01/01: file-systems: Handle LUKS2 header.

[guix-commits]

dannym pushed a commit to branch master
in repository guix.

commit 7aa28eb339dd667d07cfb8b5347e159d5da3ccd7
Author: David Trudgian <address@hidden>
Date:   Sat Jan 4 09:19:17 2020 -0600

    file-systems: Handle LUKS2 header.
    
    * gnu/build/file-systems.scm (luks-superblock?): Handle LUKS2 header.
    
    Signed-off-by: Danny Milosavljevic <address@hidden>
---
 gnu/build/file-systems.scm | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm
index 9299cc2..ee63755 100644
--- a/gnu/build/file-systems.scm
+++ b/gnu/build/file-systems.scm
@@ -4,6 +4,7 @@
 ;;; Copyright © 2017 Mathieu Othacehe <address@hidden>
 ;;; Copyright © 2019 Guillaume Le Vaillant <address@hidden>
 ;;; Copyright © 2019 Tobias Geerinckx-Rice <address@hidden>
+;;; Copyright © 2019 David C. Trudgian <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -343,6 +344,10 @@ if DEVICE does not contain a JFS file system."
 ;; <https://gitlab.com/cryptsetup/cryptsetup/wikis/Specification>.  We follow
 ;; version 1.2.1 of this document.
 
+;; The LUKS2 header format is described in "LUKS2 On-Disk Format 
Specification":
+;; <https://gitlab.com/cryptsetup/LUKS2-docs/blob/master/luks2_doc_wip.pdf>.
+;; It is a WIP document.
+
 (define-syntax %luks-endianness
   ;; Endianness of LUKS headers.
   (identifier-syntax (endianness big)))
@@ -356,12 +361,16 @@ if DEVICE does not contain a JFS file system."
   (let ((magic   (sub-bytevector sblock 0 6))
         (version (bytevector-u16-ref sblock 6 %luks-endianness)))
     (and (bytevector=? magic %luks-magic)
-         (= version 1))))
+         (or (= version 1) (= version 2)))))
 
 (define (read-luks-header file)
   "Read a LUKS header from FILE.  Return the raw header on success, and #f if
 not valid header was found."
-  ;; Size in bytes of the LUKS header, including key slots.
+  ;; Size in bytes of the LUKS binary header, which includes key slots in
+  ;; LUKS1.  In LUKS2 the binary header is partially backward compatible, so
+  ;; that UUID can be extracted as for LUKS1. Keyslots and other metadata are
+  ;; not part of this header in LUKS2, but are included in the JSON metadata
+  ;; area that follows.
   (read-superblock file 0 592 luks-superblock?))
 
 (define (luks-header-uuid header)