SignCommitmentTx improvements #803
Conversation
WalkthroughReplaces per-input PSBT tapscript verification with vtxo-aware verification and boarding-input checks, adds combine-by-index API, delegates prevout fetching to txutils, updates service call sites and mocks, and tweaks two tests/config timings. Changes
Sequence Diagram(s)sequenceDiagram
participant S as Service
participant B as TxBuilder
participant U as txutils
rect rgb(250,250,255)
Note over S: SignCommitmentTx (read-only commitmentTx)
S->>B: VerifyBoardingTapscriptSigs(partialTx, commitmentTx)
B->>U: GetPrevOutputFetcher(commitmentTx)
B->>U: VerifyTapscriptSigs(partialPSBT, prevoutFetcher)
U-->>B: []int (signed input indices)
alt no signed inputs
B-->>S: error INVALID_BOARDING_INPUT_SIG
else
S->>B: CombineTapscriptSigs(dest, src, indexes)
B-->>S: combinedTx
end
end
rect rgb(245,255,245)
Note over S: Offchain verification (ark/checkpoint)
S->>B: VerifyVtxoTapscriptSigs(tx, mustIncludeSignerSig)
B->>U: GetPrevOutputFetcher(...) / VerifyTapscriptSigs(...)
U-->>B: ([]int, *psbt.Packet)
B-->>S: verification result
end
Estimated code review effort🎯 4 (Complex) | ⏱️ ~45 minutes
Possibly related PRs
Suggested reviewers
Pre-merge checks and finishing touches❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
✨ Finishing touches
🧪 Generate unit tests (beta)
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
There was a problem hiding this comment.
Actionable comments posted: 3
Caution
Some comments are outside the diff and can’t be posted inline due to platform limitations.
⚠️ Outside diff range comments (1)
pkg/ark-lib/txutils/utils.go (1)
31-36: Fix the witness loop to keep the build green
for i := range witCountdoesn’t compile becauserangecan’t iterate over a scalar (witCountis auint64). Use an indexed loop so the code builds.- for i := range witCount { - witness[i], err = wire.ReadVarBytes(r, 0, txscript.MaxScriptSize, "witness") + for i := uint64(0); i < witCount; i++ { + witness[i], err = wire.ReadVarBytes(r, 0, txscript.MaxScriptSize, "witness")
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (7)
internal/core/application/service.go(4 hunks)internal/core/ports/tx_builder.go(1 hunks)internal/infrastructure/live-store/live_store_test.go(2 hunks)internal/infrastructure/tx-builder/covenantless/builder.go(3 hunks)internal/test/e2e/e2e_test.go(1 hunks)internal/test/e2e/utils_test.go(1 hunks)pkg/ark-lib/txutils/utils.go(3 hunks)
🧰 Additional context used
🧠 Learnings (4)
📓 Common learnings
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
📚 Learning: 2025-08-19T10:58:41.042Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
Applied to files:
internal/core/ports/tx_builder.gopkg/ark-lib/txutils/utils.gointernal/core/application/service.gointernal/infrastructure/tx-builder/covenantless/builder.gointernal/infrastructure/live-store/live_store_test.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern.
Applied to files:
pkg/ark-lib/txutils/utils.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern. A common bug is manually base64-decoding the string and then passing b64=true, which causes a double-decode error.
Applied to files:
pkg/ark-lib/txutils/utils.go
🧬 Code graph analysis (3)
pkg/ark-lib/txutils/utils.go (1)
pkg/ark-lib/intent/proof.go (1)
Verify(53-128)
internal/core/application/service.go (2)
pkg/errors/errors.go (2)
INVALID_BOARDING_INPUT_SIG(316-320)InvalidBoardingInputSigMetadata(186-188)pkg/ark-lib/intent/proof.go (1)
New(136-160)
internal/infrastructure/tx-builder/covenantless/builder.go (1)
pkg/ark-lib/txutils/utils.go (2)
GetPrevOutputFetcher(148-161)VerifyTapscriptSigs(43-145)
🔇 Additional comments (4)
internal/test/e2e/e2e_test.go (1)
264-264: Verify the timeout increase is necessary and not masking a performance regression.The timeout increase from 5 to 10 seconds in commit 6934426 ("Improve SignCommitmentTx") corresponds to a significant refactoring that split signature verification and combination into separate steps. While this change may require additional processing time, confirm whether:
- This 2x timeout increase was measured and validated as necessary for the refactored verification logic
- The separate verification step (
VerifyBoardingTapscriptSigsfollowed byCombineTapscriptSigs) adds proportional overhead or indicates a performance regression- A polling mechanism (checking balance state until complete or timeout) would be more reliable than a fixed sleep
internal/infrastructure/tx-builder/covenantless/builder.go (3)
52-61: LGTM! Clear rename improves API semantics.The rename from
VerifyTapscriptPartialSigstoVerifyVtxoTapscriptSigsbetter communicates that this method specifically verifies VTXO tapscript signatures, aligning with the PR's goal to distinguish between different verification contexts.
72-75: LGTM! Good consolidation to shared utility.Moving to
txutils.GetPrevOutputFetchercentralizes prevout fetching logic, improving code reuse and consistency across the codebase.
1017-1039: LGTM! Strong security approach using commitment tx for prevouts.This method correctly uses the
commitmentTx(built by the builder) to derive prevouts for signature verification, preventing attackers from manipulating prevouts intxToVerifyto produce valid-looking but fraudulent signatures. The explicit comment at lines 1031-1032 documents this important security property.
Co-authored-by: Pietralberto Mazza <[email protected]> Signed-off-by: louisinger <[email protected]>
Co-authored-by: Pietralberto Mazza <[email protected]> Signed-off-by: louisinger <[email protected]>
There was a problem hiding this comment.
Actionable comments posted: 1
♻️ Duplicate comments (1)
pkg/ark-lib/txutils/utils.go (1)
108-117: Fix the function name typo.The function
txscript.CalcTapscriptSignaturehash(lowercase "h") doesn't exist in btcsuite/btcd. The correct function name isCalcTapscriptSignatureHash(capital "H").Apply this diff:
- sighash, err = txscript.CalcTapscriptSignaturehash( + sighash, err = txscript.CalcTapscriptSignatureHash(
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (1)
pkg/ark-lib/txutils/utils.go(3 hunks)
🧰 Additional context used
🧠 Learnings (4)
📓 Common learnings
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
📚 Learning: 2025-08-19T10:58:41.042Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
Applied to files:
pkg/ark-lib/txutils/utils.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern.
Applied to files:
pkg/ark-lib/txutils/utils.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern. A common bug is manually base64-decoding the string and then passing b64=true, which causes a double-decode error.
Applied to files:
pkg/ark-lib/txutils/utils.go
🧬 Code graph analysis (1)
pkg/ark-lib/txutils/utils.go (1)
pkg/ark-lib/intent/proof.go (1)
Verify(53-128)
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)
- GitHub Check: integration tests
- GitHub Check: unit tests
🔇 Additional comments (3)
pkg/ark-lib/txutils/utils.go (3)
31-31: LGTM: Idiomatic loop refactor.The change to a range-based loop is idiomatic and correct.
41-145: Well-structured tapscript verification logic.The function correctly implements tapscript signature verification:
- Validates control blocks against expected Taproot keys
- Skips inputs appropriately (non-taproot, unsigned, or without leaf scripts)
- Properly computes leaf hashes and signature hashes
- Verifies Schnorr signatures
- Provides descriptive error messages
The logic is sound once the function name typo at line 109 is fixed.
147-161: LGTM: Correct prevout fetcher implementation.The function correctly builds a prevout fetcher from PSBT WitnessUtxo fields with appropriate error handling for missing witness data.
There was a problem hiding this comment.
Actionable comments posted: 0
♻️ Duplicate comments (2)
pkg/ark-lib/txutils/utils.go (2)
14-18: Handle the error from ParsePubKey (already flagged).This issue was already identified in a previous review: the error from
ParsePubKeyis silently discarded, and if parsing fails,unspendableKeywill be nil, causing a nil-pointer dereference at line 83.
108-117: Call the correct function name (already flagged).This critical issue was already identified:
txscript.CalcTapscriptSignaturehash(lowercase "h") doesn't exist. The correct function istxscript.CalcTaprootSignatureHash(capital "H").
🧹 Nitpick comments (1)
pkg/ark-lib/txutils/utils.go (1)
123-145: Consider consistent error wrapping.The signature parsing and verification logic is correct. As suggested in previous reviews, you might want to consistently use
%winstead of%sfor error wrapping (lines 126, 134) to preserve the error chain, though this is a minor stylistic improvement.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (1)
pkg/ark-lib/txutils/utils.go(3 hunks)
🧰 Additional context used
🧠 Learnings (4)
📓 Common learnings
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
📚 Learning: 2025-08-19T10:58:41.042Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 691
File: internal/core/application/service.go:557-562
Timestamp: 2025-08-19T10:58:41.042Z
Learning: In the arkd SubmitOffchainTx method, using the checkpoint PSBT input's tapscript (forfeit path) for the VtxoInput.Tapscript field is the correct behavior, not a bug as initially thought. The system correctly handles the relationship between checkpoint inputs and Ark transaction inputs.
Applied to files:
pkg/ark-lib/txutils/utils.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern.
Applied to files:
pkg/ark-lib/txutils/utils.go
📚 Learning: 2025-09-29T14:33:52.871Z
Learnt from: louisinger
Repo: arkade-os/arkd PR: 722
File: pkg/ark-lib/intent/proof.go:52-58
Timestamp: 2025-09-29T14:33:52.871Z
Learning: In btcsuite/btcd's psbt package, the NewFromRawBytes function's boolean parameter (b64) automatically handles base64 decoding when set to true, so passing a base64 string via strings.NewReader with b64=true is the correct usage pattern. A common bug is manually base64-decoding the string and then passing b64=true, which causes a double-decode error.
Applied to files:
pkg/ark-lib/txutils/utils.go
🧬 Code graph analysis (1)
pkg/ark-lib/txutils/utils.go (1)
pkg/ark-lib/intent/proof.go (1)
Verify(53-128)
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)
- GitHub Check: Build and Scan
- GitHub Check: unit tests
- GitHub Check: integration tests
🔇 Additional comments (4)
pkg/ark-lib/txutils/utils.go (4)
31-31: LGTM: Idiomatic range loop.The change to
for i := range witCountis cleaner and more idiomatic Go.
41-96: LGTM: Solid validation logic.The input validation flow is well-structured:
- Validates PSBT/tx input count consistency
- Correctly filters for single taproot leaf script inputs
- Validates prevout existence and type
- Properly derives and validates the taproot output key using the control block
- Provides clear error messages with context
147-151: LGTM: Clean return handling.The signed input tracking and return logic is correct.
153-167: LGTM: Clean prevout fetcher utility.The implementation correctly builds a
MultiPrevOutFetcherfrom PSBT WitnessUtxo fields with appropriate error handling for missing witness data. This aligns well with the usage pattern shown inintent/proof.go.
This PR is splitting VerifyAndCombinePartialTx into :
It aims to move signature verification before locking the commitment tx mutex. This way, an invalid tx can't block the batch session.
it renames "VerifyTapscriptPartialSigs" to "VerifyVtxoTapscriptSigs".
it removes
CountSignedTaprootInputs:VerifyBoardingTapscriptSigsreturns the count of signed inputsadd generic functions
VerifyTapscriptSigsandGetPrevOutputFetcherto txutil package in arklib.@altafan please review
Summary by CodeRabbit
New Features
Refactor
Tests
Chores