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-rw-r--r--tests/helpers/srp_helper.rb171
1 files changed, 171 insertions, 0 deletions
diff --git a/tests/helpers/srp_helper.rb b/tests/helpers/srp_helper.rb
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+++ b/tests/helpers/srp_helper.rb
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+#
+# Here are some very stripped down helper methods for SRP, useful only for
+# testing the client side.
+#
+
+require 'digest'
+require 'openssl'
+require 'securerandom'
+require 'base64'
+
+module SRP
+
+ ##
+ ## UTIL
+ ##
+
+ module Util
+ PRIME_N = <<-EOS.split.join.hex
+115b8b692e0e045692cf280b436735c77a5a9e8a9e7ed56c965f87db5b2a2ece3
+ EOS
+ BIG_PRIME_N = <<-EOS.split.join.hex # 1024 bits modulus (N)
+eeaf0ab9adb38dd69c33f80afa8fc5e86072618775ff3c0b9ea2314c9c25657
+6d674df7496ea81d3383b4813d692c6e0e0d5d8e250b98be48e495c1d6089da
+d15dc7d7b46154d6b6ce8ef4ad69b15d4982559b297bcf1885c529f566660e5
+7ec68edbc3c05726cc02fd4cbf4976eaa9afd5138fe8376435b9fc61d2fc0eb
+06e3
+ EOS
+ GENERATOR = 2 # g
+
+ def hn_xor_hg
+ byte_xor_hex(sha256_int(BIG_PRIME_N), sha256_int(GENERATOR))
+ end
+
+ # a^n (mod m)
+ def modpow(a, n, m = BIG_PRIME_N)
+ r = 1
+ while true
+ r = r * a % m if n[0] == 1
+ n >>= 1
+ return r if n == 0
+ a = a * a % m
+ end
+ end
+
+ # Hashes the (long) int args
+ def sha256_int(*args)
+ sha256_hex(*args.map{|a| "%02x" % a})
+ end
+
+ # Hashes the hex args
+ def sha256_hex(*args)
+ h = args.map{|a| a.length.odd? ? "0#{a}" : a }.join('')
+ sha256_str([h].pack('H*'))
+ end
+
+ def sha256_str(s)
+ Digest::SHA2.hexdigest(s)
+ end
+
+ def bigrand(bytes)
+ OpenSSL::Random.random_bytes(bytes).unpack("H*")[0]
+ end
+
+ def multiplier
+ @muliplier ||= calculate_multiplier
+ end
+
+ protected
+
+ def calculate_multiplier
+ sha256_int(BIG_PRIME_N, GENERATOR).hex
+ end
+
+ def byte_xor_hex(a, b)
+ a = [a].pack('H*')
+ b = [b].pack('H*')
+ a.bytes.each_with_index.map do |a_byte, i|
+ (a_byte ^ (b[i].ord || 0)).chr
+ end.join
+ end
+ end
+
+ ##
+ ## SESSION
+ ##
+
+ class Session
+ include SRP::Util
+ attr_accessor :user
+ attr_accessor :bb
+
+ def initialize(user, aa=nil)
+ @user = user
+ @a = bigrand(32).hex
+ end
+
+ def m
+ @m ||= sha256_hex(n_xor_g_long, login_hash, @user.salt.to_s(16), aa, bb, k)
+ end
+
+ def aa
+ @aa ||= modpow(GENERATOR, @a).to_s(16) # A = g^a (mod N)
+ end
+
+ protected
+
+ # client: K = H( (B - kg^x) ^ (a + ux) )
+ def client_secret
+ base = bb.hex
+ base -= modpow(GENERATOR, @user.private_key) * multiplier
+ base = base % BIG_PRIME_N
+ modpow(base, @user.private_key * u.hex + @a)
+ end
+
+ def k
+ @k ||= sha256_int(client_secret)
+ end
+
+ def n_xor_g_long
+ @n_xor_g_long ||= hn_xor_hg.bytes.map{|b| "%02x" % b.ord}.join
+ end
+
+ def login_hash
+ @login_hash ||= sha256_str(@user.username)
+ end
+
+ def u
+ @u ||= sha256_hex(aa, bb)
+ end
+ end
+
+ ##
+ ## Dummy USER
+ ##
+
+ class User
+ include SRP::Util
+
+ attr_accessor :username, :password, :salt, :verifier, :id, :session_token, :ok, :deleted
+
+ def initialize
+ @username = "test_user_" + SecureRandom.urlsafe_base64(10).downcase.gsub(/[_-]/, '')
+ @password = "password_" + SecureRandom.urlsafe_base64(10)
+ @salt = bigrand(4).hex
+ @verifier = modpow(GENERATOR, private_key)
+ @ok = false
+ @deleted = false
+ end
+
+ def private_key
+ @private_key ||= calculate_private_key
+ end
+
+ def to_params
+ {
+ 'user[login]' => @username,
+ 'user[password_verifier]' => @verifier.to_s(16),
+ 'user[password_salt]' => @salt.to_s(16)
+ }
+ end
+
+ private
+
+ def calculate_private_key
+ shex = '%x' % [@salt]
+ inner = sha256_str([@username, @password].join(':'))
+ sha256_hex(shex, inner).hex
+ end
+ end
+
+end