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Diffstat (limited to 'src/modules/m_websocket.cpp')
| -rw-r--r-- | src/modules/m_websocket.cpp | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/src/modules/m_websocket.cpp b/src/modules/m_websocket.cpp new file mode 100644 index 000000000..12102d215 --- /dev/null +++ b/src/modules/m_websocket.cpp @@ -0,0 +1,405 @@ +/* + * InspIRCd -- Internet Relay Chat Daemon + * + * Copyright (C) 2016 Attila Molnar <attilamolnar@hush.com> + * + * This file is part of InspIRCd. InspIRCd 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, version 2. + * + * 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/>. + */ + + +#include "inspircd.h" +#include "iohook.h" +#include "modules/hash.h" + +static const char MagicGUID[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"; +static const char whitespace[] = " \t\r\n"; +static dynamic_reference_nocheck<HashProvider>* sha1; + +class WebSocketHookProvider : public IOHookProvider +{ + public: + WebSocketHookProvider(Module* mod) + : IOHookProvider(mod, "websocket", IOHookProvider::IOH_UNKNOWN, true) + { + } + + void OnAccept(StreamSocket* sock, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server) CXX11_OVERRIDE; + + void OnConnect(StreamSocket* sock) CXX11_OVERRIDE + { + } +}; + +class WebSocketHook : public IOHookMiddle +{ + class HTTPHeaderFinder + { + std::string::size_type bpos; + std::string::size_type len; + + public: + bool Find(const std::string& req, const char* header, std::string::size_type headerlen, std::string::size_type maxpos) + { + std::string::size_type keybegin = req.find(header); + if ((keybegin == std::string::npos) || (keybegin > maxpos) || (keybegin == 0) || (req[keybegin-1] != '\n')) + return false; + + keybegin += headerlen; + + bpos = req.find_first_not_of(whitespace, keybegin, sizeof(whitespace)-1); + if ((bpos == std::string::npos) || (bpos > maxpos)) + return false; + + const std::string::size_type epos = req.find_first_of(whitespace, bpos, sizeof(whitespace)-1); + len = epos - bpos; + + return true; + } + + std::string ExtractValue(const std::string& req) const + { + return std::string(req, bpos, len); + } + }; + + enum OpCode + { + OP_CONTINUATION = 0x00, + OP_TEXT = 0x01, + OP_BINARY = 0x02, + OP_CLOSE = 0x08, + OP_PING = 0x09, + OP_PONG = 0x0a + }; + + enum State + { + STATE_HTTPREQ, + STATE_ESTABLISHED + }; + + static const unsigned char WS_MASKBIT = (1 << 7); + static const unsigned char WS_FINBIT = (1 << 7); + static const unsigned char WS_PAYLOAD_LENGTH_MAGIC_LARGE = 126; + static const unsigned char WS_PAYLOAD_LENGTH_MAGIC_HUGE = 127; + static const size_t WS_MAX_PAYLOAD_LENGTH_SMALL = 125; + static const size_t WS_MAX_PAYLOAD_LENGTH_LARGE = 65535; + static const size_t MAXHEADERSIZE = sizeof(uint64_t) + 2; + + // Clients sending ping or pong frames faster than this are killed + static const time_t MINPINGPONGDELAY = 10; + + State state; + time_t lastpingpong; + + static size_t FillHeader(unsigned char* outbuf, size_t sendlength, OpCode opcode) + { + size_t pos = 0; + outbuf[pos++] = WS_FINBIT | opcode; + + if (sendlength <= WS_MAX_PAYLOAD_LENGTH_SMALL) + { + outbuf[pos++] = sendlength; + } + else if (sendlength <= WS_MAX_PAYLOAD_LENGTH_LARGE) + { + outbuf[pos++] = WS_PAYLOAD_LENGTH_MAGIC_LARGE; + outbuf[pos++] = (sendlength >> 8) & 0xff; + outbuf[pos++] = sendlength & 0xff; + } + else + { + outbuf[pos++] = WS_PAYLOAD_LENGTH_MAGIC_HUGE; + const uint64_t len = sendlength; + for (int i = sizeof(uint64_t)-1; i >= 0; i--) + outbuf[pos++] = ((len >> i*8) & 0xff); + } + + return pos; + } + + static StreamSocket::SendQueue::Element PrepareSendQElem(size_t size, OpCode opcode) + { + unsigned char header[MAXHEADERSIZE]; + const size_t n = FillHeader(header, size, opcode); + + return StreamSocket::SendQueue::Element(reinterpret_cast<const char*>(header), n); + } + + int HandleAppData(StreamSocket* sock, std::string& appdataout, bool allowlarge) + { + std::string& myrecvq = GetRecvQ(); + // Need 1 byte opcode, minimum 1 byte len, 4 bytes masking key + if (myrecvq.length() < 6) + return 0; + + const std::string& cmyrecvq = myrecvq; + unsigned char len1 = (unsigned char)cmyrecvq[1]; + if (!(len1 & WS_MASKBIT)) + { + sock->SetError("WebSocket protocol violation: unmasked client frame"); + return -1; + } + + len1 &= ~WS_MASKBIT; + + // Assume the length is a single byte, if not, update values later + unsigned int len = len1; + unsigned int payloadstartoffset = 6; + const unsigned char* maskkey = reinterpret_cast<const unsigned char*>(&cmyrecvq[2]); + + if (len1 == WS_PAYLOAD_LENGTH_MAGIC_LARGE) + { + // allowlarge is false for control frames according to the RFC meaning large pings, etc. are not allowed + if (!allowlarge) + { + sock->SetError("WebSocket protocol violation: large control frame"); + return -1; + } + + // Large frame, has 2 bytes len after the magic byte indicating the length + // Need 1 byte opcode, 3 bytes len, 4 bytes masking key + if (myrecvq.length() < 8) + return 0; + + unsigned char len2 = (unsigned char)cmyrecvq[2]; + unsigned char len3 = (unsigned char)cmyrecvq[3]; + len = (len2 << 8) | len3; + + if (len <= WS_MAX_PAYLOAD_LENGTH_SMALL) + { + sock->SetError("WebSocket protocol violation: non-minimal length encoding used"); + return -1; + } + + maskkey += 2; + payloadstartoffset += 2; + } + else if (len1 == WS_PAYLOAD_LENGTH_MAGIC_HUGE) + { + sock->SetError("WebSocket: Huge frames are not supported"); + return -1; + } + + if (myrecvq.length() < payloadstartoffset + len) + return 0; + + unsigned int maskkeypos = 0; + const std::string::iterator endit = myrecvq.begin() + payloadstartoffset + len; + for (std::string::const_iterator i = myrecvq.begin() + payloadstartoffset; i != endit; ++i) + { + const unsigned char c = (unsigned char)*i; + appdataout.push_back(c ^ maskkey[maskkeypos++]); + maskkeypos %= 4; + } + + myrecvq.erase(myrecvq.begin(), endit); + return 1; + } + + int HandlePingPongFrame(StreamSocket* sock, bool isping) + { + if (lastpingpong + MINPINGPONGDELAY >= ServerInstance->Time()) + { + sock->SetError("WebSocket: Ping/pong flood"); + return -1; + } + + lastpingpong = ServerInstance->Time(); + + std::string appdata; + const int result = HandleAppData(sock, appdata, false); + // If it's a pong stop here regardless of the result so we won't generate a reply + if ((result <= 0) || (!isping)) + return result; + + StreamSocket::SendQueue::Element elem = PrepareSendQElem(appdata.length(), OP_PONG); + elem.append(appdata); + GetSendQ().push_back(elem); + + SocketEngine::ChangeEventMask(sock, FD_ADD_TRIAL_WRITE); + return 1; + } + + int HandleWS(StreamSocket* sock, std::string& destrecvq) + { + if (GetRecvQ().empty()) + return 0; + + unsigned char opcode = (unsigned char)GetRecvQ().c_str()[0]; + opcode &= ~WS_FINBIT; + + switch (opcode) + { + case OP_CONTINUATION: + case OP_TEXT: + case OP_BINARY: + { + return HandleAppData(sock, destrecvq, true); + } + + case OP_PING: + { + return HandlePingPongFrame(sock, true); + } + + case OP_PONG: + { + // A pong frame may be sent unsolicited, so we have to handle it. + // It may carry application data which we need to remove from the recvq as well. + return HandlePingPongFrame(sock, false); + } + + case OP_CLOSE: + { + sock->SetError("Connection closed"); + return -1; + } + + default: + { + sock->SetError("WebSocket: Invalid opcode"); + return -1; + } + } + } + + void FailHandshake(StreamSocket* sock, const char* httpreply, const char* sockerror) + { + GetSendQ().push_back(StreamSocket::SendQueue::Element(httpreply)); + sock->DoWrite(); + sock->SetError(sockerror); + } + + int HandleHTTPReq(StreamSocket* sock) + { + std::string& recvq = GetRecvQ(); + const std::string::size_type reqend = recvq.find("\r\n\r\n"); + if (reqend == std::string::npos) + return 0; + + HTTPHeaderFinder keyheader; + if (!keyheader.Find(recvq, "Sec-WebSocket-Key:", 18, reqend)) + { + FailHandshake(sock, "HTTP/1.1 501 Not Implemented\r\nConnection: close\r\n\r\n", "WebSocket: Received HTTP request which is not a websocket upgrade"); + return -1; + } + + if (!*sha1) + { + FailHandshake(sock, "HTTP/1.1 503 Service Unavailable\r\nConnection: close\r\n\r\n", "WebSocket: SHA-1 provider missing"); + return -1; + } + + state = STATE_ESTABLISHED; + + std::string key = keyheader.ExtractValue(recvq); + key.append(MagicGUID); + + std::string reply = "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "; + reply.append(BinToBase64((*sha1)->GenerateRaw(key), NULL, '=')).append("\r\n\r\n"); + GetSendQ().push_back(StreamSocket::SendQueue::Element(reply)); + + SocketEngine::ChangeEventMask(sock, FD_ADD_TRIAL_WRITE); + + recvq.erase(0, reqend + 4); + + return 1; + } + + public: + WebSocketHook(IOHookProvider* Prov, StreamSocket* sock) + : IOHookMiddle(Prov) + , state(STATE_HTTPREQ) + , lastpingpong(0) + { + sock->AddIOHook(this); + } + + int OnStreamSocketWrite(StreamSocket* sock, StreamSocket::SendQueue& uppersendq) CXX11_OVERRIDE + { + StreamSocket::SendQueue& mysendq = GetSendQ(); + + // Return 1 to allow sending back an error HTTP response + if (state != STATE_ESTABLISHED) + return (mysendq.empty() ? 0 : 1); + + if (!uppersendq.empty()) + { + StreamSocket::SendQueue::Element elem = PrepareSendQElem(uppersendq.bytes(), OP_BINARY); + mysendq.push_back(elem); + mysendq.moveall(uppersendq); + } + + return 1; + } + + int OnStreamSocketRead(StreamSocket* sock, std::string& destrecvq) CXX11_OVERRIDE + { + if (state == STATE_HTTPREQ) + { + int httpret = HandleHTTPReq(sock); + if (httpret <= 0) + return httpret; + } + + int wsret; + do + { + wsret = HandleWS(sock, destrecvq); + } + while ((!GetRecvQ().empty()) && (wsret > 0)); + + return wsret; + } + + void OnStreamSocketClose(StreamSocket* sock) CXX11_OVERRIDE + { + } +}; + +void WebSocketHookProvider::OnAccept(StreamSocket* sock, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server) +{ + new WebSocketHook(this, sock); +} + +class ModuleWebSocket : public Module +{ + dynamic_reference_nocheck<HashProvider> hash; + reference<WebSocketHookProvider> hookprov; + + public: + ModuleWebSocket() + : hash(this, "hash/sha1") + , hookprov(new WebSocketHookProvider(this)) + { + sha1 = &hash; + } + + void OnCleanup(ExtensionItem::ExtensibleType type, Extensible* item) CXX11_OVERRIDE + { + if (type != ExtensionItem::EXT_USER) + return; + + LocalUser* user = IS_LOCAL(static_cast<User*>(item)); + if ((user) && (user->eh.GetModHook(this))) + ServerInstance->Users.QuitUser(user, "WebSocket module unloading"); + } + + Version GetVersion() CXX11_OVERRIDE + { + return Version("Provides RFC 6455 WebSocket support", VF_VENDOR); + } +}; + +MODULE_INIT(ModuleWebSocket) |