fix(baseapp): audit changes

CHANGELOG.md

@@ -75,6 +75,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [#16547](https://github.com/cosmos/cosmos-sdk/pull/16547) Ensure a transaction's gas limit cannot exceed the block gas limit.
 * (x/auth/types) [#16554](https://github.com/cosmos/cosmos-sdk/pull/16554) `ModuleAccount.Validate` now reports a nil `.BaseAccount` instead of panicking.
 * (baseapp) [#16613](https://github.com/cosmos/cosmos-sdk/pull/16613) Ensure each message in a transaction has a registered handler, otherwise `CheckTx` will fail.
+* (baseapp) [#16596](https://github.com/cosmos/cosmos-sdk/pull/16596) Return error during ExtendVote and VerifyVoteExtension if the request height is earlier than `VoteExtensionsEnableHeight`.
 * (x/consensus) [#16713](https://github.com/cosmos/cosmos-sdk/pull/16713) Add missing ABCI param in MsgUpdateParams.
 * [#16639](https://github.com/cosmos/cosmos-sdk/pull/16639) Make sure we don't execute blocks beyond the halt height.
 * (baseapp) [#16700](https://github.com/cosmos/cosmos-sdk/pull/16700) Fix: Consensus Failure in returning no response to malformed transactions

UPGRADING.md

@@ -29,6 +29,21 @@ Additionally, the SDK is starting its abstraction from CometBFT Go types thoroug
 * The usage of CometBFT have been replaced to use the Cosmos SDK logger interface (`cosmossdk.io/log.Logger`).
 * The usage of `github.com/cometbft/cometbft/libs/bytes.HexByte` have been replaced by `[]byte`.
 
+### Enable Vote Extensions
+
+> This is an optional feature that is disabled by default.
+
+Once all the code changes required to implement Vote Extensions are in place,
+they can be enabled by setting the consensus param `Abci.VoteExtensionsEnableHeight`
+to a value greater than zero.
+
+In a new chain, this can be done in the `genesis.json` file.
+
+For existing chains this can be done in two ways:
+
+- During an upgrade the value is set in an upgrade handler.
+- A governance proposal that changes the consensus param **after a coordinated upgrade has taken place**.
+
 ### BaseApp
 
 All ABCI methods now accept a pointer to the request and response types defined

baseapp/abci.go

@@ -556,7 +556,9 @@ func (app *BaseApp) ExtendVote(_ context.Context, req *abci.RequestExtendVote) (
 	// If vote extensions are not enabled, as a safety precaution, we return an
 	// error.
 	cp := app.GetConsensusParams(app.voteExtensionState.ctx)
-	if cp.Abci != nil && cp.Abci.VoteExtensionsEnableHeight <= 0 {
+
+	extsEnabled := cp.Abci != nil && req.Height >= cp.Abci.VoteExtensionsEnableHeight && cp.Abci.VoteExtensionsEnableHeight != 0
+	if !extsEnabled {
 		return nil, fmt.Errorf("vote extensions are not enabled; unexpected call to ExtendVote at height %d", req.Height)
 	}
 
@@ -569,6 +571,7 @@ func (app *BaseApp) ExtendVote(_ context.Context, req *abci.RequestExtendVote) (
 		WithHeaderInfo(coreheader.Info{
 			ChainID: app.chainID,
 			Height:  req.Height,
+			Hash:    req.Hash,
 		})
 
 	// add a deferred recover handler in case extendVote panics
@@ -607,7 +610,9 @@ func (app *BaseApp) VerifyVoteExtension(req *abci.RequestVerifyVoteExtension) (r
 	// If vote extensions are not enabled, as a safety precaution, we return an
 	// error.
 	cp := app.GetConsensusParams(app.voteExtensionState.ctx)
-	if cp.Abci != nil && cp.Abci.VoteExtensionsEnableHeight <= 0 {
+
+	extsEnabled := cp.Abci != nil && req.Height >= cp.Abci.VoteExtensionsEnableHeight && cp.Abci.VoteExtensionsEnableHeight != 0
+	if !extsEnabled {
 		return nil, fmt.Errorf("vote extensions are not enabled; unexpected call to VerifyVoteExtension at height %d", req.Height)
 	}