fix: aura don't add `SystemTime::now()` (#10720)

This commit does the following:
- Prevent overflow in `verify_timestamp()` by not adding `now` to found faulty timestamp
- Use explicit `CheckedSystemTime::checked_add` to prevent potential consensus issues because SystemTime is platform
depedent
- remove `#[cfg(not(time_checked_add))]` conditional compilation

ethcore/src/engines/authority_round/mod.rs

@@ -22,7 +22,7 @@ use std::iter::FromIterator;
 use std::ops::Deref;
 use std::sync::atomic::{AtomicUsize, AtomicBool, Ordering as AtomicOrdering};
 use std::sync::{Weak, Arc};
-use std::time::{UNIX_EPOCH, SystemTime, Duration};
+use std::time::{UNIX_EPOCH, Duration};
 
 use block::*;
 use client::EngineClient;
@@ -42,14 +42,12 @@ use itertools::{self, Itertools};
 use rlp::{encode, Decodable, DecoderError, Encodable, RlpStream, Rlp};
 use ethereum_types::{H256, H520, Address, U128, U256};
 use parking_lot::{Mutex, RwLock};
+use time_utils::CheckedSystemTime;
 use types::BlockNumber;
 use types::header::{Header, ExtendedHeader};
 use types::ancestry_action::AncestryAction;
 use unexpected::{Mismatch, OutOfBounds};
 
-#[cfg(not(time_checked_add))]
-use time_utils::CheckedSystemTime;
-
 mod finality;
 
 /// `AuthorityRound` params.
@@ -584,10 +582,10 @@ fn verify_timestamp(step: &Step, header_step: u64) -> Result<(), BlockError> {
 			// Returning it further won't recover the sync process.
 			trace!(target: "engine", "verify_timestamp: block too early");
 
-			let now = SystemTime::now();
-			let found = now.checked_add(Duration::from_secs(oob.found)).ok_or(BlockError::TimestampOverflow)?;
-			let max = oob.max.and_then(|m| now.checked_add(Duration::from_secs(m)));
-			let min = oob.min.and_then(|m| now.checked_add(Duration::from_secs(m)));
+			let found = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(oob.found))
+				.ok_or(BlockError::TimestampOverflow)?;
+			let max = oob.max.and_then(|m| CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(m)));
+			let min = oob.min.and_then(|m| CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(m)));
 
 			let new_oob = OutOfBounds { min, max, found };
 

ethcore/src/engines/clique/block_state.rs

@@ -24,13 +24,11 @@ use engines::clique::{VoteType, DIFF_INTURN, DIFF_NOTURN, NULL_AUTHOR, SIGNING_D
 use error::{Error, BlockError};
 use ethereum_types::{Address, H64};
 use rand::Rng;
+use time_utils::CheckedSystemTime;
 use types::BlockNumber;
 use types::header::Header;
 use unexpected::Mismatch;
 
-#[cfg(not(feature = "time_checked_add"))]
-use time_utils::CheckedSystemTime;
-
 /// Type that keeps track of the state for a given vote
 // Votes that go against the proposal aren't counted since it's equivalent to not voting
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
@@ -268,7 +266,7 @@ impl CliqueBlockState {
 	// This is a quite bad API because we must mutate both variables even when already `inturn` fails
 	// That's why we can't return early and must have the `if-else` in the end
 	pub fn calc_next_timestamp(&mut self, timestamp: u64, period: u64) -> Result<(), Error> {
-		let inturn = UNIX_EPOCH.checked_add(Duration::from_secs(timestamp.saturating_add(period)));
+		let inturn = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(timestamp.saturating_add(period)));
 
 		self.next_timestamp_inturn = inturn;
 

ethcore/src/engines/clique/mod.rs

@@ -81,12 +81,10 @@ use parking_lot::RwLock;
 use rand::Rng;
 use super::signer::EngineSigner;
 use unexpected::{Mismatch, OutOfBounds};
+use time_utils::CheckedSystemTime;
 use types::BlockNumber;
 use types::header::{ExtendedHeader, Header};
 
-#[cfg(not(feature = "time_checked_add"))]
-use time_utils::CheckedSystemTime;
-
 use self::block_state::CliqueBlockState;
 use self::params::CliqueParams;
 
@@ -545,7 +543,7 @@ impl Engine<EthereumMachine> for Clique {
 
 		// Don't waste time checking blocks from the future
 		{
-			let limit = SystemTime::now().checked_add(Duration::from_secs(self.period))
+			let limit = CheckedSystemTime::checked_add(SystemTime::now(), Duration::from_secs(self.period))
 				.ok_or(BlockError::TimestampOverflow)?;
 
 			// This should succeed under the contraints that the system clock works
@@ -555,7 +553,7 @@ impl Engine<EthereumMachine> for Clique {
 
 			let hdr = Duration::from_secs(header.timestamp());
 			if hdr > limit_as_dur {
-				let found = UNIX_EPOCH.checked_add(hdr).ok_or(BlockError::TimestampOverflow)?;
+				let found = CheckedSystemTime::checked_add(UNIX_EPOCH, hdr).ok_or(BlockError::TimestampOverflow)?;
 
 				Err(BlockError::TemporarilyInvalid(OutOfBounds {
 					min: None,
@@ -666,8 +664,8 @@ impl Engine<EthereumMachine> for Clique {
 		// Ensure that the block's timestamp isn't too close to it's parent
 		let limit = parent.timestamp().saturating_add(self.period);
 		if limit > header.timestamp() {
-			let max = UNIX_EPOCH.checked_add(Duration::from_secs(header.timestamp()));
-			let found = UNIX_EPOCH.checked_add(Duration::from_secs(limit))
+			let max = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(header.timestamp()));
+			let found = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(limit))
 				.ok_or(BlockError::TimestampOverflow)?;
 
 			Err(BlockError::InvalidTimestamp(OutOfBounds {

ethcore/src/lib.rs

@@ -15,7 +15,6 @@
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
 #![warn(missing_docs, unused_extern_crates)]
-#![cfg_attr(feature = "time_checked_add", feature(time_checked_add))]
 
 //! Ethcore library
 //!
@@ -103,6 +102,7 @@ extern crate parity_util_mem as malloc_size_of;
 extern crate rustc_hex;
 extern crate serde;
 extern crate stats;
+extern crate time_utils;
 extern crate triehash_ethereum as triehash;
 extern crate unexpected;
 extern crate using_queue;
@@ -153,9 +153,6 @@ extern crate fetch;
 #[cfg(all(test, feature = "price-info"))]
 extern crate parity_runtime;
 
-#[cfg(not(time_checked_add))]
-extern crate time_utils;
-
 pub mod block;
 pub mod builtin;
 pub mod client;

ethcore/src/verification/verification.rs

@@ -40,7 +40,6 @@ use types::{BlockNumber, header::Header};
 use types::transaction::SignedTransaction;
 use verification::queue::kind::blocks::Unverified;
 
-#[cfg(not(time_checked_add))]
 use time_utils::CheckedSystemTime;
 
 /// Preprocessed block data gathered in `verify_block_unordered` call
@@ -303,7 +302,7 @@ pub fn verify_header_params(header: &Header, engine: &dyn EthEngine, is_full: bo
 		// this will resist overflow until `year 2037`
 		let max_time = SystemTime::now() + ACCEPTABLE_DRIFT;
 		let invalid_threshold = max_time + ACCEPTABLE_DRIFT * 9;
-		let timestamp = UNIX_EPOCH.checked_add(Duration::from_secs(header.timestamp()))
+		let timestamp = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(header.timestamp()))
 			.ok_or(BlockError::TimestampOverflow)?;
 
 		if timestamp > invalid_threshold {
@@ -327,9 +326,9 @@ fn verify_parent(header: &Header, parent: &Header, engine: &dyn EthEngine) -> Re
 
 	if !engine.is_timestamp_valid(header.timestamp(), parent.timestamp()) {
 		let now = SystemTime::now();
-		let min = now.checked_add(Duration::from_secs(parent.timestamp().saturating_add(1)))
+		let min = CheckedSystemTime::checked_add(now, Duration::from_secs(parent.timestamp().saturating_add(1)))
 			.ok_or(BlockError::TimestampOverflow)?;
-		let found = now.checked_add(Duration::from_secs(header.timestamp()))
+		let found = CheckedSystemTime::checked_add(now, Duration::from_secs(header.timestamp()))
 			.ok_or(BlockError::TimestampOverflow)?;
 		return Err(From::from(BlockError::InvalidTimestamp(OutOfBounds { max: None, min: Some(min), found }.into())))
 	}