From 9db18750be9ae286e03bc9ddcde2663a4e70bab4 Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Thu, 1 Jun 2017 14:59:19 +0200
Subject: [PATCH] Added ValidateBasic() to all Tx for easy stateless
 pre-filtering

---
 errors/common.go |  5 +++++
 tx.go            |  1 +
 txs/base.go      | 32 ++++++++++++++++++++++++++++++++
 txs/sigs.go      | 20 ++++++++++++++++++++
 4 files changed, 58 insertions(+)

diff --git a/errors/common.go b/errors/common.go
index 3ea5a409e..eedaf8057 100644
--- a/errors/common.go
+++ b/errors/common.go
@@ -14,6 +14,7 @@ const (
 	msgInvalidSequence = "Invalid Sequence"
 	msgNoInputs        = "No Input Coins"
 	msgNoOutputs       = "No Output Coins"
+	msgTooLarge        = "Input size too large"
 )
 
 func DecodingError() TMError {
@@ -43,3 +44,7 @@ func NoInputs() TMError {
 func NoOutputs() TMError {
 	return New(msgNoOutputs, abci.CodeType_BaseInvalidOutput)
 }
+
+func TooLarge() TMError {
+	return New(msgTooLarge, abci.CodeType_EncodingError)
+}
diff --git a/tx.go b/tx.go
index 5a74a7f90..23e262b90 100644
--- a/tx.go
+++ b/tx.go
@@ -4,6 +4,7 @@ package basecoin
 // +gen wrapper:"Tx"
 type TxInner interface {
 	Wrap() Tx
+	ValidateBasic() error
 }
 
 // TxLayer provides a standard way to deal with "middleware" tx,
diff --git a/txs/base.go b/txs/base.go
index f67f09db1..d7ecdb349 100644
--- a/txs/base.go
+++ b/txs/base.go
@@ -2,6 +2,7 @@ package txs
 
 import (
 	"github.com/tendermint/basecoin"
+	"github.com/tendermint/basecoin/errors"
 	"github.com/tendermint/basecoin/types"
 	"github.com/tendermint/go-wire/data"
 )
@@ -30,6 +31,10 @@ const (
 	TypeMultiSig = "multisig"
 )
 
+const (
+	rawMaxSize = 2000 * 1000
+)
+
 func init() {
 	basecoin.TxMapper.
 		RegisterImplementation(Raw{}, TypeRaw, ByteRaw).
@@ -47,6 +52,13 @@ func (r Raw) Wrap() basecoin.Tx {
 	return basecoin.Tx{r}
 }
 
+func (r Raw) ValidateBasic() error {
+	if len(r.Bytes) > rawMaxSize {
+		return errors.TooLarge()
+	}
+	return nil
+}
+
 func NewRaw(d []byte) Raw {
 	return Raw{data.Bytes(d)}
 }
@@ -65,6 +77,11 @@ func NewFee(tx basecoin.Tx, fee types.Coin, addr []byte) *Fee {
 	return &Fee{Tx: tx, Fee: fee, Payer: addr}
 }
 
+func (f *Fee) ValidateBasic() error {
+	// TODO: more checks
+	return f.Tx.ValidateBasic()
+}
+
 func (f *Fee) Wrap() basecoin.Tx {
 	return basecoin.Tx{f}
 }
@@ -82,6 +99,16 @@ func (mt *MultiTx) Wrap() basecoin.Tx {
 	return basecoin.Tx{mt}
 }
 
+func (mt *MultiTx) ValidateBasic() error {
+	for _, t := range mt.Txs {
+		err := t.ValidateBasic()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 /*** Chain ****/
 
 // Chain locks this tx to one chain, wrap with this before signing
@@ -97,3 +124,8 @@ func NewChain(tx basecoin.Tx, chainID string) *Chain {
 func (c *Chain) Wrap() basecoin.Tx {
 	return basecoin.Tx{c}
 }
+
+func (c *Chain) ValidateBasic() error {
+	// TODO: more checks? chainID?
+	return c.Tx.ValidateBasic()
+}
diff --git a/txs/sigs.go b/txs/sigs.go
index c8ed07ac0..8336bb7c0 100644
--- a/txs/sigs.go
+++ b/txs/sigs.go
@@ -14,6 +14,7 @@ a basecoin.Tx.
 package txs
 
 import (
+	// TODO: merge in usage of pkg/errors into basecoin/errors and remove this
 	"github.com/pkg/errors"
 
 	crypto "github.com/tendermint/go-crypto"
@@ -21,6 +22,7 @@ import (
 	"github.com/tendermint/go-wire/data"
 
 	"github.com/tendermint/basecoin"
+	berrs "github.com/tendermint/basecoin/errors"
 )
 
 // Signed holds one signature of the data
@@ -59,6 +61,14 @@ func (s *OneSig) Wrap() basecoin.Tx {
 	return basecoin.Tx{s}
 }
 
+func (s *OneSig) ValidateBasic() error {
+	// TODO: VerifyBytes here, we do it in Signers?
+	if s.Empty() || !s.Pubkey.VerifyBytes(s.SignBytes(), s.Sig) {
+		return berrs.Unauthorized()
+	}
+	return s.Tx.ValidateBasic()
+}
+
 // TxBytes returns the full data with signatures
 func (s *OneSig) TxBytes() ([]byte, error) {
 	return data.ToWire(s)
@@ -121,6 +131,16 @@ func (s *MultiSig) Wrap() basecoin.Tx {
 	return basecoin.Tx{s}
 }
 
+func (s *MultiSig) ValidateBasic() error {
+	// TODO: more efficient
+	_, err := s.Signers()
+	if err != nil {
+		// TODO: better return value
+		return berrs.Unauthorized()
+	}
+	return s.Tx.ValidateBasic()
+}
+
 // TxBytes returns the full data with signatures
 func (s *MultiSig) TxBytes() ([]byte, error) {
 	return data.ToWire(s)