/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/build/shepherd.scm'>
<input type='hidden' name='id' value='db170ee9210431cdbb3716a6b9a26ca5b6d931ee'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/commit/?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>root</a>/<a href='/guix/commit/gnu?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>gnu</a>/<a href='/guix/commit/gnu/build?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>build</a>/<a href='/guix/commit/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>shepherd.scm</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='db170ee9210431cdbb3716a6b9a26ca5b6d931ee'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Ludovic Courtès &lt;ludo@gnu.org&gt;</td><td class='right'>2020-06-24 10:47:23 +0200</td></tr>
<tr><th>committer</th><td>Ludovic Courtès &lt;ludo@gnu.org&gt;</td><td class='right'>2020-06-25 01:20:31 +0200</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/guix/commit/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>db170ee9210431cdbb3716a6b9a26ca5b6d931ee</a> (<a href='/guix/patch/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/guix/tree/?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>2a7c74ed55c44432e5f8efa977c37ab9f155ed3c</a> /<a href='/guix/tree/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>gnu/build/shepherd.scm</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/guix/commit/gnu/build/shepherd.scm?id=5adaf17bb0511ca6c65b81c714d14c40b70f1db9'>5adaf17bb0511ca6c65b81c714d14c40b70f1db9</a> (<a href='/guix/diff/gnu/build/shepherd.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee&amp;id2=5adaf17bb0511ca6c65b81c714d14c40b70f1db9'>diff</a>)</td></tr><tr><th>download</th><td colspan='2' class='oid'><a href='/guix/snapshot/guix-db170ee9210431cdbb3716a6b9a26ca5b6d931ee.tar.gz'>guix-db170ee9210431cdbb3716a6b9a26ca5b6d931ee.tar.gz</a><br/><a href='/guix/snapshot/guix-db170ee9210431cdbb3716a6b9a26ca5b6d931ee.zip'>guix-db170ee9210431cdbb3716a6b9a26ca5b6d931ee.zip</a><br/></td></tr></table>
<div class='commit-subject'>services: Add missing (ice-9 format) import.</div><div class='commit-msg'>These issues were reported by -Wformat, though they were harmless in
practice because importing (ice-9 format) changes the global 'format'
binding currently.

* gnu/services/nix.scm: Import (ice-9 format).
* gnu/services/web.scm: Likewise.
* gnu/system/mapped-devices.scm: Likewise.
</div><div class='diffstat-header'><a href='/guix/diff/?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>Diffstat</a> (limited to 'gnu/build/shepherd.scm')</div><table summary='diffstat' class='diffstat'></table><div class='diffstat-summary'>0 files changed, 0 insertions, 0 deletions</div><table summary='diff' class='diff'><tr><td></td></tr></table></div> <!-- class=content -->
                         <div class=footer>generated by
                             <a href="https://git.zx2c4.com/cgit/about/">
                                 cgit
                             </a>
                         </div>
                        </div> <!-- id=cgit -->
</body>
</html>
ring-append #$output "/" name))))

                    ;; Since <pam-service> objects cannot be compared with
                    ;; 'equal?' since they contain gexps, which contain
                    ;; closures, use 'delete-duplicates' on the build-side
                    ;; instead.  See <http://bugs.gnu.org/20037>.
                    (delete-duplicates '#$(zip names files)))))

    (computed-file "pam.d" builder)))

(define %pam-other-services
  ;; The "other" PAM configuration, which denies everything (see
  ;; <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-example.html>.)
  (let ((deny (pam-entry
               (control "required")
               (module "pam_deny.so"))))
    (pam-service
     (name "other")
     (account (list deny))
     (auth (list deny))
     (password (list deny))
     (session (list deny)))))

(define unix-pam-service
  (let ((unix (pam-entry
               (control "required")
               (module "pam_unix.so")))
        (env  (pam-entry ; to honor /etc/environment.
               (control "required")
               (module "pam_env.so"))))
    (lambda* (name #:key allow-empty-passwords? (allow-root? #f) motd)
      "Return a standard Unix-style PAM service for NAME.  When
ALLOW-EMPTY-PASSWORDS? is true, allow empty passwords.  When ALLOW-ROOT? is
true, allow root to run the command without authentication.  When MOTD is
true, it should be a file-like object used as the message-of-the-day."
      ;; See <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-example.html>.
      (let ((name* name))
        (pam-service
         (name name*)
         (account (list unix))
         (auth (append (if allow-root?
                           (list (pam-entry
                                  (control "sufficient")
                                  (module "pam_rootok.so")))
                           '())
                       (list (if allow-empty-passwords?
                                 (pam-entry
                                  (control "required")
                                  (module "pam_unix.so")
                                  (arguments '("nullok")))
                                 unix))))
         (password (list (pam-entry
                          (control "required")
                          (module "pam_unix.so")
                          ;; Store SHA-512 encrypted passwords in /etc/shadow.
                          (arguments '("sha512" "shadow")))))
         (session (if motd
                      (list env unix
                            (pam-entry
                             (control "optional")
                             (module "pam_motd.so")
                             (arguments
                              (list #~(string-append "motd=" #$motd)))))
                      (list env unix))))))))

(define (rootok-pam-service command)
  "Return a PAM service for COMMAND such that 'root' does not need to
authenticate to run COMMAND."
  (let ((unix (pam-entry
               (control "required")
               (module "pam_unix.so"))))
    (pam-service
     (name command)
     (account (list unix))
     (auth (list (pam-entry
                  (control "sufficient")
                  (module "pam_rootok.so"))))
     (password (list unix))
     (session (list unix)))))

(define* (base-pam-services #:key allow-empty-passwords?)
  "Return the list of basic PAM services everyone would want."
  ;; TODO: Add other Shadow programs?
  (append (list %pam-other-services)

          ;; These programs are setuid-root.
          (map (cut unix-pam-service <>
                    #:allow-empty-passwords? allow-empty-passwords?)
               '("passwd" "sudo"))
          ;; This is setuid-root, as well.  Allow root to run "su" without
          ;; authenticating.
          (list (unix-pam-service "su"
                                  #:allow-empty-passwords? allow-empty-passwords?
                                  #:allow-root? #t))

          ;; These programs are not setuid-root, and we want root to be able
          ;; to run them without having to authenticate (notably because
          ;; 'useradd' and 'groupadd' are run during system activation.)
          (map rootok-pam-service
               '("useradd" "userdel" "usermod"
                 "groupadd" "groupdel" "groupmod"))))


;;;
;;; System-wide environment variables.
;;;

(define (environment-variables->environment-file vars)
  "Return a file for pam_env(8) that contains environment variables VARS."
  (apply mixed-text-file "environment"
         (append-map (match-lambda
                       ((key . value)
                        (list key "=" value "\n")))
                     vars)))

(define session-environment-service-type
  (service-type
   (name 'session-environment)
   (extensions
    (list (service-extension
           etc-service-type
           (lambda (vars)
             (list `("environment"
                     ,(environment-variables->environment-file vars)))))))
   (compose concatenate)
   (extend append)
   (description
    "Populate @file{/etc/environment}, which is honored by @code{pam_env},
with the specified environment variables.  The value of this service is a list
of name/value pairs for environments variables, such as:

@example
'((\"TZ\" . \"Canada/Pacific\"))
@end example\n")))

(define (session-environment-service vars)
  "Return a service that builds the @file{/etc/environment}, which can be read
by PAM-aware applications to set environment variables for sessions.

VARS should be an association list in which both the keys and the values are
strings or string-valued gexps."
  (service session-environment-service-type vars))



;;;
;;; PAM root service.
;;;

;; Overall PAM configuration: a list of services, plus a procedure that takes
;; one <pam-service> and returns a <pam-service>.  The procedure is used to
;; implement cross-cutting concerns such as the use of the 'elogind.so'
;; session module that keeps track of logged-in users.
(define-record-type* <pam-configuration>
  pam-configuration make-pam-configuration? pam-configuration?
  (services  pam-configuration-services)          ;list of <pam-service>
  (transform pam-configuration-transform))        ;procedure

(define (/etc-entry config)
  "Return the /etc/pam.d entry corresponding to CONFIG."
  (match config
    (($ <pam-configuration> services transform)
     (let ((services (map transform services)))
       `(("pam.d" ,(pam-services->directory services)))))))

(define (extend-configuration initial extensions)
  "Extend INITIAL with NEW."
  (let-values (((services procs)
                (partition pam-service? extensions)))
    (pam-configuration
     (services (append (pam-configuration-services initial)
                       services))
     (transform (apply compose
                       (pam-configuration-transform initial)
                       procs)))))

(define pam-root-service-type
  (service-type (name 'pam)
                (extensions (list (service-extension etc-service-type
                                                     /etc-entry)))

                ;; Arguments include <pam-service> as well as procedures.
                (compose concatenate)
                (extend extend-configuration)))

(define* (pam-root-service base #:key (transform identity))
  "The \"root\" PAM service, which collects <pam-service> instance and turns
them into a /etc/pam.d directory, including the <pam-service> listed in BASE.
TRANSFORM is a procedure that takes a <pam-service> and returns a
<pam-service>.  It can be used to implement cross-cutting concerns that affect
all the PAM services."
  (service pam-root-service-type
           (pam-configuration (services base)
                              (transform transform))))