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ethcore: fix pow difficulty validation #9328

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1 change: 1 addition & 0 deletions Cargo.lock

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11 changes: 6 additions & 5 deletions ethash/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,14 @@ authors = ["Parity Technologies <admin@parity.io>"]
[lib]

[dependencies]
log = "0.4"
keccak-hash = { git = "https://github.com/paritytech/parity-common" }
primal = "0.2.3"
parking_lot = "0.6"
crunchy = "0.1.0"
memmap = "0.6"
either = "1.0.0"
ethereum-types = "0.3"
keccak-hash = { git = "https://github.com/paritytech/parity-common" }
log = "0.4"
memmap = "0.6"
parking_lot = "0.6"
primal = "0.2.3"

[dev-dependencies]
tempdir = "0.3"
Expand Down
66 changes: 64 additions & 2 deletions ethash/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -16,10 +16,11 @@

#![cfg_attr(feature = "benches", feature(test))]

extern crate primal;
extern crate parking_lot;
extern crate either;
extern crate ethereum_types;
extern crate memmap;
extern crate parking_lot;
extern crate primal;

#[macro_use]
extern crate crunchy;
Expand All @@ -38,6 +39,7 @@ mod shared;
pub use cache::{NodeCacheBuilder, OptimizeFor};
pub use compute::{ProofOfWork, quick_get_difficulty, slow_hash_block_number};
use compute::Light;
use ethereum_types::{U256, U512};
use keccak::H256;
use parking_lot::Mutex;
pub use seed_compute::SeedHashCompute;
Expand Down Expand Up @@ -136,6 +138,29 @@ impl EthashManager {
}
}

/// Convert an Ethash boundary to its original difficulty. Basically just `f(x) = 2^256 / x`.
pub fn boundary_to_difficulty(boundary: &ethereum_types::H256) -> U256 {
difficulty_to_boundary_aux(&**boundary)
}

/// Convert an Ethash difficulty to the target boundary. Basically just `f(x) = 2^256 / x`.
pub fn difficulty_to_boundary(difficulty: &U256) -> ethereum_types::H256 {
difficulty_to_boundary_aux(difficulty).into()
}

fn difficulty_to_boundary_aux<T: Into<U512>>(difficulty: T) -> ethereum_types::U256 {
let difficulty = difficulty.into();

assert!(!difficulty.is_zero());

if difficulty == U512::one() {
U256::max_value()
} else {
// difficulty > 1, so result should never overflow 256 bits
U256::from((U512::one() << 256) / difficulty)
}
}

#[test]
fn test_lru() {
use tempdir::TempDir;
Expand All @@ -155,6 +180,43 @@ fn test_lru() {
assert_eq!(ethash.cache.lock().prev_epoch.unwrap(), 0);
}

#[test]
fn test_difficulty_to_boundary() {
use ethereum_types::H256;
use std::str::FromStr;

assert_eq!(difficulty_to_boundary(&U256::from(1)), H256::from(U256::max_value()));
assert_eq!(difficulty_to_boundary(&U256::from(2)), H256::from_str("8000000000000000000000000000000000000000000000000000000000000000").unwrap());
assert_eq!(difficulty_to_boundary(&U256::from(4)), H256::from_str("4000000000000000000000000000000000000000000000000000000000000000").unwrap());
assert_eq!(difficulty_to_boundary(&U256::from(32)), H256::from_str("0800000000000000000000000000000000000000000000000000000000000000").unwrap());
}

#[test]
fn test_difficulty_to_boundary_regression() {
use ethereum_types::H256;

// the last bit was originally being truncated when performing the conversion
// https://github.com/paritytech/parity-ethereum/issues/8397
for difficulty in 1..9 {
assert_eq!(U256::from(difficulty), boundary_to_difficulty(&difficulty_to_boundary(&difficulty.into())));
assert_eq!(H256::from(difficulty), difficulty_to_boundary(&boundary_to_difficulty(&difficulty.into())));
assert_eq!(U256::from(difficulty), boundary_to_difficulty(&boundary_to_difficulty(&difficulty.into()).into()));
assert_eq!(H256::from(difficulty), difficulty_to_boundary(&difficulty_to_boundary(&difficulty.into()).into()));
}
}

#[test]
#[should_panic]
fn test_difficulty_to_boundary_panics_on_zero() {
difficulty_to_boundary(&U256::from(0));
}

#[test]
#[should_panic]
fn test_boundary_to_difficulty_panics_on_zero() {
boundary_to_difficulty(&ethereum_types::H256::from(0));
}

#[cfg(feature = "benches")]
mod benchmarks {
extern crate test;
Expand Down
35 changes: 3 additions & 32 deletions ethcore/src/ethereum/ethash.rs
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ use std::collections::BTreeMap;
use std::sync::Arc;
use hash::{KECCAK_EMPTY_LIST_RLP};
use engines::block_reward::{self, RewardKind};
use ethash::{quick_get_difficulty, slow_hash_block_number, EthashManager, OptimizeFor};
use ethash::{self, quick_get_difficulty, slow_hash_block_number, EthashManager, OptimizeFor};
use ethereum_types::{H256, H64, U256, Address};
use unexpected::{OutOfBounds, Mismatch};
use block::*;
Expand Down Expand Up @@ -302,7 +302,7 @@ impl Engine<EthereumMachine> for Arc<Ethash> {
return Err(From::from(BlockError::DifficultyOutOfBounds(OutOfBounds { min: Some(min_difficulty), max: None, found: header.difficulty().clone() })))
}

let difficulty = Ethash::boundary_to_difficulty(&H256(quick_get_difficulty(
let difficulty = ethash::boundary_to_difficulty(&H256(quick_get_difficulty(
&header.bare_hash().0,
seal.nonce.low_u64(),
&seal.mix_hash.0
Expand All @@ -324,7 +324,7 @@ impl Engine<EthereumMachine> for Arc<Ethash> {

let result = self.pow.compute_light(header.number() as u64, &header.bare_hash().0, seal.nonce.low_u64());
let mix = H256(result.mix_hash);
let difficulty = Ethash::boundary_to_difficulty(&H256(result.value));
let difficulty = ethash::boundary_to_difficulty(&H256(result.value));
trace!(target: "miner", "num: {num}, seed: {seed}, h: {h}, non: {non}, mix: {mix}, res: {res}",
num = header.number() as u64,
seed = H256(slow_hash_block_number(header.number() as u64)),
Expand Down Expand Up @@ -447,25 +447,6 @@ impl Ethash {
}
target
}

/// Convert an Ethash boundary to its original difficulty. Basically just `f(x) = 2^256 / x`.
pub fn boundary_to_difficulty(boundary: &H256) -> U256 {
let d = U256::from(*boundary);
if d <= U256::one() {
U256::max_value()
} else {
((U256::one() << 255) / d) << 1
}
}

/// Convert an Ethash difficulty to the target boundary. Basically just `f(x) = 2^256 / x`.
pub fn difficulty_to_boundary(difficulty: &U256) -> H256 {
if *difficulty <= U256::one() {
U256::max_value().into()
} else {
(((U256::one() << 255) / *difficulty) << 1).into()
}
}
}

fn ecip1017_eras_block_reward(era_rounds: u64, mut reward: U256, block_number:u64) -> (u64, U256) {
Expand Down Expand Up @@ -766,16 +747,6 @@ mod tests {
}
}

#[test]
fn test_difficulty_to_boundary() {
// result of f(0) is undefined, so do not assert the result
let _ = Ethash::difficulty_to_boundary(&U256::from(0));
assert_eq!(Ethash::difficulty_to_boundary(&U256::from(1)), H256::from(U256::max_value()));
assert_eq!(Ethash::difficulty_to_boundary(&U256::from(2)), H256::from_str("8000000000000000000000000000000000000000000000000000000000000000").unwrap());
assert_eq!(Ethash::difficulty_to_boundary(&U256::from(4)), H256::from_str("4000000000000000000000000000000000000000000000000000000000000000").unwrap());
assert_eq!(Ethash::difficulty_to_boundary(&U256::from(32)), H256::from_str("0800000000000000000000000000000000000000000000000000000000000000").unwrap());
}

#[test]
fn difficulty_frontier() {
let machine = new_homestead_test_machine();
Expand Down
5 changes: 2 additions & 3 deletions ethcore/src/miner/stratum.rs
Original file line number Diff line number Diff line change
Expand Up @@ -22,8 +22,7 @@ use std::fmt;

use client::{Client, ImportSealedBlock};
use ethereum_types::{H64, H256, clean_0x, U256};
use ethereum::ethash::Ethash;
use ethash::SeedHashCompute;
use ethash::{self, SeedHashCompute};
#[cfg(feature = "work-notify")]
use ethcore_miner::work_notify::NotifyWork;
#[cfg(feature = "work-notify")]
Expand Down Expand Up @@ -167,7 +166,7 @@ impl StratumJobDispatcher {
/// Serializes payload for stratum service
fn payload(&self, pow_hash: H256, difficulty: U256, number: u64) -> String {
// TODO: move this to engine
let target = Ethash::difficulty_to_boundary(&difficulty);
let target = ethash::difficulty_to_boundary(&difficulty);
let seed_hash = &self.seed_compute.lock().hash_block_number(number);
let seed_hash = H256::from_slice(&seed_hash[..]);
format!(
Expand Down
1 change: 1 addition & 0 deletions json/src/spec/ethash.rs
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ use hash::Address;
pub struct EthashParams {
/// See main EthashParams docs.
#[serde(rename="minimumDifficulty")]
#[serde(deserialize_with="uint::validate_non_zero")]
pub minimum_difficulty: Uint,
/// See main EthashParams docs.
#[serde(rename="difficultyBoundDivisor")]
Expand Down
11 changes: 1 addition & 10 deletions miner/src/work_notify.rs
Original file line number Diff line number Diff line change
Expand Up @@ -67,19 +67,10 @@ impl WorkPoster {
}
}

/// Convert an Ethash difficulty to the target boundary. Basically just `f(x) = 2^256 / x`.
fn difficulty_to_boundary(difficulty: &U256) -> H256 {
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good catch! I didn't know that we have it in more than 1 place

if *difficulty <= U256::one() {
U256::max_value().into()
} else {
(((U256::one() << 255) / *difficulty) << 1).into()
}
}

impl NotifyWork for WorkPoster {
fn notify(&self, pow_hash: H256, difficulty: U256, number: u64) {
// TODO: move this to engine
let target = difficulty_to_boundary(&difficulty);
let target = ethash::difficulty_to_boundary(&difficulty);
let seed_hash = &self.seed_compute.lock().hash_block_number(number);
let seed_hash = H256::from_slice(&seed_hash[..]);
let body = format!(
Expand Down
5 changes: 2 additions & 3 deletions rpc/src/v1/impls/eth.rs
Original file line number Diff line number Diff line change
Expand Up @@ -24,10 +24,9 @@ use rlp::{self, Rlp};
use ethereum_types::{U256, H64, H256, Address};
use parking_lot::Mutex;

use ethash::SeedHashCompute;
use ethash::{self, SeedHashCompute};
use ethcore::account_provider::AccountProvider;
use ethcore::client::{BlockChainClient, BlockId, TransactionId, UncleId, StateOrBlock, StateClient, StateInfo, Call, EngineInfo};
use ethcore::ethereum::Ethash;
use ethcore::filter::Filter as EthcoreFilter;
use ethcore::header::{BlockNumber as EthBlockNumber};
use ethcore::log_entry::LogEntry;
Expand Down Expand Up @@ -758,7 +757,7 @@ impl<C, SN: ?Sized, S: ?Sized, M, EM, T: StateInfo + 'static> Eth for EthClient<
})?;

let (pow_hash, number, timestamp, difficulty) = work;
let target = Ethash::difficulty_to_boundary(&difficulty);
let target = ethash::difficulty_to_boundary(&difficulty);
let seed_hash = self.seed_compute.lock().hash_block_number(number);

let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap_or_default().as_secs();
Expand Down