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change(consensus): Lower mandatory checkpoint height (#8629) 

* Lowers the mandatory checkpoint height to the block before Canopy activation

* Apply suggestions from code review

Co-authored-by: Marek <mail@marek.onl>

---------

Co-authored-by: Marek <mail@marek.onl>
This commit is contained in:
Arya 2024-06-27 12:16:23 -04:00 committed by GitHub
parent d1a9004b32
commit 549a7bb599
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GPG Key ID: B5690EEEBB952194
2 changed files with 15 additions and 75 deletions
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67
zebra-chain/src/parameters/network.rs
View File

@ -5,7 +5,7 @@ use std::{fmt, str::FromStr, sync::Arc};
use thiserror::Error;
use crate::{
block::{self, Height, HeightDiff},
block::{self, Height},
parameters::NetworkUpgrade,
};
@ -15,42 +15,6 @@ pub mod testnet;
#[cfg(test)]
mod tests;
/// The ZIP-212 grace period length after the Canopy activation height.
///
/// # Consensus
///
/// ZIP-212 requires Zcash nodes to validate that Sapling spends and Orchard actions follows a
/// specific plaintext format after Canopy's activation.
///
/// > [Heartwood onward] All Sapling and Orchard outputs in coinbase transactions MUST decrypt to a
/// > note plaintext , i.e. the procedure in § 4.19.3 ‘Decryption using a Full Viewing Key (Sapling
/// > and Orchard)’ on p. 67 does not return ⊥, using a sequence of 32 zero bytes as the outgoing
/// > viewing key . (This implies that before Canopy activation, Sapling outputs of a coinbase
/// > transaction MUST have note plaintext lead byte equal to 0x01.)
///
/// > [Canopy onward] Any Sapling or Orchard output of a coinbase transaction decrypted to a note
/// > plaintext according to the preceding rule MUST have note plaintext lead byte equal to 0x02.
/// > (This applies even during the “grace period” specified in [ZIP-212].)
///
/// <https://zips.z.cash/protocol/protocol.pdf#txnencodingandconsensus>
///
/// Wallets have a grace period of 32,256 blocks after Canopy's activation to validate those blocks,
/// but nodes do not.
///
/// > There is a "grace period" of 32256 blocks starting from the block at which this ZIP activates,
/// > during which note plaintexts with lead byte 0x01 MUST still be accepted [by wallets].
/// >
/// > Let ActivationHeight be the activation height of this ZIP, and let GracePeriodEndHeight be
/// > ActivationHeight + 32256.
///
/// <https://zips.z.cash/zip-0212#changes-to-the-process-of-receiving-sapling-or-orchard-notes>
///
/// Zebra uses `librustzcash` to validate that rule, but it won't validate it during the grace
/// period. Therefore Zebra must validate those blocks during the grace period using checkpoints.
/// Therefore the mandatory checkpoint height ([`Network::mandatory_checkpoint_height`]) must be
/// after the grace period.
const ZIP_212_GRACE_PERIOD_DURATION: HeightDiff = 32_256;
/// An enum describing the kind of network, whether it's the production mainnet or a testnet.
// Note: The order of these variants is important for correct bincode (de)serialization
// of history trees in the db format.
@ -234,34 +198,17 @@ impl Network {
/// Mandatory checkpoints are a Zebra-specific feature.
/// If a Zcash consensus rule only applies before the mandatory checkpoint,
/// Zebra can skip validation of that rule.
///
/// ZIP-212 grace period is only applied to default networks.
/// This is necessary because Zebra can't fully validate the blocks prior to Canopy.
// TODO:
// - Support constructing pre-Canopy coinbase tx and block templates and return `Height::MAX` instead of panicking
// when Canopy activation height is `None` (#8434)
// - Add semantic block validation during the ZIP-212 grace period and update this method to always apply the ZIP-212 grace period
pub fn mandatory_checkpoint_height(&self) -> Height {
// Currently this is after the ZIP-212 grace period.
//
// See the `ZIP_212_GRACE_PERIOD_DURATION` documentation for more information.
let canopy_activation = NetworkUpgrade::Canopy
// Currently this is just before Canopy activation
NetworkUpgrade::Canopy
.activation_height(self)
.expect("Canopy activation height must be present for both networks");
let is_a_default_network = match self {
Network::Mainnet => true,
Network::Testnet(params) => params.is_default_testnet(),
};
if is_a_default_network {
(canopy_activation + ZIP_212_GRACE_PERIOD_DURATION)
.expect("ZIP-212 grace period ends at a valid block height")
} else {
canopy_activation
.previous()
.expect("Canopy activation must be above Genesis height")
}
.expect("Canopy activation height must be present on all networks")
.previous()
.expect("Canopy activation height must be above min height")
}
/// Return the network name as defined in

23
zebra-chain/src/parameters/network/tests/prop.rs
View File

@ -1,32 +1,25 @@
use proptest::prelude::*;
use super::super::{Network, ZIP_212_GRACE_PERIOD_DURATION};
use super::super::Network;
use crate::{
block::Height,
parameters::{NetworkUpgrade, TESTNET_MAX_TIME_START_HEIGHT},
};
proptest! {
/// Check that the mandatory checkpoint is after the ZIP-212 grace period.
///
/// This is necessary because Zebra can't fully validate the blocks during the grace period due
/// to a limitation of `librustzcash`.
///
/// See [`ZIP_212_GRACE_PERIOD_DURATION`] for more information.
/// Check that the mandatory checkpoint is immediately before Canopy activation.
#[test]
fn mandatory_checkpoint_is_after_zip212_grace_period(network in any::<Network>()) {
fn mandatory_checkpoint_is_immediately_before_canopy(network in any::<Network>()) {
let _init_guard = zebra_test::init();
let canopy_activation = NetworkUpgrade::Canopy
let pre_canopy_activation = NetworkUpgrade::Canopy
.activation_height(&network)
.expect("Canopy activation height is set");
.expect("Canopy activation height is set")
.previous()
.expect("Canopy activation should be above min height");
let grace_period_end_height = (canopy_activation + ZIP_212_GRACE_PERIOD_DURATION)
.expect("ZIP-212 grace period ends in a valid block height");
assert!(network.mandatory_checkpoint_height() >= grace_period_end_height);
assert!(network.mandatory_checkpoint_height() >= pre_canopy_activation);
}
#[test]
/// Asserts that the activation height is correct for the block
/// maximum time rule on Testnet is correct.