Subject: [PATCH v2 2/2] gnu: bootloaders: Add uefi-uki-bootloader.

From: Lilah Tascheter <[email-masked]>
Date: Sun, 28 Jan 2024 03:51:41 -0600

* doc/guix.texi (Bootloader Configuration)[bootloader,targets]: Document
  uefi-uki-bootloader and uefi-uki-signed-bootloader.
  (Keyboard Layout, Networking, and Partitioning)[Disk Partitioning]:
  Note use of uefi-uki-bootloader and uefi-uki-signed-bootloader.
* gnu/bootloader/uki.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add bootloader/uki.scm.

Change-Id: I2097da9f3dd35137b3419f6d0545de26d53cb6da
---
 doc/guix.texi          |  45 ++++++++++----
 gnu/bootloader/uki.scm | 129 +++++++++++++++++++++++++++++++++++++++++
 gnu/local.mk           |   1 +
 3 files changed, 163 insertions(+), 12 deletions(-)
 create mode 100644 gnu/bootloader/uki.scm

diff --git a/doc/guix.texi b/doc/guix.texi
index c458befb76..30fd5d022b 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2723,12 +2723,13 @@ Keyboard Layout and Networking and Partitioning
 for @command{cryptsetup luksFormat}.  You can check which key derivation
 function is being used by a device by running @command{cryptsetup
 luksDump @var{device}}, and looking for the PBKDF field of your
-keyslots.
+keyslots.  UEFI stub bootloaders, such as @code{uefi-uki-bootloader}, can
+however use the default, more secure key derivation function.
 @end quotation
 
-Assuming you want to store the root partition on @file{/dev/sda2}, the
-command sequence to format it as a LUKS2 partition would be along these
-lines:
+Assuming you want to store the root partition on @file{/dev/sda2} and use GRUB
+as your bootloader, the command sequence to format it as a LUKS2 partition would
+be along these lines:
 
 @example
 cryptsetup luksFormat --type luks2 --pbkdf pbkdf2 /dev/sda2
@@ -41136,8 +41137,9 @@ Bootloader Configuration
 The bootloader to use, as a @code{bootloader} object.  For now
 @code{grub-bootloader}, @code{grub-efi-bootloader},
 @code{grub-efi-removable-bootloader}, @code{grub-efi-netboot-bootloader},
-@code{grub-efi-netboot-removable-bootloader}, @code{extlinux-bootloader}
-and @code{u-boot-bootloader} are supported.
+@code{grub-efi-netboot-removable-bootloader}, @code{extlinux-bootloader},
+@code{u-boot-bootloader}, @code{uefi-uki-bootloader}, and
+@code{uefi-uki-signed-bootloader} are supported.
 
 @cindex ARM, bootloaders
 @cindex AArch64, bootloaders
@@ -41244,6 +41246,25 @@ Bootloader Configuration
 unbootable.
 @end quotation
 
+@vindex uefi-uki-bootloader
+@code{uefi-uki-bootloader} boots a linux kernel directly through UEFI, without
+an intermediary like GRUB. The main practical advantage of this is allowing
+root/store encryption without an extra GRUB password entry and slow decryption
+step.
+
+@vindex uefi-uki-signed-bootloader
+@code{uefi-uki-signed-bootloader} is like @code{uefi-uki-bootloader}, except
+that it is a procedure that returns a bootloader compatible with UEFI secure
+boot. You must provide it with two paths: an out-of-store secure boot db
+certificate (in PEM format), and out-of-store db key, in that order.
+
+@quotation Warning
+When using @code{uefi-uki-bootloader} or @code{uefi-uki-signed-bootloader},
+@emph{do not} turn off your computer if a system reconfigure failed at
+installing the bootloader.  Until bootloader installation succeeds, your system
+is in an unbootable state.
+@end quotation
+
 @item @code{targets}
 This is a list of strings denoting the targets onto which to install the
 bootloader.
@@ -41252,12 +41273,12 @@ Bootloader Configuration
 For @code{grub-bootloader}, for example, they should be device names
 understood by the bootloader @command{installer} command, such as
 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
-GNU GRUB Manual}).  For @code{grub-efi-bootloader} and
-@code{grub-efi-removable-bootloader} they should be mount
-points of the EFI file system, usually @file{/boot/efi}.  For
-@code{grub-efi-netboot-bootloader}, @code{targets} should be the mount
-points corresponding to TFTP root directories served by your TFTP
-server.
+GNU GRUB Manual}).  For @code{grub-efi-bootloader},
+@code{grub-efi-removable-bootloader}, @code{uefi-uki-bootloader}, and
+@code{uefi-uki-signed-bootloader}, they should be mount points of the EFI file
+system, usually @file{/boot/efi}.  For @code{grub-efi-netboot-bootloader},
+@code{targets} should be the mount points corresponding to TFTP root directories
+served by your TFTP server.
 
 @item @code{menu-entries} (default: @code{'()})
 A possibly empty list of @code{menu-entry} objects (see below), denoting
diff --git a/gnu/bootloader/uki.scm b/gnu/bootloader/uki.scm
new file mode 100644
index 0000000000..0ef62295d6
--- /dev/null
+++ b/gnu/bootloader/uki.scm
@@ -0,0 +1,129 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2024 Lilah Tascheter <[email-masked]>
+;;;
+;;; 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 bootloader uki)
+  #:use-module (gnu bootloader)
+  #:use-module (gnu packages bootloaders)
+  #:use-module (gnu packages efi)
+  #:use-module (gnu packages linux)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:use-module (srfi srfi-1)
+  #:export (uefi-uki-bootloader uefi-uki-signed-bootloader))
+
+;; config generator makes script creating uki images
+;; install runs script
+;; install device is path to uefi dir
+(define vendor "Guix")
+(define script-loc "/boot/install-uki.scm")
+
+(define* (uefi-uki-configuration-file #:optional cert privkey)
+  (lambda* (config entries #:key (old-entries '()) #:allow-other-keys)
+
+    (define (menu-entry->args e)
+      (let* ((boot (bootloader-configuration-bootloader config))
+             (stub (bootloader-package boot)))
+        #~(list "--os-release" #$(menu-entry-label e)
+            "--linux" #$(menu-entry-linux e) "--initrd" #$(menu-entry-initrd e)
+            "--cmdline" (string-join (list #$@(menu-entry-linux-arguments e)))
+            "--stub" #$(file-append stub "/libexec/" (systemd-stub-name))
+            #$@(if cert #~("--secureboot-certificate" #$cert) #~())
+            #$@(if privkey #~("--secureboot-private-key" #$privkey) #~()))))
+
+    (define (enum-filenames . args) ; same args as iota
+      (map (lambda (n) (string-append (number->string n) ".efi"))
+        (apply iota (map length args))))
+
+    (program-file "install-uki"
+      (with-imported-modules (source-module-closure '((guix build syscalls)
+                                                      (guix build utils)))
+        #~(let* ((target (cadr (command-line)))
+                 (vendir (string-append target "/EFI/" #$vendor))
+                 (schema (string-append vendir "/boot.mgr"))
+                 (findmnt #$(file-append util-linux "/bin/findmnt"))
+                 (efibootmgr #$(file-append efibootmgr "/sbin/efibootmgr")))
+            (use-modules (guix build syscalls) (guix build utils)
+                         (ice-9 popen) (ice-9 textual-ports))
+
+            (define (out name) (string-append vendir "/" name))
+            (define disk
+              (call-with-port
+                (open-pipe* OPEN_READ findmnt "-fnro" "SOURCE" "-T" target)
+                (lambda (port) (get-line port)))) ; only 1 line: the device
+
+            ;; delete all boot entries and files we control
+            (when (file-exists? schema)
+              (call-with-input-file schema
+                (lambda (port)
+                  (for-each (lambda (l)
+                              (unless (string-null? l)
+                                (system* efibootmgr "-B" "-L" l "-q")))
+                    (string-split (get-string-all port) #\lf)))))
+            (when (directory-exists? vendir) (delete-file-recursively vendir))
+            (mkdir-p vendir)
+
+            (define (install port boot? oos)
+              (lambda (args label name)
+                (let ((minbytes (* 2 (stat:size (stat #$script-loc)))))
+                  (put-string port label)
+                  (put-char port #\lf)
+                  (force-output port) ; make sure space is alloc'd
+                  (apply invoke #$(file-append ukify "/bin/ukify")
+                    "build" "-o" (out name) args)
+                  ;; make sure we have enough space for next install-uki.scm
+                  (when (and oos (< (free-disk-space vendir) minbytes)) (oos))
+                  (invoke efibootmgr (if boot? "-c" "-C") "-L" label "-d" disk
+                    "-l" (string-append "\\EFI\\" #$vendor "\\" name) "-q"))))
+
+            (call-with-output-file schema
+              (lambda (port) ; prioritize latest UKIs in limited ESP space
+                (for-each (install port #t #f)
+                  (list #$@(map-in-order menu-entry->args entries))
+                  (list #$@(map-in-order menu-entry-label entries))
+                  (list #$@(enum-filenames entries)))
+                (for-each ; old-entries can fail (out of space) we don't care
+                  (lambda (args label name)
+                    (define (cleanup . _) ; do exit early if out of space tho
+                      (when (file-exists? (out name)) (delete-file (out name)))
+                      (exit))
+                    (with-exception-handler cleanup
+                      (lambda _ ((install port #f cleanup) args label name))))
+                  (list #$@(map-in-order menu-entry->args old-entries))
+                  (list #$@(map-in-order menu-entry-label old-entries))
+                  (list #$@(enum-filenames old-entries entries))))))))))
+
+(define install-uefi-uki
+  #~(lambda (bootloader target mount-point)
+      (invoke (string-append mount-point #$script-loc)
+              (string-append mount-point target))))
+
+(define* (make-uefi-uki-bootloader #:optional cert privkey)
+  (bootloader
+    (name 'uefi-uki)
+    (package systemd-stub)
+    (installer install-uefi-uki)
+    (disk-image-installer #f)
+    (configuration-file script-loc)
+    (configuration-file-generator (uefi-uki-configuration-file cert privkey))))
+
+;; IMPORTANT NOTE: if bootloader install fails, do not turn off your computer! until
+;; install succeeds, your system is unbootable.
+(define uefi-uki-bootloader (make-uefi-uki-bootloader))
+;; use ukify genkey to generate cert and privkey. DO NOT include in store.
+(define (uefi-uki-signed-bootloader cert privkey)
+  (make-uefi-uki-bootloader cert privkey))
diff --git a/gnu/local.mk b/gnu/local.mk
index ab63bd5881..0a15251ddf 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -90,6 +90,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/bootloader/extlinux.scm                   \
   %D%/bootloader/u-boot.scm                     \
   %D%/bootloader/depthcharge.scm                \
+  %D%/bootloader/uki.scm                        \
   %D%/ci.scm					\
   %D%/compression.scm				\
   %D%/home.scm					\
-- 
2.41.0