fix for https://ghostforum.org/t/critical-unlimited-token-minting-via-weaver-session-replay/100

Signed-off-by: Uncle Stinky <uncle.stinky@ghostchain.io>

pallets/exodus/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ghost-exodus"
-version = "0.0.17"
+version = "0.0.19"
 description = "Threshold signature generation with DKG included"
 license.workspace = true
 authors.workspace = true

pallets/exodus/src/benchmarking.rs

@@ -85,8 +85,7 @@ mod benchmarks {
         dkg_state.insert_index(authority_index);
         QualificationDkgState::<T>::insert(&network_curve, dkg_state);
 
-        let mut rng = Pallet::<T>::get_offchain_rng(authority_index);
-
+        let mut rng = ChaCha20Rng::seed_from_u64(694201337);
         let (_, public_package) = network_curve.dkg_part1(
             authority_index,
             max_signers,
@@ -353,11 +352,8 @@ mod benchmarks {
                 dummy_verifying_key,
             ).expect("Bounded verifying key should be correct");
 
-        let metadata_hashes = [
-            SubstrateBlake2Hasher::hash(dummy_merkle_root.as_ref()),
-            SubstrateBlake2Hasher::hash(bounded_verifying_key.as_ref()),
-        ];
-        let verifying_hash = sequential_hash::<SubstrateBlake2Hasher, _>(metadata_hashes);
+        let metadata_hashes = [dummy_merkle_root.as_ref(), bounded_verifying_key.as_ref()];
+        let verifying_hash = cumulative_hash::<SubstrateBlake2Hasher, _>(metadata_hashes);
 
         let verification_key = (network_curve, dkg_index, verifying_hash);
         let participants = Verifications::<T>::get(verification_key);

pallets/exodus/src/lib.rs

@@ -31,7 +31,7 @@ use sp_io::hashing::blake2_256;
 
 use ghost_helpers::{
     get_byzantium_quorum_threshold, SubstrateBlake2Hasher,
-    hash_chain::sequential_hash,
+    hash_chain::cumulative_hash,
     networks::{NetworkData, NetworkCurve, NetworkType},
     bounded_bitmap::{validate_bitmap_sizes, BoundedBitmap},
 };
@@ -40,7 +40,6 @@ use ghost_helpers::{
 use ghost_traits::exodus::IdentifierConverter;
 
 use ghost_traits::{
-    hashing::GhostHasher,
     bounded_bitmap::{
         BoundedBitmapGenerator, BoundedBitmapWriter, BoundedBitmapReader,
         BoundedBitmapIterable,
@@ -1254,11 +1253,9 @@ pub mod pallet {
                 return Err(Error::<T>::Round5PackageInvalidProof.into());
             };
 
-            let metadata_hashes = [
-                SubstrateBlake2Hasher::hash(round5.merkle_root.as_ref()),
-                SubstrateBlake2Hasher::hash(round5.verifying_key.as_ref()),
-            ];
-            let verifying_hash = sequential_hash::<SubstrateBlake2Hasher, _>(metadata_hashes);
+            let metadata_hashes = [round5.merkle_root.as_ref(), round5.verifying_key.as_ref()];
+            let verifying_hash = cumulative_hash::<SubstrateBlake2Hasher, _>(metadata_hashes);
+
             let state = QualificationDkgState::<T>::get(&network_curve);
             ensure!(state.is_fifth_phase(), Error::<T>::DkgWrongRound);
 
@@ -3559,12 +3556,10 @@ impl<T: Config> Pallet<T> {
         let authority_index = exodus_storage.authority_index;
         let network_curve = exodus_storage.network_curve;
 
-        #[cfg(not(any(test, feature = "runtime-benchmarks")))]
-        let mut rng = Self::get_offchain_rng();
-
-        #[cfg(any(test, feature = "runtime-benchmarks"))]
-        let mut rng = Self::get_offchain_rng(authority_index);
+        let exodus_storage_encoded = exodus_storage.encode();
+        let rng_context = [exodus_storage_encoded.as_slice(), secret_share];
 
+        let mut rng = Self::get_offchain_rng(&rng_context);
         let (nonce, hiding_commitment, binding_commitment) = network_curve
             .generate_nonce_commitment(secret_share, &mut rng)?;
 
@@ -3776,12 +3771,15 @@ impl<T: Config> Pallet<T> {
             ));
         }
 
-        #[cfg(not(any(test, feature = "runtime-benchmarks")))]
-        let mut rng = Self::get_offchain_rng();
+        let dkg_storage_encoded = dkg_storage.encode();
+        let qualification_state_encoded = qualification_state.encode();
 
-        #[cfg(any(test, feature = "runtime-benchmarks"))]
-        let mut rng = Self::get_offchain_rng(authority_index);
+        let rng_context = [
+            dkg_storage_encoded.as_slice(),
+            qualification_state_encoded.as_slice(),
+        ];
 
+        let mut rng = Self::get_offchain_rng(&rng_context);
         let (secret_package, public_package) = network_curve
             .dkg_part1(authority_index, max_signers, min_signers, &mut rng)?;
 
@@ -4736,11 +4734,17 @@ impl<T: Config> Pallet<T> {
         dkg_index: DkgIndex,
         network_curve: NetworkCurve,
     ) {
-        #[cfg(not(any(test, feature = "runtime-benchmarks")))]
-        let mut rng = Self::get_offchain_rng();
+        let authority_index_bytes = authority_index.to_le_bytes();
+        let dkg_index_bytes = dkg_index.to_le_bytes();
+        let network_curve_bytes = [network_curve as u8];
 
-        #[cfg(any(test, feature = "runtime-benchmarks"))]
-        let mut rng = Self::get_offchain_rng(authority_index);
+        let rng_context = [
+            round1_secret_package,
+            authority_index_bytes.as_slice(),
+            dkg_index_bytes.as_slice(),
+            network_curve_bytes.as_slice(),
+        ];
+        let mut rng = Self::get_offchain_rng(&rng_context);
 
         for (&receiver_index, round2_package) in round2_packages.iter() {
             if receiver_index == authority_index { continue; }
@@ -4811,26 +4815,13 @@ impl<T: Config> Pallet<T> {
         }
     }
 
-    #[cfg(any(test, feature = "runtime-benchmarks"))]
-    fn get_offchain_rng(authority_index: AuthIndex) -> ChaCha20Rng {
-        let mut seed = [0u8; 32];
-
-        let unique_id = (authority_index as u64).saturating_add(1);
-        let index_bytes = unique_id.to_le_bytes();
-
-        for (i, &byte) in index_bytes.iter().enumerate() {
-            if i < seed.len() {
-                seed[i] ^= byte;
-            }
-        }
-
-        rand_chacha::ChaCha20Rng::from_seed(seed)
-    }
-
-    #[cfg(not(any(test, feature = "runtime-benchmarks")))]
-    fn get_offchain_rng() -> ChaCha20Rng {
+    fn get_offchain_rng(context: &[&[u8]]) -> ChaCha20Rng {
         let seed = sp_io::offchain::random_seed();
-        ChaCha20Rng::from_seed(seed)
+        let seeded_context = sp_std::iter::once(&seed[..])
+            .chain(context.iter().copied());
+
+        let hashed_seed = cumulative_hash::<SubstrateBlake2Hasher, _>(seeded_context);
+        ChaCha20Rng::from_seed(hashed_seed.to_fixed_bytes())
     }
 
     fn create_storage_key(first: &[u8], second: &[u8]) -> Vec<u8> {

pallets/exodus/src/types/local_storage.rs

@@ -75,7 +75,7 @@ impl<ExodusInnerType> ExodusStorageWrapper<ExodusInnerType> {
     }
 }
 
-#[derive(Default)]
+#[derive(Default, Encode)]
 pub struct ExodusStorage<BlockNumber, NetworkCurve>
 where
 	BlockNumber: Default,
@@ -365,7 +365,7 @@ where
     }
 }
 
-#[derive(Default, Clone, Copy)]
+#[derive(Default, Encode, Clone, Copy)]
 pub struct DkgStorage<BlockNumber, NetworkCurve>
 where
 	BlockNumber: Copy + Clone,

pallets/helpers/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ghost-helpers"
-version = "0.0.11"
+version = "0.0.13"
 description = "Cryptographic utility suite for custom runtimes: optimized Bitmaps, UTXO parsing, Merkle Tree proofs, and Hash Chain components."
 license.workspace = true
 authors.workspace = true

pallets/helpers/src/utxo.rs

@@ -3,6 +3,8 @@ use sp_std::vec::Vec;
 
 const MAX_INPUTS: usize = 3;
 const MAX_OUTPUTS: usize = 4;
+const MAX_FLAGS_LEN: usize = 8;
+const MAX_HASHES_LEN: usize = 16;
 const MAX_SCRIPT_LEN: usize = 512;
 pub const MAX_TX_LEN: usize = 4096;
 
@@ -27,20 +29,17 @@ pub struct Transaction<H: GhostHasher> {
     lock_time: u32,
 }
 
-pub struct Header<H: GhostHasher> {
-    pub merkle_root: H::Hash,
-    pub tx_count: u32,
-    pub tree_hashes: Vec<H::Hash>,
-    pub flags: Vec<u8>,
-}
+pub struct Header<H: GhostHasher>(sp_std::marker::PhantomData<H>);
 
 impl<H: GhostHasher> Header<H> {
-    fn calc_tree_width(&self, h: u32) -> u32 {
-        (self.tx_count + (1 << h) - 1) >> h
+    fn calc_tree_width(tx_count: u32, h: u32) -> u32 {
+        (tx_count + (1 << h) - 1) >> h
     }
 
     fn traverse(
-        &self,
+        tx_count: u32,
+        flags: &[u8],
+        tree_hashes: &[H::Hash],
         height: u32,
         pos: u32,
         bits_used: &mut u32,
@@ -51,19 +50,19 @@ impl<H: GhostHasher> Header<H> {
         let byte_idx = (*bits_used / 8) as usize;
         let bit_idx = (*bits_used % 8) as u8;
 
-        if byte_idx >= self.flags.len() {
+        if byte_idx >= flags.len() {
             return Err(ParseError::InvalidVarint(VarintError::BufferTooShort));
         }
 
-        let parent_of_match = ((self.flags[byte_idx] >> bit_idx) & 1) == 1;
+        let parent_of_match = ((flags[byte_idx] >> bit_idx) & 1) == 1;
         *bits_used += 1;
 
         if height == 0 || !parent_of_match {
-            if *hash_used as usize >= self.tree_hashes.len() {
+            if *hash_used as usize >= tree_hashes.len() {
                 return Err(ParseError::InvalidLength);
             }
 
-            let curr_hash = self.tree_hashes[*hash_used as usize];
+            let curr_hash = tree_hashes[*hash_used as usize];
             *hash_used += 1;
 
             if height == 0 && parent_of_match && curr_hash == target_txid {
@@ -73,7 +72,10 @@ impl<H: GhostHasher> Header<H> {
             return Ok(curr_hash);
         }
 
-        let left = self.traverse(
+        let left = Self::traverse(
+            tx_count,
+            flags,
+            tree_hashes,
             height - 1,
             pos * 2,
             bits_used,
@@ -82,8 +84,11 @@ impl<H: GhostHasher> Header<H> {
             target_txid,
         )?;
 
-        let right = if pos * 2 + 1 < self.calc_tree_width(height - 1) {
-            let right = self.traverse(
+        let right = if pos * 2 + 1 < Self::calc_tree_width(tx_count, height - 1) {
+            let right = Self::traverse(
+                tx_count,
+                flags,
+                tree_hashes,
                 height - 1,
                 pos * 2 + 1,
                 bits_used,
@@ -109,17 +114,83 @@ impl<H: GhostHasher> Header<H> {
         Ok(current_node_hash)
     }
 
-    pub fn extract_proof(&self, target_txid: H::Hash) -> Result<H::Hash, ParseError> {
+    pub fn verify_utxo_merkle_proof(
+        txproof_bytes: &[u8],
+        target_txid: H::Hash,
+    ) -> Result<(), ParseError> {
+        if txproof_bytes.len() < 85 {
+            return Err(ParseError::InvalidLength);
+        }
+
+        let header_bytes = &txproof_bytes[..80];
+        let mut bytes = &txproof_bytes[80..];
+
+        let mut merkle_root = [0u8; 32];
+        merkle_root.copy_from_slice(&header_bytes[36..68]);
+
+        if bytes.len() < 4 {
+            return Err(ParseError::InvalidLength);
+        }
+
+        let tx_count = u32::from_le_bytes(
+            bytes[..4]
+                .try_into()
+                .map_err(|_| ParseError::TypeConversionFailed)?,
+        );
+        bytes = &bytes[4..];
+        let hash_count = read_varint(&mut bytes)?;
+
+        if hash_count > MAX_HASHES_LEN {
+            return Err(ParseError::InvalidLength);
+        }
+
+        let hash_count_bytes = hash_count
+            .checked_mul(32)
+            .ok_or(ParseError::TypeConversionFailed)?;
+
+        if bytes.len() < hash_count_bytes {
+            return Err(ParseError::InvalidLength);
+        }
+
+        let tree_hashes_bytes = &bytes[..hash_count_bytes];
+        bytes = &bytes[hash_count_bytes..];
+
+        let tree_hashes: Vec<H::Hash> = tree_hashes_bytes
+            .chunks_exact(32)
+            .map(|chunk| H::from_slice(chunk))
+            .collect();
+
+        let flags_count = read_varint(&mut bytes)?;
+
+        if flags_count > MAX_FLAGS_LEN {
+            return Err(ParseError::InvalidLength);
+        }
+
+        if bytes.len() < flags_count {
+            return Err(ParseError::InvalidLength);
+        }
+
+        let flags = bytes[..flags_count].to_vec();
+        bytes = &bytes[flags_count..];
+
+        if !bytes.is_empty() {
+            return Err(ParseError::InvalidLength);
+        }
+
         let mut bits_used = 0u32;
         let mut hash_used = 0u32;
 
         let mut matched_index = None;
         let mut max_height = 0;
-        while (1 << max_height) < self.tx_count {
+
+        while (1 << max_height) < tx_count {
             max_height += 1;
         }
 
-        let computed_root = self.traverse(
+        let computed_root = Self::traverse(
+            tx_count,
+            &flags,
+            &tree_hashes,
             max_height,
             0,
             &mut bits_used,
@@ -128,19 +199,23 @@ impl<H: GhostHasher> Header<H> {
             target_txid,
         )?;
 
-        if hash_used as usize != self.tree_hashes.len() {
+        if hash_used as usize != tree_hashes.len() {
             return Err(ParseError::InvalidLength);
         }
 
-        if (bits_used + 7) / 8 != self.flags.len() as u32 {
+        if (bits_used + 7) / 8 != flags.len() as u32 {
             return Err(ParseError::InvalidLength);
         }
 
-        if matched_index.is_some() {
-            Ok(computed_root)
-        } else {
-            Err(ParseError::TransactionNotFoundInProof)
+        if matched_index.is_none() {
+            return Err(ParseError::TransactionNotFoundInProof);
         }
+
+        if computed_root != H::from_slice(&merkle_root) {
+            return Err(ParseError::InvalidMerkleRoot);
+        }
+
+        Ok(())
     }
 }
 
@@ -357,6 +432,9 @@ fn read_varint(bytes: &mut &[u8]) -> Result<usize, VarintError> {
                     .try_into()
                     .map_err(|_| VarintError::TypeConversionFailed)?,
             );
+            if val < 0xfd {
+                return Err(VarintError::TypeConversionFailed);
+            }
             *bytes = &bytes[2..];
             Ok(val as usize)
         }
@@ -369,6 +447,9 @@ fn read_varint(bytes: &mut &[u8]) -> Result<usize, VarintError> {
                     .try_into()
                     .map_err(|_| VarintError::TypeConversionFailed)?,
             );
+            if val < 0x10000 {
+                return Err(VarintError::TypeConversionFailed);
+            }
             *bytes = &bytes[4..];
             Ok(val as usize)
         }
@@ -381,6 +462,9 @@ fn read_varint(bytes: &mut &[u8]) -> Result<usize, VarintError> {
                     .try_into()
                     .map_err(|_| VarintError::TypeConversionFailed)?,
             );
+            if val < 0x100000000 {
+                return Err(VarintError::TypeConversionFailed);
+            }
             *bytes = &bytes[8..];
             Ok(val as usize)
         }
@@ -392,6 +476,7 @@ fn read_varint(bytes: &mut &[u8]) -> Result<usize, VarintError> {
 pub enum ParseError {
     InvalidLength,
     ExceededMaxLimits,
+    InvalidMerkleRoot,
     TypeConversionFailed,
     TransactionNotFoundInProof,
     InvalidVarint(VarintError),
@@ -525,60 +610,3 @@ impl<'a, H: GhostHasher> TryFrom<&'a [u8]> for Transaction<H> {
         })
     }
 }
-
-impl<'a, H: GhostHasher> TryFrom<&'a [u8]> for Header<H> {
-    type Error = ParseError;
-
-    fn try_from(mut bytes: &[u8]) -> Result<Self, Self::Error> {
-        if bytes.len() < 85 {
-            return Err(ParseError::InvalidLength);
-        }
-
-        let header_bytes = &bytes[..80];
-        bytes = &bytes[80..];
-
-        let mut merkle_root = [0u8; 32];
-        merkle_root.copy_from_slice(&header_bytes[36..68]);
-
-        if bytes.len() < 4 {
-            return Err(ParseError::InvalidLength);
-        }
-        let tx_count = u32::from_le_bytes(
-            bytes[..4]
-                .try_into()
-                .map_err(|_| ParseError::TypeConversionFailed)?,
-        );
-        bytes = &bytes[4..];
-
-        let hash_count = read_varint(&mut bytes)?;
-        if bytes.len() < hash_count * 32 {
-            return Err(ParseError::InvalidLength);
-        }
-
-        let tree_hashes_bytes = &bytes[..hash_count * 32];
-        bytes = &bytes[hash_count * 32..];
-
-        let tree_hashes: Vec<H::Hash> = tree_hashes_bytes
-            .chunks_exact(32)
-            .map(|chunk| H::from_slice(chunk))
-            .collect();
-
-        let flags_count = read_varint(&mut bytes)?;
-        if bytes.len() < flags_count {
-            return Err(ParseError::InvalidLength);
-        }
-        let flags = bytes[..flags_count].to_vec();
-        bytes = &bytes[flags_count..];
-
-        if !bytes.is_empty() {
-            return Err(ParseError::InvalidLength);
-        }
-
-        Ok(Self {
-            merkle_root: H::from_slice(&merkle_root),
-            tx_count,
-            tree_hashes,
-            flags,
-        })
-    }
-}

pallets/weaver/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ghost-weaver"
-version = "0.0.14"
+version = "0.0.19"
 description = "Weaving a secure cryptographic tapestry across different external chains."
 license.workspace = true
 authors.workspace = true

pallets/weaver/src/benchmarking.rs

@@ -35,6 +35,9 @@ fn prepare_pallet<T: Config>(
     T::NetworkDataHandler::register(network_id, network_data)
         .expect("network should be valid for insertion");
 
+    let current_block = T::BlockNumberProvider::current_block_number();
+    Pallet::<T>::on_initialize(current_block);
+
     (network_id, authority, 0)
 }
 

pallets/weaver/src/lib.rs

@@ -330,22 +330,13 @@ pub mod pallet {
 
             let external_block = block_attestation.external_block;
 
-            let current_authorities_count = Authorities::<T>::decode_len().
-                unwrap_or_default();
-
             NetworkAttestations::<T>::try_mutate(
                 &network_id,
                 |attestations| -> DispatchResult {
-                    if attestations.is_empty() {
-                        attestations.bounded_resize(current_authorities_count, None);
-                    }
+                    let index = authority_index as usize;
 
-                    ensure!(
-                        (authority_index as usize) < attestations.len(),
-                        Error::<T>::TooManyAttestations,
-                    );
-
-                    attestations[authority_index as usize] = Some(external_block);
+                    ensure!(index < attestations.len(), Error::<T>::TooManyAttestations);
+                    attestations[index] = Some(external_block);
 
                     Ok(())
                 })?;
@@ -518,8 +509,9 @@ pub mod pallet {
                             CurrentWeavingSession::<T>::insert(&network_id, next_session);
                         }
 
-                        weight.saturating_accrue(T::DbWeight::get().writes(1));
+                        weight.saturating_accrue(T::DbWeight::get().writes(2));
                         TapestryDrafts::<T>::remove(&network_id);
+                        WeavingStates::<T>::remove(&network_id);
                     }
                 }
                 None => {
@@ -532,9 +524,11 @@ pub mod pallet {
                     weight.saturating_accrue(T::DbWeight::get().reads(1));
                     let attestation_len = NetworkAttestations::<T>::decode_len(&network_id);
 
-                    if attestation_len.unwrap_or(0) > len {
-                        weight.saturating_accrue(T::DbWeight::get().writes(1));
-                        NetworkAttestations::<T>::remove(&network_id);
+                    if attestation_len.unwrap_or(0) != len {
+                        weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 1));
+                        NetworkAttestations::<T>::mutate(&network_id, |attestations| {
+                            attestations.bounded_resize(len, None);
+                        });
                         return weight;
                     }
 
@@ -616,6 +610,21 @@ pub mod pallet {
                         .propagate(true)
                         .build()
                 }
+                Call::pull_thread {
+                    network_id,
+                    session,
+                    thread_proof,
+                } => {
+                    let thread_context =
+                        Self::validate_thread(network_id, session, thread_proof)?;
+
+                    ValidTransaction::with_tag_prefix("WeaverThread")
+                        .priority(T::UnsignedPriority::get())
+                        .and_provides(thread_context.to_fixed_bytes())
+                        .longevity(LOCK_BLOCK_EXPIRATION)
+                        .propagate(true)
+                        .build()
+                }
                 _ => InvalidTransaction::Call.into(),
             }
         }
@@ -623,6 +632,31 @@ pub mod pallet {
 }
 
 impl<T: Config> Pallet<T> {
+    fn validate_thread(
+        network_id: &NetworkIdOf<T>,
+        session: &WeavingSession,
+        thread_proof: &ThreadProof<BalanceOf<T>>,
+    ) -> Result<H256, InvalidTransaction> {
+        let network_data = T::NetworkDataHandler::get(&network_id)
+            .ok_or(InvalidTransaction::BadProof)?;
+
+        let root_hash = LoomStates::<T>::get(&network_id, &session);
+        if root_hash == Default::default() {
+            return Err(InvalidTransaction::BadProof);
+        }
+
+        thread_proof
+            .verify_thread_proof(root_hash, *network_id, &network_data.gatekeeper)
+            .ok_or(InvalidTransaction::BadProof)?;
+
+        let pulled_thread_key = thread_proof.get_unique_key(*session, *network_id);
+        if PulledThreads::<T>::contains_key(&pulled_thread_key) {
+            return Err(InvalidTransaction::Stale);
+        }
+
+        Ok(pulled_thread_key)
+    }
+
     fn validate_attestation_signature<A>(
         attestation: &A,
         signature: &<T::AuthorityId as RuntimeAppPublic>::Signature,
@@ -635,6 +669,13 @@ impl<T: Config> Pallet<T> {
         let attestation_block = attestation.block();
         let network_id = attestation.network_id();
 
+        let current_attestation_len = NetworkAttestations::<T>::decode_len(&network_id)
+            .unwrap_or(0);
+
+        if authority_index as usize >= current_attestation_len {
+            return Err(InvalidTransaction::BadSigner.into());
+        }
+
         if DisabledAuthorities::<T>::get().contains(authority_index) {
             return Err(InvalidTransaction::BadSigner);
         }

pallets/weaver/src/tests.rs

@@ -76,6 +76,7 @@ fn should_successfully_compute_median_and_start_weaving_round() {
     let networks = vec![(network_id, network_data, Default::default())];
 
     new_test_ext(authorities, networks).execute_with(|| {
+        GhostWeaver::on_initialize(1);
         System::set_block_number(2);
 
         let context = AttestationContext::default()
@@ -120,6 +121,7 @@ fn should_apply_cooldown_delay_on_consensus_failure() {
     let networks = vec![(network_id, network_data, Default::default())];
 
     new_test_ext(authorities, networks).execute_with(|| {
+        GhostWeaver::on_initialize(9);
         System::set_block_number(10);
 
         let context = AttestationContext::default()
@@ -168,6 +170,7 @@ fn validate_unsigned_should_prevent_mempool_dos_via_tags() {
     let networks = vec![(network_id, network_data, Default::default())];
 
     new_test_ext(authorities, networks).execute_with(|| {
+        GhostWeaver::on_initialize(1);
         System::set_block_number(2);
 
         let att = AttestationContext::default()
@@ -240,6 +243,9 @@ fn offchain_worker_should_fetch_block_and_submit_unsigned_tx() {
     ext.register_extension(TransactionPoolExt::new(pool));
 
     ext.execute_with(|| {
+        GhostWeaver::on_initialize(1);
+        GhostWeaver::on_initialize(2);
+
         let network_id_encoded = evm_network_id.encode();
 
         let mut endpoint_key = b"ghost-weaver::".to_vec();
@@ -406,10 +412,11 @@ fn offchain_worker_should_fetch_hash_and_submit_unsigned_tx() {
     ext.register_extension(TransactionPoolExt::new(pool));
 
     ext.execute_with(|| {
+        GhostWeaver::on_initialize(1);
+        GhostWeaver::on_initialize(2);
+
         let tapestry_draft = TapestryDraftBuilder::<crate::ExternalBlockNumber, u32>::default();
-
         let evm_tapestry_draft = tapestry_draft.with_median_external(25639556).build();
-
         let utxo_tapestry_draft = tapestry_draft.with_median_external(960129).build();
 
         CurrentWeavingSession::<TestRuntime>::insert(&evm_network_id, evm_session);
@@ -635,6 +642,8 @@ fn should_successfully_pull_evm_thread_and_mint_currency() {
     ];
 
     new_test_ext(authorities, networks).execute_with(|| {
+        GhostWeaver::on_initialize(1);
+
         // https://sepolia.etherscan.io/address/0x7fec11e652f4d54e8cf11c4b52c360380332f2bd#readContract
         // getRoot: session 0, atBlock 11716130
         let session = 0;
@@ -801,6 +810,116 @@ fn should_successfully_pull_utxo_thread_and_mint_currency() {
     });
 }
 
+#[test]
+fn should_successfully_pull_utxo_thread_and_reject_nominal_varint_encoding() {
+    let pair = AuthorityPair::from_string("//Alice", None).expect("Should be valid seed");
+    let incoming_share = 0;
+
+    let network_id = 69;
+    let network_data = NetworkDataBuilder::default()
+        .with_network_type(NetworkType::Utxo)
+        .with_incoming_share(incoming_share)
+        .with_gatekeeper(
+            // Transaction: https://blockstream.info/tx/4a3fdd9ebb30b9c6df05d4199f8474b2f0c795d1f40a58d0d73342fc666b4a2e
+            hex::decode("4635b1794a22bfbe6c5c5eba17b693f4aaf0e348")
+                .expect("Bytes32 from UTXO should be valid"),
+        )
+        .build();
+
+    let authorities = vec![pair.clone()];
+    let networks = vec![(network_id, network_data, Default::default())];
+
+    // Real world tx at block #481838
+    // Block https://blockstream.info/block/0000000000000000011bdccb39e19e942a60edffdccd9779653c5b46b337904a
+    // Transaction: https://blockstream.info/tx/4a3fdd9ebb30b9c6df05d4199f8474b2f0c795d1f40a58d0d73342fc666b4a2e
+
+    let payload = (
+        // curl --data-binary '{"jsonrpc": "2.0", "id": "test-proof", "method": "gettxoutproof", "params": [["4a3fdd9ebb30b9c6df05d4199f8474b2f0c795d1f40a58d0d73342fc666b4a2e"], "0000000000000000011bdccb39e19e942a60edffdccd9779653c5b46b337904a"]}' -H 'Content-Type: application/json' https://bitcoin-rpc.publicnode.com
+        hex::decode("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").expect("Bytes32 from UTXO should be valid"),
+        // curl --data-binary '{"jsonrpc": "2.0", "id": "test-proof", "method": "getrawtransaction", "params": ["4a3fdd9ebb30b9c6df05d4199f8474b2f0c795d1f40a58d0d73342fc666b4a2e", false]}' -H 'Content-Type: application/json' https://bitcoin-rpc.publicnode.com
+        hex::decode("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").expect("Bytes32 from UTXO should be valid"),
+        vec![
+            // curl --data-binary '{"jsonrpc": "2.0", "id": "test-proof", "method": "getblockheader", "params": ["000000000000000000e7da64065cc23d5c5a5aa402f088aaaf37c5fe1c3b6b92", false]}' -H 'Content-Type: application/json' https://bitcoin-rpc.publicnode.com
+            hex::decode("000000204a9037b3465b3c657997cddcffed602a949ee139cbdc1b010000000000000000669c3e2472384bc95993f154aada38d6b2113d8d32069e32e2724ba40915a1802a669e59e93c011801c8c735").expect("Bytes32 from UTXO should be valid"),
+            // curl --data-binary '{"jsonrpc": "2.0", "id": "test-proof", "method": "getblockheader", "params": ["00000000000000000063da6d9362c0ac3b87877d1c5ad7afd5bd706571d5b393", false]}' -H 'Content-Type: application/json' https://bitcoin-rpc.publicnode.com
+            hex::decode("02000020926b3b1cfec537afaa88f002a45a5a5c3dc25c0664dae7000000000000000000af0f270bf3f868d47089f395197809c360f1506636c960d96afed68bbd72d0b4496d9e59e93c01183ac94b67").expect("Bytes32 from UTXO should be valid"),
+            // curl --data-binary '{"jsonrpc": "2.0", "id": "test-proof", "method": "getblockheader", "params": ["000000000000000000ec6063eb743366264368be7ff5021727682cb518963026", false]}' -H 'Content-Type: application/json' https://bitcoin-rpc.publicnode.com
+            hex::decode("0000002093b3d5716570bdd5afd75a1c7d87873bacc062936dda630000000000000000009ab437e7c66b10a59b67127f290d24f381aba4e03d5e16c062a356eea4d608dea56d9e59e93c0118264f310e").expect("Bytes32 from UTXO should be valid"),
+        ],
+    );
+
+    let encodings = vec![
+        vec![0x02],                                                 // canonical
+        vec![0xFD, 0x02, 0x00],                                     // non-minimal 3 bytes
+        vec![0xFE, 0x02, 0x00, 0x00, 0x00],                         // non-minimal 5 bytes
+        vec![0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00], // non-minimal 9 bytes
+    ];
+
+    new_test_ext(authorities, networks).execute_with(|| {
+        let session = 0;
+        let block_hash =
+            hex::decode("000000000000000000ec6063eb743366264368be7ff5021727682cb518963026")
+                .expect("Bitcoin Root hex should be valid");
+
+        let expected_root = H256::from_slice(&block_hash);
+        LoomStates::<TestRuntime>::insert(&network_id, &session, expected_root);
+
+        let expected_receiver_bytes = hex::decode("1657090d02985f0cdb41436fe2d5a83a3acb1995d963a698e7e619e927bdcc5e").unwrap();
+        let mut receiver_raw = [0u8; 32];
+        receiver_raw.copy_from_slice(&expected_receiver_bytes);
+
+        let receiver_account = sp_runtime::AccountId32::from(receiver_raw);
+        let transfer_amount: u64 = 153348847;
+        let mut expected_pure_amount: u64 = 0;
+
+        for (idx, enc) in encodings.iter().enumerate() {
+            let mut variant = Vec::with_capacity(payload.1.len() + enc.len() - 1);
+            variant.extend_from_slice(&payload.1[0..4]);
+            variant.extend_from_slice(&enc);
+            variant.extend_from_slice(&payload.1[5..]);
+
+            let utxo_thread_proof = UtxoThreadProof::new(payload.0.clone(), variant, payload.2.clone());
+            let thread_info = ThreadProof::UtxoThreadProof(utxo_thread_proof);
+            let pulled_thread_key = thread_info.get_unique_key(session, network_id);
+
+            assert_eq!(Balances::free_balance(&receiver_account), expected_pure_amount);
+            assert!(!PulledThreads::<TestRuntime>::contains_key(
+                &pulled_thread_key
+            ));
+
+            let pull_result = GhostWeaver::pull_thread(
+                RuntimeOrigin::none(),
+                network_id,
+                session,
+                thread_info
+            );
+
+            if idx == 0 {
+                assert!(pull_result.is_ok());
+                assert!(PulledThreads::<TestRuntime>::contains_key(&pulled_thread_key));
+
+                let curve_share = Perbill::from_parts(incoming_share).mul_ceil(transfer_amount);
+                expected_pure_amount += transfer_amount.saturating_sub(curve_share);
+
+                assert_eq!(Balances::free_balance(&receiver_account), expected_pure_amount);
+
+                System::assert_last_event(RuntimeEvent::GhostWeaver(Event::ThreadPulled {
+                    pulled_thread_key,
+                    network_id,
+                    receiver: receiver_account.clone(),
+                    amount: transfer_amount,
+                }));
+            } else {
+                assert!(pull_result.is_err());
+                assert!(!PulledThreads::<TestRuntime>::contains_key(&pulled_thread_key));
+                assert_eq!(Balances::free_balance(&receiver_account), expected_pure_amount);
+            }
+        }
+
+        assert_eq!(Balances::free_balance(&receiver_account), transfer_amount);
+    });
+}
+
 #[test]
 fn on_initialize_should_finalize_session_when_timeout_is_reached() {
     let pair1 = AuthorityPair::from_string("//Alice", None).expect("Should be valid seed");
@@ -818,6 +937,7 @@ fn on_initialize_should_finalize_session_when_timeout_is_reached() {
 
     new_test_ext(authorities, networks).execute_with(|| {
         let current_substrate_block = 10;
+        GhostWeaver::on_initialize(current_substrate_block);
         System::set_block_number(current_substrate_block + 1);
 
         let tapestry_draft = TapestryDraftBuilder::default()

pallets/weaver/src/types.rs

@@ -14,7 +14,6 @@ use ghost_helpers::{
     merkle_tree::verify_tree_proof,
     SubstrateBlake2Hasher, SubstrateKeccakHasher, UtxoSha2Hasher,
 };
-use ghost_traits::hashing::GhostHasher;
 
 use crate::{ExternalBlockNumber, ThreadId, WeavingSession};
 
@@ -350,8 +349,10 @@ where
 	{
         if EVM_MERKLE_DEPTH as usize != self.proof.len() { return None; }
 
+        let preimage_hash = self.get_preimage_hash(network_id)?;
+
         let proof_valid = verify_tree_proof::<SubstrateKeccakHasher, _>(
-            &self.get_preimage_slice(network_id).to_fixed_bytes(),
+            &preimage_hash.to_fixed_bytes(),
             self.proof.as_ref(),
             root_hash,
             self.proof_index,
@@ -362,22 +363,17 @@ where
         Some((self.receiver.clone(), self.amount))
     }
 
-    fn get_preimage_slice<NetworkId>(&self, network_id: NetworkId) -> H256
+    fn get_preimage_hash<NetworkId>(&self, network_id: NetworkId) -> Option<H256>
 	where
 		NetworkId: Copy + Clone + Eq + PartialEq + UniqueSaturatedInto<u64>,
 	{
         let slot_index_usize: usize = self.slot_index.unique_saturated_into();
-        let mut slot_values: Vec<H256> = self.slots.to_vec();
 
-        match slot_values.get_mut(slot_index_usize) {
-            Some(slot) => {
-                *slot = self.compute_arguments_hash(network_id);
-                cumulative_hash::<SubstrateKeccakHasher, _>(slot_values)
-            }
-            None => {
-                SubstrateKeccakHasher::empty()
-            }
-        }
+        self.slots.get(slot_index_usize)
+            .filter(|&&provided_hash| {
+                provided_hash == self.compute_arguments_hash(network_id)
+            })
+            .map(|_| cumulative_hash::<SubstrateKeccakHasher, _>(self.slots.iter()))
     }
 
     pub fn get_unique_key<NetworkId>(
@@ -483,7 +479,7 @@ impl UtxoThreadProof {
 
     pub fn verify_thread_proof<Balance>(
         &self,
-        root_hash: H256,
+        block_hash: H256,
         gatekeeper_ref: &[u8],
     ) -> Option<(AccountId32, Balance)>
 	where
@@ -498,7 +494,7 @@ impl UtxoThreadProof {
         let is_chain_valid = verify_hash_ancestry::<UtxoSha2Hasher, _>(
             header_bytes,
             self.ancestry_headers.iter(),
-            root_hash,
+            block_hash,
         );
 
         if !is_chain_valid { return None; }
@@ -507,13 +503,11 @@ impl UtxoThreadProof {
             self.getrawtransaction_bytes.as_ref()
         ).ok()?;
 
-        let header = Header::<UtxoSha2Hasher>::try_from(
-            self.gettxproof_bytes.as_ref(),
-        ).ok()?;
-
         let txid_preimage = transaction.compute_txid()?;
-        let root_hash = header.extract_proof(txid_preimage).ok()?;
-        if root_hash != header.merkle_root { return None; }
+        Header::<UtxoSha2Hasher>::verify_utxo_merkle_proof(
+            self.gettxproof_bytes.as_ref(),
+            txid_preimage,
+        ).ok()?;
 
         #[cfg(not(any(test, feature = "runtime-benchmarks")))]
         let destination_script = Transaction::<UtxoSha2Hasher>::convert_into_p2tr(gatekeeper_ref)?;