fix: add nil checks for controller and host keeper services (#2308)

## Description

closes: #XXXX

---

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- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
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(cherry picked from commit 888c4a0)

# Conflicts:
#	CHANGELOG.md
#	modules/apps/27-interchain-accounts/controller/keeper/migrations.go
#	modules/apps/27-interchain-accounts/module.go

CHANGELOG.md

@@ -62,7 +62,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (apps/27-interchain-accounts) [\#2193](https://github.com/cosmos/ibc-go/pull/2193) Adding `InterchainAccount` gRPC query endpont to ICS27 `controller` submodule to allow users to retrieve registered interchain account addresses.
 
 ### Bug Fixes
+<<<<<<< HEAD
 
+=======
+
+* (27-interchain-accounts) [\#2308](https://github.com/cosmos/ibc-go/pull/2308) Nil checks have been added to ensure services are not registered for nil host or controller keepers.
+>>>>>>> 888c4a0 (fix: add nil checks for controller and host keeper services (#2308))
 * (makefile) [\#1785](https://github.com/cosmos/ibc-go/pull/1785) Fetch the correct versions of protocol buffers dependencies from tendermint, cosmos-sdk, and ics23.
 * (modules/core/04-channel)[\#1919](https://github.com/cosmos/ibc-go/pull/1919) Fixed formatting of sequence for packet "acknowledgement written" logs.
 

modules/apps/27-interchain-accounts/controller/keeper/migrations.go

@@ -0,0 +1,43 @@
+package keeper
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
+
+	"github.com/cosmos/ibc-go/v5/modules/core/23-commitment/types"
+	host "github.com/cosmos/ibc-go/v5/modules/core/24-host"
+)
+
+// Migrator is a struct for handling in-place store migrations.
+type Migrator struct {
+	keeper *Keeper
+}
+
+// NewMigrator returns a new Migrator.
+func NewMigrator(keeper *Keeper) Migrator {
+	return Migrator{keeper: keeper}
+}
+
+// AssertChannelCapabilityMigrations checks that all channel capabilities generated using the interchain accounts controller port prefix
+// are owned by the controller submodule and ibc.
+func (m Migrator) AssertChannelCapabilityMigrations(ctx sdk.Context) error {
+	if m.keeper != nil {
+		for _, ch := range m.keeper.GetAllActiveChannels(ctx) {
+			name := host.ChannelCapabilityPath(ch.PortId, ch.ChannelId)
+			cap, found := m.keeper.scopedKeeper.GetCapability(ctx, name)
+			if !found {
+				return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotFound, "failed to find capability: %s", name)
+			}
+
+			isAuthenticated := m.keeper.scopedKeeper.AuthenticateCapability(ctx, cap, name)
+			if !isAuthenticated {
+				return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotOwned, "expected capability owner: %s", types.SubModuleName)
+			}
+
+			m.keeper.SetMiddlewareEnabled(ctx, ch.PortId, ch.ChannelId)
+		}
+	}
+
+	return nil
+}

modules/apps/27-interchain-accounts/module.go

@@ -74,6 +74,7 @@ func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *r
 	if err != nil {
 		panic(err)
 	}
+
 	err = hosttypes.RegisterQueryHandlerClient(context.Background(), mux, hosttypes.NewQueryClient(clientCtx))
 	if err != nil {
 		panic(err)
@@ -148,8 +149,24 @@ func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sd
 
 // RegisterServices registers module services
 func (am AppModule) RegisterServices(cfg module.Configurator) {
+<<<<<<< HEAD
 	controllertypes.RegisterQueryServer(cfg.QueryServer(), am.controllerKeeper)
 	hosttypes.RegisterQueryServer(cfg.QueryServer(), am.hostKeeper)
+=======
+	if am.controllerKeeper != nil {
+		controllertypes.RegisterMsgServer(cfg.MsgServer(), controllerkeeper.NewMsgServerImpl(am.controllerKeeper))
+		controllertypes.RegisterQueryServer(cfg.QueryServer(), am.controllerKeeper)
+	}
+
+	if am.hostKeeper != nil {
+		hosttypes.RegisterQueryServer(cfg.QueryServer(), am.hostKeeper)
+	}
+
+	m := controllerkeeper.NewMigrator(am.controllerKeeper)
+	if err := cfg.RegisterMigration(types.ModuleName, 1, m.AssertChannelCapabilityMigrations); err != nil {
+		panic(fmt.Sprintf("failed to migrate interchainaccounts app from version 1 to 2: %v", err))
+	}
+>>>>>>> 888c4a0 (fix: add nil checks for controller and host keeper services (#2308))
 }
 
 // InitGenesis performs genesis initialization for the interchain accounts module.