sysusers: insist that root group is 0

Signed-off-by: zhaoxiaohu <zhaoxiaohu@kuaishou.com>

backport-sysusers-insist-that-root-group-is-0.patch

@@ -0,0 +1,57 @@
+From 5f9fdbbeeb15fda7b69e3dfd027f556178431202 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
+Date: Tue, 31 Jan 2023 17:04:10 +0100
+Subject: [PATCH] sysusers: insist that root group is 0
+
+In https://bugzilla.redhat.com/show_bug.cgi?id=2156900 sysusers was reporting a
+conflict between the following lines:
+  u root 0:0 "Super User" /root /bin/bash
+  u root    0     "Super User" /root
+
+The problem is that those configurations are indeed not equivalent. If group 0
+exists with a different name, the first line would just create the user, but the
+second line would create a 'root' group with a different GID. The second
+behaviour seems definitely wrong. (Or at least more confusing in practice than
+the first one. The system is in a strange shape, but the second approach takes
+an additional step than is worse than doing nothing.)
+
+When this line was initially added, we didn't have the uid:gid functionality for
+'u', so we didn't think about this too much. But now we do, so we should use it.
+
+$ build/systemd-sysusers --root=/var/tmp/inst7 --inline 'g foobar 0'
+Creating group 'foobar' with GID 0.
+
+$ build/systemd-sysusers --root=/var/tmp/inst7 --inline 'u root 0 "Zuper zuper"'
+src/sysusers/sysusers.c:1365: Creating group 'root' with GID 999.
+src/sysusers/sysusers.c:1115: Suggested user ID 0 for root already used.
+src/sysusers/sysusers.c:1183: Creating user 'root' (Zuper zuper) with UID 999 and GID 999.
+
+vs.
+
+$ build/systemd-sysusers --root=/var/tmp/inst7 --inline 'u root 0:0 "Zuper zuper"'
+src/sysusers/sysusers.c:1183: Creating user 'root' (Zuper zuper) with UID 0 and GID 0.
+
+https://github.com/systemd/systemd/pull/26270/commits/a5cca2983e5bbbe3b0582412f4b3962c585b59a1
+
+Signed-off-by: zhaoxiaohu <zhaoxiaohu@kuaishou.com>
+Signed-off-by: yuwang <yuwang@kuaishou.com>
+---
+ sysusers.d/basic.conf.in | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/sysusers.d/basic.conf.in b/sysusers.d/basic.conf.in
+index 8cc1a7c..bf274b6 100644
+--- a/sysusers.d/basic.conf.in
++++ b/sysusers.d/basic.conf.in
+@@ -6,7 +6,7 @@
+ #  (at your option) any later version.
+ 
+ # The superuser
+-u root    0     "Super User" /root
++u root    0:0     "Super User" /root
+ 
+ # The nobody user for NFS file systems
+ u {{NOBODY_USER_NAME}}  65534 "Nobody"     -
+-- 
+2.33.0
+