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* Add an initial complete frame timeout to the WebSocket processor to make it easier to write WebSocket service code that is resistant to Denial of Service attacks.

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This commit is contained in:
teravus
2013-10-04 20:37:59 -05:00
parent 083eb7679b
commit 85593d8d25
1 changed files with 65 additions and 2 deletions
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67
OpenSim/Framework/Servers/HttpServer/WebsocketServerHandler.cs
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@@ -28,8 +28,10 @@
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using HttpServer;
namespace OpenSim.Framework.Servers.HttpServer
@@ -98,6 +100,8 @@ namespace OpenSim.Framework.Servers.HttpServer
/// </summary>
public ValidateHandshake HandshakeValidateMethodOverride = null;
private ManualResetEvent _receiveDone = new ManualResetEvent(false);
private OSHttpRequest _request;
private HTTPNetworkContext _networkContext;
private IHttpClientContext _clientContext;
@@ -109,6 +113,8 @@ namespace OpenSim.Framework.Servers.HttpServer
private bool _closing;
private bool _upgraded;
private int _maxPayloadBytes = 41943040;
private int _initialMsgTimeout = 0;
private int _defaultReadTimeout = 10000;
private const string HandshakeAcceptText =
"HTTP/1.1 101 Switching Protocols\r\n" +
@@ -131,6 +137,7 @@ namespace OpenSim.Framework.Servers.HttpServer
{
_request = preq;
_networkContext = pContext.GiveMeTheNetworkStreamIKnowWhatImDoing();
_networkContext.Stream.ReadTimeout = _defaultReadTimeout;
_clientContext = pContext;
_bufferLength = bufferlen;
_buffer = new byte[_bufferLength];
@@ -205,6 +212,16 @@ namespace OpenSim.Framework.Servers.HttpServer
set { _maxPayloadBytes = value; }
}
/// <summary>
/// Set this to the maximum amount of milliseconds to wait for the first complete message to be sent or received on the websocket after upgrading
/// Default, it waits forever. Use this when your Websocket consuming code opens a connection and waits for a message from the other side to avoid a Denial of Service vector.
/// </summary>
public int InitialMsgTimeout
{
get { return _initialMsgTimeout; }
set { _initialMsgTimeout = value; }
}
/// <summary>
/// This triggers the websocket start the upgrade process
/// </summary>
@@ -245,6 +262,7 @@ namespace OpenSim.Framework.Servers.HttpServer
string rawaccept = string.Format(HandshakeAcceptText, acceptKey);
SendUpgradeSuccess(rawaccept);
}
else
{
@@ -258,6 +276,10 @@ namespace OpenSim.Framework.Servers.HttpServer
SendUpgradeSuccess(rawaccept);
}
}
public IPEndPoint GetRemoteIPEndpoint()
{
return _request.RemoteIPEndPoint;
}
/// <summary>
/// Generates a handshake response key string based on the client's
@@ -290,9 +312,16 @@ namespace OpenSim.Framework.Servers.HttpServer
WebSocketState socketState = new WebSocketState() { ReceivedBytes = new List<byte>(), Header = WebsocketFrameHeader.HeaderDefault(), FrameComplete = true};
byte[] bhandshakeResponse = Encoding.UTF8.GetBytes(pHandshakeResponse);
try
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Reset();
}
// Begin reading the TCP stream before writing the Upgrade success message to the other side of the stream.
_networkContext.Stream.BeginRead(_buffer, 0, _bufferLength, OnReceive, socketState);
@@ -303,6 +332,11 @@ namespace OpenSim.Framework.Servers.HttpServer
UpgradeCompletedDelegate d = OnUpgradeCompleted;
if (d != null)
d(this, new UpgradeCompletedEventArgs());
if (_initialMsgTimeout > 0)
{
if (!_receiveDone.WaitOne(TimeSpan.FromMilliseconds(_initialMsgTimeout)))
Close(string.Empty);
}
}
catch (IOException)
{
@@ -489,6 +523,11 @@ namespace OpenSim.Framework.Servers.HttpServer
/// <param name="message">the string message that is to be sent</param>
public void SendMessage(string message)
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
byte[] messagedata = Encoding.UTF8.GetBytes(message);
WebSocketFrame textMessageFrame = new WebSocketFrame() { Header = WebsocketFrameHeader.HeaderDefault(), WebSocketPayload = messagedata };
textMessageFrame.Header.Opcode = WebSocketReader.OpCode.Text;
@@ -499,6 +538,11 @@ namespace OpenSim.Framework.Servers.HttpServer
public void SendData(byte[] data)
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
WebSocketFrame dataMessageFrame = new WebSocketFrame() { Header = WebsocketFrameHeader.HeaderDefault(), WebSocketPayload = data};
dataMessageFrame.Header.IsEnd = true;
dataMessageFrame.Header.Opcode = WebSocketReader.OpCode.Binary;
@@ -531,6 +575,11 @@ namespace OpenSim.Framework.Servers.HttpServer
/// </summary>
public void SendPingCheck()
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
WebSocketFrame pingFrame = new WebSocketFrame() { Header = WebsocketFrameHeader.HeaderDefault(), WebSocketPayload = new byte[0] };
pingFrame.Header.Opcode = WebSocketReader.OpCode.Ping;
pingFrame.Header.IsEnd = true;
@@ -544,6 +593,11 @@ namespace OpenSim.Framework.Servers.HttpServer
/// <param name="message"></param>
public void Close(string message)
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
if (_networkContext == null)
return;
if (_networkContext.Stream != null)
@@ -583,7 +637,11 @@ namespace OpenSim.Framework.Servers.HttpServer
WebSocketReader.Mask(psocketState.Header.Mask, unmask);
psocketState.ReceivedBytes = new List<byte>(unmask);
}
if (psocketState.Header.Opcode != WebSocketReader.OpCode.Continue && _initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
switch (psocketState.Header.Opcode)
{
case WebSocketReader.OpCode.Ping:
@@ -696,6 +754,11 @@ namespace OpenSim.Framework.Servers.HttpServer
}
public void Dispose()
{
if (_initialMsgTimeout > 0)
{
_receiveDone.Set();
_initialMsgTimeout = 0;
}
if (_networkContext != null && _networkContext.Stream != null)
{
if (_networkContext.Stream.CanWrite)