maint: Suggest ‘guix git authenticate’ for initial authentication.

The previous recommendation, running ‘make authenticate’, was insecure
because it led users to run code from the very repository they want to
authenticate:

  https://lists.gnu.org/archive/html/guix-devel/2024-04/msg00252.html

* Makefile.am (commit_v1_0_0, channel_intro_commit)
(channel_intro_signer, GUIX_GIT_KEYRING, authenticate): Remove.
* Makefile.am (.git/hooks/%): New target, generalization of previous
‘.git/hooks/pre-push’ target.
(nodist_noinst_DATA): Add ‘.git/hooks/post-merge’.
* doc/contributing.texi (Building from Git): Suggest ‘guix git
authenticate’ instead of ‘make authenticate’.
* etc/git/post-merge: New file.
* etc/git/pre-push: Run ‘guix git authenticate’ instead of ‘make
authenticate’.

Reviewed-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Reported-by: Skyler Ferris <skyvine@protonmail.com>
Change-Id: Ia415aa8375013d0dd095e891116f6ce841d93efd

1 files changed, 9 insertions, 21 deletions

diff --git a/Makefile.am b/Makefile.am
index b4a06a52b8e..d0364e9dad8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,5 @@
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2012-2023 Ludovic Courtès <ludo@gnu.org>
+# Copyright © 2012-2024 Ludovic Courtès <ludo@gnu.org>
 # Copyright © 2013 Andreas Enge <andreas@enge.fr>
 # Copyright © 2015, 2017 Alex Kost <alezost@gmail.com>
 # Copyright © 2016, 2018 Mathieu Lirzin <mthl@gnu.org>
@@ -899,22 +899,6 @@ $(guix_install_go_files): install-nobase_dist_guilemoduleDATA
 install-data-hook:
         touch "$(DESTDIR)$(guileobjectdir)/guix/config.go"
 
-# Commit corresponding to the 'v1.0.0' tag.
-commit_v1_0_0 = 6298c3ffd9654d3231a6f25390b056483e8f407c
-
-# Introduction of the 'guix' channel.  Keep in sync with (guix channels)!
-channel_intro_commit = 9edb3f66fd807b096b48283debdcddccfea34bad
-channel_intro_signer = BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA
-
-# Authenticate the current Git checkout by checking signatures on every commit.
-GUIX_GIT_KEYRING = origin/keyring
-authenticate:
-        $(AM_V_at)echo "Authenticating Git checkout..." ;       \
-        guix git authenticate                                   \
-            --keyring=$(GUIX_GIT_KEYRING)                       \
-            --cache-key=channels/guix --stats                   \
-            "$(channel_intro_commit)" "$(channel_intro_signer)"
-
 # Assuming Guix is already installed and the daemon is up and running, this
 # rule builds from $(srcdir), creating and building derivations.
 as-derivation:
@@ -1231,13 +1215,13 @@ cuirass-jobs: $(GOBJECTS)
 .PHONY: gen-ChangeLog gen-AUTHORS gen-tarball-version
 .PHONY: assert-no-store-file-names assert-binaries-available
 .PHONY: assert-final-inputs-self-contained check-channel-news
-.PHONY: clean-go make-go as-derivation authenticate
+.PHONY: clean-go make-go as-derivation
 .PHONY: update-guix-package update-NEWS cuirass-jobs release
 
 # Git auto-configuration.
-.git/hooks/pre-push: etc/git/pre-push
+.git/hooks/%: etc/git/%
         $(AM_V_at)if test -d .git; then \
-        cp etc/git/pre-push .git/hooks/pre-push; \
+        cp "$<" "$@"; \
         fi
 
 .git/config: etc/git/gitconfig
@@ -1260,7 +1244,11 @@ COMMIT_MSG_MAGIC = VGhpcyBpcyB0aGUgY29tbWl0LW1zZyBob29rIG9mIEd1aXg=
 # from a tarball.  Do not add dependencies on these to *_DATA when building
 # from a tarball, as that breaks the build.
 if in_git_p
-nodist_noinst_DATA = .git/hooks/pre-push .git/config .git/hooks/commit-msg
+nodist_noinst_DATA =                            \
+  .git/hooks/pre-push                           \
+  .git/hooks/post-merge                         \
+  .git/config                                   \
+  .git/hooks/commit-msg
 endif
 
 # Downloading up-to-date PO files.