Shivani/detect faulty vals (#163)

* detects faulty validator

* fixed error kind and added test

* fixing messes

* Delete .gitignore

* global gitignore failed here

* removed reason string and added commit link to generator

tendermint/src/lite/error.rs

@@ -78,6 +78,10 @@ pub enum Kind {
     /// the implementation, if any.
     #[error("Implementation specific error")]
     ImplementationSpecific,
+
+    /// This is returned when a faulty i.e misbehaving full node is found
+    #[error("Found faulty full node")]
+    FaultyFullNode,
 }
 
 impl Kind {

tendermint/src/lite_impl/signed_header.rs

@@ -1,6 +1,7 @@
 //! [`lite::SignedHeader`] implementation for [`block::signed_header::SignedHeader`].
 
 use crate::lite::error::{Error, Kind};
+use crate::lite::ValidatorSet;
 use crate::validator::Set;
 use crate::{block, hash, lite, vote};
 use anomaly::fail;
@@ -53,36 +54,43 @@ impl lite::Commit for block::signed_header::SignedHeader {
     fn validate(&self, vals: &Self::ValidatorSet) -> Result<(), Error> {
         if self.commit.precommits.len() != vals.validators().len() {
             fail!(
-                lite::error::Kind::ImplementationSpecific,
+                Kind::ImplementationSpecific,
                 "pre-commit length: {} doesn't match validator length: {}",
                 self.commit.precommits.len(),
                 vals.validators().len()
             );
         }
 
-        // make sure each vote is for the correct header
         for precommit_opt in self.commit.precommits.iter() {
             match precommit_opt {
                 Some(precommit) => {
+                    // make sure each vote is for the correct header
                     if let Some(header_hash) = precommit.header_hash() {
                         if header_hash != self.header_hash() {
                             fail!(
-                                lite::error::Kind::ImplementationSpecific,
+                                Kind::ImplementationSpecific,
                                 "validator({}) voted for header {}, but current header is {}",
                                 precommit.validator_address,
                                 header_hash,
                                 self.header_hash()
                             );
                         }
                     }
+
+                    // returns FaultyFullNode error if it detects a signer isn't present in the validator set
+                    if vals.validator(precommit.validator_address) == None {
+                        let reason = format!(
+                            "Found a faulty signer ({}) not present in the validator set ({})",
+                            precommit.validator_address,
+                            vals.hash()
+                        );
+                        fail!(Kind::FaultyFullNode, reason);
+                    }
                 }
                 None => (),
             }
         }
 
-        // TODO: check here if all the votes are from correct validators
-        // TODO: return error kind "InvalidValidator" if we find a vote from a validator not in the val set
-
         Ok(())
     }
 }

tendermint/tests/lite.rs

@@ -119,6 +119,8 @@ impl MockRequester {
     }
 }
 
+// Link to the commit that generated below JSON test files:
+// https://github.com/Shivani912/tendermint/commit/f7d16ab59b55a4f1a5cdbfa6b0c24467aa88fdb2
 const TEST_FILES_PATH: &str = "./tests/support/lite/";
 fn read_json_fixture(name: &str) -> String {
     fs::read_to_string(PathBuf::from(TEST_FILES_PATH).join(name.to_owned() + ".json")).unwrap()