Noosfero/noosfero

# Redmine - project management software
# Copyright (C) 2006-2011  Jean-Philippe Lang
#
# 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; either version 2
# of the License, or (at your option) any later version.
#
# 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 Street, Fifth Floor, Boston, MA  02110-1301, USA.

require "net/ldap"
require "net/ldap/dn"
require "magic"

class LdapAuthentication
  attr_accessor :host, :port, :account, :account_password, :base_dn, :attr_login, :attr_fullname, :attr_mail, :onthefly_register, :filter, :tls

  def initialize(attrs = {})
    self.host = attrs["host"]
    self.port = attrs["port"].blank? ? 389 : attrs["port"]
    self.account = attrs["account"]
    self.account_password = attrs["account_password"]
    self.base_dn = attrs["base_dn"]
    self.attr_login = attrs["attr_login"]
    self.attr_fullname = attrs["attr_fullname"]
    self.attr_mail = attrs["attr_mail"]
    self.onthefly_register = attrs["onthefly_register"]
    self.filter = attrs["filter"]
    self.tls = attrs["tls"]
  end

  def onthefly_register?
    self.onthefly_register == true
  end

  def authenticate(login, password)
    return nil if login.blank? || password.blank?

    attrs = get_user_dn(login, password)

    if attrs && attrs[:dn] && authenticate_dn(attrs[:dn], password)
      return attrs.except(:dn)
    end
  end

  private

    def ldap_filter
      if filter.present?
        Net::LDAP::Filter.construct(filter)
      end
    rescue Net::LDAP::LdapError
      nil
    end

    def validate_filter
      if filter.present? && ldap_filter.nil?
        errors.add(:filter, :invalid)
      end
    end

    def initialize_ldap_con(ldap_user, ldap_password)
      options = { host: self.host,
                  port: self.port,
                  encryption: (self.tls ? :simple_tls : nil) }
      options.merge!(auth: { method: :simple, username: ldap_user, password: ldap_password }) unless ldap_user.blank? && ldap_password.blank?
      Net::LDAP.new options
    end

    def get_user_attributes_from_ldap_entry(entry)
      attributes = entry.instance_values["myhash"]

      attributes[:dn] = entry.dn
      attributes[:fullname] = LdapAuthentication.get_attr(entry, self.attr_fullname)
      attributes[:mail] = LdapAuthentication.get_attr(entry, self.attr_mail)

      attributes
    end

    # Return the attributes needed for the LDAP search.  It will only
    # include the user attributes if on-the-fly registration is enabled
    def search_attributes
      if onthefly_register?
        nil
      else
        ["dn"]
      end
    end

    # Check if a DN (user record) authenticates with the password
    def authenticate_dn(dn, password)
      if dn.present? && password.present?
        initialize_ldap_con(dn, password).bind
      end
    end

    # Get the user's dn and any attributes for them, given their login
    def get_user_dn(login, password)
      ldap_con = nil
      if self.account && self.account.include?("$login")
        ldap_con = initialize_ldap_con(self.account.sub("$login", Net::LDAP::DN.escape(login)), password)
      else
        ldap_con = initialize_ldap_con(self.account, self.account_password)
      end
      login_filter = nil
      (self.attr_login || []).split.each do |attr|
        if (login_filter.nil?)
          login_filter = Net::LDAP::Filter.eq(attr, login)
        else
          login_filter = login_filter | Net::LDAP::Filter.eq(attr, login)
        end
      end
      object_filter = Net::LDAP::Filter.eq("objectClass", "*")

      attrs = {}

      search_filter = object_filter & login_filter
      if f = ldap_filter
        search_filter = search_filter & f
      end

      ldap_con.search(base: self.base_dn, filter: search_filter, attributes: search_attributes) do |entry|
        if onthefly_register?
          attrs = get_user_attributes_from_ldap_entry(entry)
        else
          attrs = { dn: entry.dn }
        end
      end

      attrs
    end

    def self.get_attr(entry, attr_name)
      if !attr_name.blank?
        val = entry[attr_name].is_a?(Array) ? entry[attr_name].first : entry[attr_name]
        if val.nil?
          Rails.logger.warn "LDAP entry #{entry.dn} has no attr #{attr_name}."
          nil
        elsif val == "" || val == " "
          Rails.logger.warn "LDAP entry #{entry.dn} has attr #{attr_name} empty."
          ""
        else
          charset = Magic.guess_string_mime_encoding(val)
          val.encode "utf-8", charset, invalid: :replace, undef: :replace
        end
      end
    end
end