canvas-lms/lib/authentication_methods.rb

332 lines
11 KiB
Ruby

#
# Copyright (C) 2011 - 2013 Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas 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 Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
module AuthenticationMethods
def authorized(*groups)
authorized_roles = groups
return true
end
def authorized_roles
@authorized_roles ||= []
end
def consume_authorized_roles
authorized_roles = []
end
def load_pseudonym_from_policy
if (policy_encoded = params['Policy']) &&
(signature = params['Signature']) &&
signature == Base64.encode64(OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha1'), Attachment.shared_secret, policy_encoded)).gsub(/\n/, '') &&
(policy = JSON.parse(Base64.decode64(policy_encoded)) rescue nil) &&
policy['conditions'] &&
(credential = policy['conditions'].detect{ |cond| cond.is_a?(Hash) && cond.has_key?("pseudonym_id") })
@policy_pseudonym_id = credential['pseudonym_id']
# so that we don't have to explicitly skip verify_authenticity_token
params[self.class.request_forgery_protection_token] ||= form_authenticity_token
end
yield if block_given?
end
class AccessTokenError < Exception
end
class LoggedOutError < Exception
end
def self.access_token(request, params_method = :params)
auth_header = request.authorization
if auth_header.present? && (header_parts = auth_header.split(' ', 2)) && header_parts[0] == 'Bearer'
header_parts[1]
else
request.send(params_method)['access_token'].presence
end
end
def self.user_id(request)
request.session[:user_id]
end
def load_pseudonym_from_jwt
return unless api_request?
token_string = AuthenticationMethods.access_token(request)
return unless token_string.present?
begin
services_jwt = Canvas::Security::ServicesJwt.new(token_string)
@current_user = User.find(services_jwt.user_global_id)
@current_pseudonym = @current_user.find_pseudonym_for_account(@domain_root_account, true)
unless @current_user && @current_pseudonym
raise AccessTokenError
end
@authenticated_with_jwt = true
rescue JSON::JWT::InvalidFormat, Canvas::Security::TokenExpired, Canvas::Security::InvalidToken
# could still be a regular access token
return
end
end
def load_pseudonym_from_access_token
return unless api_request? || (params[:controller] == 'oauth2_provider' && params[:action] == 'destroy')
token_string = AuthenticationMethods.access_token(request)
if token_string
@access_token = AccessToken.authenticate(token_string)
if !@access_token
raise AccessTokenError
end
if !@access_token.authorized_for_account?(@domain_root_account)
raise AccessTokenError
end
@current_user = @access_token.user
@current_pseudonym = @current_user.find_pseudonym_for_account(@domain_root_account, true)
unless @current_user && @current_pseudonym
raise AccessTokenError
end
@access_token.used!
RequestContextGenerator.add_meta_header('at', @access_token.global_id)
RequestContextGenerator.add_meta_header('dk', @access_token.global_developer_key_id) if @access_token.developer_key_id
end
end
def load_user
@current_user = @current_pseudonym = nil
masked_authenticity_token # ensure that the cookie is set
load_pseudonym_from_jwt
unless @current_pseudonym.present?
load_pseudonym_from_access_token
end
if !@current_pseudonym
if @policy_pseudonym_id
@current_pseudonym = Pseudonym.where(id: @policy_pseudonym_id).first
elsif @pseudonym_session = PseudonymSession.find
@current_pseudonym = @pseudonym_session.record
# if the session was created before the last time the user explicitly
# logged out (of any session for any of their pseudonyms), invalidate
# this session
invalid_before = @current_pseudonym.user.last_logged_out
# they logged out in the future?!? something's busted; just ignore it -
# either my clock is off or whoever set this value's clock is off
invalid_before = nil if invalid_before && invalid_before > Time.now.utc
if invalid_before &&
(session_refreshed_at = request.env['encrypted_cookie_store.session_refreshed_at']) &&
session_refreshed_at < invalid_before
logger.info "Invalidating session: Session created before user logged out."
destroy_session
@current_pseudonym = nil
if api_request? || request.format.json?
raise LoggedOutError
end
end
if @current_pseudonym &&
session[:cas_session] &&
@current_pseudonym.cas_ticket_expired?(session[:cas_session])
logger.info "Invalidating session: CAS ticket expired - #{session[:cas_session]}."
destroy_session
@current_pseudonym = nil
raise LoggedOutError if api_request? || request.format.json?
redirect_to_login
end
end
if params[:login_success] == '1' && !@current_pseudonym
# they just logged in successfully, but we can't find the pseudonym now?
# sounds like somebody hates cookies.
return redirect_to(login_url(:needs_cookies => '1'))
end
@current_user = @current_pseudonym && @current_pseudonym.user
end
if @current_user && @current_user.unavailable?
@current_pseudonym = nil
@current_user = nil
end
# required by the user throttling middleware
session[:user_id] = @current_user.global_id if @current_user
if @current_user && %w(become_user_id me become_teacher become_student).any? { |k| params.key?(k) }
request_become_user = nil
if params[:become_user_id]
request_become_user = User.where(id: params[:become_user_id]).first
elsif params.keys.include?('me')
request_become_user = @current_user
elsif params.keys.include?('become_teacher')
course = Course.find(params[:course_id] || params[:id]) rescue nil
teacher = course.teachers.first if course
if teacher
request_become_user = teacher
else
flash[:error] = I18n.t('lib.auth.errors.teacher_not_found', "No teacher found")
end
elsif params.keys.include?('become_student')
course = Course.find(params[:course_id] || params[:id]) rescue nil
student = course.students.first if course
if student
request_become_user = student
else
flash[:error] = I18n.t('lib.auth.errors.student_not_found', "No student found")
end
end
if request_become_user && request_become_user.id != session[:become_user_id].to_i && request_become_user.can_masquerade?(@current_user, @domain_root_account)
params_without_become = params.dup
params_without_become.delete_if {|k,v| [ 'become_user_id', 'become_teacher', 'become_student', 'me' ].include? k }
params_without_become[:only_path] = true
session[:masquerade_return_to] = url_for(params_without_become)
return redirect_to user_masquerade_url(request_become_user.id)
end
end
as_user_id = api_request? && params[:as_user_id].presence
as_user_id ||= session[:become_user_id]
if as_user_id
begin
user = api_find(User, as_user_id)
rescue ActiveRecord::RecordNotFound
end
if user && user.can_masquerade?(@current_user, @domain_root_account)
@real_current_user = @current_user
@current_user = user
@real_current_pseudonym = @current_pseudonym
@current_pseudonym = @current_user.find_pseudonym_for_account(@domain_root_account, true)
logger.warn "#{@real_current_user.name}(#{@real_current_user.id}) impersonating #{@current_user.name} on page #{request.url}"
elsif api_request?
# fail silently for UI, but not for API
render :json => {:errors => "Invalid as_user_id"}, :status => :unauthorized
return false
end
end
@current_user
end
private :load_user
def require_user
if @current_user && @current_pseudonym
true
else
redirect_to_login
false
end
end
protected :require_user
def clean_return_to(url)
return nil if url.blank?
begin
uri = URI.parse(url)
rescue URI::Error
return nil
end
return nil unless uri.path[0] == '/'
return "#{request.protocol}#{request.host_with_port}#{uri.path}#{uri.query && "?#{uri.query}"}#{uri.fragment && "##{uri.fragment}"}"
end
def return_to(url, fallback)
url = clean_return_to(url) || clean_return_to(fallback)
redirect_to url
end
def store_location(uri=nil, overwrite=true)
if overwrite || !session[:return_to]
uri ||= request.get? ? request.fullpath : request.referrer
session[:return_to] = clean_return_to(uri)
end
end
protected :store_location
def redirect_back_or_default(default)
redirect_to(session[:return_to] || default)
session.delete(:return_to)
end
protected :redirect_back_or_default
def redirect_to_referrer_or_default(default)
redirect_to(:back)
rescue ActionController::RedirectBackError
redirect_to(default)
end
def redirect_to_login
return unless fix_ms_office_redirects
respond_to do |format|
format.html {
store_location
flash[:warning] = I18n.t('lib.auth.errors.not_authenticated', "You must be logged in to access this page") unless request.path == '/'
redirect_to login_url(params.slice(:canvas_login, :authentication_provider))
}
format.json { render_json_unauthorized }
end
end
def render_json_unauthorized
add_www_authenticate_header if api_request? && !@current_user
if @current_user
render :json => {
:status => I18n.t('lib.auth.status_unauthorized', 'unauthorized'),
:errors => [{ :message => I18n.t('lib.auth.not_authorized', "user not authorized to perform that action") }]
},
:status => :unauthorized
else
render :json => {
:status => I18n.t('lib.auth.status_unauthenticated', 'unauthenticated'),
:errors => [{ :message => I18n.t('lib.auth.authentication_required', "user authorization required") }]
},
:status => :unauthorized
end
end
def add_www_authenticate_header
response['WWW-Authenticate'] = %{Bearer realm="canvas-lms"}
end
# Reset the session, and copy the specified keys over to the new session.
# Please consider the security implications of any keys you copy over.
def reset_session_saving_keys(*keys)
# can't use slice, because session has a different ctor than a normal hash
saved = {}
keys.each { |k| saved[k] = session[k] if session[k] }
reset_session
saved.each_pair { |k, v| session[k] = v }
end
# this really belongs on Login::Shared, but is left here for plugins that
# have always overridden it here
def delegated_auth_redirect_uri(uri)
uri
end
end