Package: guix-patches;
Reported by: Sisiutl <sisiutl <at> egregore.fun>
Date: Sun, 6 Oct 2024 09:45:01 UTC
Severity: normal
Tags: moreinfo, patch
Done: Maxim Cournoyer <maxim.cournoyer <at> gmail.com>
Bug is archived. No further changes may be made.
Message #14 received at 73654 <at> debbugs.gnu.org (full text, mbox):
From: soeren <at> soeren-tempel.net To: 73654 <at> debbugs.gnu.org Cc: sisiutl <at> egregore.fun, hako <at> ultrarare.space, ludo <at> gnu.org Subject: [PATCH v2] mapped-devices: luks: Support passing --allow-discards during open Date: Sun, 9 Mar 2025 16:55:49 +0100
From: Sisiutl <sisiutl <at> egregore.fun>
* gnu/system/mapped-devices.scm (open-luks-device): Support opening
LUKS devices with the --allow-discards option.
* gnu/system/mapped-devices.scm (luks-device-mapping-with-options):
Pass through the allow-discards? keyword argument.
* doc/guix.texi (Mapped Devices): Update documentation for the
luks-device-mapping-with-options procedure.
Signed-off-by: Sören Tempel <soeren <at> soeren-tempel.net>
---
Not the author of the original patchset, but I needed this for my
own setup as well so I might as well pick up the slack. I made
the following changes since the v1:
* Mention allow-discards? in the docstring of open-luks-device.
* Reference the new option in luks-device-mapping-with-options.
* Expand the related documentation in doc/guix.texi.
* Revise the commit message slightly.
* Restore the linefeed.
doc/guix.texi | 11 +++++++++-
gnu/system/mapped-devices.scm | 39 ++++++++++++++++++++---------------
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/doc/guix.texi b/doc/guix.texi
index 05c855c5ea..bc3ba1f2ed 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -18461,7 +18461,7 @@ Mapped Devices
@code{dm-crypt} Linux kernel module.
@end defvar
-@deffn {Procedure} luks-device-mapping-with-options [#:key-file]
+@deffn {Procedure} luks-device-mapping-with-options [#:key-file #:allow-discards?]
Return a @code{luks-device-mapping} object, which defines LUKS block
device encryption using the @command{cryptsetup} command from the
package with the same name. It relies on the @code{dm-crypt} Linux
@@ -18483,6 +18483,15 @@ Mapped Devices
(type (luks-device-mapping-with-options
#:key-file "/crypto.key")))
@end lisp
+
+If @code{allow-discards?} is provided, then the use of discard (TRIM)
+requests is allowed for the underlying device. This is useful for
+Solid State Drives. However, this option can have a negative security
+impact because it can make filesystem-level operations visible on the
+physical device. For more information, refer to the description of
+the @code{--allow-discards} option in the @code{cryptsetup-open(8)}
+man page.
+
@end deffn
@defvar raid-device-mapping
diff --git a/gnu/system/mapped-devices.scm b/gnu/system/mapped-devices.scm
index 931c371425..c3eaf9ff6e 100644
--- a/gnu/system/mapped-devices.scm
+++ b/gnu/system/mapped-devices.scm
@@ -194,9 +194,10 @@ (define (check-device-initrd-modules device linux-modules location)
;;; Common device mappings.
;;;
-(define* (open-luks-device source targets #:key key-file)
+(define* (open-luks-device source targets #:key key-file allow-discards?)
"Return a gexp that maps SOURCE to TARGET as a LUKS device, using
-'cryptsetup'."
+'cryptsetup'. When ALLOW-DISCARDS? is true, the use of discard (TRIM) requests is
+allowed for the underlying device."
(with-imported-modules (source-module-closure
'((gnu build file-systems)
(guix build utils))) ;; For mkdir-p
@@ -234,17 +235,19 @@ (define* (open-luks-device source targets #:key key-file)
(loop (- tries-left 1))))))
(error "LUKS partition not found" source))
source)))
- ;; We want to fallback to the password unlock if the keyfile fails.
- (or (and keyfile
- (zero? (system*/tty
- #$(file-append cryptsetup-static "/sbin/cryptsetup")
- "open" "--type" "luks"
- "--key-file" keyfile
- partition #$target)))
- (zero? (system*/tty
- #$(file-append cryptsetup-static "/sbin/cryptsetup")
- "open" "--type" "luks"
- partition #$target)))))))))
+ (let* ((cryptsetup-flags (list "open" "--type" "luks" partition #$target))
+ (cryptsetup-flags (if allow-discards?
+ (cons "--allow-discards" cryptsetup-flags)
+ cryptsetup-flags)))
+ ;; We want to fallback to the password unlock if the keyfile fails.
+ (or (and keyfile
+ (zero? (apply system*/tty
+ #$(file-append cryptsetup-static "/sbin/cryptsetup")
+ "--key-file" keyfile
+ cryptsetup-flags)))
+ (zero? (apply system*/tty
+ #$(file-append cryptsetup-static "/sbin/cryptsetup")
+ cryptsetup-flags))))))))))
(define (close-luks-device source targets)
"Return a gexp that closes TARGET, a LUKS device."
@@ -286,13 +289,15 @@ (define luks-device-mapping
((gnu build file-systems)
#:select (find-partition-by-luks-uuid system*/tty))))))
-(define* (luks-device-mapping-with-options #:key key-file)
+(define* (luks-device-mapping-with-options #:key key-file allow-discards?)
"Return a luks-device-mapping object with open modified to pass the arguments
-into the open-luks-device procedure."
+(key-file and allow-discards?) into the open-luks-device procedure."
(mapped-device-kind
(inherit luks-device-mapping)
- (open (λ (source targets) (open-luks-device source targets
- #:key-file key-file)))))
+ (open (λ (source targets)
+ (open-luks-device source targets
+ #:key-file key-file
+ #:allow-discards? allow-discards?)))))
(define (open-raid-device sources targets)
"Return a gexp that assembles SOURCES (a list of devices) to the RAID device
base-commit: c4f297a664869a18126b66eb5209de1fcceb42d8
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