imp: Enable custom paths for light client proof verifications (#1273)

* refactor: allow using custom path for light client proof verification

* imp: 2nd try, place serialize_path under the ClientStateCommon

* feat: define concat() for PathBytes

* fix: update cw-check cargo.lock

* chore: add docs and unclog

* misc: apply some fixes

* imp: group serialize_path and verify_(non_)membership_raw methods

* nit: reword changelog

* fix grammar

* imp: rename to flatten + revert to Path::*(*)

* fix typo

* fix: make clippy happy

* fix: move changelog to features

---------

Co-authored-by: Ranadeep Biswas <[email protected]>

.changelog/unreleased/features/1255-enable-custom-paths-for-proof-verificaitons.md

@@ -0,0 +1,4 @@
+- [ibc-core-client] Enable proof verification methods to accept custom paths as
+  bytes by defining a new `serializer_path()` API allowing light client
+  developers to introduce the path serialization behavior of their system.
+  ([\#1255](https://github.com/cosmos/ibc-rs/issues/1255))

ibc-clients/cw-context/src/handlers.rs

@@ -70,7 +70,7 @@ where
 
                 let consensus_state = self.consensus_state(&client_cons_state_path)?;
 
-                client_state.verify_membership(
+                client_state.verify_membership_raw(
                     &msg.prefix,
                     &msg.proof,
                     consensus_state.root(),
@@ -91,7 +91,7 @@ where
 
                 let consensus_state = self.consensus_state(&client_cons_state_path)?;
 
-                client_state.verify_non_membership(
+                client_state.verify_non_membership_raw(
                     &msg.prefix,
                     &msg.proof,
                     consensus_state.root(),

ibc-clients/cw-context/src/types/msgs.rs

@@ -1,13 +1,12 @@
 //! Defines the messages sent to the CosmWasm contract by the 08-wasm proxy
 //! light client.
-use std::str::FromStr;
-
 use cosmwasm_schema::{cw_serde, QueryResponses};
 use cosmwasm_std::{Binary, Checksum};
 use ibc_core::client::types::proto::v1::Height as RawHeight;
 use ibc_core::client::types::Height;
 use ibc_core::commitment_types::commitment::{CommitmentPrefix, CommitmentProofBytes};
-use ibc_core::host::types::path::Path;
+use ibc_core::commitment_types::merkle::MerklePath;
+use ibc_core::host::types::path::PathBytes;
 use ibc_core::primitives::proto::Any;
 use prost::Message;
 
@@ -116,11 +115,6 @@ impl TryFrom<VerifyUpgradeAndUpdateStateMsgRaw> for VerifyUpgradeAndUpdateStateM
     }
 }
 
-#[cw_serde]
-pub struct MerklePath {
-    pub key_path: Vec<String>,
-}
-
 #[cw_serde]
 pub struct VerifyMembershipMsgRaw {
     pub proof: Binary,
@@ -134,7 +128,7 @@ pub struct VerifyMembershipMsgRaw {
 pub struct VerifyMembershipMsg {
     pub prefix: CommitmentPrefix,
     pub proof: CommitmentProofBytes,
-    pub path: Path,
+    pub path: PathBytes,
     pub value: Vec<u8>,
     pub height: Height,
     pub delay_block_period: u64,
@@ -146,17 +140,16 @@ impl TryFrom<VerifyMembershipMsgRaw> for VerifyMembershipMsg {
 
     fn try_from(mut raw: VerifyMembershipMsgRaw) -> Result<Self, Self::Error> {
         let proof = CommitmentProofBytes::try_from(raw.proof.to_vec())?;
-        let prefix = raw.path.key_path.remove(0).into_bytes();
-        let path_str = raw.path.key_path.join("");
-        let path = Path::from_str(&path_str)?;
+        let prefix = CommitmentPrefix::from(raw.path.key_path.remove(0).into_vec());
+        let path = PathBytes::flatten(raw.path.key_path);
         let height = Height::try_from(raw.height)?;
 
         Ok(Self {
             proof,
             path,
             value: raw.value.into(),
             height,
-            prefix: CommitmentPrefix::from(prefix),
+            prefix,
             delay_block_period: raw.delay_block_period,
             delay_time_period: raw.delay_time_period,
         })
@@ -175,7 +168,7 @@ pub struct VerifyNonMembershipMsgRaw {
 pub struct VerifyNonMembershipMsg {
     pub prefix: CommitmentPrefix,
     pub proof: CommitmentProofBytes,
-    pub path: Path,
+    pub path: PathBytes,
     pub height: Height,
     pub delay_block_period: u64,
     pub delay_time_period: u64,
@@ -186,15 +179,15 @@ impl TryFrom<VerifyNonMembershipMsgRaw> for VerifyNonMembershipMsg {
 
     fn try_from(mut raw: VerifyNonMembershipMsgRaw) -> Result<Self, Self::Error> {
         let proof = CommitmentProofBytes::try_from(raw.proof.to_vec())?;
-        let prefix = raw.path.key_path.remove(0).into_bytes();
-        let path_str = raw.path.key_path.join("");
-        let path = Path::from_str(&path_str)?;
+        let prefix = CommitmentPrefix::from(raw.path.key_path.remove(0).into_vec());
+        let path = PathBytes::flatten(raw.path.key_path);
         let height = raw.height.try_into()?;
+
         Ok(Self {
             proof,
             path,
             height,
-            prefix: CommitmentPrefix::from(prefix),
+            prefix,
             delay_block_period: raw.delay_block_period,
             delay_time_period: raw.delay_time_period,
         })

ibc-clients/ics07-tendermint/src/client_state/common.rs

@@ -7,11 +7,11 @@ use ibc_core_commitment_types::commitment::{
     CommitmentPrefix, CommitmentProofBytes, CommitmentRoot,
 };
 use ibc_core_commitment_types::error::CommitmentError;
-use ibc_core_commitment_types::merkle::{apply_prefix, MerkleProof};
+use ibc_core_commitment_types::merkle::{MerklePath, MerkleProof};
 use ibc_core_commitment_types::proto::ics23::{HostFunctionsManager, HostFunctionsProvider};
 use ibc_core_commitment_types::specs::ProofSpecs;
 use ibc_core_host::types::identifiers::ClientType;
-use ibc_core_host::types::path::{Path, UpgradeClientPath};
+use ibc_core_host::types::path::{Path, PathBytes, UpgradeClientPath};
 use ibc_primitives::prelude::*;
 use ibc_primitives::proto::Any;
 use ibc_primitives::ToVec;
@@ -44,22 +44,38 @@ impl ClientStateCommon for ClientState {
         proof_upgrade_consensus_state: CommitmentProofBytes,
         root: &CommitmentRoot,
     ) -> Result<(), ClientError> {
+        let last_height = self.latest_height().revision_height();
+
+        let upgrade_client_path_bytes = self.serialize_path(Path::UpgradeClient(
+            UpgradeClientPath::UpgradedClientState(last_height),
+        ))?;
+
+        let upgrade_consensus_path_bytes = self.serialize_path(Path::UpgradeClient(
+            UpgradeClientPath::UpgradedClientConsensusState(last_height),
+        ))?;
+
         verify_upgrade_client::<HostFunctionsManager>(
             self.inner(),
             upgraded_client_state,
             upgraded_consensus_state,
             proof_upgrade_client,
             proof_upgrade_consensus_state,
+            upgrade_client_path_bytes,
+            upgrade_consensus_path_bytes,
             root,
         )
     }
 
-    fn verify_membership(
+    fn serialize_path(&self, path: Path) -> Result<PathBytes, ClientError> {
+        Ok(path.to_string().into_bytes().into())
+    }
+
+    fn verify_membership_raw(
         &self,
         prefix: &CommitmentPrefix,
         proof: &CommitmentProofBytes,
         root: &CommitmentRoot,
-        path: Path,
+        path: PathBytes,
         value: Vec<u8>,
     ) -> Result<(), ClientError> {
         verify_membership::<HostFunctionsManager>(
@@ -72,12 +88,12 @@ impl ClientStateCommon for ClientState {
         )
     }
 
-    fn verify_non_membership(
+    fn verify_non_membership_raw(
         &self,
         prefix: &CommitmentPrefix,
         proof: &CommitmentProofBytes,
         root: &CommitmentRoot,
-        path: Path,
+        path: PathBytes,
     ) -> Result<(), ClientError> {
         verify_non_membership::<HostFunctionsManager>(
             &self.inner().proof_specs,
@@ -140,12 +156,15 @@ pub fn validate_proof_height(
 /// Note that this function is typically implemented as part of the
 /// [`ClientStateCommon`] trait, but has been made a standalone function
 /// in order to make the ClientState APIs more flexible.
+#[allow(clippy::too_many_arguments)]
 pub fn verify_upgrade_client<H: HostFunctionsProvider>(
     client_state: &ClientStateType,
     upgraded_client_state: Any,
     upgraded_consensus_state: Any,
     proof_upgrade_client: CommitmentProofBytes,
     proof_upgrade_consensus_state: CommitmentProofBytes,
+    upgrade_client_path_bytes: PathBytes,
+    upgrade_consensus_path_bytes: PathBytes,
     root: &CommitmentRoot,
 ) -> Result<(), ClientError> {
     // Make sure that the client type is of Tendermint type `ClientState`
@@ -178,15 +197,13 @@ pub fn verify_upgrade_client<H: HostFunctionsProvider>(
 
     let upgrade_path_prefix = CommitmentPrefix::from(upgrade_path[0].clone().into_bytes());
 
-    let last_height = latest_height.revision_height();
-
     // Verify the proof of the upgraded client state
     verify_membership::<H>(
         &client_state.proof_specs,
         &upgrade_path_prefix,
         &proof_upgrade_client,
         root,
-        Path::UpgradeClient(UpgradeClientPath::UpgradedClientState(last_height)),
+        upgrade_client_path_bytes,
         upgraded_client_state.to_vec(),
     )?;
 
@@ -196,7 +213,7 @@ pub fn verify_upgrade_client<H: HostFunctionsProvider>(
         &upgrade_path_prefix,
         &proof_upgrade_consensus_state,
         root,
-        Path::UpgradeClient(UpgradeClientPath::UpgradedClientConsensusState(last_height)),
+        upgrade_consensus_path_bytes,
         upgraded_consensus_state.to_vec(),
     )?;
 
@@ -213,7 +230,7 @@ pub fn verify_membership<H: HostFunctionsProvider>(
     prefix: &CommitmentPrefix,
     proof: &CommitmentProofBytes,
     root: &CommitmentRoot,
-    path: Path,
+    path: PathBytes,
     value: Vec<u8>,
 ) -> Result<(), ClientError> {
     if prefix.is_empty() {
@@ -222,7 +239,7 @@ pub fn verify_membership<H: HostFunctionsProvider>(
         ));
     }
 
-    let merkle_path = apply_prefix(prefix, vec![path.to_string()]);
+    let merkle_path = MerklePath::new(vec![prefix.as_bytes().to_vec().into(), path]);
     let merkle_proof = MerkleProof::try_from(proof).map_err(ClientError::InvalidCommitmentProof)?;
 
     merkle_proof
@@ -240,9 +257,9 @@ pub fn verify_non_membership<H: HostFunctionsProvider>(
     prefix: &CommitmentPrefix,
     proof: &CommitmentProofBytes,
     root: &CommitmentRoot,
-    path: Path,
+    path: PathBytes,
 ) -> Result<(), ClientError> {
-    let merkle_path = apply_prefix(prefix, vec![path.to_string()]);
+    let merkle_path = MerklePath::new(vec![prefix.as_bytes().to_vec().into(), path]);
     let merkle_proof = MerkleProof::try_from(proof).map_err(ClientError::InvalidCommitmentProof)?;
 
     merkle_proof

ibc-core/ics02-client/context/src/client_state.rs

@@ -6,7 +6,7 @@ use ibc_core_commitment_types::commitment::{
     CommitmentPrefix, CommitmentProofBytes, CommitmentRoot,
 };
 use ibc_core_host_types::identifiers::{ClientId, ClientType};
-use ibc_core_host_types::path::Path;
+use ibc_core_host_types::path::{Path, PathBytes};
 use ibc_primitives::prelude::*;
 use ibc_primitives::proto::Any;
 
@@ -52,26 +52,57 @@ pub trait ClientStateCommon: Convertible<Any> {
         root: &CommitmentRoot,
     ) -> Result<(), ClientError>;
 
-    // Verify_membership is a generic proof verification method which verifies a
-    // proof of the existence of a value at a given Path.
+    /// Serializes a given path object into a raw path bytes.
+    ///
+    /// This method provides essential information for IBC modules, enabling
+    /// them to understand how path serialization is performed on the chain this
+    /// light client represents it before passing the path bytes to either
+    /// `verify_membership_raw()` or `verify_non_membership_raw()`.
+    fn serialize_path(&self, path: Path) -> Result<PathBytes, ClientError>;
+
+    /// Verifies a proof of the existence of a value at a given raw path bytes.
+    fn verify_membership_raw(
+        &self,
+        prefix: &CommitmentPrefix,
+        proof: &CommitmentProofBytes,
+        root: &CommitmentRoot,
+        path: PathBytes,
+        value: Vec<u8>,
+    ) -> Result<(), ClientError>;
+
+    /// Verifies a proof of the existence of a value at a given path object.
     fn verify_membership(
         &self,
         prefix: &CommitmentPrefix,
         proof: &CommitmentProofBytes,
         root: &CommitmentRoot,
         path: Path,
         value: Vec<u8>,
+    ) -> Result<(), ClientError> {
+        let path_bytes = self.serialize_path(path)?;
+        self.verify_membership_raw(prefix, proof, root, path_bytes, value)
+    }
+
+    /// Verifies the absence of a given proof at a given raw path bytes.
+    fn verify_non_membership_raw(
+        &self,
+        prefix: &CommitmentPrefix,
+        proof: &CommitmentProofBytes,
+        root: &CommitmentRoot,
+        path: PathBytes,
     ) -> Result<(), ClientError>;
 
-    // Verify_non_membership is a generic proof verification method which
-    // verifies the absence of a given commitment.
+    /// Verifies the absence of a given proof at a given path object.
     fn verify_non_membership(
         &self,
         prefix: &CommitmentPrefix,
         proof: &CommitmentProofBytes,
         root: &CommitmentRoot,
         path: Path,
-    ) -> Result<(), ClientError>;
+    ) -> Result<(), ClientError> {
+        let path_bytes = self.serialize_path(path)?;
+        self.verify_non_membership_raw(prefix, proof, root, path_bytes)
+    }
 }
 
 /// `ClientState` methods which require access to the client's validation

ibc-core/ics23-commitment/types/Cargo.toml

@@ -28,9 +28,10 @@ serde           = { workspace = true, optional = true }
 subtle-encoding = { workspace = true }
 
 # ibc dependencies
-ibc-proto      = { workspace = true }
-ibc-primitives = { workspace = true }
-ics23          = { version = "0.11", default-features = false, features = [ "host-functions" ] }
+ibc-proto           = { workspace = true }
+ibc-primitives      = { workspace = true }
+ics23               = { version = "0.11", default-features = false, features = [ "host-functions" ] }
+ibc-core-host-types = { workspace = true }
 
 # parity dependencies
 parity-scale-codec = { workspace = true, optional = true }
@@ -46,30 +47,35 @@ std = [
   "serde/std",
   "subtle-encoding/std",
   "ibc-primitives/std",
+  "ibc-core-host-types/std",
   "ibc-proto/std",
   "ics23/std",
 ]
 serde = [
   "dep:serde",
   "ibc-primitives/serde",
+  "ibc-core-host-types/serde",
   "ibc-proto/serde",
   "ics23/serde",
 ]
 schema = [
   "dep:schemars",
   "ibc-proto/json-schema",
   "ibc-primitives/schema",
+  "ibc-core-host-types/schema",
   "serde",
   "std",
 ]
 borsh = [
   "dep:borsh",
   "ibc-proto/borsh",
   "ibc-primitives/borsh",
+  "ibc-core-host-types/borsh",
 ]
 parity-scale-codec = [
   "dep:parity-scale-codec",
   "dep:scale-info",
   "ibc-primitives/parity-scale-codec",
+  "ibc-core-host-types/parity-scale-codec",
   "ibc-proto/parity-scale-codec",
 ]