fix(beldex-storage-server): add missing return statement after monitor_error in MQBase pubkey validation

[localtrade1]

Motivation

This PR fixes a critical control-flow vulnerability in beldex-storage-server (beldexss/server/mqbase.cpp), identified during the Beldex workspace security audit[cite: 30]. Previously, when an invalid public key size was encountered under the p= parameter handling block, the code invoked monitor_error but omitted a return statement. This caused execution to fall through on an unauthenticated path with attacker-controlled data, leading to heap out-of-bounds reads and malformed protocol responses.

Modifications

• Add Missing Return Guard (beldexss/server/mqbase.cpp):
  • Inserted an explicit return statement immediately following the monitor_error call when the pubkey size does not equal 33 bytes[cite: 30].
  • Ensured malicious or malformed public key requests are terminated safely without falling through to dangerous memory indexing operations.

Checklist

• Format your code according to the Contributor Guide.
• Add unit tests as outlined in the Contributor Guide.
• Update documentation as needed, including docstrings or example tutorials.

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

* **Bug Fixes**
  * Improved validation of monitor message public keys.
  * Invalid or incomplete keys now stop processing immediately, preventing malformed responses and potential verification errors.


<!-- end of auto-generated comment: release notes by coderabbit.ai -->

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: a7b687dd-ddaf-4140-b26d-7e0f009112b4

📥 Commits

Reviewing files that changed from the base of the PR and between 8984149 and f541aba.

📒 Files selected for processing (1)

• beldexss/server/mqbase.cpp

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📝 Walkthrough

Walkthrough

The monitor message handler now returns immediately when the p= pubkey is not 33 bytes. The existing BAD_PUBKEY monitor error remains unchanged.

Changes

Monitor pubkey validation

Layer / File(s)	Summary
Reject invalid monitor pubkeys beldexss/server/mqbase.cpp	The pubkey size check returns the monitor_error result for invalid pubkeys instead of continuing with verification and reply construction.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to f541a

The change immediately stops processing malformed public keys after validation fails. It is localized and does not introduce an actionable merge-blocking risk beyond normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 28.57% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding a missing return after monitor_error during public key validation.
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.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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