Revision 12:46c5974a565f, committed 2017-06-01

Comitter:

IanBenzMaxim

Date:

Thu Jun 01 14:21:58 2017 -0500

Parent:

11:989eabe2a376

Child:

13:6a6225690c2e

Commit message:

Added bidirectional challenge support.

Changed in this revision

--- a/NormalOperationWindow.cpp	Wed May 03 16:08:59 2017 -0500
+++ b/NormalOperationWindow.cpp	Thu Jun 01 14:21:58 2017 -0500
@@ -96,8 +96,22 @@
     return commands;
 }
 
+// Creates a new command challenge, and adds it to an existing JSON document.
+static DS2476::CmdResult addCommandChallenge(rapidjson::Document & document, CommandChallenge & commandChallenge)
+{
+    DS2476::Buffer buffer;
+    DS2476::CmdResult result = coproc.readRng(commandChallenge.size(), buffer);
+    if (result == DS2476::Success)
+    {
+        std::copy(buffer.begin(), buffer.end(), commandChallenge.begin());
+        document.AddMember("challenge", rapidjson::Value(byteArrayToHexString(commandChallenge.data(),
+            commandChallenge.size()).c_str(), document.GetAllocator()).Move(), document.GetAllocator());
+    }
+    return result;
+}
+
 // Adds signature information to an existing JSON document.
-static DS2476::CmdResult signData(bool validSignature, const std::vector<uint8_t> & challenge, rapidjson::Document & document)
+static DS2476::CmdResult signData(bool validSignature, const ResponseChallenge & challenge, rapidjson::Document & document)
 {
     // Move contents of document to a new location and create an empty object in document.
     rapidjson::Value data(rapidjson::kObjectType);
@@ -133,13 +147,28 @@
     return result;
 }
 
+// Finalizes a command response to the server by adding the next command challenge and signing the data.
+static DS2476::CmdResult finalizeResponse(bool validSignature, const ResponseChallenge & responseChallenge,
+    rapidjson::Document & document, CommandChallenge & commandChallenge)
+{
+    DS2476::CmdResult result = addCommandChallenge(document, commandChallenge);
+    if (result == DS2476::Success)
+    {
+        result = signData(validSignature, responseChallenge, document);
+    }
+    return result;
+}
+
 // Parse and verify a signed JSON string.
-static DS2476::CmdResult verifySignedData(const std::string & verifyData, rapidjson::Document & signedData)
+template <typename VerifyDataIt>
+static DS2476::CmdResult verifySignedData(VerifyDataIt verifyDataBegin, VerifyDataIt verifyDataEnd,
+    const CommandChallenge & commandChallenge, rapidjson::Document & signedData)
 {
     using rapidjson::Value;
     using std::string;
     
     // Parse string and validate object schema.
+    string verifyData(verifyDataBegin, verifyDataEnd);
     signedData.Parse(verifyData.c_str());
     if (!(signedData.IsObject() && signedData.HasMember("data") && signedData.HasMember("signature")))
     {
@@ -179,7 +208,7 @@
     }
     std::copy(parsedBytes.begin(), parsedBytes.end(), signatureBuffer.s.begin());
     
-    // Compute hash of the data.
+    // Get data to hash.
     // Need to use string searching here since there isn't currently a way to access raw elements
     // in rapidjson, and creating another copy of the data might consume too much memory.
     const string rawDataSearch("\"data\":");
@@ -196,10 +225,16 @@
         signedData.RemoveAllMembers();
         return DS2476::AuthenticationError;
     }
+    verifyData.erase(rawDataEnd);
+    verifyData.erase(0, rawDataBegin);
+    // Add in command challenge to data that will be verified.
+    verifyData.append(commandChallenge.begin(), commandChallenge.end());
+    
+    // Compute hash of the data.
     const string::size_type chunkSize = 64;
-    for (string::size_type i = rawDataBegin; i < rawDataEnd; i += chunkSize)
+    for (string::size_type i = 0; i < verifyData.size(); i += chunkSize)
     {
-        const string::size_type remainingLength = rawDataEnd - i;
+        const string::size_type remainingLength = verifyData.size() - i;
         DS2476::CmdResult result = coproc.computeMultiblockHash(i == 0, remainingLength < chunkSize,
             DS2476::Buffer(verifyData.c_str() + i, verifyData.c_str() + i + std::min(remainingLength, chunkSize)));
         if (result != DS2476::Success)
@@ -263,7 +298,7 @@
 }
 
 NormalOperationWindow::NormalOperationWindow(std::auto_ptr<TCPSocket> & socket) :
-    socket(socket) /* Move construct */,
+    socket(socket) /* Move construct */, sendChallenge(true),
     validSignature(true), lastSensorNodeState(Disconnected), lastObjectTemp(0), lastAmbientTemp(0)
 {
     assert(this->socket.get() != NULL);
@@ -330,7 +365,7 @@
     return sensorNodeState;
 }
 
-NormalOperationWindow::Result NormalOperationWindow::sendStatus(const std::vector<uint8_t> & challenge)
+NormalOperationWindow::Result NormalOperationWindow::sendStatus(const ResponseChallenge & responseChallenge)
 {
     rapidjson::MemoryPoolAllocator<> allocator(defaultChunkSize);
     rapidjson::Document document(rapidjson::kObjectType, &allocator);
@@ -400,7 +435,7 @@
     document.AddMember("certificate", certificate, document.GetAllocator());
     
     // Sign data and transmit to server.
-    result = signData(validSignature, challenge, document);
+    result = finalizeResponse(validSignature, responseChallenge, document, commandChallenge);
     if (result != DS2476::Success)
     {
         if (windowManager() != NULL)
@@ -415,12 +450,12 @@
     return NoChange;
 }
 
-NormalOperationWindow::Result NormalOperationWindow::sendObjectTemp(const std::vector<uint8_t> & challenge)
+NormalOperationWindow::Result NormalOperationWindow::sendObjectTemp(const ResponseChallenge & responseChallenge)
 {
     rapidjson::MemoryPoolAllocator<> allocator(defaultChunkSize);
     rapidjson::Document document(rapidjson::kObjectType, &allocator);
     
-    // Read object temperatue and add to document.
+    // Read object temperature and add to document.
     double objectTemp;
     bool sensorResult = sensorNode.readTemp(SensorNode::ObjectTemp, objectTemp);
     if (!sensorResult)
@@ -436,7 +471,7 @@
     document.AddMember("objectTemp", objectTemp, document.GetAllocator());
     
     // Sign data and transmit to server.
-    DS2476::CmdResult coprocResult = signData(validSignature, challenge, document);
+    DS2476::CmdResult coprocResult = finalizeResponse(validSignature, responseChallenge, document, commandChallenge);
     if (coprocResult != DS2476::Success)
     {
         if (windowManager() != NULL)
@@ -453,12 +488,12 @@
     return NoChange;
 }
 
-NormalOperationWindow::Result NormalOperationWindow::sendAmbientTemp(const std::vector<uint8_t> & challenge)
+NormalOperationWindow::Result NormalOperationWindow::sendAmbientTemp(const ResponseChallenge & responseChallenge)
 {
     rapidjson::MemoryPoolAllocator<> allocator(defaultChunkSize);
     rapidjson::Document document(rapidjson::kObjectType, &allocator);
     
-    // Read ambient temperatue and add to document.
+    // Read ambient temperature and add to document.
     double ambientTemp;
     bool sensorResult = sensorNode.readTemp(SensorNode::AmbientTemp, ambientTemp);
     if (!sensorResult)
@@ -474,7 +509,7 @@
     document.AddMember("ambientTemp", ambientTemp, document.GetAllocator());
     
     // Sign data and transmit to server.
-    DS2476::CmdResult coprocResult = signData(validSignature, challenge, document);
+    DS2476::CmdResult coprocResult = finalizeResponse(validSignature, responseChallenge, document, commandChallenge);
     if (coprocResult != DS2476::Success)
     {
         if (windowManager() != NULL)
@@ -510,7 +545,7 @@
         rapidjson::MemoryPoolAllocator<> allocator(defaultChunkSize);
         rapidjson::Document data(&allocator);
         // Verify command signature.
-        DS2476::CmdResult verifySignedResult = verifySignedData(std::string(it->first, it->second), data);
+        DS2476::CmdResult verifySignedResult = verifySignedData(it->first, it->second, commandChallenge, data);
         switch (verifySignedResult)
         {
         case DS2476::Success: // Command passed authentication.
@@ -523,13 +558,13 @@
                     if (command.IsString())
                     {
                         // Parse challenge if included.
-                        std::vector<uint8_t> challengeData;
+                        ResponseChallenge responseChallenge;
                         if (data.HasMember("challenge"))
                         {
                             const rapidjson::Value & challenge = data["challenge"];
                             if (challenge.IsString())
                             {
-                                challengeData =
+                                responseChallenge =
                                     hexStringToByteArray(std::string(challenge.GetString(), challenge.GetStringLength()));
                             }
                         }
@@ -537,7 +572,7 @@
                         // Execute the command.
                         if (command == "getStatus")
                         {
-                            Result result = sendStatus(challengeData);
+                            Result result = sendStatus(responseChallenge);
                             if (result != NoChange)
                                 return result;
                         }
@@ -545,7 +580,7 @@
                         {
                             if ((lastSensorNodeState == ValidLaserDisabled) || (lastSensorNodeState == ValidLaserEnabled))
                             {
-                                Result result = sendObjectTemp(challengeData);
+                                Result result = sendObjectTemp(responseChallenge);
                                 if (result != NoChange)
                                     return result;
                                 invalidate();
@@ -555,7 +590,7 @@
                         {
                             if ((lastSensorNodeState == ValidLaserDisabled) || (lastSensorNodeState == ValidLaserEnabled))
                             {
-                                Result result = sendAmbientTemp(challengeData);
+                                Result result = sendAmbientTemp(responseChallenge);
                                 if (result != NoChange)
                                     return result;
                                 invalidate();
@@ -710,24 +745,39 @@
         invalidate();
     }
     
-    // Process socket data.
-    int recvResult = socket->recv(recvBuf, sizeof(recvBuf) / sizeof(recvBuf[0]));
-    if (recvResult > 0)
+    // Send challenge on first connection.
+    if (sendChallenge)
     {
-        std::printf("%*s\n", recvResult, recvBuf);
-        Result result = processReceivedData(recvResult);
-        if (result != NoChange)
-            return;
+        rapidjson::MemoryPoolAllocator<> allocator(defaultChunkSize);
+        rapidjson::Document document(rapidjson::kObjectType, &allocator);
+        DS2476::CmdResult result = addCommandChallenge(document, commandChallenge);
+        if (result == DS2476::Success)
+        {
+            sendJson(document, *socket);
+            sendChallenge = false;
+        }
     }
-    else if (recvResult != NSAPI_ERROR_WOULD_BLOCK)
+    // Process socket data.
+    else
     {
-        if (windowManager() != NULL)
+        int recvResult = socket->recv(recvBuf, sizeof(recvBuf) / sizeof(recvBuf[0]));
+        if (recvResult > 0)
         {
-            windowManager()->pop();
-            std::auto_ptr<Window> window(new ErrorWindow("Socket receive failed"));
-            windowManager()->push(window);
+            std::printf("%*s\n", recvResult, recvBuf);
+            Result result = processReceivedData(recvResult);
+            if (result != NoChange)
+                return;
         }
-        return;
+        else if (recvResult != NSAPI_ERROR_WOULD_BLOCK)
+        {
+            if (windowManager() != NULL)
+            {
+                windowManager()->pop();
+                std::auto_ptr<Window> window(new ErrorWindow("Socket receive failed"));
+                windowManager()->push(window);
+            }
+            return;
+        }
     }
 }
 

--- a/NormalOperationWindow.hpp	Wed May 03 16:08:59 2017 -0500
+++ b/NormalOperationWindow.hpp	Thu Jun 01 14:21:58 2017 -0500
@@ -36,9 +36,16 @@
 #include <memory>
 #include <vector>
 #include <TCPSocket.h>
+#include <array.h>
 #include "Button.hpp"
 #include "Window.hpp"
 
+/// Challenge received from the server with a command to sign the response against.
+typedef std::vector<uint8_t> ResponseChallenge;
+
+/// Challenge sent to the server with a command response to sign the next command against.
+typedef OneWire::array<uint8_t, 32> CommandChallenge;
+
 /// Handles normal operation of the demo including displaying status information and processing
 /// commands from the server.
 class NormalOperationWindow : public Window
@@ -72,6 +79,8 @@
     
     std::auto_ptr<TCPSocket> socket;
     char recvBuf[1280]; // Socket receive buffer. Must be large enough to hold the largest command.
+    CommandChallenge commandChallenge;
+    bool sendChallenge;
 
     // Device status information.
     bool validSignature;
@@ -91,9 +100,9 @@
     
     static SensorNodeState detectSensorNode();
     Result processReceivedData(size_t recvBufSize);
-    Result sendStatus(const std::vector<uint8_t> & challenge);
-    Result sendObjectTemp(const std::vector<uint8_t> & challenge);
-    Result sendAmbientTemp(const std::vector<uint8_t> & challenge);
+    Result sendStatus(const ResponseChallenge & responseChallenge);
+    Result sendObjectTemp(const ResponseChallenge & responseChallenge);
+    Result sendAmbientTemp(const ResponseChallenge & responseChallenge);
     void displayImage(const std::vector<uint8_t> & imageData);
 };