Fix buffer overflow errors

+remove dynamic memory allocation
+memset the rest of the data structure after read

node/main/main.ino

@@ -13,8 +13,6 @@ XBeeWrapper xbee = XBeeWrapper();
 // ACTUAL DATA
 unsigned long time;
 Node myself = Node();
-Packet recv = Packet();
-Packet send = Packet();
 
 void setup() {
 	Serial.begin(38400);
@@ -36,6 +34,7 @@ void loop() {
 	}
 
 	/* [2] Listen for incoming data */
+  Packet recv;
 	if( xbee.receive(recv) != XBWRECV_OK )
 		return;
 
@@ -43,11 +42,11 @@ void loop() {
 
 	// 1. manage discover request
 	if( opcode == OPCODE_DISCOVER )
-		return manage_discover();
+		return manage_discover(recv);
 
 	// 2. manage message data
 	else if( opcode == OPCODE_MESSAGE )
-		return manage_message();
+		return manage_message(recv);
 
 
 }
@@ -55,6 +54,7 @@ void loop() {
 void send_data(){
 	Serial.println(" -> message");
 	// 1. prepare message
+  Packet send;
 	send.setOpcode(OPCODE_MESSAGE);
 	send.setSender(SENDERID);
 	send.setDist(myself.getDist());
@@ -66,15 +66,15 @@ void send_data(){
 	// 2. broadcast
 	xbee.broadcast(send);
 
-	// 2. debug
-	screen.clear();
-	screen.printfn(0, "msg[%3d/%3d] %3d", send.getDist(), send.getTTL(), send.getSize());
-	screen.printfn_overflow(1, "%s", (char*) send.getData());
-	delay(500);
+ // 2. debug
+  screen.clear();
+  screen.printfn(0, "msg[%3d/%3d] %3d", send.getDist(), send.getTTL(), send.getSize());
+  screen.printfn_overflow(1, "%s", (char*) send.getData());
+  delay(500);
 }
 
 
-void manage_discover(){
+void manage_discover(Packet recv){
 	Serial.print(" <- discover[ ");
 	Serial.print(recv.getDist());
 	Serial.print(" / ");
@@ -91,6 +91,7 @@ void manage_discover(){
 	}
 
 	// propagate wave
+  Packet send;
 	send.setOpcode(OPCODE_DISCOVER);
 	send.setWave(myself.getWave());
 	send.setDist(myself.getDist());
@@ -99,7 +100,7 @@ void manage_discover(){
 	xbee.broadcast(send);
 }
 
-void manage_message(){
+void manage_message(Packet recv){
 	if( recv.getTTL() <= 0 )
 		return;
 

packet.cpp

@@ -1,11 +1,6 @@
 #include "packet.h"
 
-Packet::Packet(){
-	msg.data = malloc(1 * sizeof(char));
-}
-Packet::~Packet(){
-	free(msg.data);
-}
+
 /* PUBLIC
 ----------------------------------------*/
 // builds a packet from raw data and returns the error code
@@ -51,13 +46,12 @@ uint8_t Packet::getSize()           { return msg.size; }
 
 uint8_t* Packet::getData(){ return msg.data; }
 void Packet::setData(uint8_t *buffer) {
-	if( strlen(buffer) >= 255 )
+	if( strlen(buffer) >= MESSAGE_MAX_PAYLOAD )
 		return;
 
 	msg.size = strlen(buffer);
 
-	resizeMessage();
-	strcpy(msg.data, buffer);
+	strncpy(msg.data, buffer, MESSAGE_MAX_PAYLOAD);
 }
 
 
@@ -88,7 +82,7 @@ size_t Packet::write_discover(uint8_t *buf){
 
 uint8_t Packet::read_message(uint8_t *buf, const size_t size){
 	// 1. fail on invalid size
-	if( size < MESSAGE_MIN_SIZE || size > MESSAGE_MAX_SIZE )
+	if( size < PROTO_MIN_SIZE || size > PROTO_SIZE )
 		return PKTREAD_INVALID_MESSAGE_FORMAT;
 
 	// 2. fill values
@@ -102,9 +96,12 @@ uint8_t Packet::read_message(uint8_t *buf, const size_t size){
 	if( size - 5 != msg.size )
 		return PKTREAD_INVALID_MESSAGE_FORMAT;
 
-	// 4. extract message
-	resizeMessage();
+  // 4. memset data
+  //memset(msg.data,0,MESSAGE_MAX_PAYLOAD);  
+
+	// 5. extract message
 	strncpy(msg.data, buf+5, msg.size);
+  memset(msg.data+msg.size,0,MESSAGE_MAX_PAYLOAD-msg.size);
 
 	return PKTREAD_OK;
 };
@@ -116,8 +113,7 @@ size_t Packet::write_message(uint8_t *buf){
 	buf[3] = msg.ttl;
 	buf[4] = msg.size;
 
-	buf = realloc(buf, (5+msg.size+1)* sizeof(uint8_t));
-	strncpy(buf+5, msg.data, msg.size);
+	strncpy(buf+5, msg.data, MESSAGE_MAX_PAYLOAD);
 
 	return 5 + msg.size;
 };

packet.h

@@ -27,14 +27,13 @@
 
 		public:
      
-			Packet();
-			~Packet();
 			// builds a packet from raw data and returns the status code
 			uint8_t read(uint8_t* buf, const size_t size);
 
 			// writes the binary representation of the packet returns the size
 			size_t write(uint8_t* buf);
      
+
 			// GETTERS / SETTERS
 			uint8_t getOpcode();
 			void setOpcode(uint8_t value);
@@ -56,11 +55,6 @@
 			uint8_t* getData();
 			void setData(uint8_t *buffer);
 
-		protected:
-			resizeMessage(){
-				msg.data = realloc(msg.data, (msg.size+1) * sizeof(uint8_t));
-				memset(msg.data, 0, msg.size+1);
-			}
 
 	};
 

protocol.h

@@ -18,21 +18,19 @@
 		uint8_t dist;   // current node's distance
 	};
 
+  #define MESSAGE_MAX_PAYLOAD 255
+  #define PROTO_MIN_SIZE 5 * sizeof(uint8_t)
+	#define PROTO_SIZE (5 + MESSAGE_MAX_PAYLOAD) * sizeof(uint8_t)
   
-	#define MESSAGE_MIN_SIZE sizeof(uint8_t)*5
-	#define MESSAGE_MAX_SIZE (5 + 255) * sizeof(uint8_t)
 	struct message {
 		uint8_t opcode; // opcode = 1
 		uint8_t sender; // sender id
 		uint8_t dist;   // distance of the last sender
 		uint8_t ttl;    // time to live default = 10
 		uint8_t size;   // size of message in bytes
-		uint8_t *data;  // actual message
+		uint8_t data[MESSAGE_MAX_PAYLOAD];  // actual message
 	};
 
-	#define PROTO_SIZE       MESSAGE_MAX_SIZE
-
-
 	class Node{
 		private:
 			uint8_t wave = 0;

xbee_wrapper.cpp

@@ -49,14 +49,13 @@ uint8_t XBeeWrapper::broadcast(Packet& pkt){
 	XBeeAddress64 bcast = XBeeAddress64(0x00000000, 0x0000FFFF);
 
 	// build payload from packet
-	uint8_t* payload = malloc(6 * sizeof(uint8_t));
+	uint8_t payload[PROTO_SIZE];
+  memset(payload,0,PROTO_SIZE);
 	size_t payload_size = pkt.write(payload);
 
 	// send
 	Tx64Request tx = Tx64Request(bcast, payload, payload_size);
 	xbee.send(tx);
 
-	free(payload);
-
 	return XBWSEND_OK;
 };