fix: do not allow unordered txs to have sequence values set (#24581)

Co-authored-by: Alex | Interchain Labs <alex@interchainlabs.io>
Co-authored-by: Aaron Craelius <aaronc@users.noreply.github.com>

x/auth/ante/sigverify.go

@@ -120,11 +120,21 @@ func (spkd SetPubKeyDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate b
 		return ctx, err
 	}
 
+	isUnordered := false
+	utx, ok := tx.(sdk.TxWithUnordered)
+	if ok && utx.GetUnordered() {
+		isUnordered = true
+	}
+
 	var events sdk.Events
 	for i, sig := range sigs {
-		events = append(events, sdk.NewEvent(sdk.EventTypeTx,
-			sdk.NewAttribute(sdk.AttributeKeyAccountSequence, fmt.Sprintf("%s/%d", signerStrs[i], sig.Sequence)),
-		))
+		// this shouldn't happen, but if we somehow got a tx with both a sequence set, and is unordered,
+		// we shouldn't emit the event, as this is a false sequence, and won't actually be used.
+		if !isUnordered {
+			events = append(events, sdk.NewEvent(sdk.EventTypeTx,
+				sdk.NewAttribute(sdk.AttributeKeyAccountSequence, fmt.Sprintf("%s/%d", signerStrs[i], sig.Sequence)),
+			))
+		}
 
 		sigBzs, err := signatureDataToBz(sig.Data)
 		if err != nil {
@@ -334,6 +344,9 @@ func (svd SigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simul
 	}
 
 	for i, sig := range sigs {
+		if sig.Sequence > 0 && isUnordered {
+			return ctx, errorsmod.Wrapf(sdkerrors.ErrInvalidRequest, "sequence is not allowed for unordered transactions")
+		}
 		acc, err := GetSignerAcc(ctx, svd.ak, signers[i])
 		if err != nil {
 			return ctx, err

x/auth/ante/sigverify_test.go

@@ -72,6 +72,35 @@ func TestSetPubKey(t *testing.T) {
 	}
 }
 
+// TestSetPubKey_UnorderedNoEvents tests that when the tx is unordered, the sequence event is not emitted.
+func TestSetPubKey_UnorderedNoEvents(t *testing.T) {
+	suite := SetupTestSuite(t, true)
+	suite.txBuilder = suite.clientCtx.TxConfig.NewTxBuilder()
+
+	// prepare accounts for tx
+	priv1, _, addr1 := testdata.KeyTestPubAddr()
+	acc := suite.accountKeeper.NewAccountWithAddress(suite.ctx, addr1)
+	require.NoError(t, acc.SetAccountNumber(uint64(1000)))
+	suite.accountKeeper.SetAccount(suite.ctx, acc)
+	require.NoError(t, suite.txBuilder.SetMsgs(testdata.NewTestMsg(addr1)))
+
+	privs, accNums, accSeqs := []cryptotypes.PrivKey{priv1}, []uint64{0}, []uint64{0}
+	tx, err := suite.CreateTestUnorderedTx(suite.ctx, privs, accNums, accSeqs, suite.ctx.ChainID(), signing.SignMode_SIGN_MODE_DIRECT, true, time.Unix(100, 0))
+	require.NoError(t, err)
+
+	spkd := ante.NewSetPubKeyDecorator(suite.accountKeeper)
+	antehandler := sdk.ChainAnteDecorators(spkd)
+
+	ctx, err := antehandler(suite.ctx.WithBlockTime(time.Unix(95, 0)), tx, false)
+	require.NoError(t, err)
+	events := ctx.EventManager().Events()
+	for _, event := range events {
+		// if this event were emitted, the tx search by address/sequence would break when an unordered
+		// transaction uses the same sequence number as another transaction from the same sender.
+		require.NotContains(t, event.Attributes, sdk.AttributeKeyAccountSequence)
+	}
+}
+
 func TestConsumeSignatureVerificationGas(t *testing.T) {
 	suite := SetupTestSuite(t, true)
 	params := types.DefaultParams()