From bac82dc694aeeaf3b387bc04ebdd95344cabdf53 Mon Sep 17 00:00:00 2001
From: Adi Seredinschi <adi@informal.systems>
Date: Thu, 29 Apr 2021 16:41:54 +0200
Subject: [PATCH] Fix for `ft-transfer` mismatching arguments (#870)

* Fix for incoherent ft-transfer arguments

* Changelog

* Fix typo in error diagnostic; better comment

* Lowercase errors & logs
---
 CHANGELOG.md                            |  7 +++-
 relayer-cli/src/commands/tx/transfer.rs | 46 ++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7b144595a1..33d9e6e5a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,8 +7,9 @@
 - [ibc]
   - Reinstated `ics23` dependency ([#854])
   - Use proper Timestamp type to track time ([#855])
+
 - [ibc-relayer]
-  - Change the default for client creation to allow governance recovery in case of expiration or misbehaviour. ([#785])
+  - Change the default for client creation to allow governance recovery in case of expiration or misbehaviour ([#785])
 
 ### BUG FIXES
 
@@ -16,6 +17,9 @@
   - Fix pagination in gRPC query for clients ([#811])
   - Fix relayer crash when hermes starts in the same time as packets are being sent ([#851])
 
+- [ibc-relayer-cli]
+  - Fix for `ft-transfer` mismatching arguments ([#869])
+
 ### BREAKING CHANGES
 
 > Nothing yet.
@@ -25,6 +29,7 @@
 [#811]: https://github.com/informalsystems/ibc-rs/issues/811
 [#854]: https://github.com/informalsystems/ibc-rs/issues/854
 [#851]: https://github.com/informalsystems/ibc-rs/issues/851
+[#869]: https://github.com/informalsystems/ibc-rs/issues/869
 [#855]: https://github.com/informalsystems/ibc-rs/issues/855
 
 
diff --git a/relayer-cli/src/commands/tx/transfer.rs b/relayer-cli/src/commands/tx/transfer.rs
index 6dcd2ed8f0..0703057da3 100644
--- a/relayer-cli/src/commands/tx/transfer.rs
+++ b/relayer-cli/src/commands/tx/transfer.rs
@@ -5,6 +5,7 @@ use anomaly::BoxError;
 use tokio::runtime::Runtime as TokioRuntime;
 
 use ibc::events::IbcEvent;
+use ibc::ics02_client::height::Height;
 use ibc::ics24_host::identifier::{ChainId, ChannelId, PortId};
 use ibc_relayer::{
     chain::{Chain, CosmosSdkChain},
@@ -12,7 +13,7 @@ use ibc_relayer::{
     transfer::{build_and_send_transfer_messages, TransferOptions},
 };
 
-use crate::conclude::Output;
+use crate::conclude::{exit_with_unrecoverable_error, Output};
 use crate::error::{Error, Kind};
 use crate::prelude::*;
 
@@ -120,6 +121,49 @@ impl Runnable for TxIcs20MsgTransferCmd {
             Err(e) => return Output::error(format!("{}", e)).exit(),
         };
 
+        // Double check that channels and chain identifiers match.
+        // To do this, fetch from the source chain the channel end, then the associated connection
+        // end, and then the underlying client state; finally, check that this client is verifying
+        // headers for the destination chain.
+        let channel_end = src_chain
+            .query_channel(
+                &opts.packet_src_port_id,
+                &opts.packet_src_channel_id,
+                Height::zero(),
+            )
+            .unwrap_or_else(exit_with_unrecoverable_error);
+        // TODO: Support for multi-hop channels will impact this.
+        let conn_id = match channel_end.connection_hops.first() {
+            None => {
+                return Output::error(format!(
+                    "could not retrieve the connection hop underlying channel end {:?} on chain {}",
+                    channel_end, self.src_chain_id
+                ))
+                .exit()
+            }
+            Some(cid) => cid,
+        };
+        let conn_end = src_chain
+            .query_connection(conn_id, Height::zero())
+            .unwrap_or_else(exit_with_unrecoverable_error);
+        debug!("connection hop underlying the channel: {:?}", conn_end);
+        let src_chain_client_state = src_chain
+            .query_client_state(conn_end.client_id(), Height::zero())
+            .unwrap_or_else(exit_with_unrecoverable_error);
+        debug!(
+            "client state underlying the channel: {:?}",
+            src_chain_client_state
+        );
+        if src_chain_client_state.chain_id != self.dst_chain_id {
+            return Output::error(
+                format!("the requested port/channel ({}/{}) provides a path from chain '{}' to \
+                 chain '{}' (not to the destination chain '{}'). Bailing due to mismatching arguments.",
+                        opts.packet_src_port_id, opts.packet_src_channel_id,
+                        self.src_chain_id,
+                        src_chain_client_state.chain_id, self.dst_chain_id)).exit();
+        }
+
+        // Checks pass, build and send the tx
         let res: Result<Vec<IbcEvent>, Error> =
             build_and_send_transfer_messages(src_chain, dst_chain, opts)
                 .map_err(|e| Kind::Tx.context(e).into());