diff options
Diffstat (limited to 'activesupport/lib/active_support/security_utils.rb')
| -rw-r--r-- | activesupport/lib/active_support/security_utils.rb | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/security_utils.rb b/activesupport/lib/active_support/security_utils.rb new file mode 100644 index 0000000000..64c4801179 --- /dev/null +++ b/activesupport/lib/active_support/security_utils.rb @@ -0,0 +1,20 @@ +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 + end +end |