1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
// Copyright 2015 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 <http://www.gnu.org/licenses/>.
package trie
import (
"hash"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto/sha3"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
var secureKeyPrefix = []byte("secure-key-")
// SecureTrie wraps a trie with key hashing. In a secure trie, all
// access operations hash the key using keccak256. This prevents
// calling code from creating long chains of nodes that
// increase the access time.
//
// Contrary to a regular trie, a SecureTrie can only be created with
// New and must have an attached database. The database also stores
// the preimage of each key.
//
// SecureTrie is not safe for concurrent use.
type SecureTrie struct {
*Trie
hash hash.Hash
secKeyBuf []byte
hashKeyBuf []byte
}
// NewSecure creates a trie with an existing root node from db.
//
// If root is the zero hash or the sha3 hash of an empty string, the
// trie is initially empty. Otherwise, New will panic if db is nil
// and returns MissingNodeError if the root node cannot be found.
// Accessing the trie loads nodes from db on demand.
func NewSecure(root common.Hash, db Database) (*SecureTrie, error) {
if db == nil {
panic("NewSecure called with nil database")
}
trie, err := New(root, db)
if err != nil {
return nil, err
}
return &SecureTrie{Trie: trie}, nil
}
// Get returns the value for key stored in the trie.
// The value bytes must not be modified by the caller.
func (t *SecureTrie) Get(key []byte) []byte {
res, err := t.TryGet(key)
if err != nil && glog.V(logger.Error) {
glog.Errorf("Unhandled trie error: %v", err)
}
return res
}
// TryGet returns the value for key stored in the trie.
// The value bytes must not be modified by the caller.
// If a node was not found in the database, a MissingNodeError is returned.
func (t *SecureTrie) TryGet(key []byte) ([]byte, error) {
return t.Trie.TryGet(t.hashKey(key))
}
// Update associates key with value in the trie. Subsequent calls to
// Get will return value. If value has length zero, any existing value
// is deleted from the trie and calls to Get will return nil.
//
// The value bytes must not be modified by the caller while they are
// stored in the trie.
func (t *SecureTrie) Update(key, value []byte) {
if err := t.TryUpdate(key, value); err != nil && glog.V(logger.Error) {
glog.Errorf("Unhandled trie error: %v", err)
}
}
// TryUpdate associates key with value in the trie. Subsequent calls to
// Get will return value. If value has length zero, any existing value
// is deleted from the trie and calls to Get will return nil.
//
// The value bytes must not be modified by the caller while they are
// stored in the trie.
//
// If a node was not found in the database, a MissingNodeError is returned.
func (t *SecureTrie) TryUpdate(key, value []byte) error {
hk := t.hashKey(key)
err := t.Trie.TryUpdate(hk, value)
if err != nil {
return err
}
t.Trie.db.Put(t.secKey(hk), key)
return nil
}
// Delete removes any existing value for key from the trie.
func (t *SecureTrie) Delete(key []byte) {
if err := t.TryDelete(key); err != nil && glog.V(logger.Error) {
glog.Errorf("Unhandled trie error: %v", err)
}
}
// TryDelete removes any existing value for key from the trie.
// If a node was not found in the database, a MissingNodeError is returned.
func (t *SecureTrie) TryDelete(key []byte) error {
return t.Trie.TryDelete(t.hashKey(key))
}
// GetKey returns the sha3 preimage of a hashed key that was
// previously used to store a value.
func (t *SecureTrie) GetKey(shaKey []byte) []byte {
key, _ := t.Trie.db.Get(t.secKey(shaKey))
return key
}
func (t *SecureTrie) secKey(key []byte) []byte {
t.secKeyBuf = append(t.secKeyBuf[:0], secureKeyPrefix...)
t.secKeyBuf = append(t.secKeyBuf, key...)
return t.secKeyBuf
}
func (t *SecureTrie) hashKey(key []byte) []byte {
if t.hash == nil {
t.hash = sha3.NewKeccak256()
t.hashKeyBuf = make([]byte, 32)
}
t.hash.Reset()
t.hash.Write(key)
t.hashKeyBuf = t.hash.Sum(t.hashKeyBuf[:0])
return t.hashKeyBuf
}
|
