From 6cc6849ccc408ee4c0366e042c14d41066d73fc5 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Fri, 12 Apr 2019 14:05:07 -0400
Subject: [PATCH] use published timestamp for blinding

---
 libi2pd/LeaseSet.cpp  | 21 +++++++++++++--------
 libi2pd/LeaseSet.h    |  2 +-
 libi2pd/Timestamp.cpp |  8 +++++++-
 libi2pd/Timestamp.h   |  1 +
 4 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/libi2pd/LeaseSet.cpp b/libi2pd/LeaseSet.cpp
index 77751cbd..38d24cdc 100644
--- a/libi2pd/LeaseSet.cpp
+++ b/libi2pd/LeaseSet.cpp
@@ -366,16 +366,21 @@ namespace data
 		SHA256_Final (hash, &ctx);
 	}
 
-	i2p::data::IdentHash BlindedPublicKey::GetStoreHash () const
+	i2p::data::IdentHash BlindedPublicKey::GetStoreHash (const char * date) const
 	{
 		i2p::data::IdentHash hash;
 		if (m_BlindedSigType == i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519 ||
 			m_BlindedSigType == SIGNING_KEY_TYPE_EDDSA_SHA512_ED25519)
 		{
-			char date[9];
-			i2p::util::GetCurrentDate (date);
 			uint8_t blinded[32];
-			GetBlindedKey (date, blinded);		
+			if (date)
+				GetBlindedKey (date, blinded);
+			else
+			{
+				char currentDate[9];
+				i2p::util::GetCurrentDate (currentDate);
+				GetBlindedKey (currentDate, blinded);	
+			}	
 			auto stA1 = htobe16 (m_BlindedSigType);
 			SHA256_CTX ctx;
 			SHA256_Init (&ctx);
@@ -605,7 +610,7 @@ namespace data
 			{
 				// verify blinding
 				char date[9];
-				i2p::util::GetCurrentDate (date);
+				i2p::util::GetDateString (m_PublishedTimestamp, date);
 				uint8_t blinded[32];
 				key->GetBlindedKey (date, blinded);
 				if (memcmp (blindedPublicKey, blinded, 32))
@@ -862,15 +867,15 @@ namespace data
 		m_Buffer = new uint8_t[m_BufferLen + 1]; 
 		m_Buffer[0] = NETDB_STORE_TYPE_ENCRYPTED_LEASESET2;
 		BlindedPublicKey blindedKey (ls->GetIdentity ());
+		auto timestamp = i2p::util::GetSecondsSinceEpoch ();	
 		char date[9];
-		i2p::util::GetCurrentDate (date);
+		i2p::util::GetDateString (timestamp, date);
 		uint8_t blindedPriv[32], blindedPub[32];
 		blindedKey.BlindPrivateKey (keys.GetSigningPrivateKey (), date, blindedPriv, blindedPub);
 		std::unique_ptr<i2p::crypto::Signer> blindedSigner (i2p::data::PrivateKeys::CreateSigner (blindedKeyType, blindedPriv));
 		auto offset = 1;
 		htobe16buf (m_Buffer + offset, blindedKeyType); offset += 2; // Blinded Public Key Sig Type
 		memcpy (m_Buffer + offset, blindedPub, 32); offset += 32; // Blinded Public Key
-		auto timestamp = i2p::util::GetSecondsSinceEpoch ();
 		htobe32buf (m_Buffer + offset, timestamp); offset += 4; // published timestamp (seconds)
 		auto nextMidnight = (timestamp/86400LL + 1)*86400LL; // 86400 = 24*3600 seconds
 		auto expirationTime = ls->GetExpirationTime ()/1000LL; 
@@ -906,7 +911,7 @@ namespace data
 		// signature
 		blindedSigner->Sign (m_Buffer, offset, m_Buffer + offset);
 		// store hash
-		m_StoreHash = blindedKey.GetStoreHash ();		
+		m_StoreHash = blindedKey.GetStoreHash (date);		
 	}
 
 	LocalEncryptedLeaseSet2::LocalEncryptedLeaseSet2 (std::shared_ptr<const IdentityEx> identity, const uint8_t * buf, size_t len):
diff --git a/libi2pd/LeaseSet.h b/libi2pd/LeaseSet.h
index ce330ba7..b68679d5 100644
--- a/libi2pd/LeaseSet.h
+++ b/libi2pd/LeaseSet.h
@@ -144,7 +144,7 @@ namespace data
 			void GetSubcredential (const uint8_t * blinded, size_t len, uint8_t * subcredential) const; // 32 bytes
 			void GetBlindedKey (const char * date, uint8_t * blindedKey) const; // blinded key 32 bytes, date is 8 chars "YYYYMMDD" 
 			void BlindPrivateKey (const uint8_t * priv, const char * date, uint8_t * blindedPriv, uint8_t * blindedPub) const; // blinded key 32 bytes, date is 8 chars "YYYYMMDD" 
-			i2p::data::IdentHash GetStoreHash () const;
+			i2p::data::IdentHash GetStoreHash (const char * date = nullptr) const; // date is 8 chars "YYYYMMDD", use current if null
 
 		private:
 
diff --git a/libi2pd/Timestamp.cpp b/libi2pd/Timestamp.cpp
index 51b6dd4e..acc9cb10 100644
--- a/libi2pd/Timestamp.cpp
+++ b/libi2pd/Timestamp.cpp
@@ -182,7 +182,13 @@ namespace util
 
 	void GetCurrentDate (char * date)
 	{
-		time_t t = time (nullptr);
+		GetDateString (GetSecondsSinceEpoch (), date);
+	}
+
+	void GetDateString (uint64_t timestamp, char * date)
+	{
+		using clock = std::chrono::system_clock;
+		auto t = clock::to_time_t (clock::time_point (std::chrono::seconds(timestamp)));
 		struct tm tm;
 #ifdef _WIN32
 		gmtime_s(&tm, &t);
diff --git a/libi2pd/Timestamp.h b/libi2pd/Timestamp.h
index 4bbcf2de..31dc86aa 100644
--- a/libi2pd/Timestamp.h
+++ b/libi2pd/Timestamp.h
@@ -16,6 +16,7 @@ namespace util
 	uint64_t GetSecondsSinceEpoch ();
 
 	void GetCurrentDate (char * date); // returns date as YYYYMMDD string, 9 bytes	
+	void GetDateString (uint64_t timestamp, char * date); // timestap is seconds since epoch, returns date as YYYYMMDD string, 9 bytes	
 
 	class NTPTimeSync
 	{