sitoctt/static/octt-runtime.js

122 lines
3.4 KiB
JavaScript

(function(){
var publicKeys = [null,
`MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAMWyBISJnLZgeSeU6y+eMxlTHdegfxj1
vaNp2PerVDzUvdLlZKazGYIHXb5xduSnRp4HRHU9TMzSyuP5fr9XohcCAwEAAQ==`,
];
var signatureScheme = 'RSASSA-PKCS1-v1_5';
var encryptionType = {name: signatureScheme, hash: {name: "SHA-256"}};
async function makeSignedScript (scriptText, keyIndex, pemPrivateKey) {
return ('1,'
+ keyIndex + ','
+ base64ToUrlsafe(arrayBufferToBase64(await signTextMessage(
scriptText,
(pemPrivateKey || OcttRuntime.privateKeys[keyIndex])))) + ','
+ base64ToUrlsafe(btoa(scriptText)));
}
function verifyAndRunScript (scriptCipher) {
var [reserved, publicKeyIndex, scriptSignature, scriptText, metadata] = scriptCipher.split(',');
scriptText = atob(base64FromUrlsafe(scriptText));
scriptSignature = base64ToArrayBuffer(base64FromUrlsafe(scriptSignature));
verifyTextMessage(scriptText, scriptSignature, ('-----BEGIN PUBLIC KEY-----\n'
+ publicKeys[publicKeyIndex] + '\n-----END PUBLIC KEY-----'))
.then(function(verificationResult){
if (verificationResult) {
eval(scriptText);
}
}).catch(function(err){
console.error(err);
});
}
function signTextMessage (messageText, pemPrivateKey) {
return (new Promise(function(resolve, reject){
signingKeyFromPrivateKeyPEM(pemPrivateKey)
.then(function(signingKey){
crypto.subtle
.sign({name: signatureScheme}, signingKey, (new TextEncoder().encode(messageText)))
.then(function(messageSignature){
resolve(messageSignature);
});
}).catch(function(err){
reject(err);
});
}));
}
function verifyTextMessage (messageText, messageSignature, pemPublicKey) {
return (new Promise(function(resolve, reject){
verificationKeyFromPublicKeyPEM(pemPublicKey)
.then(function(verificationKey){
crypto.subtle.verify(signatureScheme, verificationKey, messageSignature, (new TextEncoder().encode(messageText)))
.then(function(success){
(success ? resolve : reject)(success);
});
}).catch(function(err){
reject(err);
});
}));
}
function base64ToUrlsafe (unsafe) {
return unsafe.replace(/\//g, '_').replace(/\+/g, '-');
}
function base64FromUrlsafe (safe) {
return safe.replace(/_/g, '/').replace(/-/g, '+')
}
function arrayBufferToBase64 (arrayBuffer) {
return btoa(String.fromCharCode.apply(null, new Uint8Array(arrayBuffer)));
}
function base64ToArrayBuffer (base64) {
return Uint8Array.from(atob(base64), (function(char){ return char.charCodeAt(0); }));
}
function stringToArrayBuffer (str) {
var buf = new ArrayBuffer(str.length);
var bufView = new Uint8Array(buf);
for (var i=0, strLen=str.length; i<strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
function signingKeyFromPrivateKeyPEM (pemPrivateKey) {
return crypto.subtle.importKey(
'pkcs8',
stringToArrayBuffer(
forge.asn1.toDer(
forge.pki.wrapRsaPrivateKey(
forge.pki.privateKeyToAsn1(
forge.pki.privateKeyFromPem(pemPrivateKey)))).data),
encryptionType,
false,
["sign"]);
}
function verificationKeyFromPublicKeyPEM (pemPublicKey) {
return crypto.subtle.importKey(
'spki',
stringToArrayBuffer(
forge.asn1.toDer(
forge.pki.publicKeyToAsn1(
forge.pki.publicKeyFromPem(pemPublicKey))).data),
encryptionType,
false,
["verify"]);
}
window.OcttRuntime = { makeSignedScript, verifyAndRunScript };
var scriptCipher = (new URLSearchParams(location.search)).get('octtRuntime');
if (scriptCipher) {
verifyAndRunScript(scriptCipher);
}
})();