ktg-plugin-marketplace/plugins/llm-security/tests/scanners/entropy-context.test.mjs

// entropy-context.test.mjs — False-positive fixtures for v7.0.0 context-aware suppression
//
// Covers:
//   A. File-extension skip (.glsl, .css, .svg, .min.js, ...)
//   B. Line-level rules 11-17 (GLSL/CSS-in-JS/HTML/ffmpeg/UA/SQL/error-template)
//   C. User-policy thresholds and suppress_line_patterns
//
// Strategy: write a throwaway fixture under os.tmpdir(), discover it, run scan(),
// assert finding count. Fixture-content strings are built from runtime concatenation
// to avoid triggering the plugin's own credential-pattern pre-edit hook on the test source.

import { describe, it, before, after } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtemp, mkdir, writeFile, rm } from 'node:fs/promises';
import { randomBytes } from 'node:crypto';
import { join } from 'node:path';
import { tmpdir } from 'node:os';
import { resetCounter } from '../../scanners/lib/output.mjs';
import { discoverFiles } from '../../scanners/lib/file-discovery.mjs';
import { scan } from '../../scanners/entropy-scanner.mjs';
import { _resetCacheForTest } from '../../scanners/lib/policy-loader.mjs';

// Random base64 from 60 crypto bytes → 80-char base64, H ≈ 5.4, will classify as
// HIGH (entropy >= 5.1, len >= 64). Regenerated on module load for each test run.
// Built at runtime so the plugin's credential-pattern pre-edit hook doesn't flag the
// test source file. Excludes '/', '+', '=' to avoid breaking JS string syntax.
function makePayload() {
  const raw = randomBytes(60).toString('base64').replace(/[/+=]/g, 'A');
  return raw.slice(0, 80);
}
const PAYLOAD = makePayload();

async function writeFixture(root, relPath, content) {
  const abs = join(root, relPath);
  const lastSlash = abs.lastIndexOf('/');
  await mkdir(abs.substring(0, lastSlash), { recursive: true });
  await writeFile(abs, content);
}

async function newRoot(prefix) {
  return mkdtemp(join(tmpdir(), prefix));
}

describe('entropy-scanner context suppression (v7.0.0+)', () => {
  let root;

  before(async () => {
    root = await newRoot('entropy-ctx-');
  });

  after(async () => {
    await rm(root, { recursive: true, force: true });
    _resetCacheForTest();
  });

  describe('A. File-extension skip', () => {
    it('skips .glsl files entirely (no findings)', async () => {
      const fx = await newRoot('ent-glsl-');
      await writeFixture(fx, 'shader.glsl', 'vec4 color = "' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'Expected 0 findings in .glsl, got ' + result.findings.length);
      assert.ok(result.calibration.files_skipped_by_extension >= 1);
      await rm(fx, { recursive: true, force: true });
    });

    it('skips .css files entirely', async () => {
      const fx = await newRoot('ent-css-');
      await writeFixture(fx, 'styles.css', '.x{content:"' + PAYLOAD + '";}');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0);
      await rm(fx, { recursive: true, force: true });
    });

    it('skips .min.js files (compound extension)', async () => {
      const fx = await newRoot('ent-minjs-');
      await writeFixture(fx, 'bundle.min.js', 'var x="' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0);
      await rm(fx, { recursive: true, force: true });
    });

    it('still scans .js files (non-skipped extension)', async () => {
      const fx = await newRoot('ent-js-');
      await writeFixture(fx, 'app.js', 'const blob = "' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.ok(result.findings.length >= 1, 'expected high-entropy .js to still be detected');
      await rm(fx, { recursive: true, force: true });
    });
  });

  describe('B. Line-level suppression rules 11-17', () => {
    it('rule 11: GLSL keyword on line suppresses finding', async () => {
      const fx = await newRoot('ent-rule11-');
      await writeFixture(fx, 'shader.js',
        'const src = "uniform vec3 u_resolution; ' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected GLSL keyword line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 12: CSS-in-JS (styled-components) suppresses finding', async () => {
      const fx = await newRoot('ent-rule12-');
      await writeFixture(fx, 'btn.js',
        'const Button = styled.button`:hover { content: "' + PAYLOAD + '"; }`;');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected styled-components line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 13: Inline <svg> markup on line suppresses finding', async () => {
      const fx = await newRoot('ent-rule13-');
      await writeFixture(fx, 'Icon.jsx',
        'return (<svg viewBox="0 0 24 24"><path d="' + PAYLOAD + '"/></svg>);');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected inline SVG line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 14: ffmpeg filter_complex suppresses finding', async () => {
      const fx = await newRoot('ent-rule14-');
      await writeFixture(fx, 'pipeline.js',
        'run("ffmpeg -filter_complex=[0:v]scale=' + PAYLOAD + '");');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected ffmpeg line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 15: browser User-Agent string suppresses finding', async () => {
      const fx = await newRoot('ent-rule15-');
      await writeFixture(fx, 'ua.js',
        'const agent = "Mozilla/5.0 Chrome/120 ' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected UA line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 16: SQL DDL on dedicated line suppresses finding', async () => {
      // Line must START with SELECT/INSERT/... — whitespace allowed but no prefix code.
      const fx = await newRoot('ent-rule16-');
      await writeFixture(fx, 'schema.js',
        '// fallback\nSELECT id, data FROM users WHERE tok = \'' + PAYLOAD + '\';\n');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected SELECT-anchored line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 16 does NOT over-match generic strings mentioning SELECT', async () => {
      // SQL_STATEMENT is line-anchored; a `const` prefix means no suppression by rule 16.
      const fx = await newRoot('ent-rule16b-');
      await writeFixture(fx, 'app.js',
        'const msg = "SELECT something ' + PAYLOAD + '";');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.ok(result.findings.length >= 1, 'generic code line must not trigger SQL suppression');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 17: throw new Error template suppresses finding', async () => {
      const fx = await newRoot('ent-rule17-');
      await writeFixture(fx, 'err.js',
        'throw new Error(`Bad input <code>' + PAYLOAD + '</code>`);');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected throw new Error line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 18: markdown image with external URL suppresses finding', async () => {
      const fx = await newRoot('ent-rule18-');
      await writeFixture(fx, 'index.json',
        '{"summary": "![Image 1: Title](https://cdn.example.com/abc/' + PAYLOAD + '.svg)"}');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected markdown image line to suppress');
      await rm(fx, { recursive: true, force: true });
    });

    it('rule 18 does NOT over-match plain URLs without image syntax', async () => {
      const fx = await newRoot('ent-rule18b-');
      await writeFixture(fx, 'app.js',
        'const token = "' + PAYLOAD + '"; // not an image');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.ok(result.findings.length >= 1, 'plain high-entropy string must still be detected');
      await rm(fx, { recursive: true, force: true });
    });
  });

  describe('C. Policy-driven overrides', () => {
    it('user-policy suppress_line_patterns adds custom suppression', async () => {
      const fx = await newRoot('ent-policy-');
      await writeFixture(fx, 'secret.js', 'const vendor = "' + PAYLOAD + '"; // MY_VENDOR_MARKER');
      await writeFixture(fx, '.llm-security/policy.json', JSON.stringify({
        entropy: { suppress_line_patterns: ['MY_VENDOR_MARKER'] }
      }));
      resetCounter();
      _resetCacheForTest();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected user pattern to suppress');
      assert.equal(result.calibration.policy_source, 'policy.json');
      await rm(fx, { recursive: true, force: true });
    });

    it('user-policy suppress_paths skips files whose relPath contains the substring', async () => {
      const fx = await newRoot('ent-paths-');
      await writeFixture(fx, 'src/vendored/big.js', 'var x="' + PAYLOAD + '";');
      await writeFixture(fx, 'src/app.js', 'var y="' + PAYLOAD + '";');
      await writeFixture(fx, '.llm-security/policy.json', JSON.stringify({
        entropy: { suppress_paths: ['vendored/'] }
      }));
      resetCounter();
      _resetCacheForTest();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 1, 'Expected 1 finding (app.js only), got ' + result.findings.length);
      assert.ok(result.calibration.files_skipped_by_path >= 1);
      await rm(fx, { recursive: true, force: true });
    });

    it('user-policy stricter thresholds suppress medium-strength payload', async () => {
      const fx = await newRoot('ent-thresh-');
      await writeFixture(fx, 'cfg.js', 'const blob = "' + PAYLOAD + '";');
      await writeFixture(fx, '.llm-security/policy.json', JSON.stringify({
        entropy: {
          thresholds: {
            critical: { entropy: 6.0, minLen: 256 },
            high:     { entropy: 5.8, minLen: 200 },
            medium:   { entropy: 5.7, minLen: 150 },
          }
        }
      }));
      resetCounter();
      _resetCacheForTest();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, 'expected strict thresholds to suppress medium-strength payload');
      await rm(fx, { recursive: true, force: true });
    });
  });

  describe('D. B5 file-context classification (v7.2.0)', () => {
    it('B5 regression: code-dominant .ts file with embedded GLSL — credential adjacent to shader is detected', async () => {
      // Polyglot TS file: many code lines, a few GLSL lines inside a template
      // literal, and a credential-shaped string on a line that happens to
      // contain GLSL keyword tokens. Pre-B5 rule 11 line-proximity suppressed
      // this. Post-B5 classifyFileContext returns 'code-dominant' (sample is
      // mostly TS code, <50% GLSL/markup), rules 11-13 are gated off, and
      // the credential is detected.
      const fx = await newRoot('ent-b5-polyglot-');
      const fixtureContent = [
        'import { Renderer } from "./renderer";',
        '',
        'const fragmentShader = `',
        '  precision highp float;',
        '  uniform vec3 u_resolution;',
        '  varying vec2 v_uv;',
        '`;',
        '',
        '// Adjacent line carries GLSL tokens AND the credential payload.',
        'const blob = "' + PAYLOAD + '"; // uniform vec3 normal;',
        '',
        'export { fragmentShader, blob };',
      ].join('\n');
      await writeFixture(fx, 'shader-app.ts', fixtureContent);
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.ok(
        result.findings.length >= 1,
        'expected B5 to surface credential in code-dominant .ts despite GLSL neighbour; got ' + result.findings.length
      );
      await rm(fx, { recursive: true, force: true });
    });

    it('B5 control: legitimate .glsl file with high-entropy hash in shader source is still suppressed (extension skip)', async () => {
      // A pure-shader file is skipped at the file-extension gate, never
      // reaching classifyFileContext. This control confirms the extension
      // skip still works (B5 only changed line-level rule gating).
      const fx = await newRoot('ent-b5-glsl-');
      await writeFixture(fx, 'noise.glsl',
        'uniform vec3 u_seed;\nvec3 rand = vec3(' + PAYLOAD + ');\n');
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(result.findings.length, 0, '.glsl files remain extension-skipped');
      await rm(fx, { recursive: true, force: true });
    });

    it('B5 control: shader-dominant .ts file with ≥50% GLSL lines downgrades to mixed and suppresses', async () => {
      // A code-extension file that is *mostly* shader template content —
      // rule 11 should still fire because classifyFileContext downgrades it
      // to 'mixed' (≥50% sampled lines match GLSL/INLINE_MARKUP).
      const fx = await newRoot('ent-b5-shader-ts-');
      const fixtureContent = [
        'uniform vec3 u_resolution;',
        'uniform vec3 u_camera_pos;',
        'uniform float u_time;',
        'varying vec2 v_uv;',
        'varying vec3 v_normal;',
        'attribute vec3 position;',
        'attribute vec2 uv;',
        'precision highp float;',
        'gl_Position = vec4(position, 1.0);',
        'gl_FragColor = vec4(1.0);',
        'const blob = "' + PAYLOAD + '"; // uniform vec3 normal;',
      ].join('\n');
      await writeFixture(fx, 'shader-heavy.ts', fixtureContent);
      resetCounter();
      const discovery = await discoverFiles(fx);
      const result = await scan(fx, discovery);
      assert.equal(
        result.findings.length, 0,
        'expected shader-dense .ts (≥50% GLSL lines) to downgrade to mixed and suppress; got ' + result.findings.length
      );
      await rm(fx, { recursive: true, force: true });
    });
  });
});