zebra/zebra-consensus/src/verify.rs

279 lines
8.5 KiB
Rust

//! Block verification and chain state updates for Zebra.
//!
//! Verification occurs in multiple stages:
//! - getting blocks (disk- or network-bound)
//! - context-free verification of signatures, proofs, and scripts (CPU-bound)
//! - context-dependent verification of the chain state (awaits a verified parent block)
//!
//! Verification is provided via a `tower::Service`, to support backpressure and batch
//! verification.
use futures_util::FutureExt;
use std::{
error,
future::Future,
pin::Pin,
sync::Arc,
task::{Context, Poll},
};
use tower::{buffer::Buffer, Service};
use zebra_chain::block::{Block, BlockHeaderHash};
mod script;
mod transaction;
struct BlockVerifier<S> {
state_service: S,
}
/// The error type for the BlockVerifier Service.
// TODO(jlusby): Error = Report ?
type Error = Box<dyn error::Error + Send + Sync + 'static>;
/// The BlockVerifier service implementation.
///
/// After verification, blocks are added to the underlying state service.
impl<S> Service<Arc<Block>> for BlockVerifier<S>
where
S: Service<zebra_state::Request, Response = zebra_state::Response, Error = Error>,
S::Future: Send + 'static,
{
type Response = BlockHeaderHash;
type Error = Error;
type Future =
Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send + 'static>>;
fn poll_ready(&mut self, context: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.state_service.poll_ready(context)
}
fn call(&mut self, block: Arc<Block>) -> Self::Future {
// TODO(jlusby): Error = Report, handle errors from state_service.
// TODO(teor):
// - handle chain reorgs, adjust state_service "unique block height" conditions
// - handle block validation errors (including errors in the block's transactions)
// `state_service.call` is OK here because we already called
// `state_service.poll_ready` in our `poll_ready`.
let add_block = self
.state_service
.call(zebra_state::Request::AddBlock { block });
async move {
match add_block.await? {
zebra_state::Response::Added { hash } => Ok(hash),
_ => Err("adding block to zebra-state failed".into()),
}
}
.boxed()
}
}
/// Return a block verification service, using the provided state service.
///
/// The block verifier holds a state service of type `S`, used as context for
/// block validation and to which newly verified blocks will be committed. This
/// state is pluggable to allow for testing or instrumentation.
///
/// The returned type is opaque to allow instrumentation or other wrappers, but
/// can be boxed for storage. It is also `Clone` to allow sharing of a
/// verification service.
///
/// This function should be called only once for a particular state service (and
/// the result be shared) rather than constructing multiple verification services
/// backed by the same state layer.
pub fn init<S>(
state_service: S,
) -> impl Service<
Arc<Block>,
Response = BlockHeaderHash,
Error = Error,
Future = impl Future<Output = Result<BlockHeaderHash, Error>>,
> + Send
+ Clone
+ 'static
where
S: Service<zebra_state::Request, Response = zebra_state::Response, Error = Error>
+ Send
+ 'static,
S::Future: Send + 'static,
{
Buffer::new(BlockVerifier { state_service }, 1)
}
#[cfg(test)]
mod tests {
use super::*;
use color_eyre::eyre::Report;
use color_eyre::eyre::{bail, ensure, eyre};
use tower::{util::ServiceExt, Service};
use zebra_chain::serialization::ZcashDeserialize;
fn install_tracing() {
use tracing_error::ErrorLayer;
use tracing_subscriber::prelude::*;
use tracing_subscriber::{fmt, EnvFilter};
let fmt_layer = fmt::layer().with_target(false);
let filter_layer = EnvFilter::try_from_default_env()
.or_else(|_| EnvFilter::try_new("info"))
.unwrap();
tracing_subscriber::registry()
.with(filter_layer)
.with(fmt_layer)
.with(ErrorLayer::default())
.init();
}
#[tokio::test]
#[spandoc::spandoc]
async fn verify() -> Result<(), Report> {
let block =
Arc::<Block>::zcash_deserialize(&zebra_test_vectors::BLOCK_MAINNET_415000_BYTES[..])?;
let hash: BlockHeaderHash = block.as_ref().into();
let state_service = Box::new(zebra_state::in_memory::init());
let mut block_verifier = super::init(state_service);
let verify_response = block_verifier
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(block.clone())
.await
.map_err(|e| eyre!(e))?;
ensure!(
verify_response == hash,
"unexpected response kind: {:?}",
verify_response
);
Ok(())
}
#[tokio::test]
#[spandoc::spandoc]
async fn round_trip() -> Result<(), Report> {
let block =
Arc::<Block>::zcash_deserialize(&zebra_test_vectors::BLOCK_MAINNET_415000_BYTES[..])?;
let hash: BlockHeaderHash = block.as_ref().into();
let mut state_service = zebra_state::in_memory::init();
let mut block_verifier = super::init(state_service.clone());
let verify_response = block_verifier
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(block.clone())
.await
.map_err(|e| eyre!(e))?;
ensure!(
verify_response == hash,
"unexpected response kind: {:?}",
verify_response
);
let state_response = state_service
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(zebra_state::Request::GetBlock { hash })
.await
.map_err(|e| eyre!(e))?;
match state_response {
zebra_state::Response::Block {
block: returned_block,
} => assert_eq!(block, returned_block),
_ => bail!("unexpected response kind: {:?}", state_response),
}
Ok(())
}
#[tokio::test]
#[spandoc::spandoc]
async fn verify_fail_add_block() -> Result<(), Report> {
install_tracing();
let block =
Arc::<Block>::zcash_deserialize(&zebra_test_vectors::BLOCK_MAINNET_415000_BYTES[..])?;
let hash: BlockHeaderHash = block.as_ref().into();
let mut state_service = zebra_state::in_memory::init();
let mut block_verifier = super::init(state_service.clone());
// Add the block for the first time
let verify_response = block_verifier
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(block.clone())
.await
.map_err(|e| eyre!(e))?;
ensure!(
verify_response == hash,
"unexpected response kind: {:?}",
verify_response
);
let state_response = state_service
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(zebra_state::Request::GetBlock { hash })
.await
.map_err(|e| eyre!(e))?;
match state_response {
zebra_state::Response::Block {
block: returned_block,
} => assert_eq!(block, returned_block),
_ => bail!("unexpected response kind: {:?}", state_response),
}
// Now try to add the block again, verify should fail
// TODO(teor): ignore duplicate block verifies?
let verify_result = block_verifier
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(block.clone())
.await;
ensure!(
match verify_result {
Ok(_) => false,
// TODO(teor || jlusby): check error string
_ => true,
},
"unexpected result kind: {:?}",
verify_result
);
// But the state should still return the original block we added
let state_response = state_service
.ready_and()
.await
.map_err(|e| eyre!(e))?
.call(zebra_state::Request::GetBlock { hash })
.await
.map_err(|e| eyre!(e))?;
match state_response {
zebra_state::Response::Block {
block: returned_block,
} => assert_eq!(block, returned_block),
_ => bail!("unexpected response kind: {:?}", state_response),
}
Ok(())
}
}