[bug#44623] [PATCH] archive: Warn about replacing an ACL symlink.

[bug#44623] [PATCH] archive: Warn about replacing an ACL symlink.

[Tobias Geerinckx-Rice via Guix-patches via]

* guix/scripts/archive.scm (authorize-key): Warn when %ACL-FILE is a
symbolic link and print an additional hint for Guix System users.
---
 guix/scripts/archive.scm | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/guix/scripts/archive.scm b/guix/scripts/archive.scm
index 02557ce454..d284196f41 100644
--- a/guix/scripts/archive.scm
+++ b/guix/scripts/archive.scm
@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2020 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -310,6 +311,16 @@ the input port."
         (leave (G_ "failed to read public key: ~a: ~a~%")
                (error-source err) (error-string err)))))
 
+  ;; Warn about potentially volatile ACLs, but continue: system reconfiguration
+  ;; might not be possible without (newly-authorized) substitutes.
+  (when (and (access? %acl-file F_OK)
+             (eq? 'symlink (stat:type (lstat %acl-file))))
+    (warning (G_ "replacing symbolic link ~a with a regular file~%")
+             %acl-file)
+    (when (string-prefix? (%store-prefix) (readlink %acl-file))
+      (display-hint (G_ "On Guix System, add public keys to the
+@code{authorized-keys} field of your @code{operating-system} instead."))))
+
   (let ((key (read-key))
         (acl (current-acl)))
     (unless (eq? 'public-key (canonical-sexp-nth-data key 0))
-- 
2.29.2

[bug#44623] [PATCH] archive: Warn about replacing an ACL symlink.

[Ludovic Courtès]

Tobias Geerinckx-Rice <me@tobias.gr> skribis:

> * guix/scripts/archive.scm (authorize-key): Warn when %ACL-FILE is a
> symbolic link and print an additional hint for Guix System users.

Oh, I was convinced that ‘guix archive --authorize’ would now fail on
Guix System, but indeed it doesn’t, due to the canonical rename trick.

> +  ;; Warn about potentially volatile ACLs, but continue: system reconfiguration
> +  ;; might not be possible without (newly-authorized) substitutes.
> +  (when (and (access? %acl-file F_OK)
> +             (eq? 'symlink (stat:type (lstat %acl-file))))

You can do both at once (thus avoiding a TOCTTOU race) with:

  (let ((stat (false-if-exception (lstat %acl-file))))
    (when (and stat …)
      …))

Otherwise LGTM (for ‘master’), thanks!

Ludo’.

bug#44623: [PATCH] archive: Warn about replacing an ACL symlink.

[Tobias Geerinckx-Rice via Guix-patches via]

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Ludovic Courtès 写道：
> Tobias Geerinckx-Rice <me@tobias.gr> skribis:
>
>> * guix/scripts/archive.scm (authorize-key): Warn when %ACL-FILE 
>> is a
>> symbolic link and print an additional hint for Guix System 
>> users.
>
> Oh, I was convinced that ‘guix archive --authorize’ would now 
> fail on
> Guix System, but indeed it doesn’t, due to the canonical rename 
> trick.

I don't want it to fail.

Just today I used ‘guix archive --authorize’ so ‘guix system 
reconfigure’ (to add the key!) wouldn't take all day.  Killer 
feature!

> You can do both at once (thus avoiding a TOCTTOU race) with:

That is significantly better.  Pushed as 
5d15733c426d232e98098d99a5bfe145586609a4.

Thank you!

T G-R

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