Added Web based RDP support with NLA, #3867 and #3914

rdp/asn1/ber.js

@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2014-2015 Sylvain Peyrefitte
+ *
+ * This file is part of node-rdpjs.
+ *
+ * node-rdpjs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+var type = require('../core').type;
+var log = require('../core').log;
+var error = require('../core').error;
+
+/**
+ * Parse tag(T) field of BER TLV
+ * And check with expected tag
+ * @param s {type.Stream}
+ * @param tag {spec.tag}
+ * @returns {Boolean} True for valid tag matching
+ */
+function decodeTag(s, tag) {
+	var nextTag = new type.UInt8().read(s).value;
+	if (tag.tagNumber > 30) {
+		nextTagNumber = new type.UInt8().read(s).value;
+	}
+	else {
+		nextTagNumber = nextTag & 0x1F;
+	}
+	
+	return ((nextTag & 0xE0) === (tag.tagClass | tag.tagFormat)) && (nextTagNumber === tag.tagNumber);
+};
+
+/**
+ * Parse length(L) field of BER TLV
+ * @param s {type.Stream}
+ * @returns {integer}
+ */
+function decodeLength(s) {
+	var size = new type.UInt8().read(s).value;
+	if(size & 0x80) {
+		size &= ~0x80;
+		if(size === 1) {
+			size = new type.UInt8().read(s).value;
+		}
+		else if(size === 2) {
+			size = new type.UInt16Be().read(s).value;
+		}
+		else{
+			throw new error.ProtocolError('NODE_RDP_ASN1_BER_INVALID_LENGTH');
+		}
+	}
+	return size;
+};
+
+/**
+ * Decode tuple TLV (Tag Length Value) of BER
+ * @param s {type.Stream}
+ * @param tag {spec.Asn1Tag} expected tag
+ * @returns {type.BinaryString} Value of tuple
+ */
+function decode(s, tag) {
+	if (!decodeTag(s, tag)) {
+		throw new error.ProtocolError('NODE_RDP_ASN1_BER_INVALID_TAG');
+	}
+	var length = decodeLength(s);
+	
+	if (length === 0) {
+		return new type.Stream(0);
+	}
+	return new type.BinaryString(null,{ readLength : new type.CallableValue(length) }).read(s);
+};
+
+function encodeTag(tag) {
+	if(tag.tagNumber > 30) {
+		return new type.Component([new type.UInt8(tag.tagClass | tag.tagFormat | 0x1F), new type.UInt8(tag.tagNumber)]);
+	}
+	else {
+		return new type.UInt8((tag.tagClass | tag.tagFormat) | (tag.tagNumber & 0x1F));
+	}
+}
+
+function encodeLength(length) {
+	if(length > 0x7f) {
+        return new type.Component([new type.UInt8(0x82), new type.UInt16Be(length)]);
+    }
+    else {
+        return new type.UInt8(length);
+    }
+}
+
+function encode(tag, buffer) {
+	return new type.Component([encodeTag(tag), encodeLength(buffer.size()), buffer]);
+}
+
+/**
+ * Module Export
+ */
+module.exports = {
+	decode : decode,
+	encode : encode
+};