Security Ownership Map

Security Ownership Map

Overview

Build a bipartite graph of people and files from git history, then compute ownership risk and export graph artifacts for Neo4j/Gephi. Also build a file co-change graph (Jaccard similarity on shared commits) to cluster files by how they move together while ignoring large, noisy commits.

Requirements

• Python 3
• networkx (required; community detection is enabled by default)

No separate install step: every command below runs through uv run --with networkx, which provisions networkx for that run.

Workflow

All script paths below are relative to this skill's folder (the directory containing SKILL.md); run them from there or prefix with that path.

1. Scope the repo and time window (optional --since/--until).
2. Decide sensitivity rules (use defaults or provide a CSV config).
3. Build the ownership map with scripts/run_ownership_map.py (co-change graph is on by default; use --cochange-max-files to ignore supernode commits).
4. Communities are computed by default; graphml output is optional (--graphml).
5. Query the outputs with scripts/query_ownership.py for bounded JSON slices.
6. Persist and visualize (see references/neo4j-import.md).

By default, the co-change graph ignores common “glue” files (lockfiles, .github/*, editor config) so clusters reflect actual code movement instead of shared infra edits. Override with --cochange-exclude or --no-default-cochange-excludes. Dependabot commits are excluded by default; override with --no-default-author-excludes or add patterns via --author-exclude-regex.

If you want to exclude Linux build glue like Kbuild from co-change clustering, pass:

uv run --with networkx python scripts/run_ownership_map.py \
  --repo /path/to/linux \
  --out ownership-map-out \
  --cochange-exclude "**/Kbuild"

Quick start

Run from the repo root:

uv run --with networkx python scripts/run_ownership_map.py \
  --repo . \
  --out ownership-map-out \
  --since "12 months ago" \
  --emit-commits

Defaults: author identity, author date, and merge commits excluded. Use --identity committer, --date-field committer, or --include-merges if needed.

Example (override co-change excludes):

uv run --with networkx python scripts/run_ownership_map.py \
  --repo . \
  --out ownership-map-out \
  --cochange-exclude "**/Cargo.lock" \
  --cochange-exclude "**/.github/**" \
  --no-default-cochange-excludes

Communities are computed by default. To disable:

uv run --with networkx python scripts/run_ownership_map.py \
  --repo . \
  --out ownership-map-out \
  --no-communities

Sensitivity rules

By default, the script flags common auth/crypto/secret paths. Override by providing a CSV file:

# pattern,tag,weight
**/auth/**,auth,1.0
**/crypto/**,crypto,1.0
**/*.pem,secrets,1.0

Use it with --sensitive-config path/to/sensitive.csv.

Output artifacts

ownership-map-out/ contains:

• people.csv (nodes: people)
• files.csv (nodes: files)
• edges.csv (edges: touches)
• cochange_edges.csv (file-to-file co-change edges with Jaccard weight; omitted with --no-cochange)
• summary.json (security ownership findings)
• commits.jsonl (optional, if --emit-commits)
• communities.json (computed by default from co-change edges when available; includes maintainers per community; disable with --no-communities)
• cochange.graph.json (NetworkX node-link JSON with community_id + community_maintainers; falls back to ownership.graph.json if no co-change edges)
• ownership.graphml / cochange.graphml (optional, if --graphml)

people.csv includes timezone detection based on author commit offsets: primary_tz_offset, primary_tz_minutes, and timezone_offsets.

LLM query helper

Use scripts/query_ownership.py to return small, JSON-bounded slices without loading the full graph into context.

Examples:

uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out people --limit 10
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out files --tag auth --bus-factor-max 1
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out person --person alice@corp --limit 10
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out file --file crypto/tls
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out cochange --file crypto/tls --limit 10
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out summary --section orphaned_sensitive_code
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out community --id 3

Use --community-top-owners 5 (default) to control how many maintainers are stored per community.

Basic security queries

Run these to answer common security ownership questions with bounded output:

# Orphaned sensitive code (stale + low bus factor)
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out summary --section orphaned_sensitive_code

# Hidden owners for sensitive tags
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out summary --section hidden_owners

# Sensitive hotspots with low bus factor
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out summary --section bus_factor_hotspots

# Auth/crypto files with bus factor <= 1
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out files --tag auth --bus-factor-max 1
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out files --tag crypto --bus-factor-max 1

# Who is touching sensitive code the most
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out people --sort sensitive_touches --limit 10

# Co-change neighbors (cluster hints for ownership drift)
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out cochange --file path/to/file --min-jaccard 0.05 --limit 20

# Community maintainers (for a cluster)
uv run --with networkx python scripts/query_ownership.py --data-dir ownership-map-out community --id 3

# Monthly maintainers for the community containing a file
uv run --with networkx python scripts/community_maintainers.py \
  --data-dir ownership-map-out \
  --file network/card.c \
  --since 2025-01-01 \
  --top 5

# Quarterly buckets instead of monthly
uv run --with networkx python scripts/community_maintainers.py \
  --data-dir ownership-map-out \
  --file network/card.c \
  --since 2025-01-01 \
  --bucket quarter \
  --top 5

Notes:

• Touches default to one authored commit (not per-file). Use --touch-mode file to count per-file touches.
• Use --window-days 90 or --weight recency --half-life-days 180 to smooth churn.
• Filter bots with --ignore-author-regex '(bot|dependabot)'.
• Use --min-share 0.1 to show stable maintainers only.
• Use --bucket quarter for calendar quarter groupings.
• Use --identity committer or --date-field committer to switch from author attribution.
• Use --include-merges to include merge commits (excluded by default).

Summary format (default)

Use this structure, add fields if needed:

{
  "orphaned_sensitive_code": [
    {
      "path": "crypto/tls/handshake.rs",
      "last_security_touch": "2023-03-12T18:10:04+00:00",
      "bus_factor": 1
    }
  ],
  "hidden_owners": [
    {
      "person": "alice@corp",
      "controls": "63% of auth code"
    }
  ]
}

Graph persistence

Use references/neo4j-import.md when you need to load the CSVs into Neo4j. It includes constraints, import Cypher, and visualization tips.

Notes

• bus_factor_hotspots in summary.json lists sensitive files with low bus factor; orphaned_sensitive_code is the stale subset.
• If git log is too large, narrow with --since or --until.
• Compare summary.json against CODEOWNERS to highlight ownership drift.