From fb6b3785db8ab5ee1083268fb04fc5675fc7f82b Mon Sep 17 00:00:00 2001
From: Damian Nolan <damiannolan@gmail.com>
Date: Fri, 5 Aug 2022 14:30:28 +0200
Subject: [PATCH] fix: ics27 check packet data length explicitly over nil check
 (#1882)

* using len check in favour of nil check for interchain account packet data

* adding changelog

* updating changelog

(cherry picked from commit 73fdde9968200edcf00fe72d419e003f262b3275)
---
 CHANGELOG.md                                             | 2 ++
 modules/apps/27-interchain-accounts/types/packet.go      | 2 +-
 modules/apps/27-interchain-accounts/types/packet_test.go | 9 +++++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8a11a862f04..90d44e9c891 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### State Machine Breaking
 
+* (apps/27-interchain-accounts) [\#1882](https://github.com/cosmos/ibc-go/pull/1882) Explicitly check length of interchain account packet data in favour of nil check.
+
 ### Improvements
 
 * (core/02-client) [\#1570](https://github.com/cosmos/ibc-go/pull/1570) Emitting an event when handling an upgrade client proposal.
diff --git a/modules/apps/27-interchain-accounts/types/packet.go b/modules/apps/27-interchain-accounts/types/packet.go
index e7669a77fc9..59419f8f302 100644
--- a/modules/apps/27-interchain-accounts/types/packet.go
+++ b/modules/apps/27-interchain-accounts/types/packet.go
@@ -16,7 +16,7 @@ func (iapd InterchainAccountPacketData) ValidateBasic() error {
 		return sdkerrors.Wrap(ErrInvalidOutgoingData, "packet data type cannot be unspecified")
 	}
 
-	if iapd.Data == nil {
+	if len(iapd.Data) == 0 {
 		return sdkerrors.Wrap(ErrInvalidOutgoingData, "packet data cannot be empty")
 	}
 
diff --git a/modules/apps/27-interchain-accounts/types/packet_test.go b/modules/apps/27-interchain-accounts/types/packet_test.go
index 840ca529851..59bf63ea9a9 100644
--- a/modules/apps/27-interchain-accounts/types/packet_test.go
+++ b/modules/apps/27-interchain-accounts/types/packet_test.go
@@ -40,6 +40,15 @@ func (suite *TypesTestSuite) TestValidateBasic() {
 		},
 		{
 			"empty data",
+			types.InterchainAccountPacketData{
+				Type: types.EXECUTE_TX,
+				Data: []byte{},
+				Memo: "memo",
+			},
+			false,
+		},
+		{
+			"nil data",
 			types.InterchainAccountPacketData{
 				Type: types.EXECUTE_TX,
 				Data: nil,