simplesamlphp /
simplesamlphp-module-webauthn
| Total Complexity | 98 |
| Total Lines | 794 |
| Duplicated Lines | 0 % |
| Changes | 26 | ||
| Bugs | 5 | Features | 0 |
Complex classes like WebAuthnRegistrationEvent often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use WebAuthnRegistrationEvent, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
||
| 27 | class WebAuthnRegistrationEvent extends WebAuthnAbstractEvent |
||
| 28 | { |
||
| 29 | /** |
||
| 30 | * Public key algorithm supported. This is -7 - ECDSA with curve P-256, or -275 (RS256) |
||
| 31 | */ |
||
| 32 | public const PK_ALGORITHM_ECDSA = "-7"; |
||
| 33 | |||
| 34 | public const PK_ALGORITHM_RSA = "-257"; |
||
| 35 | |||
| 36 | public const PK_ALGORITHM = [self::PK_ALGORITHM_ECDSA, self::PK_ALGORITHM_RSA]; |
||
| 37 | |||
| 38 | public const AAGUID_ASSURANCE_LEVEL_NONE = 'None'; |
||
| 39 | |||
| 40 | public const AAGUID_ASSURANCE_LEVEL_SELF = 'Self'; |
||
| 41 | |||
| 42 | public const AAGUID_ASSURANCE_LEVEL_BASIC = 'Basic'; |
||
| 43 | |||
| 44 | public const AAGUID_ASSURANCE_LEVEL_ATTCA = 'AttCA'; |
||
| 45 | |||
| 46 | // nomenclature from the MDS3 spec |
||
| 47 | public const FIDO_REVOKED = "REVOKED"; |
||
| 48 | |||
| 49 | public const CERTIFICATION_NOT_REQUIRED = "CERTIFICATION_NOT_REQUIRED"; |
||
| 50 | |||
| 51 | public const FIDO_CERTIFIED_L1 = "FIDO_CERTIFIED_L1"; |
||
| 52 | |||
| 53 | public const FIDO_CERTIFIED_L1PLUS = "FIDO_CERTIFIED_L1plus"; |
||
| 54 | |||
| 55 | public const FIDO_CERTIFIED_L2 = "FIDO_CERTIFIED_L2"; |
||
| 56 | |||
| 57 | public const FIDO_CERTIFIED_L3 = "FIDO_CERTIFIED_L3"; |
||
| 58 | |||
| 59 | public const FIDO_CERTIFIED_L3PLUS = "FIDO_CERTIFIED_L3plus"; |
||
| 60 | |||
| 61 | // Keymaster 3 - KeyMint ??? |
||
| 62 | private const ORIGINS_3 = [ // https://source.android.com/docs/security/features/keystore/tags#origin |
||
| 63 | 0 => "GENERATED", |
||
| 64 | 1 => "DERIVED", |
||
| 65 | 2 => "IMPORTED", |
||
| 66 | 3 => "UNKNOWN", |
||
| 67 | ]; |
||
| 68 | |||
| 69 | private const PURPOSE_3 = [ |
||
| 70 | 0 => "ENCRYPT", |
||
| 71 | 1 => "DECRYPT", |
||
| 72 | 2 => "SIGN", |
||
| 73 | 3 => "VERIFY", |
||
| 74 | 4 => "DERIVE_KEY", |
||
| 75 | 5 => "WRAP_KEY", |
||
| 76 | ]; |
||
| 77 | |||
| 78 | private const MIN_SUPPORTED_KEYMASTER_VERSION = 3; |
||
| 79 | |||
| 80 | |||
| 81 | /** |
||
| 82 | * the AAGUID of the newly registered authenticator |
||
| 83 | * @var string |
||
| 84 | */ |
||
| 85 | protected string $AAGUID; |
||
| 86 | |||
| 87 | /** |
||
| 88 | * how sure are we about the AAGUID? |
||
| 89 | * @var string |
||
| 90 | */ |
||
| 91 | protected string $AAGUIDAssurance; |
||
| 92 | |||
| 93 | /** |
||
| 94 | * An array of known hardware tokens |
||
| 95 | * |
||
| 96 | * @var \SimpleSAML\Module\webauthn\WebAuthn\AAGUID |
||
| 97 | */ |
||
| 98 | protected AAGUID $AAGUIDDictionary; |
||
| 99 | |||
| 100 | protected string $AttFmt; |
||
| 101 | |||
| 102 | |||
| 103 | /** |
||
| 104 | * Initialize the event object. |
||
| 105 | * |
||
| 106 | * Validates and parses the configuration. |
||
| 107 | * |
||
| 108 | * @param string $pubkeyCredType PublicKeyCredential.type |
||
| 109 | * @param string $scope the scope of the event |
||
| 110 | * @param string $challenge the challenge which was used to trigger this event |
||
| 111 | * @param string $attestationData the attestation data CBOR blob |
||
| 112 | * @param string $responseId the response ID |
||
| 113 | * @param string $clientDataJSON the client data JSON string which is present in all types of events |
||
| 114 | * @param bool $debugMode print debugging statements? |
||
| 115 | */ |
||
| 116 | public function __construct( |
||
| 117 | string $pubkeyCredType, |
||
| 118 | string $scope, |
||
| 119 | string $challenge, |
||
| 120 | string $attestationData, |
||
| 121 | string $responseId, |
||
| 122 | string $clientDataJSON, |
||
| 123 | array $acceptabilityPolicy, |
||
| 124 | bool $debugMode = false, |
||
| 125 | ) { |
||
| 126 | $this->debugBuffer .= "attestationData raw: " . $attestationData . "<br/>"; |
||
| 127 | /** |
||
| 128 | * §7.1 STEP 9 : CBOR decode attestationData. |
||
| 129 | */ |
||
| 130 | $attestationArray = $this->cborDecode($attestationData); |
||
| 131 | $authData = $attestationArray['authData']; |
||
| 132 | $this->eventType = "REG"; |
||
| 133 | parent::__construct($pubkeyCredType, $scope, $challenge, $authData, $clientDataJSON, $debugMode); |
||
| 134 | |||
| 135 | $this->AAGUIDDictionary = AAGUID::getInstance(); |
||
| 136 | |||
| 137 | // this function extracts the public key |
||
| 138 | $this->validateAttestedCredentialData(substr($authData, 37), $responseId); |
||
| 139 | // this function may need the public key to have been previously extracted |
||
| 140 | $this->validateAttestationData($attestationData); |
||
| 141 | // the following function sets the credential properties |
||
| 142 | $this->debugBuffer .= "Attestation Data (bin2hex): " . bin2hex(substr($authData, 37)) . "<br/>"; |
||
| 143 | // now check if the authenticator is acceptable as per policy |
||
| 144 | $this->verifyAcceptability($acceptabilityPolicy); |
||
| 145 | } |
||
| 146 | |||
| 147 | |||
| 148 | private function verifyAcceptability($acceptabilityPolicy) |
||
| 149 | { |
||
| 150 | if ($acceptabilityPolicy['minCertLevel'] == self::CERTIFICATION_NOT_REQUIRED) { // all is accepted |
||
| 151 | return; |
||
| 152 | } |
||
| 153 | |||
| 154 | // if we care about the content of the attestation at all, make sure we |
||
| 155 | // have a confidence level beyond "None". |
||
| 156 | if ($this->AAGUIDAssurance == self::AAGUID_ASSURANCE_LEVEL_NONE) { |
||
| 157 | throw new Exception("Authenticator did not provide a useful attestation level."); |
||
| 158 | } |
||
| 159 | if (in_array($this->AAGUID, $acceptabilityPolicy['aaguidWhitelist'])) { |
||
| 160 | return; |
||
| 161 | } |
||
| 162 | if (in_array($this->AttFmt, $acceptabilityPolicy['attFmtWhitelist'])) { |
||
| 163 | return; |
||
| 164 | } |
||
| 165 | |||
| 166 | $aaguidDb = AAGUID::getInstance(); |
||
| 167 | if (!$aaguidDb->hasToken($this->AAGUID)) { |
||
| 168 | throw new Exception("Authenticator with AAGUID " . |
||
| 169 | $this->AAGUID . |
||
| 170 | " is not known to the FIDO MDS3 database."); |
||
| 171 | } |
||
| 172 | $authenticatorData = $aaguidDb->get($this->AAGUID); |
||
| 173 | $certification = $authenticatorData['statusReports'][0]['status']; |
||
| 174 | |||
| 175 | if ($certification == self::FIDO_REVOKED) { |
||
| 176 | // phpcs:ignore Generic.Files.LineLength.TooLong |
||
| 177 | throw new InvalidCredential("FIDO Alliance has REVOKED certification of this device. It cannot be registered."); |
||
| 178 | } |
||
| 179 | |||
| 180 | switch ($acceptabilityPolicy['minCertLevel']) { |
||
| 181 | case self::FIDO_CERTIFIED_L1: |
||
| 182 | // note: always full string match - there is also a level NOT_FIDO_CERTIFIED ! |
||
| 183 | if ($certification == "FIDO_CERTIFIED" || $certification == self::FIDO_CERTIFIED_L1) { |
||
| 184 | return; |
||
| 185 | } |
||
| 186 | // intentional fall-through, higher levels are also okay |
||
| 187 | case self::FIDO_CERTIFIED_L1PLUS: |
||
| 188 | if ($certification == self::FIDO_CERTIFIED_L1PLUS) { |
||
| 189 | return; |
||
| 190 | } |
||
| 191 | // intentional fall-through, higher levels are also okay |
||
| 192 | case self::FIDO_CERTIFIED_L2: |
||
| 193 | if ($certification == self::FIDO_CERTIFIED_L2) { |
||
| 194 | return; |
||
| 195 | } |
||
| 196 | // intentional fall-through, higher levels are also okay |
||
| 197 | case self::FIDO_CERTIFIED_L3: |
||
| 198 | if ($certification == self::FIDO_CERTIFIED_L3) { |
||
| 199 | return; |
||
| 200 | } |
||
| 201 | // intentional fall-through, higher levels are also okay |
||
| 202 | case self::FIDO_CERTIFIED_L3PLUS: |
||
| 203 | if ($certification == self::FIDO_CERTIFIED_L3PLUS) { |
||
| 204 | return; |
||
| 205 | } |
||
| 206 | throw new Error("FIDO_CERTIFICATION_TOO_LOW"); |
||
| 207 | default: |
||
| 208 | throw new Exception("Configuration error: unknown minimum certification level " . |
||
| 209 | $acceptabilityPolicy['minCertLevel']); |
||
| 210 | } |
||
| 211 | } |
||
| 212 | |||
| 213 | |||
| 214 | /** |
||
| 215 | * Validate the incoming attestation data CBOR blob and return the embedded authData |
||
| 216 | * @param string $attestationData |
||
| 217 | * @return void |
||
| 218 | */ |
||
| 219 | private function validateAttestationData(string $attestationData): void |
||
| 220 | { |
||
| 221 | /** |
||
| 222 | * STEP 9 of the validation procedure in § 7.1 of the spec: CBOR-decode the attestationObject |
||
| 223 | */ |
||
| 224 | $attestationArray = $this->cborDecode($attestationData); |
||
| 225 | $this->debugBuffer .= "<pre>"; |
||
| 226 | $this->debugBuffer .= print_r($attestationArray, true); |
||
| 227 | $this->debugBuffer .= "</pre>"; |
||
| 228 | |||
| 229 | /** |
||
| 230 | * STEP 15 of the validation procedure in § 7.1 of the spec: verify attStmt values |
||
| 231 | */ |
||
| 232 | $this->AttFmt = $attestationArray['fmt']; |
||
| 233 | switch ($attestationArray['fmt']) { |
||
| 234 | case "none": |
||
| 235 | $this->validateAttestationFormatNone($attestationArray); |
||
| 236 | break; |
||
| 237 | case "packed": |
||
| 238 | $this->validateAttestationFormatPacked($attestationArray); |
||
| 239 | break; |
||
| 240 | case "fido-u2f": |
||
| 241 | $this->validateAttestationFormatFidoU2F($attestationArray); |
||
| 242 | break; |
||
| 243 | case "android-safetynet": |
||
| 244 | $this->validateAttestationFormatAndroidSafetyNet($attestationArray); |
||
| 245 | break; |
||
| 246 | case "apple": |
||
| 247 | $this->validateAttestationFormatApple($attestationArray); |
||
| 248 | break; |
||
| 249 | case "tpm": |
||
| 250 | $this->fail("TPM attestation format not supported right now."); |
||
| 251 | break; |
||
| 252 | case "android-key": |
||
| 253 | $this->validateAttestationFormatAndroidKey($attestationArray); |
||
| 254 | break; |
||
| 255 | default: |
||
| 256 | $this->fail("Unknown attestation format."); |
||
| 257 | break; |
||
| 258 | } |
||
| 259 | $this->AttFmt = $attestationArray['fmt']; |
||
| 260 | } |
||
| 261 | |||
| 262 | |||
| 263 | /** |
||
| 264 | * @param array $attestationArray |
||
| 265 | * @return void |
||
| 266 | */ |
||
| 267 | private function validateAttestationFormatNone(array $attestationArray): void |
||
| 268 | { |
||
| 269 | // § 8.7 of the spec |
||
| 270 | /** |
||
| 271 | * § 7.1 Step 16 && §8.7 Verification Procedure: stmt must be an empty array |
||
| 272 | * § 7.1 Step 17+18 are a NOOP if the format was "none" (which is acceptable as per this RPs policy) |
||
| 273 | */ |
||
| 274 | if (count($attestationArray['attStmt']) === 0) { |
||
| 275 | $this->pass("Attestation format and statement as expected, and no attestation authorities to retrieve."); |
||
| 276 | $this->AAGUIDAssurance = self::AAGUID_ASSURANCE_LEVEL_NONE; |
||
| 277 | return; |
||
| 278 | } else { |
||
| 279 | $this->fail("Non-empty attestation authorities are not expected with 'attestationFormat = none'."); |
||
| 280 | } |
||
| 281 | } |
||
| 282 | |||
| 283 | |||
| 284 | /** |
||
| 285 | * @param array $attestationArray |
||
| 286 | */ |
||
| 287 | private function validateAttestationFormatApple(array $attestationArray): void |
||
| 288 | { |
||
| 289 | // found at: https://www.apple.com/certificateauthority/private/ |
||
| 290 | |||
| 291 | $APPLE_WEBAUTHN_ROOT_CA = "-----BEGIN CERTIFICATE----- |
||
| 292 | MIICEjCCAZmgAwIBAgIQaB0BbHo84wIlpQGUKEdXcTAKBggqhkjOPQQDAzBLMR8w |
||
| 293 | HQYDVQQDDBZBcHBsZSBXZWJBdXRobiBSb290IENBMRMwEQYDVQQKDApBcHBsZSBJ |
||
| 294 | bmMuMRMwEQYDVQQIDApDYWxpZm9ybmlhMB4XDTIwMDMxODE4MjEzMloXDTQ1MDMx |
||
| 295 | NTAwMDAwMFowSzEfMB0GA1UEAwwWQXBwbGUgV2ViQXV0aG4gUm9vdCBDQTETMBEG |
||
| 296 | A1UECgwKQXBwbGUgSW5jLjETMBEGA1UECAwKQ2FsaWZvcm5pYTB2MBAGByqGSM49 |
||
| 297 | AgEGBSuBBAAiA2IABCJCQ2pTVhzjl4Wo6IhHtMSAzO2cv+H9DQKev3//fG59G11k |
||
| 298 | xu9eI0/7o6V5uShBpe1u6l6mS19S1FEh6yGljnZAJ+2GNP1mi/YK2kSXIuTHjxA/ |
||
| 299 | pcoRf7XkOtO4o1qlcaNCMEAwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQUJtdk |
||
| 300 | 2cV4wlpn0afeaxLQG2PxxtcwDgYDVR0PAQH/BAQDAgEGMAoGCCqGSM49BAMDA2cA |
||
| 301 | MGQCMFrZ+9DsJ1PW9hfNdBywZDsWDbWFp28it1d/5w2RPkRX3Bbn/UbDTNLx7Jr3 |
||
| 302 | jAGGiQIwHFj+dJZYUJR786osByBelJYsVZd2GbHQu209b5RCmGQ21gpSAk9QZW4B |
||
| 303 | 1bWeT0vT |
||
| 304 | -----END CERTIFICATE-----"; |
||
| 305 | // § 8.8 Bullet 1 of the draft spec at |
||
| 306 | // https://pr-preview.s3.amazonaws.com/alanwaketan/webauthn/pull/1491.html#sctn-apple-anonymous-attestation |
||
| 307 | // draft implemented in state of 11 Feb 2021 |
||
| 308 | // I can't help but notice that the verification procedure does NOTHING with CA certs from the chain, |
||
| 309 | // nor is there a root to validate to! |
||
| 310 | // Found the root CA with Google, see above, and will perform chain validation even if the spec doesn't say so. |
||
| 311 | // first, clear the openssl error backlog. We might need error data in case things go sideways. |
||
| 312 | while (openssl_error_string() !== false); |
||
| 313 | |||
| 314 | $stmtDecoded = $attestationArray['attStmt']; |
||
| 315 | if (!isset($stmtDecoded['x5c'])) { |
||
| 316 | $this->fail("Apple attestation statement does not contain an x5c attestation statement!"); |
||
| 317 | } |
||
| 318 | // § 8.8 Bullet 2 |
||
| 319 | $nonceToHash = $attestationArray['authData'] . $this->clientDataHash; |
||
| 320 | // § 8.8 Bullet 3 |
||
| 321 | $cryptoUtils = new Utils\Crypto(); |
||
| 322 | $nonce = hash("sha256", $nonceToHash, true); // does raw_output have to be FALSE or TRUE? |
||
| 323 | $certProps = openssl_x509_parse($cryptoUtils->der2pem($stmtDecoded['x5c'][0])); |
||
| 324 | // § 8.8 Bullet 4 |
||
| 325 | if ( |
||
| 326 | !isset($certProps['extensions']['1.2.840.113635.100.8.2']) || |
||
| 327 | empty($certProps['extensions']['1.2.840.113635.100.8.2']) |
||
| 328 | ) { |
||
| 329 | $this->fail("The required nonce value is not present in the OID."); |
||
| 330 | } |
||
| 331 | $toCompare = substr($certProps['extensions']['1.2.840.113635.100.8.2'], 6); |
||
| 332 | if ($nonce != $toCompare) { |
||
| 333 | $this->fail("There is a mismatch between the nonce and the OID (XXX $nonce XXX , XXX $toCompare XXX )."); |
||
| 334 | } |
||
| 335 | |||
| 336 | // chain validation first |
||
| 337 | foreach ($stmtDecoded['x5c'] as $runIndex => $runCert) { |
||
| 338 | if (isset($stmtDecoded['x5c'][$runIndex + 1])) { // there is a next cert, so follow the chain |
||
| 339 | $certResource = openssl_x509_read($cryptoUtils->der2pem($runCert)); |
||
| 340 | $signerPubKey = openssl_pkey_get_public($cryptoUtils->der2pem($stmtDecoded['x5c'][$runIndex + 1])); |
||
| 341 | if (openssl_x509_verify($certResource, $signerPubKey) != 1) { |
||
| 342 | // phpcs:ignore Generic.Files.LineLength.TooLong |
||
| 343 | $this->fail("Error during chain validation of the attestation certificate (while validating cert #$runIndex, which is " |
||
| 344 | . $cryptoUtils->der2pem($runCert) |
||
| 345 | . "; next cert was " |
||
| 346 | . $cryptoUtils->der2pem($stmtDecoded['x5c'][$runIndex + 1])); |
||
| 347 | } |
||
| 348 | } else { // last cert, compare to the root |
||
| 349 | $certResource = openssl_x509_read($cryptoUtils->der2pem($runCert)); |
||
| 350 | $signerPubKey = openssl_pkey_get_public($APPLE_WEBAUTHN_ROOT_CA); |
||
| 351 | if (openssl_x509_verify($certResource, $signerPubKey) != 1) { |
||
| 352 | $this->fail(sprintf( |
||
| 353 | "Error during root CA validation of the attestation chain certificate, which is %s", |
||
| 354 | $cryptoUtils->der2pem($runCert), |
||
| 355 | )); |
||
| 356 | } |
||
| 357 | } |
||
| 358 | } |
||
| 359 | |||
| 360 | $keyResource = openssl_pkey_get_public($cryptoUtils->der2pem($stmtDecoded['x5c'][0])); |
||
| 361 | if ($keyResource === false) { |
||
| 362 | $this->fail( |
||
| 363 | // phpcs:ignore Generic.Files.LineLength.TooLong |
||
| 364 | "Did not get a parseable X.509 structure out of the Apple attestation statement - x5c nr. 0 statement was: XXX " |
||
| 365 | . $stmtDecoded['x5c'][0] |
||
| 366 | . " XXX; PEM equivalent is " |
||
| 367 | . $cryptoUtils->der2pem($stmtDecoded['x5c'][0]) |
||
| 368 | . ". OpenSSL error: " |
||
| 369 | . openssl_error_string(), |
||
| 370 | ); |
||
| 371 | } |
||
| 372 | |||
| 373 | // $this->credential is a public key in CBOR, not "PEM". We need to convert it first. |
||
| 374 | $keyArray = $this->cborDecode(hex2bin($this->credential)); |
||
| 375 | $keyObject = new Ec2Key($keyArray); |
||
| 376 | $credentialResource = openssl_pkey_get_public($keyObject->asPEM()); |
||
| 377 | |||
| 378 | if ($credentialResource === false) { |
||
| 379 | $this->fail( |
||
| 380 | "Could not create a public key from CBOR credential. XXX " |
||
| 381 | . $this->credential |
||
| 382 | . " XXX; PEM equivalent is " |
||
| 383 | . $keyObject->asPEM() |
||
| 384 | . ". OpenSSL error: " |
||
| 385 | . openssl_error_string(), |
||
| 386 | ); |
||
| 387 | } |
||
| 388 | |||
| 389 | // § 8.8 Bullet 5 |
||
| 390 | $credentialDetails = openssl_pkey_get_details($credentialResource); |
||
| 391 | $keyDetails = openssl_pkey_get_details($keyResource); |
||
| 392 | if ( |
||
| 393 | $credentialDetails['bits'] != $keyDetails['bits'] || |
||
| 394 | $credentialDetails['key'] != $keyDetails['key'] || |
||
| 395 | $credentialDetails['type'] != $keyDetails['type'] |
||
| 396 | ) { |
||
| 397 | $this->fail( |
||
| 398 | "The credential public key does not match the certificate public key in attestationData. (" |
||
| 399 | . $credentialDetails['key'] |
||
| 400 | . " - " |
||
| 401 | . $keyDetails['key'] |
||
| 402 | . ")", |
||
| 403 | ); |
||
| 404 | } |
||
| 405 | $this->pass("Apple attestation format verification passed."); |
||
| 406 | return; |
||
| 407 | } |
||
| 408 | |||
| 409 | |||
| 410 | private function commonX5cSignatureChecks(array $attestationArray): void |
||
| 411 | { |
||
| 412 | $stmtDecoded = $attestationArray['attStmt']; |
||
| 413 | /** |
||
| 414 | * §8.2 Step 4 Bullet 1: check algorithm |
||
| 415 | */ |
||
| 416 | if (!in_array($stmtDecoded['alg'], self::PK_ALGORITHM)) { |
||
| 417 | $this->fail("Unexpected algorithm type in packed basic attestation: " . $stmtDecoded['alg'] . "."); |
||
| 418 | } |
||
| 419 | $keyResource = openssl_pkey_get_public($this->der2pem($stmtDecoded['x5c'][0])); |
||
| 420 | if ($keyResource === false) { |
||
| 421 | $this->fail("Unable to construct public key resource from PEM."); |
||
| 422 | } |
||
| 423 | /** |
||
| 424 | * §8.2 Step 2: check x5c attestation |
||
| 425 | */ |
||
| 426 | $sigdata = $attestationArray['authData'] . $this->clientDataHash; |
||
| 427 | /** |
||
| 428 | * §8.2 Step 2 Bullet 1: check signature |
||
| 429 | */ |
||
| 430 | $retCode = openssl_verify($sigdata, $stmtDecoded['sig'], $keyResource, "sha256"); |
||
| 431 | if ($retCode !== 1) { |
||
| 432 | $this->fail(sprintf( |
||
| 433 | // phpcs:ignore Generic.Files.LineLength.TooLong |
||
| 434 | "Packed signature mismatch (return code $retCode, for :authdata:%s - :clientDataHash:%s - :signature:%s), attestation failed.", |
||
| 435 | $attestationArray['authData'], |
||
| 436 | $this->clientDataHash, |
||
| 437 | $stmtDecoded['sig'], |
||
| 438 | )); |
||
| 439 | } |
||
| 440 | $this->pass("x5c sig check passed."); |
||
| 441 | } |
||
| 442 | |||
| 443 | |||
| 444 | /** |
||
| 445 | * @param array $attestationArray |
||
| 446 | */ |
||
| 447 | private function validateAttestationFormatPacked(array $attestationArray): void |
||
| 448 | { |
||
| 449 | $stmtDecoded = $attestationArray['attStmt']; |
||
| 450 | $this->debugBuffer .= "AttStmt: " . /** @scrutinizer ignore-type */ print_r($stmtDecoded, true) . "<br/>"; |
||
| 451 | /** |
||
| 452 | * §7.1 Step 16: attestation is either done with x5c or ecdaa. |
||
| 453 | */ |
||
| 454 | if (isset($stmtDecoded['x5c'])) { |
||
| 455 | $this->commonX5cSignatureChecks($attestationArray); |
||
| 456 | $this->validateAttestationFormatPackedX5C($attestationArray); |
||
| 457 | } elseif (isset($stmtDecoded['ecdaa'])) { |
||
| 458 | $this->fail("ecdaa attestation not supported right now."); |
||
| 459 | } else { |
||
| 460 | // if we are still here, we are in the "self" type. |
||
| 461 | // signature checks already done, nothing more to do |
||
| 462 | $this->pass("Self-Attestation verified."); |
||
| 463 | $this->AAGUIDAssurance = self::AAGUID_ASSURANCE_LEVEL_SELF; |
||
| 464 | } |
||
| 465 | } |
||
| 466 | |||
| 467 | |||
| 468 | /** |
||
| 469 | * @param array $attestationArray |
||
| 470 | * @return void |
||
| 471 | */ |
||
| 472 | private function validateAttestationFormatPackedX5C(array $attestationArray): void |
||
| 473 | { |
||
| 474 | $stmtDecoded = $attestationArray['attStmt']; |
||
| 475 | // still need to perform sanity checks on the attestation certificate |
||
| 476 | /** |
||
| 477 | * §8.2 Step 2 Bullet 2: check certificate properties listed in §8.2.1 |
||
| 478 | */ |
||
| 479 | $certProps = openssl_x509_parse($this->der2pem($stmtDecoded['x5c'][0])); |
||
| 480 | $this->debugBuffer .= "Attestation Certificate:" . |
||
| 481 | /** @scrutinizer ignore-type */ print_r($certProps, true) . "<br/>"; |
||
| 482 | if ( |
||
| 483 | $certProps['version'] !== 2 || /** §8.2.1 Bullet 1 */ |
||
| 484 | $certProps['subject']['OU'] !== "Authenticator Attestation" || /** §8.2.1 Bullet 2 [Subject-OU] */ |
||
| 485 | !isset($certProps['subject']['CN']) || /** §8.2.1 Bullet 2 [Subject-CN] */ |
||
| 486 | !isset($certProps['extensions']['basicConstraints']) || |
||
| 487 | strstr("CA:FALSE", $certProps['extensions']['basicConstraints']) === false /** §8.2.1 Bullet 4 */ |
||
| 488 | ) { |
||
| 489 | $this->fail("Attestation certificate properties are no good."); |
||
| 490 | } |
||
| 491 | |||
| 492 | if ($this->AAGUIDDictionary->hasToken($this->AAGUID)) { |
||
| 493 | $token = $this->AAGUIDDictionary->get($this->AAGUID); |
||
| 494 | /** |
||
| 495 | * Checking the OID is not programmatically possible. Text per spec: |
||
| 496 | * "If the related attetation root certificate is used for multiple |
||
| 497 | * authenticator models, the Extension OID ... MUST be present." |
||
| 498 | * |
||
| 499 | * FIDO MDS3 metadata does not disclose whether the root CAs are |
||
| 500 | * used for multiple models. |
||
| 501 | */ |
||
| 502 | /* if ($token['multi'] === true) { // need to check the OID |
||
| 503 | if ( |
||
| 504 | !isset($certProps['extensions']['1.3.6.1.4.1.45724.1.1.4']) || |
||
| 505 | empty($certProps['extensions']['1.3.6.1.4.1.45724.1.1.4']) |
||
| 506 | ) { // §8.2.1 Bullet 3 |
||
| 507 | $this->fail( |
||
| 508 | // phpcs:ignore Generic.Files.LineLength.TooLong |
||
| 509 | "This vendor uses one cert for multiple authenticator model attestations, but lacks the AAGUID OID.", |
||
| 510 | ); |
||
| 511 | } |
||
| 512 | /** |
||
| 513 | * §8.2 Step 2 Bullet 3: compare AAGUID values |
||
| 514 | */ |
||
| 515 | /* $AAGUIDFromOid = substr(bin2hex($certProps['extensions']['1.3.6.1.4.1.45724.1.1.4']), 4); |
||
| 516 | $this->debugBuffer .= "AAGUID from OID = $AAGUIDFromOid<br/>"; |
||
| 517 | if (strtolower($AAGUIDFromOid) !== strtolower($this->AAGUID)) { |
||
| 518 | $this->fail("AAGUID mismatch between attestation certificate and attestation statement."); |
||
| 519 | } |
||
| 520 | }*/ |
||
| 521 | // we would need to verify the attestation certificate against a known-good |
||
| 522 | // root CA certificate to get more than basic |
||
| 523 | /* |
||
| 524 | * §7.1 Step 17 is to look at $token['RootPEMs'] |
||
| 525 | */ |
||
| 526 | foreach ($token['metadataStatement']['attestationRootCertificates'] as $oneRoot) { |
||
| 527 | openssl_x509_parse("-----BEGIN CERTIFICATE-----\n$oneRoot\n-----END CERTIFICATE-----", true); |
||
| 528 | } |
||
| 529 | /* |
||
| 530 | * §7.1 Step 18 is skipped, and we unconditionally return "only" Basic. |
||
| 531 | */ |
||
| 532 | $this->AAGUIDAssurance = self::AAGUID_ASSURANCE_LEVEL_BASIC; |
||
| 533 | } else { |
||
| 534 | $this->warn("Unknown authenticator model found: " . $this->AAGUID . "."); |
||
| 535 | // unable to verify all cert properties, so this is not enough for BASIC. |
||
| 536 | // but it's our own fault, we should add the device to our DB. |
||
| 537 | $this->AAGUIDAssurance = self::AAGUID_ASSURANCE_LEVEL_SELF; |
||
| 538 | } |
||
| 539 | $this->pass("x5c attestation passed."); |
||
| 540 | return; |
||
| 541 | } |
||
| 542 | |||
| 543 | |||
| 544 | private function validateAttestationFormatAndroidKey(array $attestationArray): void |
||
| 625 | } |
||
| 626 | |||
| 627 | |||
| 628 | /** |
||
| 629 | * support legacy U2F tokens |
||
| 630 | * |
||
| 631 | * @param array $attestationData the incoming attestation data |
||
| 632 | * @return void |
||
| 633 | */ |
||
| 634 | private function validateAttestationFormatFidoU2F(array $attestationData): void |
||
| 635 | { |
||
| 636 | /** |
||
| 637 | * §8.6 Verification Step 1 is a NOOP: if we're here, the attStmt was |
||
| 638 | * already successfully CBOR decoded |
||
| 639 | */ |
||
| 640 | $stmtDecoded = $attestationData['attStmt']; |
||
| 641 | if (!isset($stmtDecoded['x5c'])) { |
||
| 642 | $this->fail("FIDO U2F attestation needs to have the 'x5c' key"); |
||
| 643 | } |
||
| 644 | /** |
||
| 645 | * §8.6 Verification Step 2: extract attCert and sanity check it |
||
| 646 | */ |
||
| 647 | if (count($stmtDecoded['x5c']) !== 1) { |
||
| 648 | $this->fail("FIDO U2F attestation requires 'x5c' to have only exactly one key."); |
||
| 649 | } |
||
| 650 | $attCert = $this->der2pem($stmtDecoded['x5c'][0]); |
||
| 651 | $key = openssl_pkey_get_public($attCert); |
||
| 652 | $keyProps = openssl_pkey_get_details($key); |
||
| 653 | if (!isset($keyProps['ec']['curve_name']) || $keyProps['ec']['curve_name'] !== "prime256v1") { |
||
| 654 | $this->fail("FIDO U2F attestation public key is not P-256!"); |
||
| 655 | } |
||
| 656 | /** |
||
| 657 | * §8.6 Verification Step 3 is a NOOP as these properties are already |
||
| 658 | * available as class members: |
||
| 659 | * |
||
| 660 | * $this->rpIdHash; |
||
| 661 | * $this->credentialId; |
||
| 662 | * $this->credential; |
||
| 663 | */ |
||
| 664 | /** |
||
| 665 | * §8.6 Verification Step 4: encode the public key in ANSI X9.62 format |
||
| 666 | */ |
||
| 667 | if ( |
||
| 668 | isset($this->credential[-2]) && |
||
| 669 | strlen($this->credential[-2]) === 32 && |
||
| 670 | isset($this->credential[-3]) && |
||
| 671 | strlen($this->credential[-3]) === 32 |
||
| 672 | ) { |
||
| 673 | $publicKeyU2F = chr(4) . $this->credential[-2] . $this->credential[-3]; |
||
| 674 | } else { |
||
| 675 | $publicKeyU2F = false; |
||
| 676 | $this->fail("FIDO U2F attestation: the public key is not as expected."); |
||
| 677 | } |
||
| 678 | /** |
||
| 679 | * §8.6 Verification Step 5: create verificationData |
||
| 680 | */ |
||
| 681 | $verificationData = chr(0) . $this->rpIdHash . $this->clientDataHash . $this->credentialId . $publicKeyU2F; |
||
| 682 | /** |
||
| 683 | * §8.6 Verification Step 6: verify signature |
||
| 684 | */ |
||
| 685 | if (openssl_verify($verificationData, $stmtDecoded['sig'], $attCert, OPENSSL_ALGO_SHA256) !== 1) { |
||
| 686 | $this->fail("FIDO U2F Attestation verification failed."); |
||
| 687 | } else { |
||
| 688 | $this->pass("Successfully verified FIDO U2F signature."); |
||
| 689 | } |
||
| 690 | /** |
||
| 691 | * §8.6 Verification Step 7: not performed, this is optional as per spec |
||
| 692 | */ |
||
| 693 | /** |
||
| 694 | * §8.6 Verification Step 8: so we always settle for "Basic" |
||
| 695 | */ |
||
| 696 | $this->AAGUIDAssurance = self::AAGUID_ASSURANCE_LEVEL_BASIC; |
||
| 697 | } |
||
| 698 | |||
| 699 | |||
| 700 | /** |
||
| 701 | * support Android authenticators (fingerprint etc.) |
||
| 702 | * |
||
| 703 | * @param array $attestationData the incoming attestation data |
||
| 704 | * @return void |
||
| 705 | */ |
||
| 706 | private function validateAttestationFormatAndroidSafetyNet(array $attestationData): void |
||
| 714 | } |
||
| 715 | |||
| 716 | |||
| 717 | /** |
||
| 718 | * The registration contains the actual credential. This function parses it. |
||
| 719 | * @param string $attData the attestation data binary blob |
||
| 720 | * @param string $responseId the response ID |
||
| 721 | * @return void |
||
| 722 | */ |
||
| 723 | private function validateAttestedCredentialData(string $attData, string $responseId): void |
||
| 724 | { |
||
| 725 | $aaguid = substr($attData, 0, 16); |
||
| 726 | $credIdLenBytes = substr($attData, 16, 2); |
||
| 727 | $credIdLen = intval(bin2hex($credIdLenBytes), 16); |
||
| 728 | $credId = substr($attData, 18, $credIdLen); |
||
| 729 | $this->debugBuffer .= "AAGUID (hex) = " . bin2hex($aaguid) . "</br/>"; |
||
| 730 | $this->AAGUID = bin2hex($aaguid); |
||
| 731 | $this->debugBuffer .= "Length Raw = " . bin2hex($credIdLenBytes) . "<br/>"; |
||
| 732 | $this->debugBuffer .= "Credential ID Length (decimal) = " . $credIdLen . "<br/>"; |
||
| 733 | $this->debugBuffer .= "Credential ID (hex) = " . bin2hex($credId) . "<br/>"; |
||
| 734 | if (bin2hex(WebAuthnAbstractEvent::base64urlDecode($responseId)) === bin2hex($credId)) { |
||
| 735 | $this->pass("Credential IDs in authenticator response and in attestation data match."); |
||
| 736 | } else { |
||
| 737 | $this->fail( |
||
| 738 | "Mismatch of credentialId (" . bin2hex($credId) . ") vs. response ID (" . |
||
| 739 | bin2hex(WebAuthnAbstractEvent::base64urlDecode($responseId)) . ").", |
||
| 740 | ); |
||
| 741 | } |
||
| 742 | // so far so good. Now extract the actual public key from its COSE |
||
| 743 | // encoding. |
||
| 744 | // finding out the number of bytes to CBOR decode appears non-trivial. |
||
| 745 | // The simple case is if no ED is present as the CBOR data then goes to |
||
| 746 | // the end of the byte sequence. |
||
| 747 | // since we don't know the algoritm yet, we don't know how many bytes |
||
| 748 | // of credential CBOR follow. Let's read to the end; the CBOR decoder |
||
| 749 | // silently ignores trailing extensions (if any) |
||
| 750 | $pubKeyCBOR = substr($attData, 18 + $credIdLen); |
||
| 751 | $arrayPK = $this->cborDecode($pubKeyCBOR); |
||
| 752 | $this->debugBuffer .= "pubKey in canonical form: <pre>" . |
||
| 753 | /** @scrutinizer ignore-type */ print_r($arrayPK, true) . |
||
| 754 | "</pre>"; |
||
| 755 | /** |
||
| 756 | * STEP 13 of the validation procedure in § 7.1 of the spec: is the algorithm the expected one? |
||
| 757 | */ |
||
| 758 | if (in_array($arrayPK['3'], self::PK_ALGORITHM)) { // we requested -7 or -257, so want to see it here |
||
| 759 | $this->algo = (int)$arrayPK['3']; |
||
| 760 | $this->pass("Public Key Algorithm is expected (" . |
||
| 761 | implode(' or ', WebAuthnRegistrationEvent::PK_ALGORITHM) . |
||
| 762 | ")."); |
||
| 763 | } else { |
||
| 764 | $this->fail("Public Key Algorithm mismatch!"); |
||
| 765 | } |
||
| 766 | $this->credentialId = bin2hex($credId); |
||
| 767 | $this->credential = bin2hex($pubKeyCBOR); |
||
| 768 | |||
| 769 | // now that we know credential and its length, we can CBOR-decode the |
||
| 770 | // trailing extensions |
||
| 771 | switch ($this->algo) { |
||
| 772 | case self::PK_ALGORITHM_ECDSA: |
||
| 773 | $credentialLength = 77; |
||
| 774 | break; |
||
| 775 | case self::PK_ALGORITHM_RSA: |
||
| 776 | $credentialLength = 272; |
||
| 777 | break; |
||
| 778 | default: |
||
| 779 | $this->fail("No credential length information for $this->algo"); |
||
| 780 | // be sure to end execution even if the Exception is caught |
||
| 781 | exit(1); |
||
| 782 | } |
||
| 783 | $extensions = substr($attData, 18 + $credIdLen + $credentialLength); |
||
| 784 | if (strlen($extensions) !== 0) { |
||
| 785 | $this->pass("Found the following extensions (" . |
||
| 786 | strlen($extensions) . |
||
| 787 | " bytes) during registration ceremony: "); |
||
| 788 | } |
||
| 789 | } |
||
| 790 | |||
| 791 | |||
| 792 | /** |
||
| 793 | * transform DER formatted certificate to PEM format |
||
| 794 | * |
||
| 795 | * @param string $derData blob of DER data |
||
| 796 | * @return string the PEM representation of the certificate |
||
| 797 | */ |
||
| 798 | private function der2pem(string $derData): string |
||
| 799 | { |
||
| 800 | $pem = chunk_split(base64_encode($derData), 64, "\n"); |
||
| 801 | $pem = "-----BEGIN CERTIFICATE-----\n" . $pem . "-----END CERTIFICATE-----\n"; |
||
| 802 | return $pem; |
||
| 803 | } |
||
| 804 | |||
| 805 | |||
| 806 | /** |
||
| 807 | * @return string |
||
| 808 | */ |
||
| 809 | public function getAAGUID(): string |
||
| 810 | { |
||
| 811 | return $this->AAGUID; |
||
| 812 | } |
||
| 813 | |||
| 814 | |||
| 815 | /** |
||
| 816 | * @return string |
||
| 817 | */ |
||
| 818 | public function getAttestationLevel(): string |
||
| 821 | } |
||
| 822 | } |
||
| 823 |
Loading history...
