Class: GlobalSession::Session::V1

Inherits:
Abstract
  • Object
show all
Defined in:
lib/global_session/session/v1.rb

Overview

V1 uses JSON serialization and Zlib compression. Its JSON structure is a Hash with the following format:

{'id': <uuid_string> ,
 'a': <signing_authority_string>,
 'tc': <creation_timestamp_integer>,
 'te': <expiration_timestamp_integer>,
 'ds': {<signed_data_hash>},
 'dx': {<unsigned_data_hash>},
 's': <binary_signature_string>}

Limitations of V1 include the following:

  • Compressing the JSON usually INCREASES the size of the compressed data

  • The sign and verify algorithms, while safe, do not comply fully with PKCS7; they rely on the OpenSSL low-level crypto API instead of using the higher-level EVP (envelope) API.

Instance Attribute Summary

Attributes inherited from Abstract

#authority, #created_at, #directory, #expired_at, #id, #insecure, #signed

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Abstract

#has_key?, #initialize, #inspect, #invalidate!, #new_record?, #supports_key?, #to_hash, #valid?

Constructor Details

This class inherits a constructor from GlobalSession::Session::Abstract

Class Method Details

Utility method to decode a cookie; good for console debugging. This performs no validation or security check of any sort.

Parameters

cookie(String)

well-formed global session cookie



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# File 'lib/global_session/session/v1.rb', line 47

def self.decode_cookie(cookie)
  zbin = GlobalSession::Encoding::Base64Cookie.load(cookie)
  json = Zlib::Inflate.inflate(zbin)
  return GlobalSession::Encoding::JSON.load(json)
end

Instance Method Details

#[](key) ⇒ Object

Lookup a value by its key.

Parameters

key(String)

the key

Return

value(Object)

The value associated with key, or nil if key is not present



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# File 'lib/global_session/session/v1.rb', line 124

def [](key)
  key = key.to_s #take care of symbol-style keys
  @signed[key] || @insecure[key]
end

#[]=(key, value) ⇒ Object

Set a value in the global session hash. If the supplied key is denoted as secure by the global session schema, causes a new signature to be computed when the session is next serialized.

Parameters

key(String)

The key to set

value(Object)

The value to set

Return

value(Object)

Always returns the value that was set

Raise

InvalidSession

if the session has been invalidated (and therefore can’t be written to)

ArgumentError

if the configuration doesn’t define the specified key as part of the global session

NoAuthority

if the specified key is secure and the local node is not an authority

UnserializableType

if the specified value can’t be serialized as JSON

Raises:



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# File 'lib/global_session/session/v1.rb', line 145

def []=(key, value)
  key = key.to_s #take care of symbol-style keys
  raise GlobalSession::InvalidSession unless valid?

  #Ensure that the value is serializable (will raise if not)
  canonicalize(value)

  if @schema_signed.include?(key)
    authority_check
    @signed[key] = value
    @dirty_secure = true
  elsif @schema_insecure.include?(key)
    @insecure[key] = value
    @dirty_insecure = true
  else
    raise ArgumentError, "Attribute '#{key}' is not specified in global session configuration"
  end

  return value
end

#each_pair(&block) ⇒ Object

Iterate over each key/value pair

Block

An iterator which will be called with each key/value pair

Return

Returns the value of the last expression evaluated by the block



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# File 'lib/global_session/session/v1.rb', line 112

def each_pair(&block) # :yields: |key, value|
  @signed.each_pair(&block)
  @insecure.each_pair(&block)
end

#keys ⇒ Object

Return the keys that are currently present in the global session.

Return

keys(Array)

List of keys contained in the global session



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# File 'lib/global_session/session/v1.rb', line 93

def keys
  @signed.keys + @insecure.keys
end

#renew!(expired_at = nil) ⇒ Object

Renews this global session, changing its expiry timestamp into the future. Causes a new signature will be computed when the session is next serialized.

Return

true

Always returns true



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# File 'lib/global_session/session/v1.rb', line 171

def renew!(expired_at=nil)
  super(expired_at)
  @dirty_secure = true
end

#signature_digest ⇒ Object

Return the SHA1 hash of the most recently-computed RSA signature of this session. This isn’t really intended for the end user; it exists so the Web framework integration code can optimize request speed by caching the most recently verified signature in the local session and avoid re-verifying it on every request.

Return

digest(String)

SHA1 hex-digest of most-recently-computed signature



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# File 'lib/global_session/session/v1.rb', line 183

def signature_digest
  @signature ? digest(@signature) : nil
end

#to_s ⇒ Object

Serialize the session to a form suitable for use with HTTP cookies. If any secure attributes have changed since the session was instantiated, compute a fresh RSA signature.

Return

cookie(String)

Base64Cookie-encoded, Zlib-compressed JSON-serialized global session



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# File 'lib/global_session/session/v1.rb', line 59

def to_s
  if @cookie && !@dirty_insecure && !@dirty_secure
    #use cached cookie if nothing has changed
    return @cookie
  end

  hash = {'id' => @id,
          'tc' => @created_at.to_i, 'te' => @expired_at.to_i,
          'ds' => @signed}

  if @signature && !@dirty_secure
    #use cached signature unless we've changed secure state
    authority = @authority
  else
    authority_check
    authority = @directory.local_authority_name
    hash['a'] = authority
    digest = canonical_digest(hash)
    @signature = GlobalSession::Encoding::Base64Cookie.dump(@directory.private_key.private_encrypt(digest))
  end

  hash['dx'] = @insecure
  hash['s'] = @signature
  hash['a'] = authority

  json = GlobalSession::Encoding::JSON.dump(hash)
  zbin = Zlib::Deflate.deflate(json, Zlib::BEST_COMPRESSION)
  return GlobalSession::Encoding::Base64Cookie.dump(zbin)
end

#values ⇒ Object

Return the values that are currently present in the global session.

Return

values(Array)

List of values contained in the global session



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# File 'lib/global_session/session/v1.rb', line 101

def values
  @signed.values + @insecure.values
end