First version with SendEncryptedContext

src/HAP.cpp

@@ -851,7 +851,6 @@ int HAPClient::getAccessoriesURL(){
     unauthorizedError();
     return(0);
   }
-
   LOG1("In Get Accessories #");
   LOG1(conNum);
   LOG1(" (");
@@ -859,22 +858,27 @@ int HAPClient::getAccessoriesURL(){
   LOG1(")...\n");
 
   int nBytes = homeSpan.sprintfAttributes(NULL);        // get size of HAP attributes JSON
-  TempBuffer <char> jBuf(nBytes+1,"HAPClient::getAccessoriesURL");
-  homeSpan.sprintfAttributes(jBuf.get());                  // create JSON database (will need to re-cast to uint8_t* below)
 
-  char *body;
+  // TempBuffer <char> jBuf(nBytes+1,"HAPClient::getAccessoriesURL");
-  asprintf(&body,"HTTP/1.1 200 OK\r\nContent-Type: application/hap+json\r\nContent-Length: %d\r\n\r\n",nBytes);
+  // homeSpan.sprintfAttributes(jBuf.get());                  // create JSON database (will need to re-cast to uint8_t* below)
 
-  LOG2("\n>>>>>>>>>> ");
+  // char *body;
-  LOG2(client.remoteIP());
+  // asprintf(&body,"HTTP/1.1 200 OK\r\nContent-Type: application/hap+json\r\nContent-Length: %d\r\n\r\n",nBytes);
-  LOG2(" >>>>>>>>>>\n");
-  LOG2(body);
-  LOG2(jBuf.get());
-  LOG2("\n");
   
-  sendEncrypted(body,(uint8_t *)jBuf.get(),nBytes);
+  // LOG2("\n>>>>>>>>>> ");
-  free(body);
+  // LOG2(client.remoteIP());
+  // LOG2(" >>>>>>>>>>\n");
+  // LOG2(body);
+  // LOG2(jBuf.get());
+  // LOG2("\n");
   
+  // sendEncrypted(body,(uint8_t *)jBuf.get(),nBytes);
+  // free(body);
+
+
+  SendEncryptedContext context(*this);
+  context.printf("HTTP/1.1 200 OK\r\nContent-Type: application/hap+json\r\nContent-Length: %d\r\n\r\n",nBytes);
+  homeSpan.sprintfAttributes(NULL, GET_VALUE|GET_META|GET_PERMS|GET_TYPE|GET_DESC, &context);
   return(1);
   
 } // getAccessories

src/HomeSpan.cpp

@@ -39,6 +39,7 @@
 
 #include "HomeSpan.h"
 #include "HAP.h"
+#include "SendEncryptedContext.h"
 
 const __attribute__((section(".rodata_custom_desc"))) SpanPartition spanPartition = {HOMESPAN_MAGIC_COOKIE,0};
 
@@ -1227,19 +1228,33 @@ Span& Span::setWifiCredentials(const char *ssid, const char *pwd){
 
 ///////////////////////////////
 
-int Span::sprintfAttributes(char *cBuf, int flags){
+int Span::sprintfAttributes(char *cBuf, int flags, SendEncryptedContext* sendEncryptedContext){
 
   int nBytes=0;
 
   nBytes+=snprintf(cBuf,cBuf?64:0,"{\"accessories\":[");
+  if (sendEncryptedContext != NULL)
+    sendEncryptedContext->print("{\"accessories\":[");
   
   for(int i=0;i<Accessories.size();i++){
-    nBytes+=Accessories[i]->sprintfAttributes(cBuf?(cBuf+nBytes):NULL,flags);    
+    SpanAccessory* accessory=Accessories[i];
-    if(i+1<Accessories.size())
+    int accessoryBytes=accessory->sprintfAttributes(cBuf?(cBuf+nBytes):NULL,flags); 
-      nBytes+=snprintf(cBuf?(cBuf+nBytes):NULL,cBuf?64:0,",");
+    nBytes+= accessoryBytes;
+    if (sendEncryptedContext != NULL)   
+    {
+      char* buffer = sendEncryptedContext->reserveStringBuffer(accessoryBytes);
+      accessory->sprintfAttributes(buffer, flags);
+    }
+    if(i+1<Accessories.size())
+    {
+      nBytes+=snprintf(cBuf?(cBuf+nBytes):NULL,cBuf?64:0,",");
+      if (sendEncryptedContext != NULL)
+        sendEncryptedContext->print(",");
+    }
   }
-    
   nBytes+=snprintf(cBuf?(cBuf+nBytes):NULL,cBuf?64:0,"]}");
+  if (sendEncryptedContext != NULL)
+    sendEncryptedContext->print("]}");  
   return(nBytes);
 }
 

src/HomeSpan.h

@@ -48,6 +48,7 @@
 #include "extras/Pixel.h"
 #include "Settings.h"
 #include "Utils.h"
+#include "SendEncryptedContext.h"
 #include "Network.h"
 #include "HAPConstants.h"
 #include "HapQR.h"
@@ -268,7 +269,7 @@ class Span{
   void resetStatus();                           // resets statusLED and calls statusCallback based on current HomeSpan status
   void reboot();                                // reboots device
 
-  int sprintfAttributes(char *cBuf, int flags=GET_VALUE|GET_META|GET_PERMS|GET_TYPE|GET_DESC);   // prints Attributes JSON database into buf, unless buf=NULL; return number of characters printed, excluding null terminator
+  int sprintfAttributes(char *cBuf, int flags=GET_VALUE|GET_META|GET_PERMS|GET_TYPE|GET_DESC, SendEncryptedContext* sendEncryptedContext = nullptr);   // prints Attributes JSON database into buf, unless buf=NULL; return number of characters printed, excluding null terminator
   
   void prettyPrint(char *buf, int nsp=2, int minLogLevel=0);              // print arbitrary JSON from buf to serial monitor, formatted with indentions of 'nsp' spaces, subject to specified minimum log level
   SpanCharacteristic *find(uint32_t aid, int iid);                        // return Characteristic with matching aid and iid (else NULL if not found)

src/SendEncryptedContext.cpp

@@ -0,0 +1,116 @@
+/*********************************************************************************
+ *  MIT License
+ *  
+ *  Copyright (c) 2020-2023 Michael Geramb
+ *  
+ *  https://github.com/HomeSpan/HomeSpan
+ *  
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be included in all
+ *  copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *  SOFTWARE.
+ *  
+ ********************************************************************************/
+
+#include <Arduino.h>
+#include "SendEncryptedContext.h"
+#include "HomeSpan.h"
+#include "HAP.h"
+#include "Settings.h"
+#include <sodium.h>
+
+SendEncryptedContext::SendEncryptedContext(HAPClient& hapClient)
+:   hapClient(hapClient),
+    stringBuffer(FRAME_SIZE + 1, "SendEncryptedContext dataBuffer"), 
+    sendBuffer(FRAME_SIZE + 2 + 16, "SendEncryptedContext sendBuffer") // FRAME_SIZE + AAD + Auth 
+{
+    LOG2("\n>>>>>>>>>> ");
+    LOG2(hapClient.client.remoteIP());
+    LOG2(" >>>>>>>>>>\n");
+}
+
+void SendEncryptedContext::printf(const char* format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    int len = vsnprintf(NULL, 0, format, ap);
+    char* buffer = reserveStringBuffer(len);
+    vsnprintf(buffer, len + 1, format, ap); // the reserved buffer is one byte larger because it contains the terminating '\0'
+    LOG2(buffer);
+    va_end(ap);
+}
+
+void SendEncryptedContext::print(const char* text)
+{
+    auto len = strlen(text);
+    auto buffer = reserveStringBuffer(len);
+    memcpy(buffer, text, len);
+    LOG2(buffer);
+}
+
+char* SendEncryptedContext::reserveStringBuffer(int stringLength)
+{
+    int requiredNewBufferLength = stringLength + 1; // reserve buffer for characters and string terminator '\0'
+    if (stringBuffer.len() - usedStringLength < requiredNewBufferLength)
+    {
+        // to less memory, send first exitsting buffer
+        if (usedStringLength > 0)
+        {
+            sendEncrypted(stringBuffer.get(), usedStringLength);
+            usedStringLength = 0;
+        }
+        // Check if still more memory is needed
+        if (stringBuffer.len() < requiredNewBufferLength)
+            stringBuffer = TempBuffer<char>(requiredNewBufferLength, "SendEncryptedContext::reserveMemory");
+    }
+    int alreadyInUse = usedStringLength;
+    usedStringLength += stringLength;
+    char* result = stringBuffer.get() + alreadyInUse;
+    result[stringLength] = '\0'; // add string terminator
+    return result;
+}
+
+void SendEncryptedContext::sendEncrypted(const char* buffer, int length)
+{
+    if (length == 0)
+        return;
+    sentLength += length;
+    LOG2(buffer);
+
+    for(int i=0;i<length;i+=FRAME_SIZE){      // encrypt FRAME_SIZE number of bytes in dataBuf in sequential frames
+
+        int n=length-i;           // number of bytes remaining
+        
+        if(n>FRAME_SIZE)           // maximum number of bytes to encrypt=FRAME_SIZE
+          n=FRAME_SIZE;                                     
+        
+        sendBuffer.get()[0]=n%256;    // store number of bytes that encrypts this frame (AAD bytes)
+        sendBuffer.get()[1]=n/256;
+
+        unsigned long long nBytes;
+        crypto_aead_chacha20poly1305_ietf_encrypt(sendBuffer.get()+2,&nBytes, (uint8_t*) buffer+i,n,sendBuffer.get(),2,NULL,hapClient.a2cNonce.get(),hapClient.a2cKey);   // encrypt the next portion of dataBuf with authentication tag appended
+
+        hapClient.client.write(sendBuffer.get(),nBytes+2);   // transmit encrypted frame
+        hapClient.a2cNonce.inc();                      // increment nonce
+    }
+}
+
+SendEncryptedContext::~SendEncryptedContext()
+{
+    if (usedStringLength > 0)
+        sendEncrypted(stringBuffer.get(), usedStringLength);
+    LOG2("-------- SENT ENCRYPTED! --------\n");
+}

src/SendEncryptedContext.h

@@ -0,0 +1,56 @@
+/*********************************************************************************
+ *  MIT License
+ *  
+ *  Copyright (c) 2020-2023 Michael Geramb
+ *  
+ *  https://github.com/HomeSpan/HomeSpan
+ *  
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be included in all
+ *  copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *  SOFTWARE.
+ *  
+ ********************************************************************************/
+
+#pragma once
+#include "Utils.h"
+
+struct HAPClient;
+
+
+/////////////////////////////////////////////////
+// SendEncryptedContext class
+// Write encrypted data as response to a web call
+
+class SendEncryptedContext
+{
+  const int FRAME_SIZE=1024;          // number of bytes to use in each ChaCha20-Poly1305 encrypted frame when sending encrypted JSON content to Client
+
+  TempBuffer<char> stringBuffer;
+  int usedStringLength = 0;
+  int sentLength = 0;
+  HAPClient& hapClient;
+  TempBuffer<uint8_t> sendBuffer;
+public:
+  SendEncryptedContext(HAPClient& hapClient);
+  ~SendEncryptedContext();
+ 
+  void printf(const char* format, ...);
+  void print(const char* text);
+  char* reserveStringBuffer(int stringLength);
+private:
+  void sendEncrypted(const char* buffer, int length);
+};