installer: Ask for user password and initialize /etc/shadow.

Partly fixes <https://bugs.gnu.org/35399>.

* gnu/installer/user.scm (<user>)[password]: New field.
* gnu/installer/final.scm (%seed): New variable.
(integer->alphanumeric-char, random-string)
(create-user-database): New procedures.
(install-system): Call 'create-user-database'.
* gnu/installer/newt/final.scm (run-install-shell): Add #:users and pass
it to 'install-system'.
(run-final-page): Pass #:users to 'run-install-shell'.
* gnu/installer/newt/user.scm (run-user-add-page): Add password entry.
Pass its result as the 'password' field of <user>.

1 files changed, 80 insertions, 4 deletions

diff --git a/gnu/installer/final.scm b/gnu/installer/final.scm
index 07946f72c3..4cf34d0457 100644
--- a/gnu/installer/final.scm
+++ b/gnu/installer/final.scm
@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2018 Mathieu Othacehe <m.othacehe@gmail.com>
+;;; Copyright © 2019 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -20,19 +21,94 @@
   #:use-module (gnu installer newt page)
   #:use-module (gnu installer steps)
   #:use-module (gnu installer utils)
+  #:use-module (gnu installer user)
   #:use-module (gnu services herd)
   #:use-module (guix build utils)
+  #:use-module (gnu build accounts)
+  #:use-module ((gnu system shadow) #:prefix sys:)
+  #:use-module (rnrs io ports)
   #:export (install-system))
 
-(define (install-system locale)
-  "Start COW-STORE service on target directory and launch guix install command
-in a subshell.  LOCALE must be the locale name under which that command will
-run, or #f."
+(define %seed
+  (seed->random-state
+   (logxor (getpid) (car (gettimeofday)))))
+
+(define (integer->alphanumeric-char n)
+  "Map N, an integer in the [0..62] range, to an alphanumeric character."
+  (cond ((< n 10)
+         (integer->char (+ (char->integer #\0) n)))
+        ((< n 36)
+         (integer->char (+ (char->integer #\A) (- n 10))))
+        ((< n 62)
+         (integer->char (+ (char->integer #\a) (- n 36))))
+        (else
+         (error "integer out of bounds" n))))
+
+(define (random-string len)
+  "Compute a random string of size LEN where each character is alphanumeric."
+  (let loop ((chars '())
+             (len len))
+    (if (zero? len)
+        (list->string chars)
+        (let ((n (random 62 %seed)))
+          (loop (cons (integer->alphanumeric-char n) chars)
+                (- len 1))))))
+
+(define (create-user-database users root)
+  "Create /etc/passwd, /etc/shadow, and /etc/group under ROOT for the given
+USERS."
+  (define etc
+    (string-append root "/etc"))
+
+  (define (salt)
+    ;; "$6" gives us a SHA512 password hash; the random string must be taken
+    ;; from the './0-9A-Za-z' alphabet (info "(libc) Passphrase Storage").
+    (string-append "$6$" (random-string 10)))
+
+  (define users*
+    (map (lambda (user)
+           (sys:user-account (name (user-name user))
+                             (group "users")
+                             (home-directory
+                              (user-home-directory user))
+                             (password (crypt (user-password user)
+                                              (salt)))
+
+                             ;; We need a string here, not a file-like, hence
+                             ;; this choice.
+                             (shell
+                              "/run/current-system/profile/bin/bash")))
+         users))
+
+  (define-values (group password shadow)
+    (user+group-databases users* sys:%base-groups
+                          #:current-passwd '()
+                          #:current-groups '()
+                          #:current-shadow '()))
+
+  (mkdir-p etc)
+  (write-group group (string-append etc "/group"))
+  (write-passwd password (string-append etc "/passwd"))
+  (write-shadow shadow (string-append etc "/shadow")))
+
+(define* (install-system locale #:key (users '()))
+  "Create /etc/shadow and /etc/passwd on the installation target for USERS.
+Start COW-STORE service on target directory and launch guix install command in
+a subshell.  LOCALE must be the locale name under which that command will run,
+or #f."
   (let ((install-command
          (format #f "guix system init ~a ~a"
                  (%installer-configuration-file)
                  (%installer-target-dir))))
     (mkdir-p (%installer-target-dir))
+
+    ;; We want to initialize user passwords but we don't want to store them in
+    ;; the config file since the password hashes would end up world-readable
+    ;; in the store.  Thus, create /etc/shadow & co. here such that, on the
+    ;; first boot, the activation snippet that creates accounts will reuse the
+    ;; passwords that we've put in there.
+    (create-user-database users (%installer-target-dir))
+
     (start-service 'cow-store (list (%installer-target-dir)))
     (false-if-exception (run-shell-command install-command
                                            #:locale locale))))