add_users_in_container.sh

#!/bin/bash
# This script will update the env.list file (file containing USERS environrment variable) and add the new users if there are any.

FTP_DIRECTORY="/home/aws/s3bucket/ftp-users"
CONFIG_FILE="env.list" # May need to modify config file name to reflect future changes in env file location/name
SLEEP_DURATION=60
# Change theses next two variables to set different permissions for files/directories
# These were default from vsftpd so change accordingly if necessary
FILE_PERMISSIONS=644
DIRECTORY_PERMISSIONS=750

add_users() {
  aws s3 cp s3://$CONFIG_BUCKET/$CONFIG_FILE ~/$CONFIG_FILE
  USERS=$(cat ~/"$CONFIG_FILE" | grep USERS | cut -d '=' -f2)

  for u in $USERS; do
    read username passwd <<< $(echo $u | sed 's/:/ /g')

    # If account exists set password again
    # In cases where password changes in env file
    if getent passwd "$username" >/dev/null 2>&1; then
      echo $u | chpasswd -e

      # Fix for issue when pulling files that were uploaded directly to S3 (through aws web console)
      # Permissions when uploaded directly through S3 Web client were set as:
      # 000 root:root
      # This would not allow ftp users to read the files

      # Search for files and directories not owned correctly
      find "$FTP_DIRECTORY/$username/files/" -mindepth 1 \( \! -user "$username" \! -group "$username" \) -print0 | xargs -0 -r chown "$username:$username"

      # Search for files with incorrect permissions
      find "$FTP_DIRECTORY/$username/files/" -mindepth 1 -type f \! -perm "$FILE_PERMISSIONS" -print0 | xargs -0 -r chmod "$FILE_PERMISSIONS"

      # Search for directories with incorrect permissions
      find "$FTP_DIRECTORY/$username/files/" -mindepth 1 -type d \! -perm "$DIRECTORY_PERMISSIONS" -print0 | xargs -0 -r chmod "$DIRECTORY_PERMISSIONS"

      # Search for .ssh folders and authorized_keys files with incorrect permissions/ownership
      find "$FTP_DIRECTORY/$username/.ssh" -mindepth 1 -type d \! -perm 700 -print0 | xargs -0 -r chmod 700
      find "$FTP_DIRECTORY/$username/.ssh" -mindepth 1 -type d \! -user "$username" -print0 | xargs -0 -r chown "$username"

      find "$FTP_DIRECTORY/$username/.ssh/authorized_keys" -mindepth 1 -type f \! -perm 600 -print0 | xargs -0 -r chmod 600
      find "$FTP_DIRECTORY/$username/.ssh/authorized_keys" -mindepth 1 -type f \! -user "$username" -print0 | xargs -0 -r chown "$username"
    fi

    # If user account doesn't exist create it
    if ! getent passwd "$username" >/dev/null 2>&1; then
      useradd -d "$FTP_DIRECTORY/$username" -s /usr/sbin/nologin $username
      usermod -G ftpaccess $username

      mkdir -p "$FTP_DIRECTORY/$username"
      chown root:ftpaccess "$FTP_DIRECTORY/$username"
      chmod 750 "$FTP_DIRECTORY/$username"

      mkdir -p "$FTP_DIRECTORY/$username/files"
      chown $username:ftpaccess "$FTP_DIRECTORY/$username/files"
      chmod 750 "$FTP_DIRECTORY/$username/files"
    fi
  done
}

while true; do
  add_users
  sleep $SLEEP_DURATION
done