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Editing: cert.js
"use strict"; Object.defineProperty(exports, "__esModule", { value: true }); exports.x509Certificate = void 0; const util_1 = require("../util"); const stream_1 = require("../util/stream"); const obj_1 = require("./asn1/obj"); const ext_1 = require("./ext"); const EXTENSION_OID_SUBJECT_KEY_ID = '2.5.29.14'; const EXTENSION_OID_KEY_USAGE = '2.5.29.15'; const EXTENSION_OID_SUBJECT_ALT_NAME = '2.5.29.17'; const EXTENSION_OID_BASIC_CONSTRAINTS = '2.5.29.19'; const EXTENSION_OID_AUTHORITY_KEY_ID = '2.5.29.35'; const EXTENSION_OID_SCT = '1.3.6.1.4.1.11129.2.4.2'; // List of recognized critical extensions // https://www.rfc-editor.org/rfc/rfc5280#section-4.2 const RECOGNIZED_EXTENSIONS = [ EXTENSION_OID_KEY_USAGE, EXTENSION_OID_BASIC_CONSTRAINTS, EXTENSION_OID_SUBJECT_ALT_NAME, ]; const ECDSA_SIGNATURE_ALGOS = { '1.2.840.10045.4.3.1': 'sha224', '1.2.840.10045.4.3.2': 'sha256', '1.2.840.10045.4.3.3': 'sha384', '1.2.840.10045.4.3.4': 'sha512', }; class x509Certificate { constructor(asn1) { this.root = asn1; if (!this.checkRecognizedExtensions()) { throw new Error('Certificate contains unrecognized critical extensions'); } } static parse(cert) { const der = typeof cert === 'string' ? util_1.pem.toDER(cert) : cert; const asn1 = obj_1.ASN1Obj.parseBuffer(der); return new x509Certificate(asn1); } get tbsCertificate() { return this.tbsCertificateObj; } get version() { // version number is the first element of the version context specific tag const ver = this.versionObj.subs[0].toInteger(); return `v${(ver + BigInt(1)).toString()}`; } get notBefore() { // notBefore is the first element of the validity sequence return this.validityObj.subs[0].toDate(); } get notAfter() { // notAfter is the second element of the validity sequence return this.validityObj.subs[1].toDate(); } get issuer() { return this.issuerObj.value; } get subject() { return this.subjectObj.value; } get publicKey() { return this.subjectPublicKeyInfoObj.toDER(); } get signatureAlgorithm() { const oid = this.signatureAlgorithmObj.subs[0].toOID(); return ECDSA_SIGNATURE_ALGOS[oid]; } get signatureValue() { // Signature value is a bit string, so we need to skip the first byte return this.signatureValueObj.value.subarray(1); } get extensions() { // The extension list is the first (and only) element of the extensions // context specific tag const extSeq = this.extensionsObj?.subs[0]; return extSeq?.subs || []; } get extKeyUsage() { const ext = this.findExtension(EXTENSION_OID_KEY_USAGE); return ext ? new ext_1.x509KeyUsageExtension(ext) : undefined; } get extBasicConstraints() { const ext = this.findExtension(EXTENSION_OID_BASIC_CONSTRAINTS); return ext ? new ext_1.x509BasicConstraintsExtension(ext) : undefined; } get extSubjectAltName() { const ext = this.findExtension(EXTENSION_OID_SUBJECT_ALT_NAME); return ext ? new ext_1.x509SubjectAlternativeNameExtension(ext) : undefined; } get extAuthorityKeyID() { const ext = this.findExtension(EXTENSION_OID_AUTHORITY_KEY_ID); return ext ? new ext_1.x509AuthorityKeyIDExtension(ext) : undefined; } get extSubjectKeyID() { const ext = this.findExtension(EXTENSION_OID_SUBJECT_KEY_ID); return ext ? new ext_1.x509SubjectKeyIDExtension(ext) : undefined; } get extSCT() { const ext = this.findExtension(EXTENSION_OID_SCT); return ext ? new ext_1.x509SCTExtension(ext) : undefined; } get isCA() { const ca = this.extBasicConstraints?.isCA || false; // If the KeyUsage extension is present, keyCertSign must be set if (this.extKeyUsage) { ca && this.extKeyUsage.keyCertSign; } return ca; } extension(oid) { const ext = this.findExtension(oid); return ext ? new ext_1.x509Extension(ext) : undefined; } verify(issuerCertificate) { // Use the issuer's public key if provided, otherwise use the subject's const publicKey = issuerCertificate?.publicKey || this.publicKey; const key = util_1.crypto.createPublicKey(publicKey); return util_1.crypto.verifyBlob(this.tbsCertificate.toDER(), key, this.signatureValue, this.signatureAlgorithm); } validForDate(date) { return this.notBefore <= date && date <= this.notAfter; } equals(other) { return this.root.toDER().equals(other.root.toDER()); } verifySCTs(issuer, logs) { let extSCT; // Verifying the SCT requires that we remove the SCT extension and // re-encode the TBS structure to DER -- this value is part of the data // over which the signature is calculated. Since this is a destructive action // we create a copy of the certificate so we can remove the SCT extension // without affecting the original certificate. const clone = this.clone(); // Intentionally not using the findExtension method here because we want to // remove the the SCT extension from the certificate before calculating the // PreCert structure for (let i = 0; i < clone.extensions.length; i++) { const ext = clone.extensions[i]; if (ext.subs[0].toOID() === EXTENSION_OID_SCT) { extSCT = new ext_1.x509SCTExtension(ext); // Remove the extension from the certificate clone.extensions.splice(i, 1); break; } } if (!extSCT) { throw new Error('Certificate does not contain SCT extension'); } if (extSCT?.signedCertificateTimestamps?.length === 0) { throw new Error('Certificate does not contain any SCTs'); } // Construct the PreCert structure // https://www.rfc-editor.org/rfc/rfc6962#section-3.2 const preCert = new stream_1.ByteStream(); // Calculate hash of the issuer's public key const issuerId = util_1.crypto.hash(issuer.publicKey); preCert.appendView(issuerId); // Re-encodes the certificate to DER after removing the SCT extension const tbs = clone.tbsCertificate.toDER(); preCert.appendUint24(tbs.length); preCert.appendView(tbs); // Calculate and return the verification results for each SCT return extSCT.signedCertificateTimestamps.map((sct) => ({ logID: sct.logID, verified: sct.verify(preCert.buffer, logs), })); } // Creates a copy of the certificate with a new buffer clone() { const der = this.root.toDER(); const clone = Buffer.alloc(der.length); der.copy(clone); return x509Certificate.parse(clone); } findExtension(oid) { // Find the extension with the given OID. The OID will always be the first // element of the extension sequence return this.extensions.find((ext) => ext.subs[0].toOID() === oid); } // A certificate should be considered invalid if it contains critical // extensions that are not recognized checkRecognizedExtensions() { // The extension list is the first (and only) element of the extensions // context specific tag const extSeq = this.extensionsObj?.subs[0]; const exts = extSeq?.subs.map((ext) => new ext_1.x509Extension(ext)); // Check for unrecognized critical extensions return (!exts || exts.every((ext) => !ext.critical || RECOGNIZED_EXTENSIONS.includes(ext.oid))); } ///////////////////////////////////////////////////////////////////////////// // The following properties use the documented x509 structure to locate the // desired ASN.1 object // https://www.rfc-editor.org/rfc/rfc5280#section-4.1 // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.1.1 get tbsCertificateObj() { // tbsCertificate is the first element of the certificate sequence return this.root.subs[0]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.1.2 get signatureAlgorithmObj() { // signatureAlgorithm is the second element of the certificate sequence return this.root.subs[1]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.1.3 get signatureValueObj() { // signatureValue is the third element of the certificate sequence return this.root.subs[2]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.1 get versionObj() { // version is the first element of the tbsCertificate sequence return this.tbsCertificateObj.subs[0]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.4 get issuerObj() { // issuer is the fourth element of the tbsCertificate sequence return this.tbsCertificateObj.subs[3]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.5 get validityObj() { // version is the fifth element of the tbsCertificate sequence return this.tbsCertificateObj.subs[4]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.6 get subjectObj() { // subject is the sixth element of the tbsCertificate sequence return this.tbsCertificateObj.subs[5]; } // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.7 get subjectPublicKeyInfoObj() { // subjectPublicKeyInfo is the seventh element of the tbsCertificate sequence return this.tbsCertificateObj.subs[6]; } // Extensions can't be located by index because their position varies. Instead, // we need to find the extensions context specific tag // https://www.rfc-editor.org/rfc/rfc5280#section-4.1.2.9 get extensionsObj() { return this.tbsCertificateObj.subs.find((sub) => sub.tag.isContextSpecific(0x03)); } } exports.x509Certificate = x509Certificate;
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