-
Notifications
You must be signed in to change notification settings - Fork 11
/
verify.go
286 lines (253 loc) · 10.9 KB
/
verify.go
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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
package evidence
import (
"bytes"
"errors"
"fmt"
"time"
"github.com/consideritdone/landslidecore/light"
"github.com/consideritdone/landslidecore/types"
)
// verify verifies the evidence fully by checking:
// - It has not already been committed
// - it is sufficiently recent (MaxAge)
// - it is from a key who was a validator at the given height
// - it is internally consistent with state
// - it was properly signed by the alleged equivocator and meets the individual evidence verification requirements
func (evpool *Pool) verify(evidence types.Evidence) error {
var (
state = evpool.State()
height = state.LastBlockHeight
evidenceParams = state.ConsensusParams.Evidence
ageNumBlocks = height - evidence.Height()
)
// verify the time of the evidence
blockMeta := evpool.blockStore.LoadBlockMeta(evidence.Height())
if blockMeta == nil {
return fmt.Errorf("don't have header #%d", evidence.Height())
}
evTime := blockMeta.Header.Time
if evidence.Time() != evTime {
return fmt.Errorf("evidence has a different time to the block it is associated with (%v != %v)",
evidence.Time(), evTime)
}
ageDuration := state.LastBlockTime.Sub(evTime)
// check that the evidence hasn't expired
if ageDuration > evidenceParams.MaxAgeDuration && ageNumBlocks > evidenceParams.MaxAgeNumBlocks {
return fmt.Errorf(
"evidence from height %d (created at: %v) is too old; min height is %d and evidence can not be older than %v",
evidence.Height(),
evTime,
height-evidenceParams.MaxAgeNumBlocks,
state.LastBlockTime.Add(evidenceParams.MaxAgeDuration),
)
}
// apply the evidence-specific verification logic
switch ev := evidence.(type) {
case *types.DuplicateVoteEvidence:
valSet, err := evpool.stateDB.LoadValidators(evidence.Height())
if err != nil {
return err
}
return VerifyDuplicateVote(ev, state.ChainID, valSet)
case *types.LightClientAttackEvidence:
commonHeader, err := getSignedHeader(evpool.blockStore, evidence.Height())
if err != nil {
return err
}
commonVals, err := evpool.stateDB.LoadValidators(evidence.Height())
if err != nil {
return err
}
trustedHeader := commonHeader
// in the case of lunatic the trusted header is different to the common header
if evidence.Height() != ev.ConflictingBlock.Height {
trustedHeader, err = getSignedHeader(evpool.blockStore, ev.ConflictingBlock.Height)
if err != nil {
// FIXME: This multi step process is a bit unergonomic. We may want to consider a more efficient process
// that doesn't require as much io and is atomic.
// If the node doesn't have a block at the height of the conflicting block, then this could be
// a forward lunatic attack. Thus the node must get the latest height it has
latestHeight := evpool.blockStore.Height()
trustedHeader, err = getSignedHeader(evpool.blockStore, latestHeight)
if err != nil {
return err
}
if trustedHeader.Time.Before(ev.ConflictingBlock.Time) {
return fmt.Errorf("latest block time (%v) is before conflicting block time (%v)",
trustedHeader.Time, ev.ConflictingBlock.Time,
)
}
}
}
err = VerifyLightClientAttack(ev, commonHeader, trustedHeader, commonVals, state.LastBlockTime,
state.ConsensusParams.Evidence.MaxAgeDuration)
if err != nil {
return err
}
return nil
default:
return fmt.Errorf("unrecognized evidence type: %T", evidence)
}
}
// VerifyLightClientAttack verifies LightClientAttackEvidence against the state of the full node. This involves
// the following checks:
// - the common header from the full node has at least 1/3 voting power which is also present in
// the conflicting header's commit
// - 2/3+ of the conflicting validator set correctly signed the conflicting block
// - the nodes trusted header at the same height as the conflicting header has a different hash
//
// CONTRACT: must run ValidateBasic() on the evidence before verifying
//
// must check that the evidence has not expired (i.e. is outside the maximum age threshold)
func VerifyLightClientAttack(e *types.LightClientAttackEvidence, commonHeader, trustedHeader *types.SignedHeader,
commonVals *types.ValidatorSet, now time.Time, trustPeriod time.Duration) error {
// In the case of lunatic attack there will be a different commonHeader height. Therefore the node perform a single
// verification jump between the common header and the conflicting one
if commonHeader.Height != e.ConflictingBlock.Height {
err := commonVals.VerifyCommitLightTrusting(trustedHeader.ChainID, e.ConflictingBlock.Commit, light.DefaultTrustLevel)
if err != nil {
return fmt.Errorf("skipping verification of conflicting block failed: %w", err)
}
// In the case of equivocation and amnesia we expect all header hashes to be correctly derived
} else if e.ConflictingHeaderIsInvalid(trustedHeader.Header) {
return errors.New("common height is the same as conflicting block height so expected the conflicting" +
" block to be correctly derived yet it wasn't")
}
// Verify that the 2/3+ commits from the conflicting validator set were for the conflicting header
if err := e.ConflictingBlock.ValidatorSet.VerifyCommitLight(trustedHeader.ChainID, e.ConflictingBlock.Commit.BlockID,
e.ConflictingBlock.Height, e.ConflictingBlock.Commit); err != nil {
return fmt.Errorf("invalid commit from conflicting block: %w", err)
}
// Assert the correct amount of voting power of the validator set
if evTotal, valsTotal := e.TotalVotingPower, commonVals.TotalVotingPower(); evTotal != valsTotal {
return fmt.Errorf("total voting power from the evidence and our validator set does not match (%d != %d)",
evTotal, valsTotal)
}
// check in the case of a forward lunatic attack that monotonically increasing time has been violated
if e.ConflictingBlock.Height > trustedHeader.Height && e.ConflictingBlock.Time.After(trustedHeader.Time) {
return fmt.Errorf("conflicting block doesn't violate monotonically increasing time (%v is after %v)",
e.ConflictingBlock.Time, trustedHeader.Time,
)
// In all other cases check that the hashes of the conflicting header and the trusted header are different
} else if bytes.Equal(trustedHeader.Hash(), e.ConflictingBlock.Hash()) {
return fmt.Errorf("trusted header hash matches the evidence's conflicting header hash: %X",
trustedHeader.Hash())
}
return validateABCIEvidence(e, commonVals, trustedHeader)
}
// VerifyDuplicateVote verifies DuplicateVoteEvidence against the state of full node. This involves the
// following checks:
// - the validator is in the validator set at the height of the evidence
// - the height, round, type and validator address of the votes must be the same
// - the block ID's must be different
// - The signatures must both be valid
func VerifyDuplicateVote(e *types.DuplicateVoteEvidence, chainID string, valSet *types.ValidatorSet) error {
_, val := valSet.GetByAddress(e.VoteA.ValidatorAddress)
if val == nil {
return fmt.Errorf("address %X was not a validator at height %d", e.VoteA.ValidatorAddress, e.Height())
}
pubKey := val.PubKey
// H/R/S must be the same
if e.VoteA.Height != e.VoteB.Height ||
e.VoteA.Round != e.VoteB.Round ||
e.VoteA.Type != e.VoteB.Type {
return fmt.Errorf("h/r/s does not match: %d/%d/%v vs %d/%d/%v",
e.VoteA.Height, e.VoteA.Round, e.VoteA.Type,
e.VoteB.Height, e.VoteB.Round, e.VoteB.Type)
}
// Address must be the same
if !bytes.Equal(e.VoteA.ValidatorAddress, e.VoteB.ValidatorAddress) {
return fmt.Errorf("validator addresses do not match: %X vs %X",
e.VoteA.ValidatorAddress,
e.VoteB.ValidatorAddress,
)
}
// BlockIDs must be different
if e.VoteA.BlockID.Equals(e.VoteB.BlockID) {
return fmt.Errorf(
"block IDs are the same (%v) - not a real duplicate vote",
e.VoteA.BlockID,
)
}
// pubkey must match address (this should already be true, sanity check)
addr := e.VoteA.ValidatorAddress
if !bytes.Equal(pubKey.Address(), addr) {
return fmt.Errorf("address (%X) doesn't match pubkey (%v - %X)",
addr, pubKey, pubKey.Address())
}
// validator voting power and total voting power must match
if val.VotingPower != e.ValidatorPower {
return fmt.Errorf("validator power from evidence and our validator set does not match (%d != %d)",
e.ValidatorPower, val.VotingPower)
}
if valSet.TotalVotingPower() != e.TotalVotingPower {
return fmt.Errorf("total voting power from the evidence and our validator set does not match (%d != %d)",
e.TotalVotingPower, valSet.TotalVotingPower())
}
va := e.VoteA.ToProto()
vb := e.VoteB.ToProto()
// Signatures must be valid
if !pubKey.VerifySignature(types.VoteSignBytes(chainID, va), e.VoteA.Signature) {
return fmt.Errorf("verifying VoteA: %w", types.ErrVoteInvalidSignature)
}
if !pubKey.VerifySignature(types.VoteSignBytes(chainID, vb), e.VoteB.Signature) {
return fmt.Errorf("verifying VoteB: %w", types.ErrVoteInvalidSignature)
}
return nil
}
// validateABCIEvidence validates the ABCI component of the light client attack
// evidence i.e voting power and byzantine validators
func validateABCIEvidence(
ev *types.LightClientAttackEvidence,
commonVals *types.ValidatorSet,
trustedHeader *types.SignedHeader,
) error {
if evTotal, valsTotal := ev.TotalVotingPower, commonVals.TotalVotingPower(); evTotal != valsTotal {
return fmt.Errorf("total voting power from the evidence and our validator set does not match (%d != %d)",
evTotal, valsTotal)
}
// Find out what type of attack this was and thus extract the malicious
// validators. Note, in the case of an Amnesia attack we don't have any
// malicious validators.
validators := ev.GetByzantineValidators(commonVals, trustedHeader)
// Ensure this matches the validators that are listed in the evidence. They
// should be ordered based on power.
if validators == nil && ev.ByzantineValidators != nil {
return fmt.Errorf(
"expected nil validators from an amnesia light client attack but got %d",
len(ev.ByzantineValidators),
)
}
if exp, got := len(validators), len(ev.ByzantineValidators); exp != got {
return fmt.Errorf("expected %d byzantine validators from evidence but got %d", exp, got)
}
for idx, val := range validators {
if !bytes.Equal(ev.ByzantineValidators[idx].Address, val.Address) {
return fmt.Errorf(
"evidence contained an unexpected byzantine validator address; expected: %v, got: %v",
val.Address, ev.ByzantineValidators[idx].Address,
)
}
if ev.ByzantineValidators[idx].VotingPower != val.VotingPower {
return fmt.Errorf(
"evidence contained unexpected byzantine validator power; expected %d, got %d",
val.VotingPower, ev.ByzantineValidators[idx].VotingPower,
)
}
}
return nil
}
func getSignedHeader(blockStore BlockStore, height int64) (*types.SignedHeader, error) {
blockMeta := blockStore.LoadBlockMeta(height)
if blockMeta == nil {
return nil, fmt.Errorf("don't have header at height #%d", height)
}
commit := blockStore.LoadBlockCommit(height)
if commit == nil {
return nil, fmt.Errorf("don't have commit at height #%d", height)
}
return &types.SignedHeader{
Header: &blockMeta.Header,
Commit: commit,
}, nil
}