replace memzero with zeroize crate (#10816)

* [whisper] replace memzero with zeroize

* [ethkey] replace memzero with zeroize

accounts/ethkey/Cargo.toml

@@ -11,11 +11,11 @@ eth-secp256k1 = { git = "https://github.com/paritytech/rust-secp256k1" }
 ethereum-types = "0.6.0"
 lazy_static = "1.0"
 log = "0.4"
-parity-util-mem = "0.1"
 parity-wordlist = "1.2"
 quick-error = "1.2.2"
 rand = "0.6"
 rustc-hex = "1.0"
 serde = "1.0"
 serde_derive = "1.0"
 tiny-keccak = "1.4"
+zeroize = "0.9.1"

accounts/ethkey/src/lib.rs

@@ -19,7 +19,6 @@
 extern crate edit_distance;
 extern crate parity_crypto;
 extern crate ethereum_types;
-extern crate parity_util_mem;
 extern crate parity_wordlist;
 #[macro_use]
 extern crate quick_error;
@@ -28,6 +27,7 @@ extern crate rustc_hex;
 extern crate secp256k1;
 extern crate serde;
 extern crate tiny_keccak;
+extern crate zeroize;
 
 #[macro_use]
 extern crate lazy_static;

accounts/ethkey/src/secret.rs

@@ -21,17 +21,23 @@ use rustc_hex::ToHex;
 use secp256k1::constants::{SECRET_KEY_SIZE as SECP256K1_SECRET_KEY_SIZE};
 use secp256k1::key;
 use ethereum_types::H256;
-use parity_util_mem::Memzero;
+use zeroize::Zeroize;
 use {Error, SECP256K1};
 
 #[derive(Clone, PartialEq, Eq)]
 pub struct Secret {
-	inner: Memzero<H256>,
+	inner: H256,
+}
+
+impl Drop for Secret {
+	fn drop(&mut self) {
+		self.inner.0.zeroize()
+	}
 }
 
 impl ToHex for Secret {
 	fn to_hex(&self) -> String {
-		format!("{:x}", *self.inner)
+		format!("{:x}", self.inner)
 	}
 }
 
@@ -61,12 +67,12 @@ impl Secret {
 		}
 		let mut h = H256::zero();
 		h.as_bytes_mut().copy_from_slice(&key[0..32]);
-		Some(Secret { inner: Memzero::from(h) })
+		Some(Secret { inner: h })
 	}
 
 	/// Creates zero key, which is invalid for crypto operations, but valid for math operation.
 	pub fn zero() -> Self {
-		Secret { inner: Memzero::from(H256::zero()) }
+		Secret { inner: H256::zero() }
 	}
 
 	/// Imports and validates the key.
@@ -214,7 +220,7 @@ impl FromStr for Secret {
 
 impl From<[u8; 32]> for Secret {
 	fn from(k: [u8; 32]) -> Self {
-		Secret { inner: Memzero::from(H256(k)) }
+		Secret { inner: H256(k) }
 	}
 }
 

whisper/Cargo.toml

@@ -30,3 +30,4 @@ time-utils = { path = "../util/time-utils" }
 jsonrpc-core = "10.0.1"
 jsonrpc-derive = "10.0.2"
 jsonrpc-pubsub = "10.0.1"
+zeroize = "0.9.1"

whisper/src/lib.rs

@@ -35,6 +35,7 @@ extern crate serde;
 extern crate slab;
 extern crate smallvec;
 extern crate tiny_keccak;
+extern crate zeroize;
 
 extern crate jsonrpc_core;
 extern crate jsonrpc_derive;

whisper/src/rpc/crypto.rs

@@ -20,7 +20,7 @@ use aes_gcm::{Encryptor, Decryptor};
 use ethkey::crypto::ecies;
 use ethereum_types::H256;
 use ethkey::{self, Public, Secret};
-use parity_util_mem::Memzero;
+use zeroize::Zeroizing;
 
 /// Length of AES key
 pub const AES_KEY_LEN: usize = 32;
@@ -37,7 +37,7 @@ enum AesEncode {
 }
 
 enum EncryptionInner {
-	AES(Memzero<[u8; AES_KEY_LEN]>, [u8; AES_NONCE_LEN], AesEncode),
+	AES(Zeroizing<[u8; AES_KEY_LEN]>, [u8; AES_NONCE_LEN], AesEncode),
 	ECIES(Public),
 }
 
@@ -59,15 +59,15 @@ impl EncryptionInstance {
 	///
 	/// If generating nonces with a secure RNG, limit uses such that
 	/// the chance of collision is negligible.
-	pub fn aes(key: Memzero<[u8; AES_KEY_LEN]>, nonce: [u8; AES_NONCE_LEN]) -> Self {
+	pub fn aes(key: Zeroizing<[u8; AES_KEY_LEN]>, nonce: [u8; AES_NONCE_LEN]) -> Self {
 		EncryptionInstance(EncryptionInner::AES(key, nonce, AesEncode::AppendedNonce))
 	}
 
 	/// Broadcast encryption for the message based on the given topics.
 	///
 	/// Key reuse here is extremely dangerous. It should be randomly generated
 	/// with a secure RNG.
-	pub fn broadcast(key: Memzero<[u8; AES_KEY_LEN]>, topics: Vec<H256>) -> Self {
+	pub fn broadcast(key: Zeroizing<[u8; AES_KEY_LEN]>, topics: Vec<H256>) -> Self {
 		EncryptionInstance(EncryptionInner::AES(key, BROADCAST_IV, AesEncode::OnTopics(topics)))
 	}
 
@@ -111,7 +111,7 @@ fn xor(a: &mut [u8; 32], b: &[u8; 32]) {
 }
 
 enum AesExtract {
-	AppendedNonce(Memzero<[u8; AES_KEY_LEN]>), // extract appended nonce.
+	AppendedNonce(Zeroizing<[u8; AES_KEY_LEN]>), // extract appended nonce.
 	OnTopics(usize, usize, H256), // number of topics, index we know, topic we know.
 }
 
@@ -132,7 +132,7 @@ impl DecryptionInstance {
 	}
 
 	/// 256-bit AES GCM decryption with appended nonce.
-	pub fn aes(key: Memzero<[u8; AES_KEY_LEN]>) -> Self {
+	pub fn aes(key: Zeroizing<[u8; AES_KEY_LEN]>) -> Self {
 		DecryptionInstance(DecryptionInner::AES(AesExtract::AppendedNonce(key)))
 	}
 
@@ -167,7 +167,7 @@ impl DecryptionInstance {
 						}
 						let mut salted_topic = H256::zero();
 						salted_topic.as_bytes_mut().copy_from_slice(&ciphertext[(known_index * 32)..][..32]);
-						let key = Memzero::from((salted_topic ^ known_topic).0);
+						let key = Zeroizing::new((salted_topic ^ known_topic).0);
 						let offset = num_topics * 32;
 						Decryptor::aes_256_gcm(&*key).ok()?
 							.decrypt(&BROADCAST_IV, Vec::from(&ciphertext[offset..]))
@@ -187,6 +187,7 @@ impl DecryptionInstance {
 mod tests {
 	use super::*;
 	use rand::{Rng, rngs::OsRng};
+	use std::ops::Deref;
 
 
 	#[test]
@@ -217,9 +218,9 @@ mod tests {
 	fn encrypt_symmetric() {
 		let mut rng = OsRng::new().unwrap();
 		let mut test_message = move |message: &[u8]| {
-			let key = Memzero::from(rng.gen::<[u8; 32]>());
+			let key = Zeroizing::new(rng.gen::<[u8; 32]>());
 
-			let instance = EncryptionInstance::aes(key.clone(), rng.gen());
+			let instance = EncryptionInstance::aes(Zeroizing::new(*key.deref()), rng.gen());
 			let ciphertext = instance.encrypt(message).unwrap();
 
 			if !message.is_empty() {
@@ -245,7 +246,7 @@ mod tests {
 			let all_topics = (0..5).map(|_| H256::random_using(&mut rng)).collect::<Vec<_>>();
 			let known_idx = 2;
 			let known_topic = all_topics[2];
-			let key = Memzero::from(rng.gen::<[u8; 32]>());
+			let key = Zeroizing::new(rng.gen::<[u8; 32]>());
 
 			let instance = EncryptionInstance::broadcast(key, all_topics);
 			let ciphertext = instance.encrypt(message).unwrap();

whisper/src/rpc/key_store.rs

@@ -23,7 +23,8 @@ use std::collections::HashMap;
 
 use ethereum_types::H256;
 use ethkey::{KeyPair, Public, Secret};
-use parity_util_mem::Memzero;
+use zeroize::Zeroizing;
+use std::ops::Deref;
 use rand::{Rng, rngs::OsRng};
 
 use rpc::crypto::{AES_KEY_LEN, EncryptionInstance, DecryptionInstance};
@@ -35,7 +36,7 @@ pub enum Key {
 	/// and signing.
 	Asymmetric(KeyPair),
 	/// AES-256 GCM mode. Suitable for encryption, decryption, but not signing.
-	Symmetric(Memzero<[u8; AES_KEY_LEN]>),
+	Symmetric(Zeroizing<[u8; AES_KEY_LEN]>),
 }
 
 impl Key {
@@ -49,7 +50,7 @@ impl Key {
 
 	/// Generate a random symmetric key with the given cryptographic RNG.
 	pub fn new_symmetric(rng: &mut OsRng) -> Self {
-		Key::Symmetric(Memzero::from(rng.gen::<[u8; 32]>()))
+		Key::Symmetric(Zeroizing::new(rng.gen::<[u8; 32]>()))
 	}
 
 	/// From secret asymmetric key. Fails if secret is invalid.
@@ -59,7 +60,7 @@ impl Key {
 
 	/// From raw symmetric key.
 	pub fn from_raw_symmetric(key: [u8; AES_KEY_LEN]) -> Self {
-		Key::Symmetric(Memzero::from(key))
+		Key::Symmetric(Zeroizing::new(key))
 	}
 
 	/// Get a handle to the public key if this is an asymmetric key.
@@ -138,7 +139,7 @@ impl KeyStore {
 				.map_err(|_| "could not create encryption instance for id"),
 			Key::Symmetric(ref key) =>
 				 OsRng::new()
-					.map(|mut rng| EncryptionInstance::aes(key.clone(), rng.gen()))
+					.map(|mut rng| EncryptionInstance::aes(Zeroizing::new(*key.deref()), rng.gen()))
 				 	.map_err(|_| "unable to get secure randomness")
 		})
 	}
@@ -149,7 +150,7 @@ impl KeyStore {
 		self.get(id).map(|key| match *key {
 			Key::Asymmetric(ref pair) => DecryptionInstance::ecies(pair.secret().clone())
 				.expect("all keys stored are valid; qed"),
-			Key::Symmetric(ref key) => DecryptionInstance::aes(key.clone()),
+			Key::Symmetric(ref key) => DecryptionInstance::aes(Zeroizing::new(*key.deref())),
 		})
 	}
 

whisper/src/rpc/mod.rs

@@ -28,7 +28,7 @@ use jsonrpc_derive::rpc;
 use jsonrpc_pubsub::{Session, PubSubMetadata, SubscriptionId, typed::Subscriber};
 
 use ethereum_types::H256;
-use parity_util_mem::Memzero;
+use zeroize::Zeroizing;
 use parking_lot::RwLock;
 
 use self::filter::Filter;
@@ -284,7 +284,7 @@ impl<P: PoolHandle + 'static, M: Send + Sync + 'static> Whisper for WhisperClien
 				let mut rng = OsRng::new()
 					.map_err(|_| whisper_error("unable to acquire secure randomness"))?;
 
-				let key = Memzero::from(rng.gen::<[u8; 32]>());
+				let key = Zeroizing::new(rng.gen::<[u8; 32]>());
 				if req.topics.is_empty() {
 					return Err(whisper_error("must supply at least one topic for broadcast message"));
 				}