From f7e4afc2827d285b66fb570f82f411bd6f9b94bb Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Thu, 9 Aug 2018 15:47:02 -0400
Subject: [PATCH] use same buffer for input and output for
 AEAD/Chacha20/Poly1305

---
 libi2pd/Crypto.cpp | 18 ++++++++++++++----
 libi2pd/NTCP2.cpp  |  6 ++----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/libi2pd/Crypto.cpp b/libi2pd/Crypto.cpp
index 0a9093a2..3f214b0e 100644
--- a/libi2pd/Crypto.cpp
+++ b/libi2pd/Crypto.cpp
@@ -1018,9 +1018,6 @@ namespace crypto
 		uint8_t polyKey[64];
 		memset(polyKey, 0, sizeof(polyKey));
 		chacha20 (polyKey, 64, nonce, key, 0);
-		// encrypt data
-		memcpy (buf, msg, msgLen);
-		chacha20 (buf, msgLen, nonce, key, 1);
 
 		// create Poly1305 message
 		if (!ad) adLen = 0;
@@ -1038,7 +1035,20 @@ namespace crypto
 				memcpy (polyMsg.data () + offset, padding, rem); offset += rem;
 			}
 		}
-		memcpy (polyMsg.data () + offset, encrypt ? buf : msg, msgLen); offset += msgLen; // encrypted data
+		// encrypt/decrypt data and add to hash
+		memcpy (buf, msg, msgLen);
+		if (encrypt)
+		{
+			chacha20 (buf, msgLen, nonce, key, 1); // encrypt
+			memcpy (polyMsg.data () + offset, buf, msgLen); // after encryption
+		}
+		else
+		{
+			memcpy (polyMsg.data () + offset, buf, msgLen); // before decryption
+			chacha20 (buf, msgLen, nonce, key, 1); // decrypt
+		}	
+		offset += msgLen; // encrypted data
+
 		auto rem = msgLen & 0x0F; // %16
 		if (rem)
 		{
diff --git a/libi2pd/NTCP2.cpp b/libi2pd/NTCP2.cpp
index 6f524920..91b897f5 100644
--- a/libi2pd/NTCP2.cpp
+++ b/libi2pd/NTCP2.cpp
@@ -697,11 +697,10 @@ namespace transport
 			i2p::transport::transports.UpdateReceivedBytes (bytes_transferred);
 			uint8_t nonce[12];
 			CreateNonce (m_ReceiveSequenceNumber, nonce); m_ReceiveSequenceNumber++;
-			uint8_t * decrypted = new uint8_t[m_NextReceivedLen];
-			if (i2p::crypto::AEADChaCha20Poly1305 (m_NextReceivedBuffer, m_NextReceivedLen-16, nullptr, 0, m_ReceiveKey, nonce, decrypted, m_NextReceivedLen, false))
+			if (i2p::crypto::AEADChaCha20Poly1305 (m_NextReceivedBuffer, m_NextReceivedLen-16, nullptr, 0, m_ReceiveKey, nonce, m_NextReceivedBuffer, m_NextReceivedLen, false))
 			{	
 				LogPrint (eLogDebug, "NTCP2: received message decrypted");
-				ProcessNextFrame (decrypted, m_NextReceivedLen-16);
+				ProcessNextFrame (m_NextReceivedBuffer, m_NextReceivedLen-16);
 				delete[] m_NextReceivedBuffer; m_NextReceivedBuffer = nullptr; // we don't need received buffer anymore
 				ReceiveLength ();
 			}
@@ -710,7 +709,6 @@ namespace transport
 				LogPrint (eLogWarning, "NTCP2: Received AEAD verification failed ");
 				SendTerminationAndTerminate (eNTCP2DataPhaseAEADFailure);
 			}	
-			delete[] decrypted;
 		}
 	}