mirror of
https://github.com/lightninglabs/loop
synced 2024-11-11 13:11:12 +00:00
8d7a272fdd
This commit fixes a possible exploit by the loop server, where - in a loop out - the server could claim money off-chain, without publishing an on-chain swap htlc. The server could do this by responding with a regular invoice, whose hash is different than the hash in the NewLoopOutSwap request. To prevent the exploit, we validate that the hash of the swap invoice is equal to the hash the client generated.
51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
package swap
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import (
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"errors"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/lntypes"
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"github.com/lightningnetwork/lnd/zpay32"
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)
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const (
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// FeeRateTotalParts defines the granularity of the fee rate.
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// Throughout the codebase, we'll use fix based arithmetic to compute
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// fees.
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FeeRateTotalParts = 1e6
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)
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// CalcFee returns the swap fee for a given swap amount.
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func CalcFee(amount, feeBase btcutil.Amount, feeRate int64) btcutil.Amount {
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return feeBase + amount*btcutil.Amount(feeRate)/
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btcutil.Amount(FeeRateTotalParts)
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}
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// FeeRateAsPercentage converts a feerate to a percentage.
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func FeeRateAsPercentage(feeRate int64) float64 {
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return float64(feeRate) / (FeeRateTotalParts / 100)
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}
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// DecodeInvoice gets the hash and the amount of an invoice.
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// It requires an amount to be specified.
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func DecodeInvoice(params *chaincfg.Params,
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payReq string) (lntypes.Hash, btcutil.Amount, error) {
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swapPayReq, err := zpay32.Decode(
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payReq, params,
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)
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if err != nil {
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return lntypes.Hash{}, 0, err
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}
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if swapPayReq.MilliSat == nil {
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return lntypes.Hash{}, 0, errors.New("no amount in invoice")
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}
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var hash lntypes.Hash
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copy(hash[:], swapPayReq.PaymentHash[:])
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return hash, swapPayReq.MilliSat.ToSatoshis(), nil
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}
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