Merge pull request #1228 from chef/dp_signing

Implements profile signing and verification [Experimental]

lib/bundles/inspec-artifact.rb

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+# encoding: utf-8
+# author: Dave Parfitt
+
+libdir = File.dirname(__FILE__)
+$LOAD_PATH.unshift(libdir) unless $LOAD_PATH.include?(libdir)
+
+require 'inspec-artifact/cli'

lib/bundles/inspec-artifact/README.md

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+# TODO

lib/bundles/inspec-artifact/cli.rb

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+# encoding: utf-8
+# frozen_string_literal: true
+require 'base64'
+require 'openssl'
+require 'pathname'
+require 'set'
+require 'tempfile'
+require 'yaml'
+
+# Notes:
+#
+# Generate keys
+#   The initial implementation uses 2048 bit RSA key pairs (public + private).
+#   Public keys must be available for a customer to install and verify an artifact.
+#   Private keys should be stored in a secure location and NOT be distributed.
+#     (They're only for creating artifacts).
+#
+#
+# .IAF file format
+#   .iaf = "Inspec Artifact File", easy to rename if you'd like something more appropriate.
+#   The iaf file wraps a binary artifact with some metadata. The first implementation
+#   looks like this:
+#
+# INSPEC-PROFILE-1
+# name_of_signing_key
+# algorithm
+# signature
+# <empty line>
+# binary-blob
+# <eof>
+#
+# Let's look at each line:
+# INSPEC-PROFILE-1:
+#   This is the artifact version descriptor. It should't change unless the
+#   format of the archive changes.
+#
+# name_of_signing_key
+#   The name of the public key that can be used to verify an artifact
+#
+# algorithm
+#   The digest used to sign, I picked SHA512 to start with.
+#   If we support multiple digests, we'll need to have the verify() method
+#   support each digest.
+#
+# signature
+#   The result of passing the binary artifact through the digest algorithm above.
+#   Result is base64 encoded.
+#
+# <empty line>
+#   We use an empty line to separate artifact header from artifact body (binary blob).
+#   The artifact body can be anything you like.
+#
+# binary-blob
+#   A binary blob, most likely a .tar.gz or tar.xz file. We'll need to pick one and
+#   stick with it as part of the "INSPEC-PROFILE-1" artifact version. If we change block
+#   format, the artifact version descriptor must be incremented, and the sign()
+#   and verify() methods must be updated to support a newer version.
+#
+#
+# Key revocation
+#   This implementation doesn't support key revocation. However, a customer
+#   can remove the public cert file before installation, and artifacts will then
+#   fail verification.
+#
+# Key locations
+#   This implementation uses the current working directory to find public and
+#   private keys. We should establish a common key directory (similar to /hab/cache/keys
+#   or ~/.hab/cache/keys in Habitat).
+#
+# Extracting artifacts outside of Inspec
+#   As in Habitat, the artifact format for Inspec allows the use of common
+#   Unix tools to read the header and body of an artifact.
+# To extract the header from a .iaf:
+#        sed '/^$/q' foo.iaf
+# To extract the raw content from a .iaf:
+#        sed '1,/^$/d' foo.iaf
+
+module Artifact
+  KEY_BITS=2048
+  KEY_ALG=OpenSSL::PKey::RSA
+
+  INSPEC_PROFILE_VERSION_1='INSPEC-PROFILE-1'.freeze
+  INSPEC_REPORT_VERSION_1='INSPEC-REPORT-1'.freeze
+
+  ARTIFACT_DIGEST=OpenSSL::Digest::SHA512
+  ARTIFACT_DIGEST_NAME='SHA512'.freeze
+
+  VALID_PROFILE_VERSIONS=Set.new [INSPEC_PROFILE_VERSION_1]
+  VALID_PROFILE_DIGESTS=Set.new [ARTIFACT_DIGEST_NAME]
+
+  SIGNED_PROFILE_SUFFIX='iaf'.freeze
+  SIGNED_REPORT_SUFFIX='iar'.freeze
+
+  # rubocop:disable Metrics/ClassLength
+  class CLI < Inspec::BaseCLI
+    namespace 'artifact'
+
+    # TODO: find another solution, once https://github.com/erikhuda/thor/issues/261 is fixed
+    def self.banner(command, _namespace = nil, _subcommand = false)
+      "#{basename} #{subcommand_prefix} #{command.usage}"
+    end
+
+    def self.subcommand_prefix
+      namespace
+    end
+
+    desc 'generate', 'Generate a RSA key pair for signing and verification'
+    option :keyname, type: :string, required: true,
+      desc: 'Desriptive name of key'
+    option :keydir, type: :string, default: './',
+      desc: 'Directory to search for keys'
+    def generate_keys
+      puts 'Generating keys'
+      keygen
+    end
+
+    desc 'sign-profile', 'Create a signed .iaf artifact'
+    option :profile, type: :string, required: true,
+      desc: 'Path to profile directory'
+    option :keyname, type: :string, required: true,
+      desc: 'Desriptive name of key'
+    def sign_profile
+      profile_sign
+    end
+
+    desc 'verify-profile', 'Verify a signed .iaf artifact'
+    option :infile, type: :string, required: true,
+        desc: '.iaf file to verify'
+    def verify_profile
+      profile_verify
+    end
+
+    desc 'install-profile', 'Verify and install a signed .iaf artifact'
+    option :infile, type: :string, required: true,
+        desc: '.iaf file to install'
+    option :destdir, type: :string, required: true,
+      desc: 'Installation directory'
+    def install_profile
+      profile_install
+    end
+
+    private
+
+    def keygen
+      key = KEY_ALG.new KEY_BITS
+      puts 'Generating private key'
+      open "#{options['keyname']}.pem.key", 'w' do |io| io.write key.to_pem end
+      puts 'Generating public key'
+      open "#{options['keyname']}.pem.pub", 'w' do |io| io.write key.public_key.to_pem end
+    end
+
+    def read_profile_metadata(path_to_profile)
+      begin
+        p = Pathname.new(path_to_profile)
+        p = p.join('inspec.yml')
+        if not p.exist?
+          fail "#{path_to_profile} doesn't appear to be a valid Inspec profile"
+        end
+        yaml = YAML.load_file(p.to_s)
+        yaml = yaml.to_hash
+
+        if not yaml.key? 'name'
+          fail 'Profile is invalid, name is not defined'
+        end
+
+        if not yaml.key? 'version'
+          fail 'Profile is invalid, version is not defined'
+        end
+      rescue => e
+        # rewrap it and pass it up to the CLI
+        raise "Error reading Inspec profile metadata: #{e}"
+      end
+
+      yaml
+    end
+
+    def profile_compress(path_to_profile, profile_md, workdir)
+      profile_name = profile_md['name']
+      profile_version = profile_md['version']
+      outfile_name = "#{workdir}/#{profile_name}-#{profile_version}.tar.gz"
+      `tar czf #{outfile_name} -C #{path_to_profile} .`
+      outfile_name
+    end
+
+    def profile_sign
+      Dir.mktmpdir do |workdir|
+        puts "Signing #{options['profile']} with key #{options['keyname']}"
+        path_to_profile = options['profile']
+        profile_md = read_profile_metadata(path_to_profile)
+        artifact_filename = "#{profile_md['name']}-#{profile_md['version']}.#{SIGNED_PROFILE_SUFFIX}"
+        tarfile = profile_compress(path_to_profile, profile_md, workdir)
+        content = IO.binread(tarfile)
+        signing_key = KEY_ALG.new File.read "#{options['keyname']}.pem.key"
+        sha = ARTIFACT_DIGEST.new
+        signature = signing_key.sign sha, content
+        # convert the signature to Base64
+        signature_base64 = Base64.encode64(signature)
+        tar_content = IO.binread(tarfile)
+        File.open(artifact_filename, 'wb') do |f|
+          f.puts(INSPEC_PROFILE_VERSION_1)
+          f.puts(options['keyname'])
+          f.puts(ARTIFACT_DIGEST_NAME)
+          f.puts(signature_base64)
+          f.puts('') # newline separates artifact header with body
+          f.write(tar_content)
+        end
+        puts "Successfully generated #{artifact_filename}"
+      end
+    end
+
+    def valid_header?(file_alg, file_version, file_keyname)
+      public_keyfile = "#{file_keyname}.pem.pub"
+      puts "Looking for #{public_keyfile} to verify artifact"
+      if not File.exist? public_keyfile
+        fail "Can't find #{public_keyfile}"
+      end
+
+      if not VALID_PROFILE_DIGESTS.member? file_alg
+        fail 'Invalid artifact digest algorithm detected'
+      end
+
+      if not VALID_PROFILE_VERSIONS.member? file_version
+        fail 'Invalid artifact version detected'
+      end
+    end
+
+    def verify(file_to_verifiy, &content_block)
+      f = File.open(file_to_verifiy, 'r')
+      file_version = f.readline.strip!
+      file_keyname = f.readline.strip!
+      file_alg = f.readline.strip!
+
+      file_sig = ''
+      # the signature is multi-line
+      while (line = f.readline) != "\n"
+        file_sig += line
+      end
+      file_sig.strip!
+      f.close
+
+      valid_header?(file_alg, file_version, file_keyname)
+
+      public_keyfile = "#{file_keyname}.pem.pub"
+      verification_key = KEY_ALG.new File.read public_keyfile
+
+      f = File.open(file_to_verifiy, 'r')
+      while f.readline != "\n" do end
+      content = f.read
+
+      signature = Base64.decode64(file_sig)
+      digest = ARTIFACT_DIGEST.new
+      if verification_key.verify digest, signature, content
+        content_block.yield(content)
+      else
+        puts 'Artifact is invalid'
+      end
+    end
+
+    def profile_verify
+      file_to_verifiy = options['infile']
+      puts "Verifying #{file_to_verifiy}"
+      verify(file_to_verifiy) do ||
+        puts 'Artifact is valid'
+      end
+    end
+
+    def profile_install
+      puts 'Installing profile'
+      file_to_verifiy = options['infile']
+      dest_dir = options['destdir']
+      verify(file_to_verifiy) do |content|
+        Dir.mktmpdir do |workdir|
+          tmpfile = Pathname.new(workdir).join('artifact_to_install.tar.gz')
+          File.write(tmpfile, content)
+          puts "Installing to #{dest_dir}"
+          `tar xzf #{tmpfile} -C #{dest_dir}`
+        end
+      end
+    end
+  end
+
+  # register the subcommand to Inspec CLI registry
+  Inspec::Plugins::CLI.add_subcommand(Artifact::CLI, 'artifact', 'artifact SUBCOMMAND ...', 'Sign, verify and install artifacts', {})
+end

test/functional/inspec_artifact_test.rb

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+# encoding: utf-8
+
+require 'fileutils'
+require 'functional/helper'
+require 'securerandom'
+
+describe 'inspec exec' do
+  include FunctionalHelper
+
+  it 'can generate keys' do
+    unique_key_name = SecureRandom.uuid()
+    out = inspec("artifact generate --keyname #{unique_key_name}")
+    # haha, ruby so shitty, there's ALWAYS gem problems
+    #out.stderr.must_equal ''
+    out.exit_status.must_equal 0
+    stdout = out.stdout.force_encoding(Encoding::UTF_8)
+    stdout.must_include 'Generating private key'
+    stdout.must_include 'Generating public key'
+
+    FileUtils.rm("#{unique_key_name}.pem.pub")
+    FileUtils.rm("#{unique_key_name}.pem.key")
+  end
+
+  it 'can sign, verify and install a signed profile' do
+    FileUtils.rm_f('profile-1.0.0.iaf')
+    unique_key_name = SecureRandom.uuid()
+    install_dir = SecureRandom.uuid()
+    FileUtils.mkdir(install_dir)
+
+    out = inspec("artifact generate --keyname #{unique_key_name}")
+    out.exit_status.must_equal 0
+
+    out = inspec("artifact sign-profile --profile #{example_profile} --keyname #{unique_key_name}")
+    out.exit_status.must_equal 0
+
+    out = inspec("artifact install-profile --infile profile-1.0.0.iaf --destdir #{install_dir}")
+    out.exit_status.must_equal 0
+    stdout = out.stdout.force_encoding(Encoding::UTF_8)
+    stdout.must_include "Installing to #{install_dir}"
+    entries = Dir.entries install_dir
+    entries.join.must_include "inspec.yml"
+    FileUtils.rm_rf(install_dir)
+    FileUtils.rm("#{unique_key_name}.pem.pub")
+    FileUtils.rm("#{unique_key_name}.pem.key")
+    FileUtils.rm('profile-1.0.0.iaf')
+  end
+
+end