Remove time-utils #11410

vorot93 · 2020-01-27T00:39:29Z

SystemTime::checked_add and SystemTime::checked_sub have been stable since 1.34.

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README.md

niklasad1

This may cause consensus issues because that SystemTime is platform dependent. It may represent it as i64 or i32 where some platforms might cap ì32::max_value and others at i64::max_value. Thus, previously forged timestamp might become valid. That's why we kept the library, it will always cap at i32::max.

ordian · 2020-01-27T13:53:08Z

I'm not sure we should worry about https://en.wikipedia.org/wiki/Year_2038_problem for now, the code will probably change by then.

niklasad1 · 2020-01-27T15:52:54Z

I'm not sure we should worry about https://en.wikipedia.org/wiki/Year_2038_problem for now, the code will probably change by then.

I'm not referring to the 2028 year problem. I mean that a Block's timestamp is an u64 and it may be forged. So, it may cause consensus issues. Whether a node decides that i32::max_value + 10 is overflow and another one decides that it is legit on different platforms.

Still, we might have some plausibility checks on the timestamps but I'm not sure if those catches this.

vorot93 · 2020-01-27T15:57:32Z

What if a block timestamp is forged but still fits i32? This code can't catch this in any way.

niklasad1 · 2020-01-28T11:44:39Z

What if a block timestamp is forged but still fits i32? This code can't catch this in any way.

I was not talking about that just the difference between i32/i64 for SystemTime.

However, actually we check that timestamp is less than now + 15 seconds and reject timestamps further on in the future, see https://github.com/paritytech/parity-ethereum/blob/master/ethcore/verification/src/verification.rs#L339-#L364.

But still, we are doing the checked arithmetics before doing those checks so I don't think we are safe on different platforms. In practice, we should return TimestampOverflow or TemporaryInvalid in such cases because we are still a long time away from year 2028 and I'm not sure exactly on the cases in different engines such as AuRA or Clique.

If somebody can prove how we are sure I'm fine merging it.

ordian · 2020-01-28T17:25:49Z

ethcore/engines/authority-round/src/lib.rs

-			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 max = oob.max.and_then(|m| UNIX_EPOCH.checked_add(Duration::from_secs(m)));
+			let min = oob.min.and_then(|m| UNIX_EPOCH.checked_add(Duration::from_secs(m)));


for authority-round the issue of SystemTime being platform dependant doesn't really matter, since we use it in the error path here anyway.

ordian · 2020-01-28T17:30:32Z

ethcore/engines/clique/src/lib.rs

@@ -571,7 +570,7 @@ impl Engine for Clique {

 		// Don't waste time checking blocks from the future
 		{
-			let limit = CheckedSystemTime::checked_add(SystemTime::now(), Duration::from_secs(self.period))
+			let limit = SystemTime::now().checked_add(Duration::from_secs(self.period))


here it doesn't matter if we're not taking 2038 problem into account as self.period is a config param and if it's misconfigured, it's not going to work anyway

ordian · 2020-01-28T17:31:16Z

ethcore/engines/clique/src/lib.rs

@@ -581,7 +580,7 @@ impl Engine for Clique {

 			let hdr = Duration::from_secs(header.timestamp());
 			if hdr > limit_as_dur {
-				let found = CheckedSystemTime::checked_add(UNIX_EPOCH, hdr).ok_or(BlockError::TimestampOverflow)?;
+				let found = UNIX_EPOCH.checked_add(hdr).ok_or(BlockError::TimestampOverflow)?;


and here we're in the error path anyway

ordian · 2020-01-28T17:31:27Z

ethcore/engines/clique/src/lib.rs

-			let max = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(header.timestamp()));
-			let found = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(limit))
+			let max = UNIX_EPOCH.checked_add(Duration::from_secs(header.timestamp()));
+			let found = UNIX_EPOCH.checked_add(Duration::from_secs(limit))


error path again

ordian · 2020-01-28T17:49:31Z

ethcore/engines/clique/src/block_state.rs

@@ -273,7 +272,7 @@ 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 = CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(timestamp.saturating_add(period)));
+		let inturn = UNIX_EPOCH.checked_add(Duration::from_secs(timestamp.saturating_add(period)));


this is the tricky part that needs to be audited

dvdplm approved these changes Jan 27, 2020

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dvdplm requested a review from niklasad1 January 27, 2020 08:33

dvdplm added A8-looksgood 🦄 Pull request is reviewed well. M4-core ⛓ Core client code / Rust. labels Jan 27, 2020

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niklasad1 added A0-pleasereview 🤓 Pull request needs code review. and removed A8-looksgood 🦄 Pull request is reviewed well. labels Jan 27, 2020

ordian reviewed Jan 28, 2020

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vorot93 added 2 commits January 31, 2020 08:48

Remove time-utils

b80bd52

remove parity-clib reference

d53528b

vorot93 force-pushed the rm-time-utils branch from e8fd2af to d53528b Compare January 31, 2020 05:49

sorpaas added A5-grumble 🔥 Pull request has minor issues that must be addressed before merging. and removed A0-pleasereview 🤓 Pull request needs code review. labels Jul 29, 2020

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Remove time-utils #11410

Remove time-utils #11410

vorot93 commented Jan 27, 2020

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ordian Jan 28, 2020

ordian Jan 28, 2020

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ordian Jan 28, 2020

ordian Jan 28, 2020

Remove time-utils #11410

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Remove time-utils #11410

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