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lightningnetwork / lnd / 12293715361

12 Dec 2024 09:38AM UTC coverage: 57.483% (+7.9%) from 49.538%
12293715361

Pull #9348

github

ziggie1984
github: update goveralls tool

The goverall tool had a bug regarding the module versioning of
golang packages see also
https://github.com/mattn/goveralls/pull/222 for more background.
Goveralls is wrapped by another library to make it available for
github actions. So the relevant PR which is referenced here in
LND is:
https://github.com/shogo82148/actions-goveralls/pull/521.
Pull Request #9348: github: update goveralls tool

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61.09
/lnwallet/btcwallet/signer.go
1
package btcwallet
2

3
import (
4
        "fmt"
5

6
        "github.com/btcsuite/btcd/btcec/v2"
7
        "github.com/btcsuite/btcd/btcec/v2/ecdsa"
8
        "github.com/btcsuite/btcd/btcec/v2/schnorr"
9
        "github.com/btcsuite/btcd/btcutil"
10
        "github.com/btcsuite/btcd/btcutil/hdkeychain"
11
        "github.com/btcsuite/btcd/btcutil/psbt"
12
        "github.com/btcsuite/btcd/chaincfg/chainhash"
13
        "github.com/btcsuite/btcd/txscript"
14
        "github.com/btcsuite/btcd/wire"
15
        "github.com/btcsuite/btcwallet/waddrmgr"
16
        "github.com/btcsuite/btcwallet/walletdb"
17
        "github.com/lightningnetwork/lnd/input"
18
        "github.com/lightningnetwork/lnd/keychain"
19
        "github.com/lightningnetwork/lnd/lnwallet"
20
)
21

22
// FetchOutpointInfo queries for the WalletController's knowledge of the passed
23
// outpoint. If the base wallet determines this output is under its control,
24
// then the original txout should be returned. Otherwise, a non-nil error value
25
// of ErrNotMine should be returned instead.
26
//
27
// This is a part of the WalletController interface.
28
func (b *BtcWallet) FetchOutpointInfo(prevOut *wire.OutPoint) (*lnwallet.Utxo,
29
        error) {
88✔
30

88✔
31
        prevTx, txOut, confirmations, err := b.wallet.FetchOutpointInfo(prevOut)
88✔
32
        if err != nil {
88✔
33
                return nil, err
×
34
        }
×
35

36
        // Then, we'll populate all of the information required by the struct.
37
        addressType := lnwallet.UnknownAddressType
88✔
38
        switch {
88✔
39
        case txscript.IsPayToWitnessPubKeyHash(txOut.PkScript):
88✔
40
                addressType = lnwallet.WitnessPubKey
88✔
41
        case txscript.IsPayToScriptHash(txOut.PkScript):
×
42
                addressType = lnwallet.NestedWitnessPubKey
×
43
        case txscript.IsPayToTaproot(txOut.PkScript):
×
44
                addressType = lnwallet.TaprootPubkey
×
45
        }
46

47
        return &lnwallet.Utxo{
88✔
48
                AddressType:   addressType,
88✔
49
                Value:         btcutil.Amount(txOut.Value),
88✔
50
                PkScript:      txOut.PkScript,
88✔
51
                Confirmations: confirmations,
88✔
52
                OutPoint:      *prevOut,
88✔
53
                PrevTx:        prevTx,
88✔
54
        }, nil
88✔
55
}
56

57
// FetchDerivationInfo queries for the wallet's knowledge of the passed
58
// pkScript and constructs the derivation info and returns it.
59
func (b *BtcWallet) FetchDerivationInfo(
60
        pkScript []byte) (*psbt.Bip32Derivation, error) {
×
61

×
62
        return b.wallet.FetchDerivationInfo(pkScript)
×
63
}
×
64

65
// ScriptForOutput returns the address, witness program and redeem script for a
66
// given UTXO. An error is returned if the UTXO does not belong to our wallet or
67
// it is not a managed pubKey address.
68
func (b *BtcWallet) ScriptForOutput(output *wire.TxOut) (
69
        waddrmgr.ManagedPubKeyAddress, []byte, []byte, error) {
×
70

×
71
        return b.wallet.ScriptForOutput(output)
×
72
}
×
73

74
// deriveFromKeyLoc attempts to derive a private key using a fully specified
75
// KeyLocator.
76
func deriveFromKeyLoc(scopedMgr *waddrmgr.ScopedKeyManager,
77
        addrmgrNs walletdb.ReadWriteBucket,
78
        keyLoc keychain.KeyLocator) (*btcec.PrivateKey, error) {
9✔
79

9✔
80
        path := waddrmgr.DerivationPath{
9✔
81
                InternalAccount: uint32(keyLoc.Family),
9✔
82
                Account:         uint32(keyLoc.Family),
9✔
83
                Branch:          0,
9✔
84
                Index:           keyLoc.Index,
9✔
85
        }
9✔
86
        addr, err := scopedMgr.DeriveFromKeyPath(addrmgrNs, path)
9✔
87
        if err != nil {
9✔
88
                return nil, err
×
89
        }
×
90

91
        return addr.(waddrmgr.ManagedPubKeyAddress).PrivKey()
9✔
92
}
93

94
// deriveKeyByBIP32Path derives a key described by a BIP32 path. We expect the
95
// first three elements of the path to be hardened according to BIP44, so they
96
// must be a number >= 2^31.
97
func (b *BtcWallet) deriveKeyByBIP32Path(path []uint32) (*btcec.PrivateKey,
98
        error) {
25✔
99

25✔
100
        // Make sure we get a full path with exactly 5 elements. A path is
25✔
101
        // either custom purpose one with 4 dynamic and one static elements:
25✔
102
        //    m/1017'/coinType'/keyFamily'/0/index
25✔
103
        // Or a default BIP49/89 one with 5 elements:
25✔
104
        //    m/purpose'/coinType'/account'/change/index
25✔
105
        const expectedDerivationPathDepth = 5
25✔
106
        if len(path) != expectedDerivationPathDepth {
25✔
107
                return nil, fmt.Errorf("invalid BIP32 derivation path, "+
×
108
                        "expected path length %d, instead was %d",
×
109
                        expectedDerivationPathDepth, len(path))
×
110
        }
×
111

112
        // Assert that the first three parts of the path are actually hardened
113
        // to avoid under-flowing the uint32 type.
114
        if err := assertHardened(path[0], path[1], path[2]); err != nil {
27✔
115
                return nil, fmt.Errorf("invalid BIP32 derivation path, "+
2✔
116
                        "expected first three elements to be hardened: %w", err)
2✔
117
        }
2✔
118

119
        purpose := path[0] - hdkeychain.HardenedKeyStart
23✔
120
        coinType := path[1] - hdkeychain.HardenedKeyStart
23✔
121
        account := path[2] - hdkeychain.HardenedKeyStart
23✔
122
        change, index := path[3], path[4]
23✔
123

23✔
124
        // Is this a custom lnd internal purpose key?
23✔
125
        switch purpose {
23✔
126
        case keychain.BIP0043Purpose:
8✔
127
                // Make sure it's for the same coin type as our wallet's
8✔
128
                // keychain scope.
8✔
129
                if coinType != b.chainKeyScope.Coin {
9✔
130
                        return nil, fmt.Errorf("invalid BIP32 derivation "+
1✔
131
                                "path, expected coin type %d, instead was %d",
1✔
132
                                b.chainKeyScope.Coin, coinType)
1✔
133
                }
1✔
134

135
                return b.deriveKeyByLocator(keychain.KeyLocator{
7✔
136
                        Family: keychain.KeyFamily(account),
7✔
137
                        Index:  index,
7✔
138
                })
7✔
139

140
        // Is it a standard, BIP defined purpose that the wallet understands?
141
        case waddrmgr.KeyScopeBIP0044.Purpose,
142
                waddrmgr.KeyScopeBIP0049Plus.Purpose,
143
                waddrmgr.KeyScopeBIP0084.Purpose,
144
                waddrmgr.KeyScopeBIP0086.Purpose:
15✔
145

146
                // We're going to continue below the switch statement to avoid
147
                // unnecessary indentation for this default case.
148

149
        // Currently, there is no way to import any other key scopes than the
150
        // one custom purpose or three standard ones into lnd's wallet. So we
151
        // shouldn't accept any other scopes to sign for.
152
        default:
×
153
                return nil, fmt.Errorf("invalid BIP32 derivation path, "+
×
154
                        "unknown purpose %d", purpose)
×
155
        }
156

157
        // Okay, we made sure it's a BIP49/84 key, so we need to derive it now.
158
        // Interestingly, the btcwallet never actually uses a coin type other
159
        // than 0 for those keys, so we need to make sure this behavior is
160
        // replicated here.
161
        if coinType != 0 {
16✔
162
                return nil, fmt.Errorf("invalid BIP32 derivation path, coin " +
1✔
163
                        "type must be 0 for BIP49/84 btcwallet keys")
1✔
164
        }
1✔
165

166
        // We only expect to be asked to sign with key scopes that we know
167
        // about. So if the scope doesn't exist, we don't create it.
168
        scope := waddrmgr.KeyScope{
14✔
169
                Purpose: purpose,
14✔
170
                Coin:    coinType,
14✔
171
        }
14✔
172
        scopedMgr, err := b.wallet.Manager.FetchScopedKeyManager(scope)
14✔
173
        if err != nil {
14✔
174
                return nil, fmt.Errorf("error fetching manager for scope %v: "+
×
175
                        "%w", scope, err)
×
176
        }
×
177

178
        // Let's see if we can hit the private key cache.
179
        keyPath := waddrmgr.DerivationPath{
14✔
180
                InternalAccount: account,
14✔
181
                Account:         account,
14✔
182
                Branch:          change,
14✔
183
                Index:           index,
14✔
184
        }
14✔
185
        privKey, err := scopedMgr.DeriveFromKeyPathCache(keyPath)
14✔
186
        if err == nil {
23✔
187
                return privKey, nil
9✔
188
        }
9✔
189

190
        // The key wasn't in the cache, let's fully derive it now.
191
        err = walletdb.View(b.db, func(tx walletdb.ReadTx) error {
10✔
192
                addrmgrNs := tx.ReadBucket(waddrmgrNamespaceKey)
5✔
193

5✔
194
                addr, err := scopedMgr.DeriveFromKeyPath(addrmgrNs, keyPath)
5✔
195
                if err != nil {
7✔
196
                        return fmt.Errorf("error deriving private key: %w", err)
2✔
197
                }
2✔
198

199
                privKey, err = addr.(waddrmgr.ManagedPubKeyAddress).PrivKey()
3✔
200
                return err
3✔
201
        })
202
        if err != nil {
7✔
203
                return nil, fmt.Errorf("error deriving key from path %#v: %w",
2✔
204
                        keyPath, err)
2✔
205
        }
2✔
206

207
        return privKey, nil
3✔
208
}
209

210
// assertHardened makes sure each given element is >= 2^31.
211
func assertHardened(elements ...uint32) error {
25✔
212
        for idx, element := range elements {
98✔
213
                if element < hdkeychain.HardenedKeyStart {
75✔
214
                        return fmt.Errorf("element at index %d is not hardened",
2✔
215
                                idx)
2✔
216
                }
2✔
217
        }
218

219
        return nil
23✔
220
}
221

222
// deriveKeyByLocator attempts to derive a key stored in the wallet given a
223
// valid key locator.
224
func (b *BtcWallet) deriveKeyByLocator(
225
        keyLoc keychain.KeyLocator) (*btcec.PrivateKey, error) {
43✔
226

43✔
227
        // We'll assume the special lightning key scope in this case.
43✔
228
        scopedMgr, err := b.wallet.Manager.FetchScopedKeyManager(
43✔
229
                b.chainKeyScope,
43✔
230
        )
43✔
231
        if err != nil {
43✔
232
                return nil, err
×
233
        }
×
234

235
        // First try to read the key from the cached store, if this fails, then
236
        // we'll fall through to the method below that requires a database
237
        // transaction.
238
        path := waddrmgr.DerivationPath{
43✔
239
                InternalAccount: uint32(keyLoc.Family),
43✔
240
                Account:         uint32(keyLoc.Family),
43✔
241
                Branch:          0,
43✔
242
                Index:           keyLoc.Index,
43✔
243
        }
43✔
244
        privKey, err := scopedMgr.DeriveFromKeyPathCache(path)
43✔
245
        if err == nil {
77✔
246
                return privKey, nil
34✔
247
        }
34✔
248

249
        var key *btcec.PrivateKey
9✔
250
        err = walletdb.Update(b.db, func(tx walletdb.ReadWriteTx) error {
18✔
251
                addrmgrNs := tx.ReadWriteBucket(waddrmgrNamespaceKey)
9✔
252

9✔
253
                key, err = deriveFromKeyLoc(scopedMgr, addrmgrNs, keyLoc)
9✔
254
                if waddrmgr.IsError(err, waddrmgr.ErrAccountNotFound) {
9✔
255
                        // If we've reached this point, then the account
×
256
                        // doesn't yet exist, so we'll create it now to ensure
×
257
                        // we can sign.
×
258
                        acctErr := scopedMgr.NewRawAccount(
×
259
                                addrmgrNs, uint32(keyLoc.Family),
×
260
                        )
×
261
                        if acctErr != nil {
×
262
                                return acctErr
×
263
                        }
×
264

265
                        // Now that we know the account exists, we'll attempt
266
                        // to re-derive the private key.
267
                        key, err = deriveFromKeyLoc(
×
268
                                scopedMgr, addrmgrNs, keyLoc,
×
269
                        )
×
270
                        if err != nil {
×
271
                                return err
×
272
                        }
×
273
                }
274

275
                return err
9✔
276
        })
277
        if err != nil {
9✔
278
                return nil, err
×
279
        }
×
280

281
        return key, nil
9✔
282
}
283

284
// fetchPrivKey attempts to retrieve the raw private key corresponding to the
285
// passed public key if populated, or the key descriptor path (if non-empty).
286
func (b *BtcWallet) fetchPrivKey(
287
        keyDesc *keychain.KeyDescriptor) (*btcec.PrivateKey, error) {
79✔
288

79✔
289
        // If the key locator within the descriptor *isn't* empty, then we can
79✔
290
        // directly derive the keys raw.
79✔
291
        emptyLocator := keyDesc.KeyLocator.IsEmpty()
79✔
292
        if !emptyLocator || keyDesc.PubKey == nil {
115✔
293
                return b.deriveKeyByLocator(keyDesc.KeyLocator)
36✔
294
        }
36✔
295

296
        hash160 := btcutil.Hash160(keyDesc.PubKey.SerializeCompressed())
43✔
297
        addr, err := btcutil.NewAddressWitnessPubKeyHash(hash160, b.netParams)
43✔
298
        if err != nil {
43✔
299
                return nil, err
×
300
        }
×
301

302
        // Otherwise, we'll attempt to derive the key based on the address.
303
        // This will only work if we've already derived this address in the
304
        // past, since the wallet relies on a mapping of addr -> key.
305
        key, err := b.wallet.PrivKeyForAddress(addr)
43✔
306
        switch {
43✔
307
        // If we didn't find this key in the wallet, then there's a chance that
308
        // this is actually an "empty" key locator. The legacy KeyLocator
309
        // format failed to properly distinguish an empty key locator from the
310
        // very first in the index (0, 0).IsEmpty() == true.
311
        case waddrmgr.IsError(err, waddrmgr.ErrAddressNotFound) && emptyLocator:
×
312
                return b.deriveKeyByLocator(keyDesc.KeyLocator)
×
313

314
        case err != nil:
×
315
                return nil, err
×
316

317
        default:
43✔
318
                return key, nil
43✔
319
        }
320
}
321

322
// maybeTweakPrivKey examines the single and double tweak parameters on the
323
// passed sign descriptor and may perform a mapping on the passed private key
324
// in order to utilize the tweaks, if populated.
325
func maybeTweakPrivKey(signDesc *input.SignDescriptor,
326
        privKey *btcec.PrivateKey) (*btcec.PrivateKey, error) {
95✔
327

95✔
328
        var retPriv *btcec.PrivateKey
95✔
329
        switch {
95✔
330

331
        case signDesc.SingleTweak != nil:
4✔
332
                retPriv = input.TweakPrivKey(privKey,
4✔
333
                        signDesc.SingleTweak)
4✔
334

335
        case signDesc.DoubleTweak != nil:
4✔
336
                retPriv = input.DeriveRevocationPrivKey(privKey,
4✔
337
                        signDesc.DoubleTweak)
4✔
338

339
        default:
87✔
340
                retPriv = privKey
87✔
341
        }
342

343
        return retPriv, nil
95✔
344
}
345

346
// SignOutputRaw generates a signature for the passed transaction according to
347
// the data within the passed SignDescriptor.
348
//
349
// This is a part of the WalletController interface.
350
func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
351
        signDesc *input.SignDescriptor) (input.Signature, error) {
63✔
352

63✔
353
        witnessScript := signDesc.WitnessScript
63✔
354

63✔
355
        // First attempt to fetch the private key which corresponds to the
63✔
356
        // specified public key.
63✔
357
        privKey, err := b.fetchPrivKey(&signDesc.KeyDesc)
63✔
358
        if err != nil {
63✔
359
                return nil, err
×
360
        }
×
361

362
        // If a tweak (single or double) is specified, then we'll need to use
363
        // this tweak to derive the final private key to be used for signing
364
        // this output.
365
        privKey, err = maybeTweakPrivKey(signDesc, privKey)
63✔
366
        if err != nil {
63✔
367
                return nil, err
×
368
        }
×
369

370
        // In case of a taproot output any signature is always a Schnorr
371
        // signature, based on the new tapscript sighash algorithm.
372
        if txscript.IsPayToTaproot(signDesc.Output.PkScript) {
63✔
373
                sigHashes := txscript.NewTxSigHashes(
×
374
                        tx, signDesc.PrevOutputFetcher,
×
375
                )
×
376

×
377
                // Are we spending a script path or the key path? The API is
×
378
                // slightly different, so we need to account for that to get the
×
379
                // raw signature.
×
380
                var rawSig []byte
×
381
                switch signDesc.SignMethod {
×
382
                case input.TaprootKeySpendBIP0086SignMethod,
383
                        input.TaprootKeySpendSignMethod:
×
384

×
385
                        // This function tweaks the private key using the tap
×
386
                        // root key supplied as the tweak.
×
387
                        rawSig, err = txscript.RawTxInTaprootSignature(
×
388
                                tx, sigHashes, signDesc.InputIndex,
×
389
                                signDesc.Output.Value, signDesc.Output.PkScript,
×
390
                                signDesc.TapTweak, signDesc.HashType,
×
391
                                privKey,
×
392
                        )
×
393
                        if err != nil {
×
394
                                return nil, err
×
395
                        }
×
396

397
                case input.TaprootScriptSpendSignMethod:
×
398
                        leaf := txscript.TapLeaf{
×
399
                                LeafVersion: txscript.BaseLeafVersion,
×
400
                                Script:      witnessScript,
×
401
                        }
×
402
                        rawSig, err = txscript.RawTxInTapscriptSignature(
×
403
                                tx, sigHashes, signDesc.InputIndex,
×
404
                                signDesc.Output.Value, signDesc.Output.PkScript,
×
405
                                leaf, signDesc.HashType, privKey,
×
406
                        )
×
407
                        if err != nil {
×
408
                                return nil, err
×
409
                        }
×
410

411
                default:
×
412
                        return nil, fmt.Errorf("unknown sign method: %v",
×
413
                                signDesc.SignMethod)
×
414
                }
415

416
                // The signature returned above might have a sighash flag
417
                // attached if a non-default type was used. We'll slice this
418
                // off if it exists to ensure we can properly parse the raw
419
                // signature.
420
                sig, err := schnorr.ParseSignature(
×
421
                        rawSig[:schnorr.SignatureSize],
×
422
                )
×
423
                if err != nil {
×
424
                        return nil, err
×
425
                }
×
426

427
                return sig, nil
×
428
        }
429

430
        // TODO(roasbeef): generate sighash midstate if not present?
431

432
        amt := signDesc.Output.Value
63✔
433
        sig, err := txscript.RawTxInWitnessSignature(
63✔
434
                tx, signDesc.SigHashes, signDesc.InputIndex, amt,
63✔
435
                witnessScript, signDesc.HashType, privKey,
63✔
436
        )
63✔
437
        if err != nil {
63✔
438
                return nil, err
×
439
        }
×
440

441
        // Chop off the sighash flag at the end of the signature.
442
        return ecdsa.ParseDERSignature(sig[:len(sig)-1])
63✔
443
}
444

445
// ComputeInputScript generates a complete InputScript for the passed
446
// transaction with the signature as defined within the passed SignDescriptor.
447
// This method is capable of generating the proper input script for both
448
// regular p2wkh output and p2wkh outputs nested within a regular p2sh output.
449
//
450
// This is a part of the WalletController interface.
451
func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
452
        signDesc *input.SignDescriptor) (*input.Script, error) {
32✔
453

32✔
454
        // If a tweak (single or double) is specified, then we'll need to use
32✔
455
        // this tweak to derive the final private key to be used for signing
32✔
456
        // this output.
32✔
457
        privKeyTweaker := func(k *btcec.PrivateKey) (*btcec.PrivateKey, error) {
64✔
458
                return maybeTweakPrivKey(signDesc, k)
32✔
459
        }
32✔
460

461
        // Let the wallet compute the input script now.
462
        witness, sigScript, err := b.wallet.ComputeInputScript(
32✔
463
                tx, signDesc.Output, signDesc.InputIndex, signDesc.SigHashes,
32✔
464
                signDesc.HashType, privKeyTweaker,
32✔
465
        )
32✔
466
        if err != nil {
32✔
467
                return nil, err
×
468
        }
×
469

470
        return &input.Script{
32✔
471
                Witness:   witness,
32✔
472
                SigScript: sigScript,
32✔
473
        }, nil
32✔
474
}
475

476
// A compile time check to ensure that BtcWallet implements the Signer
477
// interface.
478
var _ input.Signer = (*BtcWallet)(nil)
479

480
// SignMessage attempts to sign a target message with the private key that
481
// corresponds to the passed key locator. If the target private key is unable to
482
// be found, then an error will be returned. The actual digest signed is the
483
// double SHA-256 of the passed message.
484
//
485
// NOTE: This is a part of the MessageSigner interface.
486
func (b *BtcWallet) SignMessage(keyLoc keychain.KeyLocator,
487
        msg []byte, doubleHash bool) (*ecdsa.Signature, error) {
×
488

×
489
        // First attempt to fetch the private key which corresponds to the
×
490
        // specified public key.
×
491
        privKey, err := b.fetchPrivKey(&keychain.KeyDescriptor{
×
492
                KeyLocator: keyLoc,
×
493
        })
×
494
        if err != nil {
×
495
                return nil, err
×
496
        }
×
497

498
        // Double hash and sign the data.
499
        var msgDigest []byte
×
500
        if doubleHash {
×
501
                msgDigest = chainhash.DoubleHashB(msg)
×
502
        } else {
×
503
                msgDigest = chainhash.HashB(msg)
×
504
        }
×
505
        return ecdsa.Sign(privKey, msgDigest), nil
×
506
}
507

508
// A compile time check to ensure that BtcWallet implements the MessageSigner
509
// interface.
510
var _ lnwallet.MessageSigner = (*BtcWallet)(nil)
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