From fd68bc7cfda1592114f574e2bd2101ae62acd255 Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Mon, 3 Apr 2017 16:18:03 +0200
Subject: [PATCH] Test Tx proofs secure

---
 types/tx_test.go | 105 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 types/tx_test.go

diff --git a/types/tx_test.go b/types/tx_test.go
new file mode 100644
index 000000000..2d4abc5b0
--- /dev/null
+++ b/types/tx_test.go
@@ -0,0 +1,105 @@
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	cmn "github.com/tendermint/go-common"
+	ctest "github.com/tendermint/go-common/test"
+	wire "github.com/tendermint/go-wire"
+)
+
+func makeTxs(cnt, size int) Txs {
+	txs := make(Txs, cnt)
+	for i := 0; i < cnt; i++ {
+		txs[i] = cmn.RandBytes(size)
+	}
+	return txs
+}
+
+func randInt(low, high int) int {
+	off := cmn.RandInt() % (high - low)
+	return low + off
+}
+
+func TestValidTxProof(t *testing.T) {
+	assert := assert.New(t)
+	cases := []struct {
+		txs Txs
+	}{
+		{Txs{{1, 4, 34, 87, 163, 1}}},
+		{Txs{{5, 56, 165, 2}, {4, 77}}},
+		{Txs{Tx("foo"), Tx("bar"), Tx("baz")}},
+		{makeTxs(20, 5)},
+		{makeTxs(7, 81)},
+		{makeTxs(61, 15)},
+	}
+
+	for h, tc := range cases {
+		txs := tc.txs
+		root := txs.Hash()
+		// make sure valid proof for every tx
+		for i := range txs {
+			leaf := txs[i]
+			leafHash := leaf.Hash()
+			proof := txs.Proof(i)
+			assert.Equal(i, proof.Index, "%d: %d", h, i)
+			assert.Equal(len(txs), proof.Total, "%d: %d", h, i)
+			assert.Equal(root, proof.RootHash, "%d: %d", h, i)
+			assert.Equal(leaf, proof.Data, "%d: %d", h, i)
+			assert.Equal(leafHash, proof.LeafHash(), "%d: %d", h, i)
+			assert.Nil(proof.Validate(root), "%d: %d", h, i)
+			assert.NotNil(proof.Validate([]byte("foobar")), "%d: %d", h, i)
+
+			// read-write must also work
+			var p2 TxProof
+			bin := wire.BinaryBytes(proof)
+			err := wire.ReadBinaryBytes(bin, &p2)
+			if assert.Nil(err, "%d: %d: %+v", h, i, err) {
+				assert.Nil(p2.Validate(root), "%d: %d", h, i)
+			}
+		}
+	}
+}
+
+func TestTxProofUnchangable(t *testing.T) {
+	// run the other test a bunch...
+	for i := 0; i < 4; i++ {
+		testTxProofUnchangable(t)
+	}
+}
+
+func testTxProofUnchangable(t *testing.T) {
+	assert := assert.New(t)
+
+	// make some proof
+	txs := makeTxs(randInt(2, 100), randInt(16, 128))
+	root := txs.Hash()
+	i := randInt(0, len(txs)-1)
+	proof := txs.Proof(i)
+
+	// make sure it is valid to start with
+	assert.Nil(proof.Validate(root))
+	bin := wire.BinaryBytes(proof)
+
+	// try mutating the data and make sure nothing breaks
+	for j := 0; j < 50; j++ {
+		bad := ctest.MutateByteSlice(bin)
+		assertBadProof(t, root, bad)
+	}
+}
+
+// this make sure the proof doesn't deserialize into something valid
+func assertBadProof(t *testing.T, root []byte, bad []byte) {
+	// we kind of expect this to panic sometimes... (bad, go-wire, bad)
+	defer func() {
+		recover()
+	}()
+
+	var proof TxProof
+	err := wire.ReadBinaryBytes(bad, &proof)
+	if err == nil {
+		err = proof.Validate(root)
+		assert.NotNil(t, err, "%+v", err)
+	}
+}