MariaDB で mysql_secure_installation は必要か？

apt update
apt -y install mariadb-server

# mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 31
Server version: 10.11.8-MariaDB-0ubuntu0.24.04.1 Ubuntu 24.04

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

# mysql_secure_installation

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
haven't set the root password yet, you should just press enter here.

Enter current password for root (enter for none): 
OK, successfully used password, moving on...

Setting the root password or using the unix_socket ensures that nobody
can log into the MariaDB root user without the proper authorisation.

You already have your root account protected, so you can safely answer 'n'.

Switch to unix_socket authentication [Y/n] 
Enabled successfully!
Reloading privilege tables..
 ... Success!


You already have your root account protected, so you can safely answer 'n'.

Change the root password? [Y/n] 
New password: 
Re-enter new password: 
Password updated successfully!
Reloading privilege tables..
 ... Success!


By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] 
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] 
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] 
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] 
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

# which mysql_secure_installation
/usr/bin/mysql_secure_installation

MariaDB [(none)]> select user, host from mysql.user;
+-------------+-----------+
| User        | Host      |
+-------------+-----------+
| mariadb.sys | localhost |
| mysql       | localhost |
| root        | localhost |
+-------------+-----------+

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+

#!/bin/sh

# Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved.
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA

config=".my.cnf.$$"
command=".mysql.$$"
output=".my.output.$$"

trap "interrupt" 1 2 3 6 15

rootpass=""
echo_n=
echo_c=
basedir=
defaults_file=
defaults_extra_file=
no_defaults=

parse_arg()
{
  echo "$1" | sed -e 's/^[^=]*=//'
}

parse_arguments()
{
  # We only need to pass arguments through to the server if we don't
  # handle them here.  So, we collect unrecognized options (passed on
  # the command line) into the args variable.
  pick_args=
  if test "$1" = PICK-ARGS-FROM-ARGV
  then
    pick_args=1
    shift
  fi

  for arg
  do
    case "$arg" in
      --basedir=*) basedir=`parse_arg "$arg"` ;;
      --defaults-file=*) defaults_file="$arg" ;;
      --defaults-extra-file=*) defaults_extra_file="$arg" ;;
      --no-defaults) no_defaults="$arg" ;;
      *)
        if test -n "$pick_args"
        then
          # This sed command makes sure that any special chars are quoted,
          # so the arg gets passed exactly to the server.
          # XXX: This is broken; true fix requires using eval and proper
          # quoting of every single arg ($basedir, $ldata, etc.)
          #args="$args "`echo "$arg" | sed -e 's,\([^a-zA-Z0-9_.-]\),\\\\\1,g'`
          args="$args $arg"
        fi
        ;;
    esac
  done
}

# Try to find a specific file within --basedir which can either be a binary
# release or installed source directory and return the path.
find_in_basedir()
{
  return_dir=0
  found=0
  case "$1" in
    --dir)
      return_dir=1; shift
      ;;
  esac

  file=$1; shift

  for dir in "$@"
  do
    if test -f "$basedir/$dir/$file"
    then
      found=1
      if test $return_dir -eq 1
      then
        echo "$basedir/$dir"
      else
        echo "$basedir/$dir/$file"
      fi
      break
    fi
  done

  if test $found -eq 0
  then
      # Test if command is in PATH
      $file --no-defaults --version > /dev/null 2>&1
      status=$?
      if test $status -eq 0
      then
        echo $file
      fi
  fi
}

cannot_find_file()
{
  echo
  echo "FATAL ERROR: Could not find $1"

  shift
  if test $# -ne 0
  then
    echo
    echo "The following directories were searched:"
    echo
    for dir in "$@"
    do
      echo "    $dir"
    done
  fi

  echo
  echo "If you compiled from source, you need to run 'make install' to"
  echo "copy the software into the correct location ready for operation."
  echo
  echo "If you are using a binary release, you must either be at the top"
  echo "level of the extracted archive, or pass the --basedir option"
  echo "pointing to that location."
  echo
}

# Ok, let's go.  We first need to parse arguments which are required by
# my_print_defaults so that we can execute it first, then later re-parse
# the command line to add any extra bits that we need.
parse_arguments PICK-ARGS-FROM-ARGV "$@"

#
# We can now find my_print_defaults.  This script supports:
#
#   --srcdir=path pointing to compiled source tree
#   --basedir=path pointing to installed binary location
#
# or default to compiled-in locations.
#

if test -n "$basedir"
then
  print_defaults=`find_in_basedir my_print_defaults bin extra`
  echo "print: $print_defaults"
  if test -z "$print_defaults"
  then
    cannot_find_file my_print_defaults $basedir/bin $basedir/extra
    exit 1
  fi
  mysql_command=`find_in_basedir mariadb bin`
  if test -z "$mysql_command"
  then
      cannot_find_file mariadb $basedir/bin
      exit 1
  fi
else
  print_defaults="/usr/bin/my_print_defaults"
  mysql_command="/usr/bin/mariadb"
fi

if test ! -x "$print_defaults"
then
  cannot_find_file "$print_defaults"
  exit 1
fi

if test ! -x "$mysql_command"
then
  cannot_find_file "$mysql_command"
  exit 1
fi

# Now we can get arguments from the group [client] and [client-server]
# in the my.cfg file, then re-run to merge with command line arguments.
parse_arguments `$print_defaults $defaults_file $defaults_extra_file $no_defaults client client-server client-mariadb`
parse_arguments PICK-ARGS-FROM-ARGV "$@"

set_echo_compat() {
    case `echo "testing\c"`,`echo -n testing` in
    *c*,-n*) echo_n=   echo_c=     ;;
    *c*,*)   echo_n=-n echo_c=     ;;
    *)       echo_n=   echo_c='\c' ;;
    esac
}

validate_reply () {
    ret=0
    if [ -z "$1" ]; then
    reply=y
    return $ret
    fi
    case $1 in
        y|Y|yes|Yes|YES) reply=y ;;
        n|N|no|No|NO)    reply=n ;;
        *) ret=1 ;;
    esac
    return $ret
}

prepare() {
    touch $config $command
    chmod 600 $config $command
}

do_query() {
    echo "$1" >$command
    #sed 's,^,> ,' < $command  # Debugging
    $mysql_command --defaults-file=$config $defaults_extra_file $no_defaults $args <$command >$output
    return $?
}

# Simple escape mechanism (\-escape any ' and \), suitable for two contexts:
# - single-quoted SQL strings
# - single-quoted option values on the right hand side of = in my.cnf
#
# These two contexts don't handle escapes identically.  SQL strings allow
# quoting any character (\C => C, for any C), but my.cnf parsing allows
# quoting only \, ' or ".  For example, password='a\b' quotes a 3-character
# string in my.cnf, but a 2-character string in SQL.
#
# This simple escape works correctly in both places.
basic_single_escape () {
    # The quoting on this sed command is a bit complex.  Single-quoted strings
    # don't allow *any* escape mechanism, so they cannot contain a single
    # quote.  The string sed gets (as argv[1]) is:  s/\(['\]\)/\\\1/g
    #
    # Inside a character class, \ and ' are not special, so the ['\] character
    # class is balanced and contains two characters.
    echo "$1" | sed 's/\(['"'"'\]\)/\\\1/g'
}

#
# create a simple my.cnf file to be able to pass the root password to the mysql
# client without putting it on the command line
#
make_config() {
    echo "# mysql_secure_installation config file" >$config
    echo "[mysql]" >>$config
    echo "user=root" >>$config
    esc_pass=`basic_single_escape "$rootpass"`
    echo "password='$esc_pass'" >>$config
    #sed 's,^,> ,' < $config  # Debugging

    if test -n "$defaults_file"
    then
        dfile=`parse_arg "$defaults_file"`
        cat "$dfile" >>$config
    fi
}

get_root_password() {
    status=1
    while [ $status -eq 1 ]; do
    stty -echo
    echo $echo_n "Enter current password for root (enter for none): $echo_c"
    read password
    echo
    stty echo
    if [ "x$password" = "x" ]; then
        emptypass=1
    else
        emptypass=0
    fi
    rootpass=$password
    make_config
    do_query "show create user root@localhost"
    status=$?
    done
    if grep -q unix_socket $output; then
      emptypass=0
    fi
    echo "OK, successfully used password, moving on..."
    echo
}

set_root_password() {
    stty -echo
    echo $echo_n "New password: $echo_c"
    read password1
    echo
    echo $echo_n "Re-enter new password: $echo_c"
    read password2
    echo
    stty echo

    if [ "$password1" != "$password2" ]; then
    echo "Sorry, passwords do not match."
    echo
    return 1
    fi

    if [ "$password1" = "" ]; then
    echo "Sorry, you can't use an empty password here."
    echo
    return 1
    fi

    esc_pass=`basic_single_escape "$password1"`
    do_query "UPDATE mysql.global_priv SET priv=json_set(priv, '$.plugin', 'mysql_native_password', '$.authentication_string', PASSWORD('$esc_pass')) WHERE User='root';"
    if [ $? -eq 0 ]; then
    echo "Password updated successfully!"
    echo "Reloading privilege tables.."
    reload_privilege_tables
    if [ $? -eq 1 ]; then
        clean_and_exit
    fi
    echo
    rootpass=$password1
    make_config
    else
    echo "Password update failed!"
    clean_and_exit
    fi

    return 0
}

remove_anonymous_users() {
    do_query "DELETE FROM mysql.global_priv WHERE User='';"
    if [ $? -eq 0 ]; then
    echo " ... Success!"
    else
    echo " ... Failed!"
    clean_and_exit
    fi

    return 0
}

remove_remote_root() {
    do_query "DELETE FROM mysql.global_priv WHERE User='root' AND Host NOT IN ('localhost', '127.0.0.1', '::1');"
    if [ $? -eq 0 ]; then
    echo " ... Success!"
    else
    echo " ... Failed!"
    fi
}

remove_test_database() {
    echo " - Dropping test database..."
    do_query "DROP DATABASE IF EXISTS test;"
    if [ $? -eq 0 ]; then
    echo " ... Success!"
    else
    echo " ... Failed!  Not critical, keep moving..."
    fi

    echo " - Removing privileges on test database..."
    do_query "DELETE FROM mysql.db WHERE Db='test' OR Db='test\\_%'"
    if [ $? -eq 0 ]; then
    echo " ... Success!"
    else
    echo " ... Failed!  Not critical, keep moving..."
    fi

    return 0
}

reload_privilege_tables() {
    do_query "FLUSH PRIVILEGES;"
    if [ $? -eq 0 ]; then
    echo " ... Success!"
    return 0
    else
    echo " ... Failed!"
    return 1
    fi
}

interrupt() {
    echo
    echo "Aborting!"
    echo
    cleanup
    stty echo
    exit 1
}

cleanup() {
    echo "Cleaning up..."
    rm -f $config $command $output
}

# Remove the files before exiting.
clean_and_exit() {
    cleanup
    exit 1
}

# The actual script starts here

prepare
set_echo_compat

echo
echo "NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB"
echo "      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!"
echo
echo "In order to log into MariaDB to secure it, we'll need the current"
echo "password for the root user. If you've just installed MariaDB, and"
echo "haven't set the root password yet, you should just press enter here."
echo

get_root_password


#
# Set the root password
#

echo "Setting the root password or using the unix_socket ensures that nobody"
echo "can log into the MariaDB root user without the proper authorisation."
echo

while true ; do
    if [ $emptypass -eq 1 ]; then
    echo $echo_n "Enable unix_socket authentication? [Y/n] $echo_c"
    else
    echo "You already have your root account protected, so you can safely answer 'n'."
    echo
    echo $echo_n "Switch to unix_socket authentication [Y/n] $echo_c"
    fi
    read reply
    validate_reply $reply && break
done

if [ "$reply" = "n" ]; then
  echo " ... skipping."
else
  emptypass=0
  do_query "UPDATE mysql.global_priv SET priv=json_set(priv, '$.password_last_changed', UNIX_TIMESTAMP(), '$.plugin', 'mysql_native_password', '$.authentication_string', 'invalid', '$.auth_or', json_array(json_object(), json_object('plugin', 'unix_socket'))) WHERE User='root';"
  if [ $? -eq 0 ]; then
   echo "Enabled successfully!"
   echo "Reloading privilege tables.."
   reload_privilege_tables
   if [ $? -eq 1 ]; then
     clean_and_exit
   fi
   echo
  else
   echo "Failed!"
   clean_and_exit
  fi
fi
echo

while true ; do
    if [ $emptypass -eq 1 ]; then
    echo $echo_n "Set root password? [Y/n] $echo_c"
    else
    echo "You already have your root account protected, so you can safely answer 'n'."
    echo
    echo $echo_n "Change the root password? [Y/n] $echo_c"
    fi
    read reply
    validate_reply $reply && break
done

if [ "$reply" = "n" ]; then
    echo " ... skipping."
else
    status=1
    while [ $status -eq 1 ]; do
    set_root_password
    status=$?
    done
fi
echo


#
# Remove anonymous users
#

echo "By default, a MariaDB installation has an anonymous user, allowing anyone"
echo "to log into MariaDB without having to have a user account created for"
echo "them.  This is intended only for testing, and to make the installation"
echo "go a bit smoother.  You should remove them before moving into a"
echo "production environment."
echo

while true ; do
    echo $echo_n "Remove anonymous users? [Y/n] $echo_c"
    read reply
    validate_reply $reply && break
done
if [ "$reply" = "n" ]; then
    echo " ... skipping."
else
    remove_anonymous_users
fi
echo


#
# Disallow remote root login
#

echo "Normally, root should only be allowed to connect from 'localhost'.  This"
echo "ensures that someone cannot guess at the root password from the network."
echo
while true ; do
    echo $echo_n "Disallow root login remotely? [Y/n] $echo_c"
    read reply
    validate_reply $reply && break
done
if [ "$reply" = "n" ]; then
    echo " ... skipping."
else
    remove_remote_root
fi
echo


#
# Remove test database
#

echo "By default, MariaDB comes with a database named 'test' that anyone can"
echo "access.  This is also intended only for testing, and should be removed"
echo "before moving into a production environment."
echo

while true ; do
    echo $echo_n "Remove test database and access to it? [Y/n] $echo_c"
    read reply
    validate_reply $reply && break
done

if [ "$reply" = "n" ]; then
    echo " ... skipping."
else
    remove_test_database
fi
echo


#
# Reload privilege tables
#

echo "Reloading the privilege tables will ensure that all changes made so far"
echo "will take effect immediately."
echo

while true ; do
    echo $echo_n "Reload privilege tables now? [Y/n] $echo_c"
    read reply
    validate_reply $reply && break
done

if [ "$reply" = "n" ]; then
    echo " ... skipping."
else
    reload_privilege_tables
fi
echo

cleanup

echo
echo "All done!  If you've completed all of the above steps, your MariaDB"
echo "installation should now be secure."
echo
echo "Thanks for using MariaDB!"