Added SHA-384 hash computation to HapOut

Hashing of entire database is now done piecemeal within HapOut, preventing the need to load the entire database into a large buffer just to obtain a unique hash.

Modified updateDatabase() to use HapOut.getHash()

src/HAP.cpp

@@ -913,24 +913,6 @@ int HAPClient::getAccessoriesURL(){
 
   LOG2("\n-------- SENT ENCRYPTED! --------\n");
          
-
-//  int nBytes = homeSpan.sprintfAttributes(NULL);        // get size of HAP attributes JSON
-//  TempBuffer<char> jBuf(nBytes+1);
-//  homeSpan.sprintfAttributes(jBuf);                  // create JSON database (will need to re-cast to uint8_t* below)
-
-//  char *body;
-//  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(client.remoteIP());
-//  LOG2(" >>>>>>>>>>\n");
-//  LOG2(body);
-//  LOG2(jBuf.get());
-//  LOG2("\n");
-  
-//  sendEncrypted(body,(uint8_t *)jBuf.get(),nBytes);
-//  free(body);
-         
   return(1);
   
 } // getAccessories
@@ -1650,6 +1632,12 @@ HapOut::HapStreamBuffer::HapStreamBuffer(){
 
   buffer=(char *)HS_MALLOC(bufSize+1);                                          // add 1 for adding null terminator when printing text
   encBuf=(uint8_t *)HS_MALLOC(bufSize+18);                                      // 2-byte AAD + encrypted data + 16-byte authentication tag
+  
+  hash=(uint8_t *)HS_MALLOC(48);                                                // space for SHA-384 hash output
+  ctx = (mbedtls_sha512_context *)HS_MALLOC(sizeof(mbedtls_sha512_context));    // space for hash context
+  mbedtls_sha512_init(ctx);                                                     // initialize context
+  mbedtls_sha512_starts_ret(ctx,1);                                             // start SHA-384 hash (note second argument=1)
+  
   setp(buffer, buffer+bufSize-1);
 }
 
@@ -1670,7 +1658,7 @@ void HapOut::HapStreamBuffer::flushBuffer(){
   byteCount+=num;
 
   if(logLevel<=homeSpan.getLogLevel()){
-    buffer[num]='\0';
+    buffer[num]='\0';                             // add null terminator but DO NOT increment num (we don't want terminator considered as part of buffer)
     Serial.print(buffer);
   }
   
@@ -1687,11 +1675,12 @@ void HapOut::HapStreamBuffer::flushBuffer(){
       hapClient->client.write(encBuf,num+18);     // transmit encrypted frame
       hapClient->a2cNonce.inc();                  // increment nonce
     }
-
     delay(1);
   }
 
-  pbump(-num);
+  mbedtls_sha512_update_ret(ctx,(uint8_t *)buffer,num);   // update hash
+
+  pbump(-num);                                            // reset buffer pointers
 }
 
 //////////////////////////////////////
@@ -1718,6 +1707,9 @@ int HapOut::HapStreamBuffer::sync(){
   enablePrettyPrint=false;
   byteCount=0;
 
+  mbedtls_sha512_finish_ret(ctx,hash);    // finish SHA-384 and store hash
+  mbedtls_sha512_starts_ret(ctx,1);       // re-start hash for next time
+
   return(0);
 }
  

src/HAP.h

@@ -195,6 +195,8 @@ class HapOut : public std::ostream {
     int logLevel=255;                     // default is NOT to print anything
     boolean enablePrettyPrint=false;
     size_t byteCount=0;
+    uint8_t *hash;
+    mbedtls_sha512_context *ctx;
   
     void flushBuffer();
     int_type overflow(int_type c) override;
@@ -215,6 +217,7 @@ class HapOut : public std::ostream {
   HapOut& setLogLevel(int logLevel){hapBuffer.logLevel=logLevel;return(*this);}
   HapOut& prettyPrint(){hapBuffer.enablePrettyPrint=true;hapBuffer.logLevel=0;return(*this);}
   
+  uint8_t *getHash(){return(hapBuffer.hash);}
   size_t getSize(){return(hapBuffer.getSize());}
 };
 

src/HomeSpan.cpp

@@ -1619,15 +1619,13 @@ int Span::sprintfAttributes(char **ids, int numIDs, int flags, char *cBuf){
 
 boolean Span::updateDatabase(boolean updateMDNS){
 
-  uint8_t tHash[48];
+  printfAttributes(GET_META|GET_PERMS|GET_TYPE|GET_DESC);   // stream attributes database, which automtically produces a SHA-384 hash
-  TempBuffer<char> tBuf(sprintfAttributes(NULL,GET_META|GET_PERMS|GET_TYPE|GET_DESC)+1);
+  hapOut.flush();  
-  sprintfAttributes(tBuf,GET_META|GET_PERMS|GET_TYPE|GET_DESC);  
-  mbedtls_sha512_ret((uint8_t *)tBuf.get(),tBuf.len(),tHash,1);     // create SHA-384 hash of JSON (can be any hash - just looking for a unique key)
 
   boolean changed=false;
 
-  if(memcmp(tHash,hapConfig.hashCode,48)){           // if hash code of current HAP database does not match stored hash code
+  if(memcmp(hapOut.getHash(),hapConfig.hashCode,48)){       // if hash code of current HAP database does not match stored hash code
-    memcpy(hapConfig.hashCode,tHash,48);             // update stored hash code
+    memcpy(hapConfig.hashCode,hapOut.getHash(),48);         // update stored hash code
     hapConfig.configNumber++;                               // increment configuration number
     if(hapConfig.configNumber==65536)                       // reached max value
       hapConfig.configNumber=1;                             // reset to 1

src/src.ino

@@ -27,13 +27,13 @@
 
 #include "HomeSpan.h"
 
-#define MAX_LIGHTS  3
+#define MAX_LIGHTS  4
 
 void setup() {
  
   Serial.begin(115200);
 
-  homeSpan.setLogLevel(2);
+  homeSpan.setLogLevel(0);
   homeSpan.enableWebLog(200);
 
   homeSpan.begin(Category::Lighting,"HomeSpan Max");