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| 1 | +# frozen_string_literal: true |
| 2 | + |
| 3 | +require 'openssl' |
| 4 | +require 'securerandom' |
| 5 | +require 'json' |
| 6 | +require 'legion/extensions/node/config' |
| 7 | + |
| 8 | +module Legion |
| 9 | + module Extensions |
| 10 | + module Node |
| 11 | + module ControlAuth |
| 12 | + AUTH_MODES = %w[auto required disabled].freeze |
| 13 | + |
| 14 | + class UnauthorizedControlMessage < StandardError; end |
| 15 | + |
| 16 | + module_function |
| 17 | + |
| 18 | + def sign(payload) |
| 19 | + normalized = deep_symbolize(payload).dup |
| 20 | + return normalized unless sign_control_messages? |
| 21 | + |
| 22 | + control = { |
| 23 | + sender: node_name, |
| 24 | + timestamp: Time.now.utc.to_i, |
| 25 | + nonce: SecureRandom.hex(nonce_bytes) |
| 26 | + } |
| 27 | + normalized[:control] = control.merge(signature: signature_for(normalized.merge(control: control))) |
| 28 | + normalized |
| 29 | + end |
| 30 | + |
| 31 | + def verify!(payload) |
| 32 | + normalized = deep_symbolize(payload) |
| 33 | + raise UnauthorizedControlMessage, 'missing control signature' unless normalized.is_a?(Hash) |
| 34 | + return normalized unless verify_control_messages? |
| 35 | + |
| 36 | + control = normalized[:control] |
| 37 | + raise UnauthorizedControlMessage, 'missing control signature' unless control.is_a?(Hash) |
| 38 | + |
| 39 | + signature = control[:signature].to_s |
| 40 | + raise UnauthorizedControlMessage, 'missing control signature' if signature.empty? |
| 41 | + raise UnauthorizedControlMessage, 'stale control message' unless fresh_timestamp?(control[:timestamp]) |
| 42 | + raise UnauthorizedControlMessage, 'invalid control nonce' unless valid_nonce?(control[:nonce]) |
| 43 | + |
| 44 | + unsigned_control = control.dup |
| 45 | + unsigned_control.delete(:signature) |
| 46 | + expected = signature_for(normalized.merge(control: unsigned_control)) |
| 47 | + raise UnauthorizedControlMessage, 'invalid control signature' unless secure_compare(signature, expected) |
| 48 | + |
| 49 | + normalized |
| 50 | + end |
| 51 | + |
| 52 | + def sign_control_messages? |
| 53 | + return false if auth_disabled? |
| 54 | + return true if auth_required? |
| 55 | + |
| 56 | + !secret.to_s.empty? |
| 57 | + end |
| 58 | + |
| 59 | + def verify_control_messages? |
| 60 | + return false if auth_disabled? |
| 61 | + return true if auth_required? |
| 62 | + |
| 63 | + !secret.to_s.empty? |
| 64 | + end |
| 65 | + |
| 66 | + def auth_mode |
| 67 | + configured = auth_settings[:mode] || auth_settings[:enabled] |
| 68 | + mode = case configured |
| 69 | + when true then 'required' |
| 70 | + when false then 'disabled' |
| 71 | + else configured.to_s |
| 72 | + end |
| 73 | + AUTH_MODES.include?(mode) ? mode : 'auto' |
| 74 | + end |
| 75 | + |
| 76 | + def auth_required? |
| 77 | + auth_mode == 'required' |
| 78 | + end |
| 79 | + |
| 80 | + def auth_disabled? |
| 81 | + auth_mode == 'disabled' |
| 82 | + end |
| 83 | + |
| 84 | + def auth_settings |
| 85 | + Legion::Extensions::Node::Config.control_auth |
| 86 | + end |
| 87 | + |
| 88 | + def secret |
| 89 | + configured_secret || ENV.fetch('LEGION_NODE_CONTROL_SECRET', nil) |
| 90 | + end |
| 91 | + |
| 92 | + def configured_secret |
| 93 | + if defined?(Legion::Settings) && Legion::Settings.respond_to?(:dig) |
| 94 | + auth_settings[:secret] || |
| 95 | + Legion::Settings.dig(:cluster, :control_secret) || |
| 96 | + Legion::Settings.dig(:crypt, :cluster_secret) |
| 97 | + end |
| 98 | + rescue StandardError => e |
| 99 | + log.debug("control secret lookup failed: #{e.message}") |
| 100 | + nil |
| 101 | + end |
| 102 | + |
| 103 | + def signature_for(payload) |
| 104 | + value = secret |
| 105 | + raise UnauthorizedControlMessage, 'cluster control secret is not configured' if value.to_s.empty? |
| 106 | + |
| 107 | + OpenSSL::HMAC.hexdigest('SHA256', value.to_s, canonical_json(payload)) |
| 108 | + end |
| 109 | + |
| 110 | + def canonical_json(value) |
| 111 | + ::JSON.generate(canonicalize(value)) |
| 112 | + end |
| 113 | + |
| 114 | + def canonicalize(value) |
| 115 | + case value |
| 116 | + when Hash |
| 117 | + value.each_with_object({}) do |(key, val), result| |
| 118 | + result[key.to_s] = canonicalize(val) |
| 119 | + end.sort.to_h |
| 120 | + when Array |
| 121 | + value.map { |item| canonicalize(item) } |
| 122 | + else |
| 123 | + value |
| 124 | + end |
| 125 | + end |
| 126 | + |
| 127 | + def deep_symbolize(value) |
| 128 | + case value |
| 129 | + when Hash |
| 130 | + value.each_with_object({}) do |(key, val), result| |
| 131 | + result[key.to_sym] = deep_symbolize(val) |
| 132 | + end |
| 133 | + when Array |
| 134 | + value.map { |item| deep_symbolize(item) } |
| 135 | + else |
| 136 | + value |
| 137 | + end |
| 138 | + end |
| 139 | + |
| 140 | + def fresh_timestamp?(timestamp) |
| 141 | + ts = Integer(timestamp) |
| 142 | + (Time.now.utc.to_i - ts).abs <= timestamp_skew_seconds |
| 143 | + rescue ArgumentError, TypeError => e |
| 144 | + log.debug("control timestamp validation failed: #{e.message}") |
| 145 | + false |
| 146 | + end |
| 147 | + |
| 148 | + def timestamp_skew_seconds |
| 149 | + Integer(auth_settings[:timestamp_skew_seconds]) |
| 150 | + rescue ArgumentError, TypeError => e |
| 151 | + log.debug("control timestamp skew setting invalid: #{e.message}") |
| 152 | + 300 |
| 153 | + end |
| 154 | + |
| 155 | + def nonce_bytes |
| 156 | + bytes = Integer(auth_settings[:nonce_bytes]) |
| 157 | + bytes.positive? ? bytes : 16 |
| 158 | + rescue ArgumentError, TypeError => e |
| 159 | + log.debug("control nonce byte setting invalid: #{e.message}") |
| 160 | + 16 |
| 161 | + end |
| 162 | + |
| 163 | + def valid_nonce?(nonce) |
| 164 | + nonce.to_s.match?(/\A[0-9a-f]{#{nonce_bytes * 2}}\z/i) |
| 165 | + end |
| 166 | + |
| 167 | + def secure_compare(left, right) |
| 168 | + return false unless left.bytesize == right.bytesize |
| 169 | + |
| 170 | + left.bytes.zip(right.bytes).reduce(0) { |acc, (a, b)| acc | (a ^ b) }.zero? |
| 171 | + end |
| 172 | + |
| 173 | + def node_name |
| 174 | + (Legion::Settings[:client]&.fetch(:name, nil) if defined?(Legion::Settings)) || 'unknown' |
| 175 | + rescue StandardError => e |
| 176 | + log.debug("node name lookup failed: #{e.message}") |
| 177 | + 'unknown' |
| 178 | + end |
| 179 | + |
| 180 | + def log |
| 181 | + Legion::Logging.respond_to?(:logger) ? Legion::Logging.logger : Legion::Logging |
| 182 | + end |
| 183 | + end |
| 184 | + end |
| 185 | + end |
| 186 | +end |
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