From d3062d29942a82cccc94905ad49464f7f2def965 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Thu, 25 Jul 2024 20:36:46 -0400
Subject: [PATCH] don't create full identity from buffer if only ident hash is
 needed

---
 libi2pd/Identity.cpp    |  8 ++++++++
 libi2pd/Identity.h      |  2 ++
 libi2pd_client/I2CP.cpp | 11 ++++++-----
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/libi2pd/Identity.cpp b/libi2pd/Identity.cpp
index 4168abb7..2b8b454e 100644
--- a/libi2pd/Identity.cpp
+++ b/libi2pd/Identity.cpp
@@ -420,6 +420,14 @@ namespace data
 		return CreateEncryptor (GetCryptoKeyType (), key);
 	}
 
+	size_t GetIdentityBufferLen (const uint8_t * buf, size_t len)
+	{
+		if (len < DEFAULT_IDENTITY_SIZE) return 0;
+		size_t l = DEFAULT_IDENTITY_SIZE + bufbe16toh (buf + DEFAULT_IDENTITY_SIZE - 2);
+		if (l > len) return 0;
+		return l;
+	}	
+		
 	PrivateKeys& PrivateKeys::operator=(const Keys& keys)
 	{
 		m_Public = std::make_shared<IdentityEx>(Identity (keys));
diff --git a/libi2pd/Identity.h b/libi2pd/Identity.h
index 9ff4b4ae..5edd4545 100644
--- a/libi2pd/Identity.h
+++ b/libi2pd/Identity.h
@@ -136,6 +136,8 @@ namespace data
 			uint8_t m_ExtendedBuffer[MAX_EXTENDED_BUFFER_SIZE];
 	};
 
+	size_t GetIdentityBufferLen (const uint8_t * buf, size_t len); // return actual identity length in buffer
+
 	class PrivateKeys // for eepsites
 	{
 		public:
diff --git a/libi2pd_client/I2CP.cpp b/libi2pd_client/I2CP.cpp
index 8f677203..4ed56f05 100644
--- a/libi2pd_client/I2CP.cpp
+++ b/libi2pd_client/I2CP.cpp
@@ -777,11 +777,12 @@ namespace client
 			size_t offset = 2;
 			if (m_Destination)
 			{
-				i2p::data::IdentityEx identity;
-				size_t identsize = identity.FromBuffer (buf + offset, len - offset);
-				if (identsize)
+				size_t identSize = i2p::data::GetIdentityBufferLen (buf + offset, len - offset);
+				if (identSize)
 				{
-					offset += identsize;
+					i2p::data::IdentHash identHash;
+					SHA256(buf + offset, identSize, identHash); // caclulate ident hash, because we don't need full identity
+					offset += identSize;
 					uint32_t payloadLen = bufbe32toh (buf + offset);
 					if (payloadLen + offset <= len)
 					{
@@ -791,7 +792,7 @@ namespace client
 						{	
 							if (m_IsSendAccepted)
 								SendMessageStatusMessage (nonce, eI2CPMessageStatusAccepted); // accepted
-							m_Destination->SendMsgTo (buf + offset, payloadLen, identity.GetIdentHash (), nonce);
+							m_Destination->SendMsgTo (buf + offset, payloadLen, identHash, nonce);
 						}	
 						else
 							SendMessageStatusMessage (nonce, eI2CPMessageStatusNoLocalTunnels);