[Floonet] Encrypt private slate data upon storage in DB (#2189)

* xor encrypt stored nonce and blind sum in transaction data

* rustfmt

* stop doc tests splatting wallet files throughout

wallet/src/libwallet/api.rs

@@ -99,6 +99,7 @@ where
 	/// use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	///
 	/// let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	///
 	/// // A NodeClient must first be created to handle communication between
 	/// // the wallet and the node.
@@ -148,6 +149,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -203,6 +205,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -256,6 +259,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -313,6 +317,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -389,6 +394,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -462,6 +468,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(
@@ -575,6 +582,7 @@ where
 	/// # use wallet::libwallet::api::APIOwner;
 	/// # use wallet::{LMDBBackend, HTTPNodeClient, WalletBackend,  WalletConfig};
 	/// # let mut wallet_config = WalletConfig::default();
+	/// # wallet_config.data_file_dir = "test_output/doc/wallet1".to_owned();
 	/// # let node_client = HTTPNodeClient::new(&wallet_config.check_node_api_http_addr, None);
 	/// # let mut wallet:Arc<Mutex<WalletBackend<HTTPNodeClient, ExtKeychain>>> =
 	/// # Arc::new(Mutex::new(

wallet/src/lmdb_wallet.rs

@@ -26,6 +26,8 @@ use serde_json;
 use failure::ResultExt;
 use uuid::Uuid;
 
+use crate::blake2::blake2b::Blake2b;
+
 use crate::keychain::{ChildNumber, ExtKeychain, Identifier, Keychain};
 use crate::store::{self, option_to_not_found, to_key, to_key_u64};
 
@@ -35,6 +37,7 @@ use crate::libwallet::types::*;
 use crate::libwallet::{internal, Error, ErrorKind};
 use crate::types::{WalletConfig, WalletSeed};
 use crate::util;
+use crate::util::secp::constants::SECRET_KEY_SIZE;
 use crate::util::secp::pedersen;
 
 pub const DB_DIR: &'static str = "db";
@@ -62,6 +65,39 @@ pub fn wallet_db_exists(config: WalletConfig) -> bool {
 	db_path.exists()
 }
 
+/// Helper to derive XOR keys for storing private transaction keys in the DB
+/// (blind_xor_key, nonce_xor_key)
+fn private_ctx_xor_keys<K>(
+	keychain: &K,
+	slate_id: &[u8],
+) -> Result<([u8; SECRET_KEY_SIZE], [u8; SECRET_KEY_SIZE]), Error>
+where
+	K: Keychain,
+{
+	let root_key = keychain.derive_key(0, &K::root_key_id())?;
+
+	// derive XOR values for storing secret values in DB
+	// h(root_key|slate_id|"blind")
+	let mut hasher = Blake2b::new(SECRET_KEY_SIZE);
+	hasher.update(&root_key.0[..]);
+	hasher.update(&slate_id[..]);
+	hasher.update(&"blind".as_bytes()[..]);
+	let blind_xor_key = hasher.finalize();
+	let mut ret_blind = [0; SECRET_KEY_SIZE];
+	ret_blind.copy_from_slice(&blind_xor_key.as_bytes()[0..SECRET_KEY_SIZE]);
+
+	// h(root_key|slate_id|"nonce")
+	let mut hasher = Blake2b::new(SECRET_KEY_SIZE);
+	hasher.update(&root_key.0[..]);
+	hasher.update(&slate_id[..]);
+	hasher.update(&"nonce".as_bytes()[..]);
+	let nonce_xor_key = hasher.finalize();
+	let mut ret_nonce = [0; SECRET_KEY_SIZE];
+	ret_nonce.copy_from_slice(&nonce_xor_key.as_bytes()[0..SECRET_KEY_SIZE]);
+
+	Ok((ret_blind, ret_nonce))
+}
+
 pub struct LMDBBackend<C, K> {
 	db: store::Store,
 	config: WalletConfig,
@@ -232,11 +268,19 @@ where
 
 	fn get_private_context(&mut self, slate_id: &[u8]) -> Result<Context, Error> {
 		let ctx_key = to_key(PRIVATE_TX_CONTEXT_PREFIX, &mut slate_id.to_vec());
-		option_to_not_found(
+		let (blind_xor_key, nonce_xor_key) = private_ctx_xor_keys(self.keychain(), slate_id)?;
+
+		let mut ctx: Context = option_to_not_found(
 			self.db.get_ser(&ctx_key),
 			&format!("Slate id: {:x?}", slate_id.to_vec()),
-		)
+		)?;
-		.map_err(|e| e.into())
+
+		for i in 0..SECRET_KEY_SIZE {
+			ctx.sec_key.0[i] = ctx.sec_key.0[i] ^ blind_xor_key[i];
+			ctx.sec_nonce.0[i] = ctx.sec_nonce.0[i] ^ nonce_xor_key[i];
+		}
+
+		Ok(ctx)
 	}
 
 	fn acct_path_iter<'a>(&'a self) -> Box<dyn Iterator<Item = AcctPathMapping> + 'a> {
@@ -501,11 +545,21 @@ where
 		self.save(out.clone())
 	}
 
-	//TODO: Keys stored unencrypted in DB.. not good
-	// should store keys as derivation paths instead
 	fn save_private_context(&mut self, slate_id: &[u8], ctx: &Context) -> Result<(), Error> {
 		let ctx_key = to_key(PRIVATE_TX_CONTEXT_PREFIX, &mut slate_id.to_vec());
-		self.db.borrow().as_ref().unwrap().put_ser(&ctx_key, &ctx)?;
+		let (blind_xor_key, nonce_xor_key) = private_ctx_xor_keys(self.keychain(), slate_id)?;
+
+		let mut s_ctx = ctx.clone();
+		for i in 0..SECRET_KEY_SIZE {
+			s_ctx.sec_key.0[i] = s_ctx.sec_key.0[i] ^ blind_xor_key[i];
+			s_ctx.sec_nonce.0[i] = s_ctx.sec_nonce.0[i] ^ nonce_xor_key[i];
+		}
+
+		self.db
+			.borrow()
+			.as_ref()
+			.unwrap()
+			.put_ser(&ctx_key, &s_ctx)?;
 		Ok(())
 	}