Revert "Use domain-separated ChaCha20 for in-memory key encryption"

This reverts commit 921dd8dde5.

src/cryptonote_basic/account.cpp

@@ -61,8 +61,7 @@ DISABLE_VS_WARNINGS(4244 4345)
     m_device = &hwdev;
     MCDEBUG("device", "account_keys::set_device device type: "<<typeid(hwdev).name());
   }
-
-  // Generate a derived chacha key
+  //-----------------------------------------------------------------
   static void derive_key(const crypto::chacha_key &base_key, crypto::chacha_key &key)
   {
     static_assert(sizeof(base_key) == sizeof(crypto::hash), "chacha key and hash should be the same size");
@@ -71,38 +70,25 @@ DISABLE_VS_WARNINGS(4244 4345)
     data[sizeof(base_key)] = config::HASH_KEY_MEMORY;
     crypto::generate_chacha_key(data.data(), sizeof(data), key, 1);
   }
-  
-  // Prepare IVs and start chacha for encryption
-  void account_keys::encrypt_wrapper(const crypto::chacha_key &key, const bool all_keys)
+  //-----------------------------------------------------------------
+  static epee::wipeable_string get_key_stream(const crypto::chacha_key &base_key, const crypto::chacha_iv &iv, size_t bytes)
   {
-    // Set a fresh IV only for all-key encryption
-    if (all_keys)
-      m_encryption_iv = crypto::rand<crypto::chacha_iv>();
+    // derive a new key
+    crypto::chacha_key key;
+    derive_key(base_key, key);
 
-    // Now do the chacha
-    chacha_wrapper(key, all_keys);
+    // chacha
+    epee::wipeable_string buffer0(std::string(bytes, '\0'));
+    epee::wipeable_string buffer1 = buffer0;
+    crypto::chacha20(buffer0.data(), buffer0.size(), key, iv, buffer1.data());
+    return buffer1;
   }
-
-  // Start chacha for decryption
-  void account_keys::decrypt_wrapper(const crypto::chacha_key &key, const bool all_keys)
+  //-----------------------------------------------------------------
+  void account_keys::xor_with_key_stream(const crypto::chacha_key &key)
   {
-    chacha_wrapper(key, all_keys);
-  }
-
-  // Decrypt keys using the legacy method
-  void account_keys::decrypt_legacy(const crypto::chacha_key &key)
-  {
-    // Derive domain-separated chacha key
-    crypto::chacha_key derived_key;
-    derive_key(key, derived_key);
-
-    // Build key stream
-    epee::wipeable_string temp(std::string(sizeof(crypto::secret_key)*(2 + m_multisig_keys.size()), '\0'));
-    epee::wipeable_string stream = temp;
-    crypto::chacha20(temp.data(), temp.size(), derived_key, m_encryption_iv, stream.data());
-
-    // Decrypt all keys
-    const char *ptr = stream.data();
+    // encrypt a large enough byte stream with chacha20
+    epee::wipeable_string key_stream = get_key_stream(key, m_encryption_iv, sizeof(crypto::secret_key) * (2 + m_multisig_keys.size()));
+    const char *ptr = key_stream.data();
     for (size_t i = 0; i < sizeof(crypto::secret_key); ++i)
       m_spend_secret_key.data[i] ^= *ptr++;
     for (size_t i = 0; i < sizeof(crypto::secret_key); ++i)
@@ -113,39 +99,33 @@ DISABLE_VS_WARNINGS(4244 4345)
         k.data[i] ^= *ptr++;
     }
   }
-  
-  // Perform chacha on either the view key or all keys
-  void account_keys::chacha_wrapper(const crypto::chacha_key &key, const bool all_keys)
+  //-----------------------------------------------------------------
+  void account_keys::encrypt(const crypto::chacha_key &key)
   {
-    // Derive domain-seprated chacha key
-    crypto::chacha_key derived_key;
-    derive_key(key, derived_key);
-
-    // Chacha the specified keys using the appropriate IVs
-    if (all_keys)
-    {
-      // Spend key
-      crypto::secret_key temp_key;
-      chacha20((char *) &m_spend_secret_key, sizeof(crypto::secret_key), derived_key, m_encryption_iv, (char *) &temp_key);
-      memcpy(&m_spend_secret_key, &temp_key, sizeof(crypto::secret_key));
-      memwipe(&temp_key, sizeof(crypto::secret_key));
-
-      // Multisig keys
-      std::vector<crypto::secret_key> temp_keys;
-      temp_keys.reserve(m_multisig_keys.size());
-      temp_keys.resize(m_multisig_keys.size());
-      chacha20((char *) &m_multisig_keys[0], sizeof(crypto::secret_key)*m_multisig_keys.size(), derived_key, m_encryption_iv, (char *) &temp_keys[0]);
-      memcpy(&m_multisig_keys[0], &temp_keys[0], sizeof(crypto::secret_key)*temp_keys.size());
-      memwipe(&temp_keys[0], sizeof(crypto::secret_key)*temp_keys.size());
-    }
-
-    // View key
-    crypto::secret_key temp_key;
-    chacha20((char *) &m_view_secret_key, sizeof(crypto::secret_key), derived_key, m_encryption_iv, (char *) &temp_key);
-    memcpy(&m_view_secret_key, &temp_key, sizeof(crypto::secret_key));
-    memwipe(&temp_key, sizeof(crypto::secret_key));
+    m_encryption_iv = crypto::rand<crypto::chacha_iv>();
+    xor_with_key_stream(key);
   }
-
+  //-----------------------------------------------------------------
+  void account_keys::decrypt(const crypto::chacha_key &key)
+  {
+    xor_with_key_stream(key);
+  }
+  //-----------------------------------------------------------------
+  void account_keys::encrypt_viewkey(const crypto::chacha_key &key)
+  {
+    // encrypt a large enough byte stream with chacha20
+    epee::wipeable_string key_stream = get_key_stream(key, m_encryption_iv, sizeof(crypto::secret_key) * 2);
+    const char *ptr = key_stream.data();
+    ptr += sizeof(crypto::secret_key);
+    for (size_t i = 0; i < sizeof(crypto::secret_key); ++i)
+      m_view_secret_key.data[i] ^= *ptr++;
+  }
+  //-----------------------------------------------------------------
+  void account_keys::decrypt_viewkey(const crypto::chacha_key &key)
+  {
+    encrypt_viewkey(key);
+  }
+  //-----------------------------------------------------------------
   account_base::account_base()
   {
     set_null();

src/cryptonote_basic/account.h

@@ -57,15 +57,16 @@ namespace cryptonote
 
     account_keys& operator=(account_keys const&) = default;
 
-    void encrypt_wrapper(const crypto::chacha_key &key, const bool all_keys);
-    void decrypt_wrapper(const crypto::chacha_key &key, const bool all_keys);
-    void decrypt_legacy(const crypto::chacha_key &key);
+    void encrypt(const crypto::chacha_key &key);
+    void decrypt(const crypto::chacha_key &key);
+    void encrypt_viewkey(const crypto::chacha_key &key);
+    void decrypt_viewkey(const crypto::chacha_key &key);
 
     hw::device& get_device()  const ;
     void set_device( hw::device &hwdev) ;
 
   private:
-    void chacha_wrapper(const crypto::chacha_key &key, const bool all_keys);
+    void xor_with_key_stream(const crypto::chacha_key &key);
   };
 
   /************************************************************************/
@@ -99,12 +100,10 @@ namespace cryptonote
     void forget_spend_key();
     const std::vector<crypto::secret_key> &get_multisig_keys() const { return m_keys.m_multisig_keys; }
 
-    void encrypt_keys(const crypto::chacha_key &key) { m_keys.encrypt_wrapper(key, true); }
-    void encrypt_keys_same_iv(const crypto::chacha_key &key) { m_keys.decrypt_wrapper(key, true); } // encryption with the same IV is the same as decryption due to symmetry
-    void decrypt_keys(const crypto::chacha_key &key) { m_keys.decrypt_wrapper(key, true); }
-    void encrypt_viewkey(const crypto::chacha_key &key) { m_keys.encrypt_wrapper(key, false); }
-    void decrypt_viewkey(const crypto::chacha_key &key) { m_keys.decrypt_wrapper(key, false); }
-    void decrypt_legacy(const crypto::chacha_key &key) { m_keys.decrypt_legacy(key); }
+    void encrypt_keys(const crypto::chacha_key &key) { m_keys.encrypt(key); }
+    void decrypt_keys(const crypto::chacha_key &key) { m_keys.decrypt(key); }
+    void encrypt_viewkey(const crypto::chacha_key &key) { m_keys.encrypt_viewkey(key); }
+    void decrypt_viewkey(const crypto::chacha_key &key) { m_keys.decrypt_viewkey(key); }
 
     template <class t_archive>
     inline void serialize(t_archive &a, const unsigned int /*ver*/)

src/wallet/wallet2.cpp

@@ -4336,24 +4336,9 @@ bool wallet2::load_keys_buf(const std::string& keys_buf, const epee::wipeable_st
 
   if (r)
   {
-    // Decrypt keys, using one of two possible methods
     if (encrypted_secret_keys)
     {
-      // First try the updated method
       m_account.decrypt_keys(key);
-      load_info.is_legacy_key_encryption = false;
-
-      // Test address construction to see if decryption succeeded
-      const cryptonote::account_keys &keys = m_account.get_keys();
-      hw::device &hwdev = m_account.get_device();
-      if (!hwdev.verify_keys(keys.m_view_secret_key, keys.m_account_address.m_view_public_key) || !hwdev.verify_keys(keys.m_spend_secret_key, keys.m_account_address.m_spend_public_key))
-      {
-        // Updated method failed; try the legacy method
-        // Note that we must first encrypt the keys again with the same IV
-        m_account.encrypt_keys_same_iv(key);
-        m_account.decrypt_legacy(key);
-        load_info.is_legacy_key_encryption = true;
-      }
     }
     else
     {
@@ -5557,7 +5542,6 @@ void wallet2::load(const std::string& wallet_, const epee::wipeable_string& pass
 {
   clear();
   prepare_file_names(wallet_);
-  MINFO("Keys file: " << m_keys_file);
 
   // determine if loading from file system or string buffer
   bool use_fs = !wallet_.empty();

src/wallet/wallet2.h

@@ -219,15 +219,6 @@ private:
     friend class wallet_keys_unlocker;
     friend class wallet_device_callback;
   public:
-    // Contains data on how keys were loaded, primarily for unit test purposes
-    struct load_info_t {
-        bool is_legacy_key_encryption;
-    };
-
-    const load_info_t &get_load_info() const {
-        return load_info;
-    }
-
     static constexpr const std::chrono::seconds rpc_timeout = std::chrono::minutes(3) + std::chrono::seconds(30);
 
     enum RefreshType {
@@ -1417,8 +1408,6 @@ private:
     static std::string get_default_daemon_address() { CRITICAL_REGION_LOCAL(default_daemon_address_lock); return default_daemon_address; }
 
   private:
-    load_info_t load_info;
-
     /*!
      * \brief  Stores wallet information to wallet file.
      * \param  keys_file_name Name of wallet file

tests/unit_tests/account.cpp

@@ -29,30 +29,14 @@
 #include "gtest/gtest.h"
 
 #include "cryptonote_basic/account.h"
-#include "ringct/rctOps.h"
 
-// Tests in-memory encryption of account secret keys
 TEST(account, encrypt_keys)
 {
-  // Generate account keys and random multisig keys
   cryptonote::keypair recovery_key = cryptonote::keypair::generate(hw::get_device("default"));
   cryptonote::account_base account;
   crypto::secret_key key = account.generate(recovery_key.sec);
-
-  const size_t n_multisig = 4;
-  std::vector<crypto::secret_key> multisig_keys;
-  multisig_keys.reserve(n_multisig);
-  multisig_keys.resize(0);
-  for (size_t i = 0; i < n_multisig; ++i)
-  {
-    multisig_keys.push_back(rct::rct2sk(rct::skGen()));
-  }
-  ASSERT_TRUE(account.make_multisig(account.get_keys().m_view_secret_key, account.get_keys().m_spend_secret_key, account.get_keys().m_account_address.m_spend_public_key, multisig_keys));
-
   const cryptonote::account_keys keys = account.get_keys();
-  ASSERT_EQ(keys.m_multisig_keys.size(),n_multisig);
 
-  // Encrypt and decrypt keys
   ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
   ASSERT_EQ(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
   ASSERT_EQ(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
@@ -66,40 +50,22 @@ TEST(account, encrypt_keys)
   ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
   ASSERT_NE(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
   ASSERT_NE(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_NE(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
 
   account.decrypt_viewkey(chacha_key);
 
   ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
   ASSERT_NE(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
   ASSERT_EQ(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_NE(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
 
   account.encrypt_viewkey(chacha_key);
 
   ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
   ASSERT_NE(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
   ASSERT_NE(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_NE(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
-
-  account.decrypt_viewkey(chacha_key);
-
-  ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
-  ASSERT_NE(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
-  ASSERT_EQ(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_NE(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
-
-  account.encrypt_viewkey(chacha_key);
-
-  ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
-  ASSERT_NE(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
-  ASSERT_NE(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_NE(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
 
   account.decrypt_keys(chacha_key);
 
   ASSERT_EQ(account.get_keys().m_account_address, keys.m_account_address);
   ASSERT_EQ(account.get_keys().m_spend_secret_key, keys.m_spend_secret_key);
   ASSERT_EQ(account.get_keys().m_view_secret_key, keys.m_view_secret_key);
-  ASSERT_EQ(account.get_keys().m_multisig_keys, keys.m_multisig_keys);
 }

tests/unit_tests/serialization.cpp

@@ -616,46 +616,6 @@ TEST(Serialization, serializes_ringct_types)
   ASSERT_EQ(bp0, bp1);
 }
 
-TEST(Serialization, key_encryption_transition)
-{
-  const cryptonote::network_type nettype = cryptonote::TESTNET;
-  tools::wallet2 w(nettype);
-  const boost::filesystem::path wallet_file = unit_test::data_dir / "wallet_9svHk1";
-  const boost::filesystem::path key_file = unit_test::data_dir / "wallet_9svHk1.keys";
-  const boost::filesystem::path temp_wallet_file = unit_test::data_dir / "wallet_9svHk1_temp";
-  const boost::filesystem::path temp_key_file = unit_test::data_dir / "wallet_9svHk1_temp.keys";
-  string password = "test";
-  bool r = false;
-
-  // Copy the original files for this test
-  boost::filesystem::copy(wallet_file,temp_wallet_file);
-  boost::filesystem::copy(key_file,temp_key_file);
-
-  try
-  {
-    // Key transition
-    w.load(temp_wallet_file.string(), password); // legacy decryption method
-    ASSERT_TRUE(w.get_load_info().is_legacy_key_encryption);
-    const crypto::secret_key view_secret_key = w.get_account().get_keys().m_view_secret_key;
-
-    w.rewrite(temp_wallet_file.string(), password); // transition to new key format
-
-    w.load(temp_wallet_file.string(), password); // new decryption method
-    ASSERT_FALSE(w.get_load_info().is_legacy_key_encryption);
-    ASSERT_EQ(w.get_account().get_keys().m_view_secret_key,view_secret_key);
-
-    r = true;
-  }
-  catch (const exception& e)
-  {}
-
-  // Remove the temporary files
-  boost::filesystem::remove(temp_wallet_file);
-  boost::filesystem::remove(temp_key_file);
-
-  ASSERT_TRUE(r);
-}
-
 TEST(Serialization, portability_wallet)
 {
   const cryptonote::network_type nettype = cryptonote::TESTNET;