mysql_install_db enhancements to facilitate Debian bug#848616 fix

In Debian, the default install is made more secure by omitting the anonymous
user and by making the root account authenticate by unix socket
authentication instead of the default password-less root. However, Debian
hard-codes this change in mysql_install_db, which breaks that program for
other users.

This commit instead implements new general options for mysql_install_db that
can be used by anyone to similarly perform a more secure install:

  --skip-auth-anonymous-user: omits the anonymous user.

  --auth-root-authentication-method=normal: Keeps the existing behaviour
    with a password-less root account. Currently on by default.

  --auth-root-socket-user=USER
  --auth-root-authentication-method=socket: creates the MariaDB root user
    with the name USER (defaults to 'root') and using unix socket
    authentication. This way, only that user has MariaDB root access
    after install.

The idea with --auth-root-authentication-method=normal is that
applications that need this behaviour can give that option explicitly.
Then eventually we could make --auth-root-authentication-method=socket
the default, giving a more secure default installation.

Note that it is perfectly possible to do a secure install with
--auth-root-authentication-method=normal. For example, installing a
private server just for local access by a single OS-level user, by
using --skip-networking and putting the connection socket in a
location without public access. So it is important to preserve this
API for backwards compatibility.

2 files changed, 57 insertions, 10 deletions

diff --git a/scripts/mysql_install_db.sh b/scripts/mysql_install_db.sh
index 5eb0796c647..364cc4fb9e0 100644
--- a/scripts/mysql_install_db.sh
+++ b/scripts/mysql_install_db.sh
@@ -34,11 +34,26 @@ force=0
 in_rpm=0
 ip_only=0
 cross_bootstrap=0
+install_params=""
+auth_root_authentication_method=normal
+auth_root_socket_user='root'
 
 usage()
 {
   cat <<EOF
 Usage: $0 [OPTIONS]
+  --auth-root-authentication-method=normal|socket
+                       Chooses the authentication method for the created initial
+                       root user. The default is 'normal' to creates a root user
+                       that can login without password, which can be insecure.
+                       The alternative 'socket' allows only the system root user
+                       to login as MariaDB root; this requires the unix socket
+                       authentication plugin.
+  --auth-root-socket-user=user
+                       Used with --auth-root-authentication-method=socket. It
+                       specifies the name of the MariaDB root account, as well
+                       as of the system account allowed to access it. Defaults
+                       to 'root'.
   --basedir=path       The path to the MariaDB installation directory.
   --builddir=path      If using --srcdir with out-of-directory builds, you
                        will need to set this to the location of the build
@@ -59,6 +74,8 @@ Usage: $0 [OPTIONS]
   --defaults-file=path Read only this configuration file.
   --rpm                For internal use.  This option is used by RPM files
                        during the MariaDB installation process.
+  --skip-auth-anonymous-user
+                       Do not install an unprivileged anonymous user.
   --skip-name-resolve  Use IP addresses rather than hostnames when creating
                        grant table entries.  This option can be useful if
                        your DNS does not work.
@@ -141,6 +158,17 @@ parse_arguments()
         #
         # --windows is a deprecated alias
         cross_bootstrap=1 ;;
+      --skip-auth-anonymous-user)
+	install_params="$install_params
+SET @skip_auth_anonymous=1;" ;;
+      --auth-root-authentication-method=normal)
+	auth_root_authentication_method=normal ;;
+      --auth-root-authentication-method=socket)
+	auth_root_authentication_method=socket ;;
+      --auth-root-authentication-method=*)
+        usage ;;
+      --auth-root-socket-user=*)
+        auth_root_socket_user="$(parse_arg "$arg")" ;;
 
       *)
         if test -n "$pick_args"
@@ -430,7 +458,17 @@ mysqld_install_cmd_line()
 
 # Create the system and help tables by passing them to "mysqld --bootstrap"
 s_echo "Installing MariaDB/MySQL system tables in '$ldata' ..."
-if { echo "use mysql;"; cat "$create_system_tables" "$create_system_tables2" "$fill_system_tables"; } | eval "$filter_cmd_line" | mysqld_install_cmd_line > /dev/null
+case "$auth_root_authentication_method" in
+  normal)
+    install_params="$install_params
+SET @skip_auth_root_nopasswd=NULL;
+SET @auth_root_socket=NULL;" ;;
+  socket)
+    install_params="$install_params
+SET @skip_auth_root_nopasswd=1;
+SET @auth_root_socket='$auth_root_socket_user';" ;;
+esac
+if { echo "use mysql;$install_params"; cat "$create_system_tables" "$create_system_tables2" "$fill_system_tables"; } | eval "$filter_cmd_line" | mysqld_install_cmd_line > /dev/null
 then
   s_echo "OK"
 else
diff --git a/scripts/mysql_system_tables_data.sql b/scripts/mysql_system_tables_data.sql
index 075aafd5e3b..9556e7ba160 100644
--- a/scripts/mysql_system_tables_data.sql
+++ b/scripts/mysql_system_tables_data.sql
@@ -38,15 +38,24 @@ DROP TABLE tmp_db;
 
 -- Fill "user" table with default users allowing root access
 -- from local machine if "user" table didn't exist before
-CREATE TEMPORARY TABLE tmp_user LIKE user;
-INSERT INTO tmp_user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N', 'N','', 0);
-REPLACE INTO tmp_user SELECT @current_hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N','',0 FROM dual WHERE @current_hostname != 'localhost';
-REPLACE INTO tmp_user VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N','',0);
-REPLACE INTO tmp_user VALUES ('::1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N', '', 0);
-INSERT INTO tmp_user (host,user) VALUES ('localhost','');
-INSERT INTO tmp_user (host,user) SELECT @current_hostname,'' FROM dual WHERE @current_hostname != 'localhost';
-INSERT INTO user SELECT * FROM tmp_user WHERE @had_user_table=0;
-DROP TABLE tmp_user;
+CREATE TEMPORARY TABLE tmp_user_nopasswd LIKE user;
+CREATE TEMPORARY TABLE tmp_user_socket LIKE user;
+CREATE TEMPORARY TABLE tmp_user_anonymous LIKE user;
+-- Classic passwordless root account.
+INSERT INTO tmp_user_nopasswd VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N', 'N','', 0);
+REPLACE INTO tmp_user_nopasswd SELECT @current_hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N','',0 FROM dual WHERE @current_hostname != 'localhost';
+REPLACE INTO tmp_user_nopasswd VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N','',0);
+REPLACE INTO tmp_user_nopasswd VALUES ('::1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N', '', 0);
+-- More secure root account using unix sucket auth.
+INSERT INTO tmp_user_socket VALUES ('localhost',IFNULL(@auth_root_socket, 'root'),'','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'unix_socket','','N', 'N','', 0);
+-- Anonymous user with no privileges.
+INSERT INTO tmp_user_anonymous (host,user) VALUES ('localhost','');
+INSERT INTO tmp_user_anonymous (host,user) SELECT @current_hostname,'' FROM dual WHERE @current_hostname != 'localhost';
+
+INSERT INTO user SELECT * FROM tmp_user_nopasswd WHERE @had_user_table=0 AND @skip_auth_root_nopasswd IS NULL;
+INSERT INTO user SELECT * FROM tmp_user_socket WHERE @had_user_table=0 AND @auth_root_socket IS NOT NULL;
+INSERT INTO user SELECT * FROM tmp_user_anonymous WHERE @had_user_table=0 AND @skip_auth_anonymous IS NULL;
+DROP TABLE tmp_user_nopasswd, tmp_user_socket, tmp_user_anonymous;
 
 CREATE TEMPORARY TABLE tmp_proxies_priv LIKE proxies_priv;
 INSERT INTO tmp_proxies_priv VALUES ('localhost', 'root', '', '', TRUE, '', now());