1
0
Fork 0
mirror of https://github.com/rails/rails.git synced 2022-11-09 12:12:34 -05:00
rails--rails/activesupport/lib/active_support/security_utils.rb
Xavier Noria d66e7835be applies new string literal convention in activesupport/lib
The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.
2016-08-06 18:10:53 +02:00

27 lines
798 B
Ruby

require "digest"
module ActiveSupport
module SecurityUtils
# Constant time string comparison.
#
# The values compared should be of fixed length, such as strings
# that have already been processed by HMAC. This should not be used
# on variable length plaintext strings because it could leak length info
# via timing attacks.
def secure_compare(a, b)
return false unless a.bytesize == b.bytesize
l = a.unpack "C#{a.bytesize}"
res = 0
b.each_byte { |byte| res |= byte ^ l.shift }
res == 0
end
module_function :secure_compare
def variable_size_secure_compare(a, b) # :nodoc:
secure_compare(::Digest::SHA256.hexdigest(a), ::Digest::SHA256.hexdigest(b))
end
module_function :variable_size_secure_compare
end
end