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Updated authenticode sign/unsign commands.

This commit is contained in:
Ylian Saint-Hilaire 2022-05-26 21:08:50 -07:00
parent c76aa4dd03
commit d1e1309c4c
1 changed files with 81 additions and 28 deletions
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109
authenticode.js
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@ -1,4 +1,4 @@
/**
/**
* @description Authenticode parsing
* @author Bryan Roe & Ylian Saint-Hilaire
* @copyright Intel Corporation 2018-2022
@ -57,15 +57,15 @@ function createAuthenticodeHandler(path) {
obj.fd = fs.openSync(path);
obj.stats = fs.fstatSync(obj.fd);
obj.filesize = obj.stats.size;
if (obj.filesize < 64) { throw ('File too short'); }
if (obj.filesize < 64) { throw ('File too short.'); }
// Read the PE header size
var buf = readFileSlice(60, 4);
obj.header.header_size = buf.readUInt32LE(0);
// Check file size and PE header
if (obj.filesize < (160 + obj.header.header_size)) { throw ('Invalid SizeOfHeaders'); }
if (readFileSlice(obj.header.header_size, 4).toString('hex') != '50450000') { throw ('Invalid PE File'); }
if (obj.filesize < (160 + obj.header.header_size)) { throw ('Invalid SizeOfHeaders.'); }
if (readFileSlice(obj.header.header_size, 4).toString('hex') != '50450000') { throw ('Invalid PE File.'); }
// Check header magic data
var magic = readFileSlice(obj.header.header_size + 24, 2).readUInt16LE(0);
@ -86,6 +86,9 @@ function createAuthenticodeHandler(path) {
if (obj.header.signed) {
// Read signature block
// Check if the file size allows for the signature block
if (obj.filesize < (obj.header.sigpos + obj.header.siglen)) { throw ('Executable file too short to contain the signature block.'); }
// Remove the padding if needed
var i, pkcs7raw = readFileSlice(obj.header.sigpos + 8, obj.header.siglen - 8);
var derlen = forge.asn1.getBerValueLength(forge.util.createBuffer(pkcs7raw.slice(1, 5))) + 4;
@ -110,6 +113,11 @@ function createAuthenticodeHandler(path) {
var pkcs7 = p7.messageFromAsn1(pkcs7der);
var pkcs7content = forge.asn1.fromDer(pkcs7.rawCapture.content.value[0].value);
//console.log('p7content', JSON.stringify(pkcs7content));
// DEBUG: Print out the content
//console.log(Buffer.from(pkcs7.rawCapture.content.value[0].value, 'binary').toString('hex'));
// Set the certificate chain
obj.certificates = pkcs7.certificates;
@ -175,7 +183,8 @@ function createAuthenticodeHandler(path) {
if ((cert == null) || (key == null)) { var c = obj.createSelfSignedCert(); cert = c.cert; key = c.key; }
var fileHash = getHash('sha384');
var p7 = forge.pkcs7.createSignedData();
p7.content = forge.util.createBuffer(fileHash, 'utf8');
p7.content = forge.util.createBuffer(fileHash, 'utf8'); // DEBUG: NOT CORRRECT
//p7.content = { "tagClass": 0, "type": 16, "constructed": true, "composed": true, "value": [{ "tagClass": 0, "type": 16, "constructed": true, "composed": true, "value": [{ "tagClass": 0, "type": 6, "constructed": false, "composed": false, "value": forge.asn1.oidToDer("1.3.6.1.4.1.311.2.1.15") }, { "tagClass": 0, "type": 16, "constructed": true, "composed": true, "value": [{ "tagClass": 0, "type": 3, "constructed": false, "composed": false, "value": "\u0000", "bitStringContents": "\u0000", "original": { "tagClass": 0, "type": 3, "constructed": false, "composed": false, "value": "\u0000" } }, { "tagClass": 128, "type": 0, "constructed": true, "composed": true, "value": [{ "tagClass": 128, "type": 2, "constructed": true, "composed": true, "value": [{ "tagClass": 128, "type": 0, "constructed": false, "composed": false, "value": "" }] }] }] }] }, { "tagClass": 0, "type": 16, "constructed": true, "composed": true, "value": [{ "tagClass": 0, "type": 16, "constructed": true, "composed": true, "value": [{ "tagClass": 0, "type": 6, "constructed": false, "composed": false, "value": forge.asn1.oidToDer(forge.pki.oids.sha384).data }, { "tagClass": 0, "type": 5, "constructed": false, "composed": false, "value": "" }] }, { "tagClass": 0, "type": 4, "constructed": false, "composed": false, "value": fileHash.toString('binary') }] }] };
p7.addCertificate(cert);
p7.addSigner({
key: key,
@ -205,40 +214,82 @@ function createAuthenticodeHandler(path) {
var p7signature = Buffer.from(forge.pkcs7.messageToPem(p7).split('-----BEGIN PKCS7-----')[1].split('-----END PKCS7-----')[0], 'base64');
console.log('p7signature', p7signature.toString('base64'));
// Create the output filename
var outputFileName = this.path.split('.');
outputFileName[outputFileName.length - 2] += '-jsigned';
outputFileName = outputFileName.join('.');
// Open the file
var output = fs.openSync(outputFileName, 'w');
var tmp, written = 0;
var executableSize = obj.header.sigpos ? obj.header.sigpos : this.filesize;
// Compute pre-header length and copy that to the new file
var preHeaderLen = (obj.header.header_size + 152 + (obj.header.pe32plus * 16));
var tmp = readFileSlice(written, preHeaderLen);
fs.writeSync(output, tmp);
written += tmp.length;
// Quad Align the results, adding padding if necessary
var len = this.filesize + p7signature.length;
var len = executableSize + p7signature.length;
var padding = (8 - ((len) % 8)) % 8;
// Write the signature header
var addresstable = Buffer.alloc(8);
addresstable.writeUInt32LE(this.filesize);
console.log('executableSize', executableSize);
console.log('signLength', p7signature.length, padding);
addresstable.writeUInt32LE(executableSize);
addresstable.writeUInt32LE(8 + p7signature.length + padding, 4);
fs.writeSync(output, addresstable);
written += addresstable.length;
var b = this.path.split('.');
b[b.length - 2] += '-jsigned';
var output = fs.openSync(b.join('.'), 'w');
var written = 0;
var bytesLeft = this.filesize;
var tmp;
// TODO: This copies the entire file including the old signature block.
// Need to be fixed to only copy the file without the signature block
while ((this.filesize - written) > 0) {
tmp = readFileSlice(written, (this.filesize - written) > 65535 ? 65535 : this.filesize - written);
// Copy the rest of the file until the start of the signature block
while ((executableSize - written) > 0) {
tmp = readFileSlice(written, Math.min(executableSize - written, 65536));
fs.writeSync(output, tmp);
written += tmp.length;
}
// Write the signature block
// Write the signature block header and signature
var win = Buffer.alloc(8); // WIN CERTIFICATE Structure
win.writeUInt32LE(p7signature.length + padding + 8); // DWORD length
win.writeUInt16LE(512, 4); // WORD revision
win.writeUInt16LE(2, 6); // WORD type
fs.writeSync(output, win);
fs.writeSync(output, p7signature);
if (padding > 0) { fs.writeSync(output, Buffer.alloc(padding, 0)); }
fs.writeSync(output, addresstable, 0, addresstable.length, this.header.header_size + 152 + (this.header.pe32plus * 16));
// Close the file
fs.closeSync(output);
}
// Save an executable without the signature
obj.unsign = function (cert, key) {
// Create the output filename
var outputFileName = this.path.split('.');
outputFileName[outputFileName.length - 2] += '-junsigned';
outputFileName = outputFileName.join('.');
// Open the file
var output = fs.openSync(outputFileName, 'w');
var written = 0, totalWrite = obj.header.sigpos;
// Compute pre-header length and copy that to the new file
var preHeaderLen = (obj.header.header_size + 152 + (obj.header.pe32plus * 16));
var tmp = readFileSlice(written, preHeaderLen);
fs.writeSync(output, tmp);
written += tmp.length;
// Write the new signature header
fs.writeSync(output, Buffer.alloc(8));
written += 8;
// Copy the rest of the file until the start of the signature block
while ((totalWrite - written) > 0) {
tmp = readFileSlice(written, Math.min(totalWrite - written, 65536));
fs.writeSync(output, tmp);
written += tmp.length;
}
fs.closeSync(output);
}
@ -253,13 +304,14 @@ function start() {
console.log("Usage:");
console.log(" node authenticode.js [command] [exepath]");
console.log("Commands:");
console.log(" info - Show information about this executable.");
console.log(" sign - Sign the executable using a dummy certificate.");
console.log(" info - Show information about an executable.");
console.log(" sign - Sign an executable using a dummy certificate.");
console.log(" unsign - Remove the signature from the executable.");
return;
}
// Check that a valid command is passed in
if (['info', 'sign'].indexOf(process.argv[2].toLowerCase()) == -1) {
if (['info', 'sign', 'unsign'].indexOf(process.argv[2].toLowerCase()) == -1) {
console.log("Invalid command: " + process.argv[2]);
return;
}
@ -285,10 +337,11 @@ function start() {
if (exe.signatureBlock) { console.log('Signature', exe.signatureBlock.toString('hex')); }
console.log('FileLen: ' + exe.filesize);
}
if (command == 'sign') {
console.log('Signing...');
exe.sign();
console.log('Signing...'); exe.sign();
}
if (command == 'unsign') {
if (exe.header.signed) { console.log('Unsigning...'); exe.unsign(); } else { console.log('Executable is not signed.'); }
}
// Close the file