Initial Validation Checks - Message, Timestamp and Block Sig

blockchain/blocks/src/errors.rs

@@ -1,21 +1,33 @@
 // Copyright 2020 ChainSafe Systems
 // SPDX-License-Identifier: Apache-2.0, MIT
 
-use std::fmt;
+use std::{fmt, time::SystemTimeError as TimeErr};
 
 #[derive(Debug, PartialEq)]
 pub enum Error {
     /// Tipset contains invalid data, as described by the string parameter.
     InvalidTipSet(String),
     /// The given tipset has no blocks
     NoBlocks,
+    /// Invalid signature
+    InvalidSignature(String),
+    /// Error in validating arbitrary data
+    Validation(String),
 }
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Error::InvalidTipSet(msg) => write!(f, "Invalid tipset: {}", msg),
             Error::NoBlocks => write!(f, "No blocks for tipset"),
+            Error::InvalidSignature(msg) => write!(f, "Invalid signature: {}", msg),
+            Error::Validation(msg) => write!(f, "Error validating data: {}", msg),
         }
     }
 }
+
+impl From<TimeErr> for Error {
+    fn from(e: TimeErr) -> Error {
+        Error::Validation(e.to_string())
+    }
+}

blockchain/blocks/src/header.rs

@@ -1,11 +1,11 @@
 // Copyright 2020 ChainSafe Systems
 // SPDX-License-Identifier: Apache-2.0, MIT
 
-use super::{EPostProof, Ticket, TipSetKeys};
+use super::{EPostProof, Error, FullTipset, Ticket, TipSetKeys};
 use address::Address;
 use cid::{Cid, Error as CidError};
 use clock::ChainEpoch;
-use crypto::Signature;
+use crypto::{is_valid_signature, Signature};
 use derive_builder::Builder;
 use encoding::{
     de::{self, Deserializer},
@@ -16,6 +16,7 @@ use num_bigint::BigUint;
 use raw_block::RawBlock;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::time::{SystemTime, UNIX_EPOCH};
 
 /// Header of a block
 ///
@@ -279,6 +280,48 @@ impl BlockHeader {
         self.cached_cid = Cid::from_bytes_default(&self.cached_bytes).map_err(|e| e.to_string())?;
         Ok(())
     }
+    /// Check to ensure block signature is valid
+    pub fn check_block_signature(&self, addr: &Address) -> Result<(), Error> {
+        if self.signature().bytes().is_empty() {
+            return Err(Error::InvalidSignature(
+                "Signature is nil in header".to_string(),
+            ));
+        }
+
+        if !is_valid_signature(&self.cid().to_bytes(), addr, self.signature()) {
+            return Err(Error::InvalidSignature(
+                "Block signature is invalid".to_string(),
+            ));
+        }
+
+        Ok(())
+    }
+    /// Validates timestamps to ensure BlockHeader was generated at the correct time
+    pub fn validate_timestamps(&self, base_tipset: &FullTipset) -> Result<(), Error> {
+        // first check that it is not in the future; see https://github.com/filecoin-project/specs/blob/6ab401c0b92efb6420c6e198ec387cf56dc86057/validation.md
+        // allowing for some small grace period to deal with small asynchrony
+        // using ALLOWABLE_CLOCK_DRIFT from Lotus; see https://github.com/filecoin-project/lotus/blob/master/build/params_shared.go#L34:7
+        const ALLOWABLE_CLOCK_DRIFT: u64 = 1;
+        let time_now = SystemTime::now().duration_since(UNIX_EPOCH)?;
+        if self.timestamp() > time_now.as_secs() + ALLOWABLE_CLOCK_DRIFT
+            || self.timestamp() > time_now.as_secs()
+        {
+            return Err(Error::Validation("Header was from the future".to_string()));
+        }
+        const FIXED_BLOCK_DELAY: u64 = 45;
+        // check that it is appropriately delayed from its parents including null blocks
+        if self.timestamp()
+            < base_tipset.tipset()?.min_timestamp()?
+                + FIXED_BLOCK_DELAY
+                    * (*self.epoch() - *base_tipset.tipset()?.tip_epoch()).chain_epoch()
+        {
+            return Err(Error::Validation(
+                "Header was generated too soon".to_string(),
+            ));
+        }
+
+        Ok(())
+    }
 }
 
 /// human-readable string representation of a block CID

blockchain/blocks/src/tipset.rs

@@ -25,6 +25,10 @@ pub struct TipSetKeys {
 // https://github.com/ChainSafe/forest/issues/143
 
 impl TipSetKeys {
+    /// constructor
+    pub fn new(cids: Vec<Cid>) -> Self {
+        Self { cids }
+    }
     /// checks whether the set contains exactly the same CIDs as another.
     fn equals(&self, key: &TipSetKeys) -> bool {
         if self.cids.len() != key.cids.len() {
@@ -157,7 +161,7 @@ impl Tipset {
         Ok(self.blocks[0].ticket().clone())
     }
     /// Returns the smallest timestamp of all blocks in the tipset
-    fn min_timestamp(&self) -> Result<u64, Error> {
+    pub fn min_timestamp(&self) -> Result<u64, Error> {
         if self.blocks.is_empty() {
             return Err(Error::NoBlocks);
         }
@@ -216,7 +220,8 @@ impl FullTipset {
         for block in self.blocks() {
             headers.push(block.to_header().clone())
         }
-        Ok(Tipset::new(headers))?
+        let tip: Tipset = Tipset::new(headers)?;
+        Ok(tip)
     }
 }
 

blockchain/sync_manager/Cargo.toml

@@ -16,6 +16,9 @@ chain = { path ="../chain" }
 message = { package = "forest_message", path = "../../vm/message" }
 raw_block = { package = "raw_block", path = "../raw_block" }
 multihash = "0.9.4"
+state = { package = "state_tree", path = "../../vm/state_tree/" }
+num-bigint =  { git = "https://github.com/austinabell/num-bigint", rev = "f7084a9ed5a2b08d9bfb67790cb4ce9212193f31" }
+crypto = { path= "../../crypto" }
 
 [dev-dependencies]
 cid = { package = "forest_cid", path = "../../ipld/cid" }

blockchain/sync_manager/src/errors.rs

@@ -7,7 +7,7 @@ use chain::Error as StoreErr;
 use cid::Error as CidErr;
 use db::Error as DbErr;
 use encoding::{error::Error as SerdeErr, Error as EncErr};
-use std::fmt;
+use std::{fmt, time::SystemTimeError as TimeErr};
 
 #[derive(Debug, PartialEq)]
 pub enum Error {
@@ -26,6 +26,10 @@ pub enum Error {
     KeyValueStore(String),
     /// Error originating from the AMT
     AMT(String),
+    /// Error originating from state
+    State(String),
+    /// Error in validating arbitrary data
+    Validation(String),
 }
 
 impl fmt::Display for Error {
@@ -45,6 +49,8 @@ impl fmt::Display for Error {
             Error::InvalidCid(msg) => write!(f, "Error originating from CID construction: {}", msg),
             Error::Store(msg) => write!(f, "Error originating from ChainStore: {}", msg),
             Error::AMT(msg) => write!(f, "Error originating from the AMT: {}", msg),
+            Error::State(msg) => write!(f, "Error originating from the State: {}", msg),
+            Error::Validation(msg) => write!(f, "Error validating data: {}", msg),
         }
     }
 }
@@ -90,3 +96,9 @@ impl From<AmtErr> for Error {
         Error::AMT(e.to_string())
     }
 }
+
+impl From<TimeErr> for Error {
+    fn from(e: TimeErr) -> Error {
+        Error::Validation(e.to_string())
+    }
+}

blockchain/sync_manager/src/sync.rs

@@ -5,13 +5,18 @@
 
 use super::errors::Error;
 use super::manager::SyncManager;
+use address::Address;
 use amt::{BlockStore, AMT};
 use blocks::{Block, FullTipset, TipSetKeys, Tipset};
 use chain::ChainStore;
 use cid::{Cid, Error as CidError};
+use crypto::is_valid_signature;
 use libp2p::core::PeerId;
-use message::MsgMeta;
+use message::{Message, MsgMeta};
+use num_bigint::BigUint;
 use raw_block::RawBlock;
+use state::{HamtStateTree, StateTree};
+use std::collections::HashMap;
 
 pub struct Syncer<'a> {
     // TODO add ability to send msg to all subscribers indicating incoming blocks
@@ -28,6 +33,12 @@ pub struct Syncer<'a> {
     _own: PeerId,
 }
 
+/// Message data used to ensure valid state transition
+struct MsgMetaData {
+    balance: BigUint,
+    sequence: u64,
+}
+
 impl<'a> Syncer<'a> {
     /// TODO add constructor
 
@@ -63,8 +74,7 @@ impl<'a> Syncer<'a> {
     /// bls and secp messages contained in the passed in block and stores them in a key-value store
     fn validate_msg_data(&self, block: &Block) -> Result<(), Error> {
         let sm_root = self.compute_msg_data(block)?;
-        // TODO change message_receipts to messages() once #192 is in
-        if block.to_header().message_receipts() != &sm_root {
+        if block.to_header().messages() != &sm_root {
             return Err(Error::InvalidRoots);
         }
 
@@ -102,7 +112,7 @@ impl<'a> Syncer<'a> {
         Ok(fts)
     }
     /// Returns a reconstructed FullTipset from store if keys exist
-    fn load_fts(&self, keys: TipSetKeys) -> Result<FullTipset, Error> {
+    pub fn load_fts(&self, keys: TipSetKeys) -> Result<FullTipset, Error> {
         let mut blocks = Vec::new();
         // retrieve tipset from store based on passed in TipSetKeys
         let ts = self.chain_store.tipset(keys.tipset_keys())?;
@@ -122,6 +132,114 @@ impl<'a> Syncer<'a> {
         let fts = FullTipset::new(blocks);
         Ok(fts)
     }
+    // Block message validation checks
+    pub fn check_blk_msgs(&self, block: Block, _tip: Tipset) -> Result<(), Error> {
+        // TODO retrieve bls public keys for verify_bls_aggregate
+        // for _m in block.bls_msgs() {
+        // }
+        // TODO verify_bls_aggregate
+
+        // check msgs for validity
+        fn check_msg<T: Message>(
+            msg: &T,
+            msg_meta_data: &mut HashMap<Address, MsgMetaData>,
+            tree: &HamtStateTree,
+        ) -> Result<(), Error>
+        where
+            T: Message,
+        {
+            let updated_state: MsgMetaData = match msg_meta_data.get(msg.from()) {
+                // address is present begin validity checks
+                Some(MsgMetaData { sequence, balance }) => {
+                    // sequence equality check
+                    if *sequence != msg.sequence() {
+                        return Err(Error::Validation("Sequences are not equal".to_string()));
+                    }
+
+                    // sufficient funds check
+                    if *balance < msg.required_funds() {
+                        return Err(Error::Validation(
+                            "Insufficient funds for message execution".to_string(),
+                        ));
+                    }
+                    // update balance and increment sequence by 1
+                    MsgMetaData {
+                        balance: balance - msg.required_funds(),
+                        sequence: sequence + 1,
+                    }
+                }
+                // MsgMetaData not found with provided address key, insert sequence and balance with address as key
+                None => {
+                    let actor = tree.get_actor(msg.from()).ok_or_else(|| {
+                        Error::State("Could not retrieve actor from state tree".to_owned())
+                    })?;
+
+                    MsgMetaData {
+                        sequence: actor.sequence,
+                        balance: actor.balance,
+                    }
+                }
+            };
+            // update hash map with updated state
+            msg_meta_data.insert(msg.from().clone(), updated_state);
+            Ok(())
+        }
+        let mut msg_meta_data: HashMap<Address, MsgMetaData> = HashMap::new();
+        // TODO retrieve tipset state and load state tree
+        // temporary
+        let tree = HamtStateTree::default();
+        // loop through bls messages and check msg validity
+        for m in block.bls_msgs() {
+            check_msg(m, &mut msg_meta_data, &tree)?;
+        }
+        // loop through secp messages and check msg validity and signature
+        for m in block.secp_msgs() {
+            check_msg(m, &mut msg_meta_data, &tree)?;
+            // signature validation
+            if !is_valid_signature(&m.cid()?.to_bytes(), m.from(), m.signature()) {
+                return Err(Error::Validation(
+                    "Message signature is not valid".to_string(),
+                ));
+            }
+        }
+        // validate message root from header matches message root
+        let sm_root = self.compute_msg_data(&block)?;
+        if block.to_header().messages() != &sm_root {
+            return Err(Error::InvalidRoots);
+        }
+
+        Ok(())
+    }
+
+    /// Validates block semantically according to https://github.com/filecoin-project/specs/blob/6ab401c0b92efb6420c6e198ec387cf56dc86057/validation.md
+    pub fn validate(&self, block: Block) -> Result<(), Error> {
+        // get header from full block
+        let header = block.to_header();
+
+        // check if block has been signed
+        if header.signature().bytes().is_empty() {
+            return Err(Error::Validation("Signature is nil in header".to_string()));
+        }
+
+        let base_tipset = self.load_fts(TipSetKeys::new(header.parents().cids.clone()))?;
+        // time stamp checks
+        header.validate_timestamps(&base_tipset)?;
+
+        // check messages to ensure valid state transitions
+        self.check_blk_msgs(block.clone(), base_tipset.tipset()?)?;
+
+        // block signature check
+        // TODO need to pass in raw miner address; temp using header miner address
+        // see https://github.com/filecoin-project/lotus/blob/master/chain/sync.go#L611
+        header.check_block_signature(header.miner_address())?;
+
+        // TODO winner_check
+        // TODO miner_check
+        // TODO verify_ticket_vrf
+        // TODO verify_election_proof_check
+
+        Ok(())
+    }
 }
 
 pub fn cids_from_messages<T: RawBlock>(messages: &[T]) -> Result<Vec<Cid>, CidError> {

node/clock/src/lib.rs

@@ -8,6 +8,7 @@ use encoding::{
 };
 use std::convert::TryInto;
 use std::num::TryFromIntError;
+use std::ops::Sub;
 
 const _ISO_FORMAT: &str = "%FT%X.%.9F";
 const EPOCH_DURATION: i32 = 15;
@@ -75,9 +76,23 @@ impl ChainEpochClock {
     }
 }
 
+impl Sub for ChainEpoch {
+    type Output = ChainEpoch;
+
+    fn sub(self, other: ChainEpoch) -> ChainEpoch {
+        ChainEpoch {
+            0: self.0 - other.0,
+        }
+    }
+}
+
 impl ChainEpoch {
     /// Returns ChainEpoch based on the given unix timestamp
     pub fn new(timestamp: i64) -> Result<ChainEpoch, TryFromIntError> {
         Ok(ChainEpoch(timestamp.try_into()?))
     }
+    // Returns chain epoch
+    pub fn chain_epoch(&self) -> &u64 {
+        &self.0
+    }
 }