#94 add support for AES-CFB and AES-CTR

html5/js/Client.js

@@ -115,6 +115,7 @@ XpraClient.prototype.init_state = function(container) {
 	this.mediasource_codecs = {};
 	// encryption
 	this.encryption = false;
+	this.encryption_mode = null;
 	this.encryption_key = null;
 	this.cipher_in_caps = null;
 	this.cipher_out_caps = null;
@@ -1198,8 +1199,11 @@ XpraClient.prototype._make_hello_base = function() {
 	if(this.encryption) {
 		this.cipher_in_caps = {
 			"cipher"					: this.encryption,
+			"cipher.mode"				: this.encryption_mode || "CBC",
 			"cipher.iv"					: Utilities.getSecureRandomString(16),
 			"cipher.key_salt"			: Utilities.getSecureRandomString(32),
+			"cipher.key_size"			: 32,
+			"cipher.key_hash"			: "SHA1",
 			"cipher.key_stretch_iterations"	: 1000,
 			"cipher.padding.options"	: ["PKCS#7"],
 		};
@@ -1799,7 +1803,11 @@ XpraClient.prototype._process_hello = function(packet, ctx) {
 	// check for server encryption caps update
 	if(ctx.encryption) {
 		ctx.cipher_out_caps = {};
-		const CIPHER_CAPS = ["", ".iv", ".key_salt", ".key_stretch_iterations"];
+		const CIPHER_CAPS = [
+			"", ".mode", ".iv",
+			".key_salt", ".key_size", ".key_hash", ".key_stretch_iterations",
+			".padding", ".padding.options",
+			];
 		for (let i=0; i<CIPHER_CAPS.length; ++i) {
 			const cipher_key = "cipher"+CIPHER_CAPS[i];
 			ctx.cipher_out_caps[cipher_key] = hello[cipher_key];

html5/js/Protocol.js

@@ -307,7 +307,7 @@ XpraProtocol.prototype.do_process_receive_queue = function() {
 
 	// work out padding if necessary
 	let padding = 0;
-	if (proto_crypto) {
+	if (proto_crypto && this.cipher_in_block_size>0) {
 		padding = (this.cipher_in_block_size - packet_size % this.cipher_in_block_size);
 		packet_size += padding;
 	}
@@ -356,11 +356,10 @@ XpraProtocol.prototype.do_process_receive_queue = function() {
 	if (proto_crypto) {
 		this.cipher_in.update(forge.util.createBuffer(uintToString(packet_data)));
 		const decrypted = this.cipher_in.output.getBytes();
-		packet_data = [];
-		for (i=0; i<decrypted.length; i++) {
-			packet_data.push(decrypted[i].charCodeAt(0));
+		packet_data = new Uint8Array(packet_size-padding);
+		for (i=0; i<packet_size-padding; i++) {
+			packet_data[i] = decrypted[i].charCodeAt(0);
 		}
-		packet_data = new Uint8Array(packet_data.slice(0, -1 * padding));
 	}
 
 	//decompress it if needed:
@@ -575,28 +574,93 @@ XpraProtocol.prototype.set_packet_handler = function(callback, ctx) {
 };
 
 XpraProtocol.prototype.set_cipher_in = function(caps, key) {
-	this.cipher_in_block_size = 32;
+	if (!key) {
+		throw "missing encryption key";
+	}
 	// stretch the password
-	const secret = forge.pkcs5.pbkdf2(key, caps['cipher.key_salt'], caps['cipher.key_stretch_iterations'], this.cipher_in_block_size);
+	const cipher = caps["cipher"];
+	if (cipher!="AES") {
+		throw "unsupported encryption specified: '"+cipher+"'";
+	}
+	const salt = caps["cipher.key_salt"];
+	const iterations = caps["cipher.key_stretch_iterations"];
+	if (iterations<0) {
+		throw "invalid number of iterations: "+iterations;
+	}
+	const DEFAULT_KEYSIZE = 32;
+	const key_size = caps["cipher.key_size"] || DEFAULT_KEYSIZE;
+	if (key_size<=16) {
+		throw "invalid key size '"+key_size+"'";
+	}
+	const DEFAULT_KEY_HASH = "SHA1";
+	const key_hash = (caps["cipher.key_hash"] || DEFAULT_KEY_HASH).toLowerCase();
+	const secret = forge.pkcs5.pbkdf2(key, salt, iterations, key_size, key_hash);
+	const DEFAULT_MODE = "CBC";
+	const mode = caps["cipher.mode"] || DEFAULT_MODE;
+    if (mode=="CBC") {
+		this.cipher_in_block_size = 32;
+	}
+	else if (["CFB", "CTR"].indexOf(mode)>=0){
+		this.cipher_in_block_size = 0;
+	}
+	else {
+		throw "unsupported AES mode '"+mode+"'";
+	}
 	// start the cipher
-	this.cipher_in = forge.cipher.createDecipher('AES-CBC', secret);
-	this.cipher_in.start({iv: caps['cipher.iv']});
+	this.cipher_in = forge.cipher.createDecipher(cipher+"-"+mode, secret);
+	const iv = caps["cipher.iv"];
+	if (!iv) {
+		throw "missing IV";
+	}
+	this.cipher_in.start({iv: iv, tagLength : 0, tag : ""});
 };
 
 XpraProtocol.prototype.set_cipher_out = function(caps, key) {
-	this.cipher_out_block_size = 32;
-	// stretch the password
+	if (!key) {
+		throw "missing encryption key";
+	}
 	function cipher_cap(k) {
 		var value = caps['cipher'+k];
 		if ((typeof value) === 'object' && value.constructor===Uint8Array) {
 			value = String.fromCharCode.apply(null, value);
 		}
 		return value;
 	}
-	const secret = forge.pkcs5.pbkdf2(key, cipher_cap('.key_salt'), cipher_cap('.key_stretch_iterations'), this.cipher_out_block_size);
+	const cipher = cipher_cap("") || "AES";
+	if (cipher!="AES") {
+		throw "unsupported encryption specified: '"+cipher+"'";
+	}
+	const key_salt = cipher_cap('.key_salt');
+	const iterations = cipher_cap('.key_stretch_iterations');
+	if (iterations<0) {
+		throw "invalid number of iterations: "+iterations;
+	}
+	const DEFAULT_KEYSIZE = 32;
+	const key_size = cipher_cap('.key_size') || DEFAULT_KEYSIZE;
+	if (key_size<=16) {
+		throw "invalid key size '"+key_size+"'";
+	}
+	// stretch the password
+	const DEFAULT_KEY_HASH = "SHA1";
+	const key_hash = (cipher_cap(".key_hash") || DEFAULT_KEY_HASH).toLowerCase();
+	const secret = forge.pkcs5.pbkdf2(key, key_salt, iterations, key_size, key_hash);
+	const DEFAULT_MODE = "CBC";
+	const mode = cipher_cap(".mode") || DEFAULT_MODE;
+    if (mode=="CBC") {
+		this.cipher_out_block_size = 32;
+	}
+	else if (["CFB", "CTR"].indexOf(mode)>=0){
+		this.cipher_out_block_size = 0;
+	}
+	else {
+		throw "unsupported AES mode '"+mode+"'";
+	}
 	// start the cipher
 	const iv = cipher_cap('.iv');
-	this.cipher_out = forge.cipher.createCipher('AES-CBC', secret);
+	if (!iv) {
+		throw "missing IV";
+	}
+	this.cipher_out = forge.cipher.createCipher(cipher+"-"+mode, secret);
 	this.cipher_out.start({iv: iv});
 };