fix(ffi): validate account seed lengths

[thepastaclaw]

FFI account seed-length validation

Summary

• Add FFI-side seed-length validation for BLS seed derivation helpers before
  slicing or deriving.
• Add EdDSA seed-length validation at the FFI boundary to mirror the underlying
  SLIP-10 contract.
• Cover invalid BLS and EdDSA seed lengths with focused regression tests while
  leaving generic secp256k1 account seed behavior unchanged.

Validation

• cargo fmt -- key-wallet-ffi/src/account_derivation.rs \ key-wallet-ffi/src/account_derivation_tests.rs
• cargo test -p key-wallet-ffi --features eddsa,bls account_derivation -- \ --nocapture — 6 passed
• code-review dashpay/rust-dashcore upstream/v0.42-dev \ fix-ffi-seed-length-validation "Validate key-wallet FFI BLS/EdDSA account \ seed lengths before slicing/deriving while preserving secp256k1 generic \ account seed behavior" — no significant issues found; recommendation:
  ship

Notes

Draft until human review marks it ready.

Summary by CodeRabbit

• Bug Fixes

  • Improved account derivation input validation. BLS derivation now accepts seeds from 16 to 64 bytes, while EdDSA derivation requires at least 16 bytes.
  • Invalid seed lengths now fail safely with an invalid-input error instead of producing an account.

• Tests

  • Added coverage confirming invalid seed lengths are rejected for both BLS and EdDSA account derivation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 846b4717-4806-4372-b84d-f75fc7c86d75

📥 Commits

Reviewing files that changed from the base of the PR and between 0d8f959 and 94918c7.

📒 Files selected for processing (2)

• key-wallet-ffi/src/account_derivation.rs
• key-wallet-ffi/src/account_derivation_tests.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• key-wallet-ffi/src/account_derivation.rs

---

📝 Walkthrough

Walkthrough

This PR adds private seed-length validators, enforces 16-byte minimums for BLS and EdDSA derivation, keeps the BLS maximum at 64 bytes, and adds regression tests for null results and FFIErrorCode::InvalidInput.

Changes

Seed-Length Validation

Layer / File(s)	Summary
Validation and derivation guards key-wallet-ffi/src/account_derivation.rs	Adds BLS and EdDSA validators. BLS accepts 16–64 bytes. EdDSA requires at least 16 bytes. Invalid input sets FFIErrorCode::InvalidInput and returns null.
Regression tests key-wallet-ffi/src/account_derivation_tests.rs	Adds feature-gated tests for invalid BLS and EdDSA seed lengths.

Estimated code review effort: 2 (Simple) | ~12 minutes

Suggested reviewers: quantumexplorer

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding FFI validation for account seed lengths.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[thepastaclaw]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@key-wallet-ffi/src/account_derivation_tests.rs`:
- Around line 282-292: The second negative test reuses the prior FFIError
(error) so a stale error.code can mask a missing error from
bls_account_derive_private_key_from_seed; before calling
bls_account_derive_private_key_from_seed for the long_seed test,
reinitialize/reset error (e.g., create a fresh FFIError/default or zeroed
instance) so the function must set it for the assert to be valid—ensure you
reset the same variable named error used with ffi_account and too_long prior to
the call and then assert error.code == FFIErrorCode::InvalidInput.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 1d48f1d3-d750-4723-91a4-211dd0735532

📥 Commits

Reviewing files that changed from the base of the PR and between dca03ce and d60981f.

📒 Files selected for processing (2)

• key-wallet-ffi/src/account_derivation.rs
• key-wallet-ffi/src/account_derivation_tests.rs

[thepastaclaw]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 74.72%. Comparing base (9cbe4e7) to head (94918c7).
⚠️ Report is 38 commits behind head on dev.

Files with missing lines	Patch %	Lines
key-wallet-ffi/src/account_derivation.rs	95.45%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #752      +/-   ##
==========================================
- Coverage   74.76%   74.72%   -0.05%     
==========================================
  Files         328      328              
  Lines       76593    76613      +20     
==========================================
- Hits        57267    57251      -16     
- Misses      19326    19362      +36     

Flag	Coverage Δ
core	77.29% <ø> (ø)
ffi	49.13% <95.45%> (-0.59%)	⬇️
rpc	20.00% <ø> (ø)
spv	91.14% <ø> (+0.19%)	⬆️
wallet	75.69% <ø> (ø)

Files with missing lines	Coverage Δ
key-wallet-ffi/src/account_derivation.rs	21.52% <95.45%> (+15.12%)	⬆️

... and 21 files with indirect coverage changes

[thepastaclaw]

@coderabbitai review

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[thepastaclaw]

✅ Review complete (commit 0d8f959)

[thepastaclaw]

CI note: the new red evaluate run is not a code/test failure. It ran after the PR was marked ready for review, detected that CodeRabbit approved and all CI checks passed, then failed while trying to add the ready-for-review label because the workflow token lacks label-write permission (GraphQL: Resource not accessible by integration (addLabelsToLabelable)). The Rust/test matrix remains green, so I am leaving the branch unchanged.

[thepastaclaw]

Ownership sweep follow-up: this PR looks ready for maintainer review. CodeRabbit approved the current head (0d8f959), Codecov/project and patch are green, and the Rust CI matrix is green; the remaining red evaluate job is the known Ready for Review Label workflow permission failure when adding the label, not a code/test failure. Could a maintainer take a pass or final decision when available?

[github-actions]

This PR has merge conflicts with the base branch. Please rebase or merge the base branch into your branch to resolve them.

[github-actions]

This PR has merge conflicts with the base branch. Please rebase or merge the base branch into your branch to resolve them.