mirror of
https://github.com/Ylianst/MeshCentral.git
synced 2024-12-27 15:45:53 -05:00
298 lines
12 KiB
JavaScript
298 lines
12 KiB
JavaScript
/**
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* @description Authenticode parsing
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* @author Bryan Roe & Ylian Saint-Hilaire
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* @copyright Intel Corporation 2018-2022
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* @license Apache-2.0
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* @version v0.0.1
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*/
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function createAuthenticodeHandler(path) {
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const obj = {};
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const fs = require('fs');
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const crypto = require('crypto');
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const forge = require('node-forge');
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const pki = forge.pki;
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const p7 = forge.pkcs7;
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obj.header = { path: path }
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// Read a file slice
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function readFileSlice(start, length) {
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var buffer = Buffer.alloc(length);
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var len = fs.readSync(obj.fd, buffer, 0, buffer.length, start);
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if (len < buffer.length) { buffer = buffer.slice(0, len); }
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return buffer;
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}
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// Close the file
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obj.close = function () {
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if (obj.fd == null) return;
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fs.closeSync(obj.fd);
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delete obj.fd;
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}
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// Private OIDS
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obj.Oids = {
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SPC_INDIRECT_DATA_OBJID: '1.3.6.1.4.1.311.2.1.4',
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SPC_STATEMENT_TYPE_OBJID: '1.3.6.1.4.1.311.2.1.11',
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SPC_SP_OPUS_INFO_OBJID: '1.3.6.1.4.1.311.2.1.12',
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SPC_INDIVIDUAL_SP_KEY_PURPOSE_OBJID: '1.3.6.1.4.1.311.2.1.21',
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SPC_COMMERCIAL_SP_KEY_PURPOSE_OBJID: '1.3.6.1.4.1.311.2.1.22',
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SPC_MS_JAVA_SOMETHING: '1.3.6.1.4.1.311.15.1',
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SPC_PE_IMAGE_DATA_OBJID: '1.3.6.1.4.1.311.2.1.15',
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SPC_CAB_DATA_OBJID: '1.3.6.1.4.1.311.2.1.25',
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SPC_TIME_STAMP_REQUEST_OBJID: '1.3.6.1.4.1.311.3.2.1',
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SPC_SIPINFO_OBJID: '1.3.6.1.4.1.311.2.1.30',
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SPC_PE_IMAGE_PAGE_HASHES_V1: '1.3.6.1.4.1.311.2.3.1',
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SPC_PE_IMAGE_PAGE_HASHES_V2: '1.3.6.1.4.1.311.2.3.2',
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SPC_NESTED_SIGNATURE_OBJID: '1.3.6.1.4.1.311.2.4.1',
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SPC_RFC3161_OBJID: '1.3.6.1.4.1.311.3.3.1'
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}
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// Open the file and read header information
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function openFile() {
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if (obj.fd != null) return;
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// Open the file descriptor
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obj.path = path;
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obj.fd = fs.openSync(path);
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obj.stats = fs.fstatSync(obj.fd);
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obj.filesize = obj.stats.size;
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if (obj.filesize < 64) { throw ('File too short'); }
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// Read the PE header size
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var buf = readFileSlice(60, 4);
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obj.header.header_size = buf.readUInt32LE(0);
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// Check file size and PE header
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if (obj.filesize < (160 + obj.header.header_size)) { throw ('Invalid SizeOfHeaders'); }
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if (readFileSlice(obj.header.header_size, 4).toString('hex') != '50450000') { throw ('Invalid PE File'); }
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// Check header magic data
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var magic = readFileSlice(obj.header.header_size + 24, 2).readUInt16LE(0);
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switch (magic) {
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case 0x20b: obj.header.pe32plus = 1; break;
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case 0x10b: obj.header.pe32plus = 0; break;
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default: throw ('Invalid Magic in PE');
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}
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// Read PE header information
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obj.header.pe_checksum = readFileSlice(obj.header.header_size + 88, 4).readUInt32LE(0);
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obj.header.numRVA = readFileSlice(obj.header.header_size + 116 + (obj.header.pe32plus * 16), 4).readUInt32LE(0);
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buf = readFileSlice(obj.header.header_size + 152 + (obj.header.pe32plus * 16), 8);
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obj.header.sigpos = buf.readUInt32LE(0);
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obj.header.siglen = buf.readUInt32LE(4);
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obj.header.signed = ((obj.header.sigpos != 0) && (obj.header.siglen != 0));
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if (obj.header.signed) {
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// Read signature block
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// Remove the padding if needed
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var i, pkcs7raw = readFileSlice(obj.header.sigpos + 8, obj.header.siglen - 8);
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var derlen = forge.asn1.getBerValueLength(forge.util.createBuffer(pkcs7raw.slice(1, 5))) + 4;
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if (derlen != pkcs7raw.length) { pkcs7raw = pkcs7raw.slice(0, derlen); }
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// Decode the signature block
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var pkcs7der = forge.asn1.fromDer(forge.util.createBuffer(pkcs7raw));
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// To work around ForgeJS PKCS#7 limitation
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// Switch content type from 1.3.6.1.4.1.311.2.1.4 to forge.pki.oids.data (1.2.840.113549.1.7.1)
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// TODO: Find forge.asn1.oidToDer('1.3.6.1.4.1.311.2.1.4').data and switch it.
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pkcs7der.value[1].value[0].value[2].value[0].value = forge.asn1.oidToDer(forge.pki.oids.data).data;
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// Convert the ASN1 content data into binary and place back
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var pkcs7content = forge.asn1.toDer(pkcs7der.value[1].value[0].value[2].value[1].value[0]).data;
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pkcs7der.value[1].value[0].value[2].value[1].value[0] = { tagClass: 0, type: 4, constructed: false, composed: false, value: pkcs7content };
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// DEBUG: Print out the new DER
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//console.log(Buffer.from(forge.asn1.toDer(pkcs7der).data, 'binary').toString('hex'));
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// Decode the PKCS7 message
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var pkcs7 = p7.messageFromAsn1(pkcs7der);
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var pkcs7content = forge.asn1.fromDer(pkcs7.rawCapture.content.value[0].value);
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// Set the certificate chain
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obj.certificates = pkcs7.certificates;
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// Get the file hashing algorithm
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var hashAlgoOid = forge.asn1.derToOid(pkcs7content.value[1].value[0].value[0].value);
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switch (hashAlgoOid) {
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case forge.pki.oids.sha256: { obj.fileHashAlgo = 'sha256'; break; }
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case forge.pki.oids.sha384: { obj.fileHashAlgo = 'sha384'; break; }
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case forge.pki.oids.sha512: { obj.fileHashAlgo = 'sha512'; break; }
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case forge.pki.oids.sha224: { obj.fileHashAlgo = 'sha224'; break; }
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case forge.pki.oids.md5: { obj.fileHashAlgo = 'md5'; break; }
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}
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// Get the signed file hash
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obj.fileHashSigned = Buffer.from(pkcs7content.value[1].value[1].value, 'binary')
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// Compute the actual file hash
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if (obj.fileHashAlgo != null) { obj.fileHashActual = getHash(obj.fileHashAlgo); }
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}
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}
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// Hash the file using the selected hashing system
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function getHash(algo) {
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var hash = crypto.createHash(algo);
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runHash(hash, 0, obj.header.header_size + 88);
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runHash(hash, obj.header.header_size + 88 + 4, obj.header.header_size + 152 + (obj.header.pe32plus * 16));
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runHash(hash, obj.header.header_size + 152 + (obj.header.pe32plus * 16) + 8, obj.header.sigpos > 0 ? obj.header.sigpos : obj.filesize);
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return hash.digest();
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}
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// Hash the file from start to end loading 64k chunks
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function runHash(hash, start, end) {
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var ptr = start;
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while (ptr < end) { const buf = readFileSlice(ptr, Math.min(65536, end - ptr)); hash.update(buf); ptr += buf.length; }
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}
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// Generate a test self-signed certificate with code signing extension
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obj.createSelfSignedCert = function () {
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var keys = pki.rsa.generateKeyPair(2048);
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var cert = pki.createCertificate();
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cert.publicKey = keys.publicKey;
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cert.serialNumber = '00000001';
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cert.validity.notBefore = new Date();
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cert.validity.notAfter = new Date();
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cert.validity.notAfter.setFullYear(cert.validity.notBefore.getFullYear() + 3);
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var attrs = [
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{ name: 'commonName', value: 'example.org' },
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{ name: 'countryName', value: 'US' },
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{ shortName: 'ST', value: 'California' },
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{ name: 'localityName', value: 'Santa Clara' },
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{ name: 'organizationName', value: 'Test' },
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{ shortName: 'OU', value: 'Test' }
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];
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cert.setSubject(attrs);
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cert.setIssuer(attrs);
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cert.setExtensions([{ name: 'basicConstraints', cA: false }, { name: 'keyUsage', keyCertSign: false, digitalSignature: true, nonRepudiation: false, keyEncipherment: false, dataEncipherment: false }, { name: 'extKeyUsage', codeSigning: true }, { name: "subjectKeyIdentifier" }]);
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cert.sign(keys.privateKey, forge.md.sha384.create());
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return { cert: cert, key: keys.privateKey };
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}
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// Sign the file using the certificate and key. If none is specified, generate a dummy one
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obj.sign = function (cert, key) {
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if ((cert == null) || (key == null)) { var c = obj.createSelfSignedCert(); cert = c.cert; key = c.key; }
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var fileHash = getHash('sha384');
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var p7 = forge.pkcs7.createSignedData();
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p7.content = forge.util.createBuffer(fileHash, 'utf8');
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p7.addCertificate(cert);
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p7.addSigner({
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key: key,
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certificate: cert,
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digestAlgorithm: forge.pki.oids.sha384,
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authenticatedAttributes:
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[
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{
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type: obj.Oids.SPC_INDIRECT_DATA_OBJID,
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},
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{
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type: forge.pki.oids.contentType,
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value: forge.pki.oids.data
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},
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{
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type: forge.pki.oids.messageDigest
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// value will be auto-populated at signing time
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},
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{
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type: forge.pki.oids.signingTime,
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// value can also be auto-populated at signing time
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value: new Date()
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}
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]
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});
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p7.sign();
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var p7signature = Buffer.from(forge.pkcs7.messageToPem(p7).split('-----BEGIN PKCS7-----')[1].split('-----END PKCS7-----')[0], 'base64');
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console.log('p7signature', p7signature.toString('base64'));
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// Quad Align the results, adding padding if necessary
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var len = this.filesize + p7signature.length;
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var padding = (8 - ((len) % 8)) % 8;
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var addresstable = Buffer.alloc(8);
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addresstable.writeUInt32LE(this.filesize);
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addresstable.writeUInt32LE(8 + p7signature.length + padding, 4);
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var b = this.path.split('.');
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b[b.length - 2] += '-jsigned';
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var output = fs.openSync(b.join('.'), 'w');
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var written = 0;
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var bytesLeft = this.filesize;
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var tmp;
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// TODO: This copies the entire file including the old signature block.
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// Need to be fixed to only copy the file without the signature block
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while ((this.filesize - written) > 0) {
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tmp = readFileSlice(written, (this.filesize - written) > 65535 ? 65535 : this.filesize - written);
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fs.writeSync(output, tmp);
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written += tmp.length;
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}
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// Write the signature block
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var win = Buffer.alloc(8); // WIN CERTIFICATE Structure
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win.writeUInt32LE(p7signature.length + padding + 8); // DWORD length
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win.writeUInt16LE(512, 4); // WORD revision
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win.writeUInt16LE(2, 6); // WORD type
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fs.writeSync(output, win);
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fs.writeSync(output, p7signature);
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if (padding > 0) { fs.writeSync(output, Buffer.alloc(padding, 0)); }
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fs.writeSync(output, addresstable, 0, addresstable.length, this.header.header_size + 152 + (this.header.pe32plus * 16));
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fs.closeSync(output);
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}
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openFile();
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return obj;
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}
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function start() {
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// Show tool help
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if (process.argv.length < 4) {
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console.log("MeshCentral Authenticode Tool.");
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console.log("Usage:");
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console.log(" node authenticode.js [command] [exepath]");
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console.log("Commands:");
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console.log(" info - Show information about this executable.");
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console.log(" sign - Sign the executable using a dummy certificate.");
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return;
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}
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// Check that a valid command is passed in
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if (['info', 'sign'].indexOf(process.argv[2].toLowerCase()) == -1) {
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console.log("Invalid command: " + process.argv[2]);
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return;
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}
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// Check the file exists
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var stats = null;
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try { stats = require('fs').statSync(process.argv[3]); } catch (ex) { }
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if (stats == null) {
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console.log("Unable to open file: " + process.argv[3]);
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return;
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}
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// Open the file
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var exe = createAuthenticodeHandler(process.argv[3]);
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// Execute the command
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var command = process.argv[2].toLowerCase();
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if (command == 'info') {
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console.log('Header', exe.header);
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if (exe.fileHashAlgo != null) { console.log('fileHashMethod', exe.fileHashAlgo); }
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if (exe.fileHashSigned != null) { console.log('fileHashSigned', exe.fileHashSigned.toString('hex')); }
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if (exe.fileHashActual != null) { console.log('fileHashActual', exe.fileHashActual.toString('hex')); }
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if (exe.signatureBlock) { console.log('Signature', exe.signatureBlock.toString('hex')); }
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console.log('FileLen: ' + exe.filesize);
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}
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if (command == 'sign') {
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console.log('Signing...');
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exe.sign();
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}
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// Close the file
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exe.close();
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}
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start(); |