Sync with 2.30.5

* maint-2.30:
  Git 2.30.5
  setup: tighten ownership checks post CVE-2022-24765
  git-compat-util: allow root to access both SUDO_UID and root owned
  t0034: add negative tests and allow git init to mostly work under sudo
  git-compat-util: avoid failing dir ownership checks if running privileged
  t: regression git needs safe.directory when using sudo

Documentation/RelNotes/2.30.5.txt

@@ -0,0 +1,12 @@
+Git v2.30.5 Release Notes
+=========================
+
+This release contains minor fix-ups for the changes that went into
+Git 2.30.3 and 2.30.4, addressing CVE-2022-29187.
+
+ * The safety check that verifies a safe ownership of the Git
+   worktree is now extended to also cover the ownership of the Git
+   directory (and the `.git` file, if there is any).
+
+Carlo Marcelo Arenas Belón (1):
+      setup: tighten ownership checks post CVE-2022-24765

Documentation/config/safe.txt

@@ -26,3 +26,17 @@ directory was listed in the `safe.directory` list. If `safe.directory=*`
 is set in system config and you want to re-enable this protection, then
 initialize your list with an empty value before listing the repositories
 that you deem safe.
++
+As explained, Git only allows you to access repositories owned by
+yourself, i.e. the user who is running Git, by default.  When Git
+is running as 'root' in a non Windows platform that provides sudo,
+however, git checks the SUDO_UID environment variable that sudo creates
+and will allow access to the uid recorded as its value in addition to
+the id from 'root'.
+This is to make it easy to perform a common sequence during installation
+"make && sudo make install".  A git process running under 'sudo' runs as
+'root' but the 'sudo' command exports the environment variable to record
+which id the original user has.
+If that is not what you would prefer and want git to only trust
+repositories that are owned by root instead, then you can remove
+the `SUDO_UID` variable from root's environment before invoking git.