llm-security/hooks/scripts/pre-edit-secrets.mjs

#!/usr/bin/env node
// Hook: pre-edit-secrets.mjs (consolidated)
// Event: PreToolUse (Edit|Write)
// Purpose: Detect secrets/credentials in file content before writing.
// Consolidates patterns from global, kiur, llm-security, and ms-ai-architect.
//
// Protocol:
//   - Read JSON from stdin: { tool_name, tool_input }
//   - tool_input.file_path  — destination path
//   - tool_input.content    — full content (Write)
//   - tool_input.new_string — replacement text (Edit)
//   - Block: stderr + exit 2
//   - Allow: exit 0

import { readFileSync } from 'node:fs';
import { normalize } from 'node:path';
import { getPolicyValue } from '../../scanners/lib/policy-loader.mjs';
import { SECRET_PATTERNS as COMMONS_SECRET_PATTERNS } from '../../scanners/lib/secret-egress.mjs';

// ---------------------------------------------------------------------------
// Secret detection patterns
// ---------------------------------------------------------------------------
//
// The 19 fixed entries (union of global, kiur, llm-security, ms-ai-architect)
// were regex literals here until the v8 Phase 5 swap; they now come from
// `signatures/secret-egress.json` in the vendored commons, via
// scanners/lib/secret-egress.mjs — measured position-by-position before the
// swap (order, name, source, flags), zero divergences. Order is load-bearing:
// first match wins, and the entry a finding is reported AS depends on it.
// See that module's header for what happens when commons is unresolvable.
//
// Policy-defined patterns are appended after, unchanged: they are the scanned
// project's own policy, not commons data, and must never displace the fixed
// table's labels.
const SECRET_PATTERNS = [
  ...COMMONS_SECRET_PATTERNS,
  ...getPolicyValue('secrets', 'additional_patterns', []).map((p, i) => ({
    name: `Custom pattern ${i + 1}`,
    pattern: new RegExp(p),
  })),
];

// ---------------------------------------------------------------------------
// Exclusions: files that may contain example patterns for documentation
// ---------------------------------------------------------------------------
function isExcluded(filePath) {
  if (!filePath) return false;
  const n = normalize(filePath);
  if (/[\\/]knowledge[\\/].+\.md$/i.test(n)) return true;
  if (/[\\/]references[\\/].+\.md$/i.test(n)) return true;
  if (/\.(test|spec|mock)\.[jt]sx?$/.test(n)) return true;
  if (/\.(example|template|sample)(\.|$)/.test(n)) return true;
  return false;
}

// ---------------------------------------------------------------------------
// Main
// ---------------------------------------------------------------------------
let input;
try {
  const raw = readFileSync(0, 'utf-8');
  input = JSON.parse(raw);
} catch { process.exit(0); }

const toolInput = input?.tool_input ?? {};
const filePath = toolInput.file_path ?? '';

if (isExcluded(filePath)) process.exit(0);

const contentToCheck = [toolInput.content ?? '', toolInput.new_string ?? ''].join('\n');
if (!contentToCheck.trim()) process.exit(0);

for (const { name, pattern } of SECRET_PATTERNS) {
  if (pattern.test(contentToCheck)) {
    process.stderr.write(
      `BLOCKED: Potential secret detected — ${name}\n` +
      `  File: ${filePath || '(unknown)'}\n` +
      `  Remove the credential before writing. Use <YOUR_KEY_HERE> or .env.\n`
    );
    process.exit(2);
  }
}

process.exit(0);