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Added WebRTC "Volkswagen mode" which encrypts packets but sends them plaintext anyway

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This commit is contained in:
Thulinma 2020-05-22 23:53:35 +02:00
parent 26de8c0389
commit 2124d10a9b
2 changed files with 95 additions and 24 deletions
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117
src/output/output_webrtc.cpp
View file

@ -54,6 +54,8 @@ namespace Mist{
videoBitrate = 6 * 1000 * 1000;
RTP::MAX_SEND = 1350 - 28;
didReceiveKeyFrame = false;
doDTLS = true;
volkswagenMode = false;
if (cert.init("NL", "webrtc", "webrtc") != 0){
onFail("Failed to create the certificate.", true);
@ -175,10 +177,26 @@ namespace Mist{
HIGH_MSG("Ignoring non-text websocket frame");
return;
}
JSON::Value command = JSON::fromString(webSock->data, webSock->data.size());
JSON::Value commandResult;
if(command.isMember("encrypt")){
doDTLS = false;
volkswagenMode = false;
if(command["encrypt"].asString() == "no" || command["encrypt"].asString() == "none"){
INFO_MSG("Disabling encryption");
}else if(command["encrypt"].asString() == "placebo" || command["encrypt"].asString() == "volkswagen"){
INFO_MSG("Entering volkswagen mode: encrypt data, but send plaintext for easier analysis");
srtpWriter.init("SRTP_AES128_CM_SHA1_80", "volkswagen modus", "volkswagenmode");
volkswagenMode = true;
}else{
doDTLS = true;
}
}
// Check if there's a command type
if (!command.isMember("type")){
sendSignalingError("error", "Received a command but no type property was given.");
@ -209,6 +227,7 @@ namespace Mist{
}
if (!sdpParser.parseSDP(offerStr) || !sdpAnswer.parseOffer(offerStr)){
sendSignalingError("offer_sdp", "Failed to parse the offered SDP");
WARN_MSG("offer parse failed");
return;
}
@ -885,7 +904,7 @@ namespace Mist{
stun_writer.writeMessageIntegrity(passwordLocal);
stun_writer.writeFingerprint();
stun_writer.end();
udp.SendNow((const char *)stun_writer.getBufferPtr(), stun_writer.getBufferSize());
myConn.addUp(stun_writer.getBufferSize());
}
@ -1152,11 +1171,13 @@ namespace Mist{
rtpOutBuffer.assign(data, nbytes);
int protectedSize = nbytes;
if (srtpWriter.protectRtp((uint8_t *)(void *)rtpOutBuffer, &protectedSize) != 0){
ERROR_MSG("Failed to protect the RTP message.");
return;
}
if (doDTLS){
if (srtpWriter.protectRtp((uint8_t *)(void *)rtpOutBuffer, &protectedSize) != 0){
ERROR_MSG("Failed to protect the RTP message.");
return;
}
}
udp.SendNow(rtpOutBuffer, (size_t)protectedSize);
RTP::Packet tmpPkt(rtpOutBuffer, protectedSize);
@ -1164,6 +1185,13 @@ namespace Mist{
uint16_t seq = tmpPkt.getSequence();
outBuffers[pSSRC].assign(seq, rtpOutBuffer, protectedSize);
myConn.addUp(protectedSize);
if (volkswagenMode){
if (srtpWriter.protectRtp((uint8_t *)(void *)rtpOutBuffer, &protectedSize) != 0){
ERROR_MSG("Failed to protect the RTP message.");
return;
}
}
}
void OutWebRTC::onRTPPacketizerHasRTCPPacket(const char *data, uint32_t nbytes){
@ -1180,13 +1208,24 @@ namespace Mist{
rtpOutBuffer.allocate(nbytes + 256);
rtpOutBuffer.assign(data, nbytes);
int rtcpPacketSize = nbytes;
if (srtpWriter.protectRtcp((uint8_t *)(void *)rtpOutBuffer, &rtcpPacketSize) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
if (doDTLS){
if (srtpWriter.protectRtcp((uint8_t *)(void *)rtpOutBuffer, &rtcpPacketSize) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
udp.SendNow(rtpOutBuffer, rtcpPacketSize);
myConn.addUp(rtcpPacketSize);
if (volkswagenMode){
if (srtpWriter.protectRtcp((uint8_t *)(void *)rtpOutBuffer, &rtcpPacketSize) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
}
// This function was implemented (it's virtual) to handle
@ -1198,10 +1237,11 @@ namespace Mist{
void OutWebRTC::sendHeader(){
// first make sure that we complete the DTLS handshake.
while (keepGoing() && !dtlsHandshake.hasKeyingMaterial()){
if (!handleWebRTCInputOutput()){Util::sleep(10);}
if(doDTLS){
while (keepGoing() && !dtlsHandshake.hasKeyingMaterial()){
if (!handleWebRTCInputOutput()){Util::sleep(10);}
}
}
sentHeader = true;
}
@ -1396,13 +1436,22 @@ namespace Mist{
size_t trailer_space = SRTP_MAX_TRAILER_LEN + 4;
for (size_t i = 0; i < trailer_space; ++i){buffer.push_back(0x00);}
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
if (doDTLS){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
udp.SendNow((const char *)&buffer[0], buffer_size_in_bytes);
myConn.addUp(buffer_size_in_bytes);
if (volkswagenMode){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
}
void OutWebRTC::sendRTCPFeedbackPLI(const WebRTCTrack &rtcTrack){
@ -1427,13 +1476,23 @@ namespace Mist{
// protect.
int buffer_size_in_bytes = (int)buffer.size();
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
if (doDTLS){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
udp.SendNow((const char *)&buffer[0], buffer_size_in_bytes);
myConn.addUp(buffer_size_in_bytes);
if (volkswagenMode){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
}
// Notify sender that we lost a packet. See
@ -1468,13 +1527,23 @@ namespace Mist{
// protect.
int buffer_size_in_bytes = (int)buffer.size();
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
if (doDTLS){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
udp.SendNow((const char *)&buffer[0], buffer_size_in_bytes);
myConn.addUp(buffer_size_in_bytes);
if (volkswagenMode){
if (srtpWriter.protectRtcp(&buffer[0], &buffer_size_in_bytes) != 0){
ERROR_MSG("Failed to protect the RTCP message.");
return;
}
}
}
void OutWebRTC::sendRTCPFeedbackRR(WebRTCTrack &rtcTrack){

2
src/output/output_webrtc.h
View file

@ -211,6 +211,8 @@ namespace Mist{
bool firstKey;
bool repeatInit;
bool stayLive;
bool doDTLS;
bool volkswagenMode;
#if defined(WEBRTC_PCAP)
PCAPWriter pcapOut; ///< Used during development to write unprotected packets that can be