Class: Rack::Protection::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/protection/base.rb

Constant Summary collapse

DEFAULT_OPTIONS = 
{
  :reaction    => :default_reaction, :logging   => true,
  :message     => 'Forbidden',       :encryptor => Digest::SHA1,
  :session_key => 'rack.session',    :status    => 403,
  :allow_empty_referrer => true,
  :report_key           => "protection.failed",
  :html_types           => %w[text/html application/xhtml]
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, options = {}) ⇒ Base

Returns a new instance of Base.



32
33
34
 
# File 'lib/rack/protection/base.rb', line 32

def initialize(app, options = {})
  @app, @options = app, default_options.merge(options)
end

Instance Attribute Details

#app ⇒ Object (readonly)

Returns the value of attribute app.



18
19
20
 
# File 'lib/rack/protection/base.rb', line 18

def app
  @app
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



18
19
20
 
# File 'lib/rack/protection/base.rb', line 18

def options
  @options
end

Class Method Details

.default_options(options) ⇒ Object 



20
21
22
 
# File 'lib/rack/protection/base.rb', line 20

def self.default_options(options)
  define_method(:default_options) { super().merge(options) }
end

.default_reaction(reaction) ⇒ Object 



24
25
26
 
# File 'lib/rack/protection/base.rb', line 24

def self.default_reaction(reaction)
  alias_method(:default_reaction, reaction)
end

Instance Method Details

#accepts?(env) ⇒ Boolean

Returns:

  • (Boolean)

Raises:

  • (NotImplementedError) 


40
41
42
 
# File 'lib/rack/protection/base.rb', line 40

def accepts?(env)
  raise NotImplementedError, "#{self.class} implementation pending"
end

#bytesize(string) ⇒ Object 



128
129
130
 
# File 'lib/rack/protection/base.rb', line 128

def bytesize(string)
  string.bytesize
end

#call(env) ⇒ Object 



44
45
46
47
48
49
50
 
# File 'lib/rack/protection/base.rb', line 44

def call(env)
  unless accepts? env
    instrument env
    result = react env
  end
  result or app.call(env)
end

#default_options ⇒ Object 



28
29
30
 
# File 'lib/rack/protection/base.rb', line 28

def default_options
  DEFAULT_OPTIONS
end

#deny(env) ⇒ Object Also known as: default_reaction 



69
70
71
72
 
# File 'lib/rack/protection/base.rb', line 69

def deny(env)
  warn env, "attack prevented by #{self.class}"
  [options[:status], {'Content-Type' => 'text/plain'}, [options[:message]]]
end

#drop_session(env) ⇒ Object 



88
89
90
 
# File 'lib/rack/protection/base.rb', line 88

def drop_session(env)
  session(env).clear if session? env
end

#encrypt(value) ⇒ Object 



109
110
111
 
# File 'lib/rack/protection/base.rb', line 109

def encrypt(value)
  options[:encryptor].hexdigest value.to_s
end

#html?(headers) ⇒ Boolean

Returns:

  • (Boolean) 


139
140
141
142
 
# File 'lib/rack/protection/base.rb', line 139

def html?(headers)
  return false unless header = headers.detect { |k,v| k.downcase == 'content-type' }
  options[:html_types].include? header.last[/^\w+\/\w+/]
end

#instrument(env) ⇒ Object 



63
64
65
66
67
 
# File 'lib/rack/protection/base.rb', line 63

def instrument(env)
  return unless i = options[:instrumenter]
  env['rack.protection.attack'] = self.class.name.split('::').last.downcase
  i.instrument('rack.protection', env)
end

#origin(env) ⇒ Object 



99
100
101
 
# File 'lib/rack/protection/base.rb', line 99

def origin(env)
  env['HTTP_ORIGIN'] || env['HTTP_X_ORIGIN']
end

#random_string(secure = defined? SecureRandom)) ⇒ Object 



103
104
105
106
107
 
# File 'lib/rack/protection/base.rb', line 103

def random_string(secure = defined? SecureRandom)
  secure ? SecureRandom.hex(16) : "%032x" % rand(2**128-1)
rescue NotImplementedError
  random_string false
end

#react(env) ⇒ Object 



52
53
54
55
 
# File 'lib/rack/protection/base.rb', line 52

def react(env)
  result = send(options[:reaction], env)
  result if Array === result and result.size == 3
end

#referrer(env) ⇒ Object 



92
93
94
95
96
97
 
# File 'lib/rack/protection/base.rb', line 92

def referrer(env)
  ref = env['HTTP_REFERER'].to_s
  return if !options[:allow_empty_referrer] and ref.empty?
  URI.parse(ref).host || Request.new(env).host
rescue URI::InvalidURIError
end

#report(env) ⇒ Object 



74
75
76
77
 
# File 'lib/rack/protection/base.rb', line 74

def report(env)
  warn env, "attack reported by #{self.class}"
  env[options[:report_key]] = true
end

#safe?(env) ⇒ Boolean

Returns:

  • (Boolean) 


36
37
38
 
# File 'lib/rack/protection/base.rb', line 36

def safe?(env)
  %w[GET HEAD OPTIONS TRACE].include? env['REQUEST_METHOD']
end

#secure_compare(a, b) ⇒ Object

The implementations of secure_compare and bytesize are taken from Rack::Utils to be able to support rack older than XXXX.



115
116
117
118
119
120
121
122
123
 
# File 'lib/rack/protection/base.rb', line 115

def secure_compare(a, b)
  return false unless bytesize(a) == bytesize(b)

  l = a.unpack("C*")

  r, i = 0, -1
  b.each_byte { |v| r |= v ^ l[i+=1] }
  r == 0
end

#session(env) ⇒ Object 



83
84
85
86
 
# File 'lib/rack/protection/base.rb', line 83

def session(env)
  return env[options[:session_key]] if session? env
  fail "you need to set up a session middleware *before* #{self.class}"
end

#session?(env) ⇒ Boolean

Returns:

  • (Boolean) 


79
80
81
 
# File 'lib/rack/protection/base.rb', line 79

def session?(env)
  env.include? options[:session_key]
end

#warn(env, message) ⇒ Object 



57
58
59
60
61
 
# File 'lib/rack/protection/base.rb', line 57

def warn(env, message)
  return unless options[:logging]
  l = options[:logger] || env['rack.logger'] || ::Logger.new(env['rack.errors'])
  l.warn(message)
end