How test-bootstrap-supply-chain.ps1 Ensures Tool Verification and Security in Reverse-Skill

test-bootstrap-supply-chain.ps1 validates tool integrity through existence checks, version verification, cryptographic hashing, and signature validation before any external binary is executed in the reverse-skill platform.

The zhaoxuya520/reverse-skill repository implements a defense-in-depth supply chain security model for reverse engineering workflows. At its core sits test-bootstrap-supply-chain.ps1, a PowerShell test driver that prevents malicious or compromised tools from entering the execution pipeline by enforcing four sequential verification gates.

Supply Chain Verification Architecture

The script operates as an orchestrator, delegating security-critical operations to specialized helper functions while maintaining a strict fail-fast policy. Any verification failure immediately halts execution with a non-zero exit code.

Loading the Verification Engine

The script initializes by sourcing the core verification library:

. (Join-Path $PSScriptRoot 'lib/BootstrapSupplyChain.ps1')

This loads functions from skills/scripts/lib/BootstrapSupplyChain.ps1 that handle hash computation, signature validation, and version parsing against the repository's trust manifest.

Tool Discovery and Manifest Enforcement

Rather than trusting arbitrary binaries on $PATH, the script first identifies explicitly permitted tools through Get-DeclaredTools in skills/scripts/lib/ToolDiscovery.ps1. This function parses the repository's tool manifest and returns a curated list of expected binaries—typically including radare2, ida, and apktool for reverse engineering operations.

Four-Layer Security Validation

Each discovered tool passes through sequential verification stages defined in BootstrapSupplyChain.ps1. The implementation references specific line ranges where these checks reside.

1. Existence and Version Verification (Assert-ToolPresent)

Lines 45-68 of BootstrapSupplyChain.ps1 implement the first gate:

• Locates the executable via $PATH or manifest-defined absolute path
• Extracts version strings through tool-specific parsing logic
• Compares against $AllowedVersions, a whitelist maintained in the verification library

Tools with versions outside the permitted range are rejected immediately, blocking known-vulnerable releases from execution.

2. Cryptographic Hash Validation (Assert-HashMatches)

Lines 71-84 enforce binary integrity through SHA-256 verification:

• Reads the complete file content
• Computes hash via Get-FileHash -Algorithm SHA256
• Matches against known-good hashes embedded in the verification state

This detects file corruption, partial downloads, or binary replacement attacks.

3. Digital Signature Verification (Assert-SignatureValid)

Lines 86-101 implement signature validation for tools providing cryptographic attestation:

• Detects companion .sig files or PGP-signed checksums
• Validates against public keys stored in keys/trusted-keys.gpg
• Rejects binaries with missing, invalid, or untrusted signatures

This blocks rebuilds from compromised build environments or unauthorized modifications to released artifacts.

4. Aggregated Reporting and Exit Code Propagation

The test driver collects individual verification results and emits structured output:

[+] radare2     → 5.8.0  (hash OK, signature verified)
[+] ida        → 7.5  (hash OK, signature verified)
[+] apktool    → 2.9.0 (hash OK, signature verified)

Failure modes produce explicit diagnostics:

[!] radare2 not found or version mismatch.
Error: Tool verification failed – aborting.

Practical Execution Patterns

Manual Verification

Run the complete supply chain check from repository root:

powershell -NoProfile -File skills/scripts/test-bootstrap-supply-chain.ps1

CI/CD Integration

Embed as a mandatory gate in GitHub Actions:

# .github/workflows/ci.yml

- name: Verify tool supply-chain
  run: powershell -NoProfile -File skills/scripts/test-bootstrap-supply-chain.ps1

The non-zero exit code on failure prevents subsequent workflow steps from executing with untrusted tools.

Critical Implementation Files

File Path	Security Function
skills/scripts/test-bootstrap-supply-chain.ps1	Orchestration driver and result aggregation
skills/scripts/lib/BootstrapSupplyChain.ps1	Core verification: Assert-ToolPresent, Assert-HashMatches, Assert-SignatureValid
skills/scripts/lib/ToolDiscovery.ps1	Manifest parsing via Get-DeclaredTools
skills/scripts/bootstrap-manifest.json	JSON trust store: allowed versions and reference hashes
keys/trusted-keys.gpg	GPG public keyring for signature validation

Summary

• test-bootstrap-supply-chain.ps1 enforces mandatory tool verification before execution in the reverse-skill platform
• Four verification layers: existence, version whitelist, SHA-256 hash, and cryptographic signature
• Fail-fast design: Any check failure aborts with non-zero exit code, protecting downstream operations
• Manifest-driven trust: Only explicitly listed tools from ToolDiscovery.ps1 are considered valid
• Reproducible security: Identical verification logic runs locally and in CI/CD pipelines

Frequently Asked Questions

What happens if a tool version is newer than the allowed list?

The script rejects it. Assert-ToolPresent compares extracted versions against $AllowedVersions in BootstrapSupplyChain.ps1 (lines 45-68). Only explicitly whitelisted versions pass; newer releases require manifest updates and hash/signature verification before approval.

How does the script handle tools without digital signatures?

Hash validation remains mandatory. Tools lacking .sig or PGP signatures skip Assert-SignatureValid (lines 86-101) but must still pass Assert-HashMatches (lines 71-84). The repository recommends prioritizing signed releases where available.

Can verification be bypassed for development purposes?

No supported bypass mechanism exists in the source. The script's design intentionally prevents override flags. To use alternate tool versions, modify bootstrap-manifest.json with new hashes and signatures, then commit the updated trust state.

Where are the trusted cryptographic keys stored?

Public keys for signature verification reside in keys/trusted-keys.gpg relative to repository root. Assert-SignatureValid references this keyring when validating tool signatures against known-good signers.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}