[stable] Backporting #4633 (#4642)

* Tweak some checks. (#4633)

* Tweak some checks.

* Fixed build and added a difficulty test

* v1.4.12


Former-commit-id: efaf4bcf1f9dbe0bb2f88503a4dff47face04592

ethcore/src/ethereum/ethash.rs

@@ -849,4 +849,22 @@ mod tests {
 		ethash.populate_from_parent(&mut header, &parent, U256::from(150_000), U256::from(150_002));
 		assert_eq!(*header.gas_limit(), U256::from(150_002));
 	}
+
+	#[test]
+	fn difficulty_max_timestamp() {
+		let spec = new_homestead_test();
+		let ethparams = get_default_ethash_params();
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(1000000);
+		parent_header.set_difficulty(U256::from_str("b69de81a22b").unwrap());
+		parent_header.set_timestamp(1455404053);
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(u64::max_value());
+
+		let difficulty = ethash.calculate_difficulty(&header, &parent_header);
+		assert_eq!(U256::from(12543204905719u64), difficulty);
+	}
 }

ethcore/src/header.rs

@@ -276,7 +276,7 @@ impl Decodable for Header {
 			number: try!(r.val_at(8)),
 			gas_limit: try!(r.val_at(9)),
 			gas_used: try!(r.val_at(10)),
-			timestamp: try!(r.val_at(11)),
+			timestamp: min(try!(r.val_at::<U256>(11)), u64::max_value().into()).as_u64(),
 			extra_data: try!(r.val_at(12)),
 			seal: vec![],
 			hash: RefCell::new(Some(r.as_raw().sha3())),

ethcore/src/verification/queue/kind.rs

@@ -186,7 +186,7 @@ pub mod headers {
 		type Verified = Header;
 
 		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
-			verify_header_params(&input, engine).map(|_| input)
+			verify_header_params(&input, engine, true).map(|_| input)
 		}
 
 		fn verify(unverified: Self::Unverified, engine: &Engine, check_seal: bool) -> Result<Self::Verified, Error> {

ethcore/src/verification/verification.rs

@@ -29,6 +29,7 @@ use header::{BlockNumber, Header};
 use rlp::{UntrustedRlp, View};
 use transaction::SignedTransaction;
 use views::BlockView;
+use time::get_time;
 
 /// Preprocessed block data gathered in `verify_block_unordered` call
 pub struct PreverifiedBlock {
@@ -50,12 +51,12 @@ impl HeapSizeOf for PreverifiedBlock {
 
 /// Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
 pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error> {
-	try!(verify_header_params(&header, engine));
+	try!(verify_header_params(&header, engine, true));
 	try!(verify_block_integrity(bytes, &header.transactions_root(), &header.uncles_hash()));
 	try!(engine.verify_block_basic(&header, Some(bytes)));
 	for u in try!(UntrustedRlp::new(bytes).at(2)).iter().map(|rlp| rlp.as_val::<Header>()) {
 		let u = try!(u);
-		try!(verify_header_params(&u, engine));
+		try!(verify_header_params(&u, engine, false));
 		try!(engine.verify_block_basic(&u, None));
 	}
 	// Verify transactions.
@@ -194,7 +195,7 @@ pub fn verify_block_final(expected: &Header, got: &Header) -> Result<(), Error>
 }
 
 /// Check basic header parameters.
-pub fn verify_header_params(header: &Header, engine: &Engine) -> Result<(), Error> {
+pub fn verify_header_params(header: &Header, engine: &Engine, is_full: bool) -> Result<(), Error> {
 	if header.number() >= From::from(BlockNumber::max_value()) {
 		return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { max: Some(From::from(BlockNumber::max_value())), min: None, found: header.number() })))
 	}
@@ -209,6 +210,12 @@ pub fn verify_header_params(header: &Header, engine: &Engine) -> Result<(), Erro
 	if header.number() != 0 && header.extra_data().len() > maximum_extra_data_size {
 		return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds { min: None, max: Some(maximum_extra_data_size), found: header.extra_data().len() })));
 	}
+	if is_full {
+		let max_time = get_time().sec as u64 + 30;
+		if header.timestamp() > max_time {
+			return Err(From::from(BlockError::InvalidTimestamp(OutOfBounds { max: Some(max_time), min: None, found: header.timestamp() })))
+		}
+	}
 	Ok(())
 }