endor-reachability-provenance

name	endor-reachability-provenance
description	Use when investigating reachability provenance mismatches in vulnerability findings—comparing dependency reachability, function reachability, and oss vulnerability metadata; contradictory finding tags/summary text; validating affected_callpath_uris attribution; or CVE/GHSA alias consistency.
disable-model-invocation	true

Reachability Provenance

Purpose

Use this skill to triage findings where reachability signals conflict, especially:

• REACHABLE_DEPENDENCY with UNREACHABLE_FUNCTION
• summary text saying no vulnerable function is reachable despite suspicious callgraph evidence
• disagreement between CVE and GHSA vulnerability records

What "oss namespace" is used for

API path rule: List and resolve OSS-plane resources under the literal namespace oss. Do not use <tenant>.oss, <customer>.oss, or a child namespace under the customer root; scope="oss" on the client separates this plane from customer namespace paths.

Use the oss namespace as the canonical vulnerability provenance source for:

• vulnerability records returned by query/evaluation
• affected entries and version ranges
• affected_callpath_uris and affected_filepaths
• alias consistency checks across CVE/GHSA IDs
• source attribution fields (for example SOURCE_OSV, SOURCE_ENDOR)

Do not infer function-level provenance from advisory prose alone when structured affected_callpath_uris are available in oss.

Where call graphs are stored (customer vs oss)

Reachability triage often mixes two graph planes:

• Customer tenant graph (project package version):
  • CallGraphData is stored under the customer namespace and is effectively keyed by the importing PackageVersion (meta.parent_uuid == <customer_pv_uuid>).
  • This graph captures app-side and resolved external-call edges as observed for that project scan.
• oss tenant graph (dependency package version):
  • For third-party packages, DependencyMetadata.spec.dependency_data.package_version_uuid can point to an oss package-version UUID.
  • That oss package version may have its own CallGraphData object(s), independently retrievable in oss.
• Finding metadata bridge:
  • Finding.spec.target_uuid is often a DependencyMetadata UUID (customer namespace), not a package-version UUID.
  • Finding.spec.finding_metadata.vulnerability commonly embeds vulnerability context sourced from oss (including affected_callpath_uris).

Practical implication: a finding can be REACHABLE_FUNCTION even when a direct path is hard to prove from only the customer CallGraphData; the path evidence can be a stitched result across customer graph + oss vulnerability/function metadata.

Workflow

0. Build unified context artifact (default path)

   • Run uv run endor-reachability-context --tenant <tenant> --namespace <namespace> --finding-uuid <finding_uuid> (default output: workspace/projects/<finding-uuid>/reachability_context.json).
   • Use --pv-uuid for direct PV analysis.
   • Treat reachability_context.json as the canonical triage bundle (customer graph plane, oss graph plane, stitching summary, warnings). --max-pages defaults to 0 (unlimited); check list_bounds and warnings when call-graph lists may be capped.
   • Bundle requirement (deterministic): include decoded call graphs from both planes:
     • customer/app side: app_call_graph_decoded_summary.json, app_call_graph_decoded_callables.json, app_call_graph_decoded_edges.json
     • oss side: oss_call_graph_decoded_summary.json, oss_call_graph_decoded_callables.json, oss_call_graph_decoded_edges.json

1. Gather finding evidence

   • Record finding UUID, tags, summary, target_dependency_package_name, extra_key, and call_graph_analysis_type.
   • Record whether reachable_paths is present.

2. Gather vulnerability provenance from oss

   • Fetch vulnerability objects by aliases (for example CVE and GHSA names) in oss.
   • For each relevant affected package entry, extract:
     • package identity + ecosystem
     • affected_callpath_uris
     • affected_filepaths
     • ranges (introduced/fixed/last_affected)
     • source field (SOURCE_*)

3. Compare strict function map vs graph evidence

   • Strict check: vulnerable function reachability should be determined from affected_callpath_uris.
   • Practical-risk check: inspect whether risky API surface in the same package is reachable even when strict vulnerable callpaths are not matched.
   • Graph-plane check: test customer graph and oss graph separately, then test stitched reachability (customer internal -> shared dependency entrypoint -> oss vulnerable function).
   • Edge-list requirement (deterministic): when triaging reachability markers, list relevant edges from the source function to candidate target symbols from decoded edge files.
   • Overloaded-symbol scaffold (deterministic): if the same symbol name appears across multiple target edges from the same source, include:
     • possible_symbol_collision: true
     • collision_symbol: <symbol>

Control-case method (reachable vs unresolved)

When validating tooling behavior, use one known reachable control and one unresolved case from the same project/tenant:

• Reachable control (example pattern): a finding where customer-tenant path plus oss callpath metadata agrees (for example Tomcat TOCTOU-style chain with explicit affected functions).
• Unresolved comparison (example pattern): a finding where customer graph reaches dependency API surface but cannot statically reach the exact vulnerable methods in affected_callpath_uris (possible CG coverage/normalization/runtime-dispatch limits).

Record both outcomes explicitly so the triage output distinguishes:

• data availability issue,
• URI/signature matching issue,
• or true function-level non-reachability.

4. Classify mismatch type

   • Provenance fragmentation: aliases disagree or one alias lacks structured function mapping.
   • Signature normalization mismatch: semantically equivalent functions fail strict URI matching.
   • True unreachable function: dependency reachable, but no strict or equivalent function evidence.
   • Likely reachable function: strict or equivalent callpath evidence exists.

5. Produce normalized verdict

   • Distinguish:
     • dependency-level reachability conclusion
     • strict function-level reachability conclusion
     • practical exploitability signal
   • State confidence and likely owner:
     • vuln metadata curation
     • function signature normalization/matching
     • callgraph coverage limitations

Output Template

Use this structure in the final triage result:

## Reachability Provenance Result

- Finding: <finding-id>
- Target dependency: <package@version>
- Call graph analysis type: <full|precomputed|unspecified>

- Dependency reachability: <reachable|unreachable|unknown>
- Function reachability (strict): <reachable|unreachable|unknown>
- Practical risk signal: <present|not present>

- OSS vulnerability provenance:
  - Alias records checked: <list>
  - Structured function map consistency: <consistent|fragmented|missing>
  - Primary source used for function attribution: <SOURCE_*>

- Likely disconnect:
  - <one sentence>

- Recommended next action:
  - <normalization/curation/coverage action>

When overloaded edges are present for a symbol, append this deterministic scaffold:

overloaded_edge_check:
  source_function: <fully-qualified-source-signature>
  possible_symbol_collision: true
  collision_symbol: <symbol-name>
  relevant_edges:
    - <source> -> <target-1>
    - <source> -> <target-2>

Guardrails

• Do not hardcode a single CVE-specific heuristic.
• Do not treat advisory text as equivalent to structured callpath mapping.
• Prefer structured affected_callpath_uris from oss for strict conclusions.
• If strict and practical signals diverge, report both explicitly.
• Keep all examples and analysis tenant-neutral and customer-neutral.

Related skills

Need	Skill
Finding UUID, project namespace, branch filters	endor-retrieve-scan-results
Per-project call graph path search	endor-fetch-and-search-call-graph
Fixed vs present, dependency graph, SBOM	endor-sca-findings
Scan aggregate metrics regressed	endor-troubleshooting-scans

Additional Resources

• For sample triage outcomes, see examples.md