Fixed infinite loop

farhadi · Oct 9, 2020 · 7c3b8c4 · 7c3b8c4
1 parent a530f60
commit 7c3b8c4
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Showing 3 changed files with 22 additions and 6 deletions.
diff --git a/lib/pdu.js b/lib/pdu.js
@@ -40,7 +40,7 @@ function PDU(command, options) {
 	}
 }
 
-PDU.fromStream = function(stream) {
+PDU.commandLength = function(stream) {
 	var buffer = stream.read(4);
 	if (!buffer) {
 		return false;
@@ -50,12 +50,19 @@ PDU.fromStream = function(stream) {
 		throw Error('PDU length was too large (' + command_length +
 			', maximum is ' + PDU.maxLength + ').');
 	}
-	stream.unshift(buffer);
-	buffer = stream.read(command_length);
+	return command_length;
+};
+
+PDU.fromStream = function(stream, command_length) {
+	var buffer = stream.read(command_length - 4);
 	if (!buffer) {
 		return false;
 	}
-	return new PDU(buffer);
+	let buf = Buffer.alloc(4);
+	buf.writeUInt32BE(command_length);
+	var pduBuffer = Buffer.concat([buf, buffer]);
+
+	return new PDU(pduBuffer);
 };
 
 PDU.fromBuffer = function(buffer) {

diff --git a/lib/smpp.js b/lib/smpp.js
@@ -16,6 +16,7 @@ function Session(options) {
 	this._busy = false;
 	this._callbacks = [];
 	this._interval = 0;
+	this._command_length = null;
 	if (options.socket) {
 		this.socket = options.socket;
 	} else {
@@ -70,13 +71,20 @@ Session.prototype._extractPDUs = function() {
 	var pdu;
 	while (!this.paused) {
 		try {
-			if (!(pdu = PDU.fromStream(this.socket))) {
+			if(!this._command_length) {
+				this._command_length = PDU.commandLength(this.socket);
+				if(!this._command_length) {
+					break;
+				}
+			}
+			if (!(pdu = PDU.fromStream(this.socket, this._command_length))) {
 				break;
 			}
 		} catch (e) {
 			this.emit('error', e);
 			return;
 		}
+		this._command_length = null;
 		this.emit('pdu', pdu);
 		this.emit(pdu.command, pdu);
 		if (pdu.isResponse() && this._callbacks[pdu.sequence_number]) {

diff --git a/test/pdu.js b/test/pdu.js
@@ -76,7 +76,8 @@ describe('PDU', function() {
 			var readable = new stream.Readable();
 			readable._read = function() {} ;
 			readable.push(buffer);
-			var pdu = PDU.fromStream(readable);
+			var commandLength = PDU.commandLength(readable);
+			var pdu = PDU.fromStream(readable, commandLength);
 			assert.deepEqual(pdu, expected);
 		});
 	});