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#
# Author:: Christopher Brown (<cb@opscode.com>)
# Author:: Christopher Walters (<cw@opscode.com>)
# Copyright:: Copyright (c) 2009, 2010 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'time'
require 'base64'
require 'digest/sha1'
require 'mixlib/authentication'
require 'mixlib/authentication/digester'
module Mixlib
module Authentication
module SignedHeaderAuth
NULL_ARG = Object.new
SUPPORTED_ALGORITHMS = ['sha1'].freeze
SUPPORTED_VERSIONS = ['1.0', '1.1'].freeze
DEFAULT_SIGN_ALGORITHM = 'sha1'.freeze
DEFAULT_PROTO_VERSION = '1.0'.freeze
# === signing_object
# This is the intended interface for signing requests with the
# Opscode/Chef signed header protocol. This wraps the constructor for a
# Struct that contains the relevant information about your request.
#
# ==== Signature Parameters:
# These parameters are used to generate the canonical representation of
# the request, which is then hashed and encrypted to generate the
# request's signature. These options are all required, with the exception
# of `:body` and `:file`, which are alternate ways to specify the request
# body (you must specify one of these).
# * `:http_method`: HTTP method as a lowercase symbol, e.g., `:get | :put | :post | :delete`
# * `:path`: The path part of the URI, e.g., `URI.parse(uri).path`
# * `:body`: An object representing the body of the request.
# Use an empty String for bodiless requests.
# * `:timestamp`: A String representing the time in any format understood
# by `Time.parse`. The server may reject the request if the timestamp is
# not close to the server's current time.
# * `:user_id`: The user or client name. This is used by the server to
# lookup the public key necessary to verify the signature.
# * `:file`: An IO object (must respond to `:read`) to be used as the
# request body.
# ==== Protocol Versioning Parameters:
# * `:proto_version`: The version of the signing protocol to use.
# Currently defaults to 1.0, but version 1.1 is also available.
# ==== Other Parameters:
# These parameters are accepted but not used in the computation of the signature.
# * `:host`: The host part of the URI
def self.signing_object(args={ })
SigningObject.new(args[:http_method], args[:path], args[:body], args[:host], args[:timestamp], args[:user_id], args[:file], args[:proto_version])
end
def algorithm
DEFAULT_SIGN_ALGORITHM
end
def proto_version
DEFAULT_PROTO_VERSION
end
# Build the canonicalized request based on the method, other headers, etc.
# compute the signature from the request, using the looked-up user secret
# ====Parameters
# private_key<OpenSSL::PKey::RSA>:: user's RSA private key.
def sign(private_key, sign_algorithm=algorithm, sign_version=proto_version)
# Our multiline hash for authorization will be encoded in multiple header
# lines - X-Ops-Authorization-1, ... (starts at 1, not 0!)
header_hash = {
"X-Ops-Sign" => "algorithm=#{sign_algorithm};version=#{sign_version};",
"X-Ops-Userid" => user_id,
"X-Ops-Timestamp" => canonical_time,
"X-Ops-Content-Hash" => hashed_body,
}
string_to_sign = canonicalize_request(sign_algorithm, sign_version)
signature = Base64.encode64(private_key.private_encrypt(string_to_sign)).chomp
signature_lines = signature.split(/\n/)
signature_lines.each_index do |idx|
key = "X-Ops-Authorization-#{idx + 1}"
header_hash[key] = signature_lines[idx]
end
Mixlib::Authentication::Log.debug "String to sign: '#{string_to_sign}'\nHeader hash: #{header_hash.inspect}"
header_hash
end
# Build the canonicalized time based on utc & iso8601
#
# ====Parameters
#
def canonical_time
Time.parse(timestamp).utc.iso8601
end
# Build the canonicalized path, which collapses multiple slashes (/) and
# removes a trailing slash unless the path is only "/"
#
# ====Parameters
#
def canonical_path
p = path.gsub(/\/+/,'/')
p.length > 1 ? p.chomp('/') : p
end
def hashed_body
# Hash the file object if it was passed in, otherwise hash based on
# the body.
# TODO: tim 2009-12-28: It'd be nice to just remove this special case,
# always sign the entire request body, using the expanded multipart
# body in the case of a file being include.
@hashed_body ||= (self.file && self.file.respond_to?(:read)) ? digester.hash_file(self.file) : digester.hash_string(self.body)
end
# Takes HTTP request method & headers and creates a canonical form
# to create the signature
#
# ====Parameters
#
#
def canonicalize_request(sign_algorithm=algorithm, sign_version=proto_version)
unless SUPPORTED_ALGORITHMS.include?(sign_algorithm) && SUPPORTED_VERSIONS.include?(sign_version)
raise AuthenticationError, "Bad algorithm '#{sign_algorithm}' (allowed: #{SUPPORTED_ALGORITHMS.inspect}) or version '#{sign_version}' (allowed: #{SUPPORTED_VERSIONS.inspect})"
end
canonical_x_ops_user_id = canonicalize_user_id(user_id, sign_version)
"Method:#{http_method.to_s.upcase}\nHashed Path:#{digester.hash_string(canonical_path)}\nX-Ops-Content-Hash:#{hashed_body}\nX-Ops-Timestamp:#{canonical_time}\nX-Ops-UserId:#{canonical_x_ops_user_id}"
end
def canonicalize_user_id(user_id, proto_version)
case proto_version
when "1.1"
digester.hash_string(user_id)
when "1.0"
user_id
else
user_id
end
end
# Parses signature version information, algorithm used, etc.
#
# ====Parameters
#
def parse_signing_description
parts = signing_description.strip.split(";").inject({ }) do |memo, part|
field_name, field_value = part.split("=")
memo[field_name.to_sym] = field_value.strip
memo
end
Mixlib::Authentication::Log.debug "Parsed signing description: #{parts.inspect}"
parts
end
def digester
Mixlib::Authentication::Digester
end
private :canonical_time, :canonical_path, :parse_signing_description, :digester, :canonicalize_user_id
end
# === SigningObject
# A Struct-based value object that contains the necessary information to
# generate a request signature. `SignedHeaderAuth.signing_object()`
# provides a more convenient interface to the constructor.
class SigningObject < Struct.new(:http_method, :path, :body, :host, :timestamp, :user_id, :file, :proto_version)
include SignedHeaderAuth
def proto_version
(self[:proto_version] or DEFAULT_PROTO_VERSION).to_s
end
end
end
end
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