diff --git a/trie/notary.go b/trie/notary.go new file mode 100644 index 0000000000..b61cc3d2c0 --- /dev/null +++ b/trie/notary.go @@ -0,0 +1,57 @@ +// Copyright 2020 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see . + +package trie + +import ( + "github.com/XinFinOrg/XDPoSChain/ethdb" + "github.com/XinFinOrg/XDPoSChain/ethdb/memorydb" +) + +// KeyValueNotary tracks which keys have been accessed through a key-value reader +// with te scope of verifying if certain proof datasets are maliciously bloated. +type KeyValueNotary struct { + ethdb.KeyValueReader + reads map[string]struct{} +} + +// NewKeyValueNotary wraps a key-value database with an access notary to track +// which items have bene accessed. +func NewKeyValueNotary(db ethdb.KeyValueReader) *KeyValueNotary { + return &KeyValueNotary{ + KeyValueReader: db, + reads: make(map[string]struct{}), + } +} + +// Get retrieves an item from the underlying database, but also tracks it as an +// accessed slot for bloat checks. +func (k *KeyValueNotary) Get(key []byte) ([]byte, error) { + k.reads[string(key)] = struct{}{} + return k.KeyValueReader.Get(key) +} + +// Accessed returns s snapshot of the original key-value store containing only the +// data accessed through the notary. +func (k *KeyValueNotary) Accessed() ethdb.KeyValueStore { + db := memorydb.New() + for keystr := range k.reads { + key := []byte(keystr) + val, _ := k.KeyValueReader.Get(key) + db.Put(key, val) + } + return db +} diff --git a/trie/proof.go b/trie/proof.go index 66aec8c7fc..6dafe269e6 100644 --- a/trie/proof.go +++ b/trie/proof.go @@ -22,7 +22,6 @@ import ( "fmt" "github.com/XinFinOrg/XDPoSChain/common" - "github.com/XinFinOrg/XDPoSChain/core/types" "github.com/XinFinOrg/XDPoSChain/ethdb" "github.com/XinFinOrg/XDPoSChain/ethdb/memorydb" "github.com/XinFinOrg/XDPoSChain/log" @@ -426,7 +425,7 @@ func hasRightElement(node node, key []byte) bool { // VerifyRangeProof checks whether the given leaf nodes and edge proof // can prove the given trie leaves range is matched with the specific root. -// Besides, the range should be consecutive(no gap inside) and monotonic +// Besides, the range should be consecutive (no gap inside) and monotonic // increasing. // // Note the given proof actually contains two edge proofs. Both of them can @@ -454,96 +453,136 @@ func hasRightElement(node node, key []byte) bool { // // Except returning the error to indicate the proof is valid or not, the function will // also return a flag to indicate whether there exists more accounts/slots in the trie. -func VerifyRangeProof(rootHash common.Hash, firstKey []byte, lastKey []byte, keys [][]byte, values [][]byte, proof ethdb.KeyValueReader) (error, bool) { +func VerifyRangeProof(rootHash common.Hash, firstKey []byte, lastKey []byte, keys [][]byte, values [][]byte, proof ethdb.KeyValueReader) (ethdb.KeyValueStore, *Trie, *KeyValueNotary, bool, error) { if len(keys) != len(values) { - return fmt.Errorf("inconsistent proof data, keys: %d, values: %d", len(keys), len(values)), false + return nil, nil, nil, false, fmt.Errorf("inconsistent proof data, keys: %d, values: %d", len(keys), len(values)) } // Ensure the received batch is monotonic increasing. for i := 0; i < len(keys)-1; i++ { if bytes.Compare(keys[i], keys[i+1]) >= 0 { - return errors.New("range is not monotonically increasing"), false + return nil, nil, nil, false, errors.New("range is not monotonically increasing") } } + // Create a key-value notary to track which items from the given proof the + // range prover actually needed to verify the data + notary := NewKeyValueNotary(proof) + // Special case, there is no edge proof at all. The given range is expected // to be the whole leaf-set in the trie. if proof == nil { - emptytrie, err := New(types.EmptyRootHash, NewDatabase(memorydb.New())) + var ( + diskdb = memorydb.New() + triedb = NewDatabase(diskdb) + ) + tr, err := New(common.Hash{}, triedb) if err != nil { - return err, false + return nil, nil, nil, false, err } for index, key := range keys { - emptytrie.TryUpdate(key, values[index]) + tr.TryUpdate(key, values[index]) } - if emptytrie.Hash() != rootHash { - return fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, emptytrie.Hash()), false + if tr.Hash() != rootHash { + return nil, nil, nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, tr.Hash()) } - return nil, false // no more element. + // Proof seems valid, serialize all the nodes into the database + if _, err := tr.Commit(nil); err != nil { + return nil, nil, nil, false, err + } + if err := triedb.Commit(rootHash, false); err != nil { + return nil, nil, nil, false, err + } + return diskdb, tr, notary, false, nil // No more elements } // Special case, there is a provided edge proof but zero key/value // pairs, ensure there are no more accounts / slots in the trie. if len(keys) == 0 { - root, val, err := proofToPath(rootHash, nil, firstKey, proof, true) + root, val, err := proofToPath(rootHash, nil, firstKey, notary, true) if err != nil { - return err, false + return nil, nil, nil, false, err } if val != nil || hasRightElement(root, firstKey) { - return errors.New("more entries available"), false + return nil, nil, nil, false, errors.New("more entries available") } - return nil, false + // Since the entire proof is a single path, we can construct a trie and a + // node database directly out of the inputs, no need to generate them + diskdb := notary.Accessed() + tr := &Trie{ + Db: NewDatabase(diskdb), + root: root, + } + return diskdb, tr, notary, hasRightElement(root, firstKey), nil } // Special case, there is only one element and two edge keys are same. // In this case, we can't construct two edge paths. So handle it here. if len(keys) == 1 && bytes.Equal(firstKey, lastKey) { - root, val, err := proofToPath(rootHash, nil, firstKey, proof, false) + root, val, err := proofToPath(rootHash, nil, firstKey, notary, false) if err != nil { - return err, false + return nil, nil, nil, false, err } if !bytes.Equal(firstKey, keys[0]) { - return errors.New("correct proof but invalid key"), false + return nil, nil, nil, false, errors.New("correct proof but invalid key") } if !bytes.Equal(val, values[0]) { - return errors.New("correct proof but invalid data"), false + return nil, nil, nil, false, errors.New("correct proof but invalid data") } - return nil, hasRightElement(root, firstKey) + // Since the entire proof is a single path, we can construct a trie and a + // node database directly out of the inputs, no need to generate them + diskdb := notary.Accessed() + tr := &Trie{ + Db: NewDatabase(diskdb), + root: root, + } + return diskdb, tr, notary, hasRightElement(root, firstKey), nil } // Ok, in all other cases, we require two edge paths available. // First check the validity of edge keys. if bytes.Compare(firstKey, lastKey) >= 0 { - return errors.New("invalid edge keys"), false + return nil, nil, nil, false, errors.New("invalid edge keys") } // todo(rjl493456442) different length edge keys should be supported if len(firstKey) != len(lastKey) { - return errors.New("inconsistent edge keys"), false + return nil, nil, nil, false, errors.New("inconsistent edge keys") } // Convert the edge proofs to edge trie paths. Then we can // have the same tree architecture with the original one. // For the first edge proof, non-existent proof is allowed. - root, _, err := proofToPath(rootHash, nil, firstKey, proof, true) + root, _, err := proofToPath(rootHash, nil, firstKey, notary, true) if err != nil { - return err, false + return nil, nil, nil, false, err } // Pass the root node here, the second path will be merged // with the first one. For the last edge proof, non-existent // proof is also allowed. - root, _, err = proofToPath(rootHash, root, lastKey, proof, true) + root, _, err = proofToPath(rootHash, root, lastKey, notary, true) if err != nil { - return err, false + return nil, nil, nil, false, err } // Remove all internal references. All the removed parts should // be re-filled(or re-constructed) by the given leaves range. if err := unsetInternal(root, firstKey, lastKey); err != nil { - return err, false + return nil, nil, nil, false, err } - // Rebuild the trie with the leave stream, the shape of trie + // Rebuild the trie with the leaf stream, the shape of trie // should be same with the original one. - newtrie := &Trie{root: root, Db: NewDatabase(memorydb.New())} + var ( + diskdb = memorydb.New() + triedb = NewDatabase(diskdb) + ) + tr := &Trie{root: root, Db: triedb} for index, key := range keys { - newtrie.TryUpdate(key, values[index]) + tr.TryUpdate(key, values[index]) } - if newtrie.Hash() != rootHash { - return fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, newtrie.Hash()), false + if tr.Hash() != rootHash { + return nil, nil, nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, tr.Hash()) } - return nil, hasRightElement(root, keys[len(keys)-1]) + // Proof seems valid, serialize all the nodes into the database + if _, err := tr.Commit(nil); err != nil { + return nil, nil, nil, false, err + } + if err := triedb.Commit(rootHash, false); err != nil { + return nil, nil, nil, false, err + } + return diskdb, tr, notary, hasRightElement(root, keys[len(keys)-1]), nil } // get returns the child of the given Node. Return nil if the diff --git a/trie/proof_test.go b/trie/proof_test.go index c3db520710..549ece5b63 100644 --- a/trie/proof_test.go +++ b/trie/proof_test.go @@ -19,6 +19,7 @@ package trie import ( "bytes" crand "crypto/rand" + "encoding/binary" mrand "math/rand" "sort" "testing" @@ -176,7 +177,7 @@ func TestRangeProof(t *testing.T) { keys = append(keys, entries[i].k) vals = append(vals, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof) if err != nil { t.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err) } @@ -227,7 +228,7 @@ func TestRangeProofWithNonExistentProof(t *testing.T) { keys = append(keys, entries[i].k) vals = append(vals, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof) if err != nil { t.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err) } @@ -248,7 +249,7 @@ func TestRangeProofWithNonExistentProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), first, last, k, v, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, k, v, proof) if err != nil { t.Fatal("Failed to verify whole rang with non-existent edges") } @@ -283,7 +284,7 @@ func TestRangeProofWithInvalidNonExistentProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), first, k[len(k)-1], k, v, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), first, k[len(k)-1], k, v, proof) if err == nil { t.Fatalf("Expected to detect the error, got nil") } @@ -305,7 +306,7 @@ func TestRangeProofWithInvalidNonExistentProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ = VerifyRangeProof(trie.Hash(), k[0], last, k, v, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), k[0], last, k, v, proof) if err == nil { t.Fatalf("Expected to detect the error, got nil") } @@ -329,7 +330,7 @@ func TestOneElementRangeProof(t *testing.T) { if err := trie.Prove(entries[start].k, 0, proof); err != nil { t.Fatalf("Failed to prove the first node %v", err) } - err, _ := VerifyRangeProof(trie.Hash(), entries[start].k, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), entries[start].k, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -344,7 +345,7 @@ func TestOneElementRangeProof(t *testing.T) { if err := trie.Prove(entries[start].k, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), first, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), first, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -359,7 +360,7 @@ func TestOneElementRangeProof(t *testing.T) { if err := trie.Prove(last, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), entries[start].k, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), entries[start].k, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -374,7 +375,7 @@ func TestOneElementRangeProof(t *testing.T) { if err := trie.Prove(last, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -396,7 +397,7 @@ func TestAllElementsProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), nil, nil, k, v, nil) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), nil, nil, k, v, nil) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -409,7 +410,7 @@ func TestAllElementsProof(t *testing.T) { if err := trie.Prove(entries[len(entries)-1].k, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), k[0], k[len(k)-1], k, v, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), k[0], k[len(k)-1], k, v, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -424,7 +425,7 @@ func TestAllElementsProof(t *testing.T) { if err := trie.Prove(last, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), first, last, k, v, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, k, v, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -457,7 +458,7 @@ func TestSingleSideRangeProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), common.Hash{}.Bytes(), k[len(k)-1], k, v, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), common.Hash{}.Bytes(), k[len(k)-1], k, v, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -493,7 +494,7 @@ func TestReverseSingleSideRangeProof(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), k[0], last.Bytes(), k, v, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), k[0], last.Bytes(), k, v, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -565,7 +566,7 @@ func TestBadRangeProof(t *testing.T) { index = mrand.Intn(end - start) vals[index] = nil } - err, _ := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof) if err == nil { t.Fatalf("%d Case %d index %d range: (%d->%d) expect error, got nil", i, testcase, index, start, end-1) } @@ -599,7 +600,7 @@ func TestGappedRangeProof(t *testing.T) { keys = append(keys, entries[i].k) vals = append(vals, entries[i].v) } - err, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof) if err == nil { t.Fatal("expect error, got nil") } @@ -626,7 +627,7 @@ func TestSameSideProofs(t *testing.T) { if err := trie.Prove(last, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ := VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof) if err == nil { t.Fatalf("Expected error, got nil") } @@ -642,7 +643,7 @@ func TestSameSideProofs(t *testing.T) { if err := trie.Prove(last, 0, proof); err != nil { t.Fatalf("Failed to prove the last node %v", err) } - err, _ = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof) + _, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof) if err == nil { t.Fatalf("Expected error, got nil") } @@ -710,7 +711,7 @@ func TestHasRightElement(t *testing.T) { k = append(k, entries[i].k) v = append(v, entries[i].v) } - err, hasMore := VerifyRangeProof(trie.Hash(), firstKey, lastKey, k, v, proof) + _, _, _, hasMore, err := VerifyRangeProof(trie.Hash(), firstKey, lastKey, k, v, proof) if err != nil { t.Fatalf("Expected no error, got %v", err) } @@ -743,13 +744,57 @@ func TestEmptyRangeProof(t *testing.T) { if err := trie.Prove(first, 0, proof); err != nil { t.Fatalf("Failed to prove the first node %v", err) } - err, _ := VerifyRangeProof(trie.Hash(), first, nil, nil, nil, proof) + db, tr, not, _, err := VerifyRangeProof(trie.Hash(), first, nil, nil, nil, proof) if c.err && err == nil { t.Fatalf("Expected error, got nil") } if !c.err && err != nil { t.Fatalf("Expected no error, got %v", err) } + // If no error was returned, ensure the returned trie and database contains + // the entire proof, since there's no value + if !c.err { + if err := tr.Prove(first, 0, memorydb.New()); err != nil { + t.Errorf("returned trie doesn't contain original proof: %v", err) + } + if memdb := db.(*memorydb.Database); memdb.Len() != proof.Len() { + t.Errorf("database entry count mismatch: have %d, want %d", memdb.Len(), proof.Len()) + } + if not == nil { + t.Errorf("missing notary") + } + } + } +} + +// TestBloatedProof tests a malicious proof, where the proof is more or less the +// whole trie. +func TestBloatedProof(t *testing.T) { + // Use a small trie + trie, kvs := nonRandomTrie(100) + var entries entrySlice + for _, kv := range kvs { + entries = append(entries, kv) + } + sort.Sort(entries) + var keys [][]byte + var vals [][]byte + + proof := memorydb.New() + for i, entry := range entries { + trie.Prove(entry.k, 0, proof) + if i == 50 { + keys = append(keys, entry.k) + vals = append(vals, entry.v) + } + } + want := memorydb.New() + trie.Prove(keys[0], 0, want) + trie.Prove(keys[len(keys)-1], 0, want) + + _, _, notary, _, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof) + if used := notary.Accessed().(*memorydb.Database); used.Len() != want.Len() { + t.Fatalf("notary proof size mismatch: have %d, want %d", used.Len(), want.Len()) } } @@ -853,7 +898,7 @@ func benchmarkVerifyRangeProof(b *testing.B, size int) { b.ResetTimer() for i := 0; i < b.N; i++ { - err, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, values, proof) + _, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, values, proof) if err != nil { b.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err) } @@ -884,3 +929,20 @@ func randBytes(n int) []byte { crand.Read(r) return r } + +func nonRandomTrie(n int) (*Trie, map[string]*kv) { + trie := new(Trie) + vals := make(map[string]*kv) + max := uint64(0xffffffffffffffff) + for i := uint64(0); i < uint64(n); i++ { + value := make([]byte, 32) + key := make([]byte, 32) + binary.LittleEndian.PutUint64(key, i) + binary.LittleEndian.PutUint64(value, i-max) + //value := &kv{common.LeftPadBytes([]byte{i}, 32), []byte{i}, false} + elem := &kv{key, value, false} + trie.Update(elem.k, elem.v) + vals[string(elem.k)] = elem + } + return trie, vals +} diff --git a/trie/trie.go b/trie/trie.go index 45b680690e..e2f7e67e76 100644 --- a/trie/trie.go +++ b/trie/trie.go @@ -19,13 +19,13 @@ package trie import ( "bytes" + "errors" "fmt" "sync" "github.com/XinFinOrg/XDPoSChain/common" "github.com/XinFinOrg/XDPoSChain/core/types" "github.com/XinFinOrg/XDPoSChain/log" - "github.com/XinFinOrg/XDPoSChain/rlp" ) // LeafCallback is a callback type invoked when a trie operation reaches a leaf @@ -162,29 +162,26 @@ func (t *Trie) TryGetNode(path []byte) ([]byte, int, error) { if item == nil { return nil, resolved, nil } - enc, err := rlp.EncodeToBytes(item) - if err != nil { - log.Error("Encoding existing trie node failed", "err", err) - return nil, resolved, err - } - return enc, resolved, err + return item, resolved, err } -func (t *Trie) tryGetNode(origNode node, path []byte, pos int) (item node, newnode node, resolved int, err error) { +func (t *Trie) tryGetNode(origNode node, path []byte, pos int) (item []byte, newnode node, resolved int, err error) { // If we reached the requested path, return the current node if pos >= len(path) { - // Don't return collapsed hash nodes though - if _, ok := origNode.(hashNode); !ok { - // Short nodes have expanded keys, compact them before returning - item := origNode - if sn, ok := item.(*shortNode); ok { - item = &shortNode{ - Key: hexToCompact(sn.Key), - Val: sn.Val, - } - } - return item, origNode, 0, nil + // Although we most probably have the original node expanded, encoding + // that into consensus form can be nasty (needs to cascade down) and + // time consuming. Instead, just pull the hash up from disk directly. + var hash hashNode + if node, ok := origNode.(hashNode); ok { + hash = node + } else { + hash, _ = origNode.cache() } + if hash == nil { + return nil, origNode, 0, errors.New("non-consensus node") + } + blob, err := t.Db.Node(common.BytesToHash(hash)) + return blob, origNode, 1, err } // Path still needs to be traversed, descend into children switch n := (origNode).(type) {