From 14ef0fb08055d312b0cd74a25b1f8487f8f3bdf6 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Thu, 15 Mar 2018 19:21:59 +0000
Subject: [PATCH] Validate the NXDN protocol in the Parrot and Gateway.

---
 NXDNGateway/IcomNetwork.cpp |  8 ++++----
 NXDNGateway/NXDNNetwork.cpp | 10 +++++++---
 NXDNParrot/Network.cpp      |  4 ++--
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/NXDNGateway/IcomNetwork.cpp b/NXDNGateway/IcomNetwork.cpp
index 6553812..757d26d 100644
--- a/NXDNGateway/IcomNetwork.cpp
+++ b/NXDNGateway/IcomNetwork.cpp
@@ -91,16 +91,16 @@ void CIcomNetwork::clock(unsigned int ms)
 	if (length <= 0)
 		return;
 
+	// Invalid packet type?
+	if (::memcmp(buffer, "ICOM", 4U) != 0)
+		return;
+
 	// Check if the data is for us
 	if (m_address.s_addr != address.s_addr || port != m_port) {
 		LogMessage("Icom packet received from an invalid source, %08X != %08X and/or %u != %u", m_address.s_addr, address.s_addr, m_port, port);
 		return;
 	}
 
-	// Invalid packet type?
-	if (::memcmp(buffer, "ICOM", 4U) != 0)
-		return;
-
 	// An Icom repeater connect request
 	if (buffer[4U] == 0x01U && buffer[5U] == 0x61U) {
 		buffer[5U]  = 0x62U;
diff --git a/NXDNGateway/NXDNNetwork.cpp b/NXDNGateway/NXDNNetwork.cpp
index 82cc886..b1b09a0 100644
--- a/NXDNGateway/NXDNNetwork.cpp
+++ b/NXDNGateway/NXDNNetwork.cpp
@@ -130,10 +130,14 @@ unsigned int CNXDNNetwork::readData(unsigned char* data, unsigned int length, in
 	if (len <= 0)
 		return 0U;
 
-	if (m_debug)
-		CUtils::dump(1U, "NXDN Network Data Received", data, len);
+	if ((::memcmp(data, "NXDNP", 5U) == 0 && len == 15) || (::memcmp(data, "NXDND", 5U) == 0 && len == 43)) {
+		if (m_debug)
+			CUtils::dump(1U, "NXDN Network Data Received", data, len);
 
-	return len;
+		return len;
+	}
+
+	return 0U;
 }
 
 void CNXDNNetwork::close()
diff --git a/NXDNParrot/Network.cpp b/NXDNParrot/Network.cpp
index 5044a91..73ad5d9 100644
--- a/NXDNParrot/Network.cpp
+++ b/NXDNParrot/Network.cpp
@@ -66,9 +66,9 @@ void CNetwork::clock(unsigned int ms)
 	m_address.s_addr = address.s_addr;
 	m_port = port;
 
-	if (::memcmp(buffer, "NXDNP", 5U) == 0) {			// A poll
+	if (::memcmp(buffer, "NXDNP", 5U) == 0 && length == 15) {			// A poll
 		write(buffer, length);
-	} else if (::memcmp(buffer, "NXDND", 5U) == 0) {
+	} else if (::memcmp(buffer, "NXDND", 5U) == 0 && length == 43) {
 		unsigned char l = length;
 		m_buffer.addData(&l, 1U);
 		m_buffer.addData(buffer, length);