Kjell Tore Guttormsen
207385fbbe
#24 the HTML-obfuscation injection patterns had overlapping unbounded runs plus a required closing quote, so a non-closing input backtracked O(N^2) (~28.7s at the 512KB cap); quantifiers bounded, pathological input now 4ms. #53 mcp-live-inspect buffered MCP-server stdout via readline with no cap, so a hostile stdio server could exhaust memory / throw an uncaught RangeError; replaced with manual line buffering capped at 4MB that rejects pending RPCs and destroys stdout. #31 vsix-fetch's same-host redirect follower had no depth cap (loop hang); added depth>=5 cap mirroring the sibling fetcher. #25/#51 mcp-description-cache and skill-registry wrote JSON via bare writeFileSync (non-atomic: concurrent load-modify-save loses updates, a torn read silently yields an empty registry); both now write a temp file then renameSync. Suite 1931/0. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TcQyMTQfyrsAapaCMPxTtQ
36 lines
1.5 KiB
JavaScript
36 lines
1.5 KiB
JavaScript
// mcp-live-inspect-stdout-cap.test.mjs — #53 (v7.8.3): a hostile MCP stdio
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// server emitting a giant newline-less stdout line must not buffer unbounded
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// memory or crash the inspector. The session must abort with a cap error.
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// Zero external dependencies: node:test + node:assert only.
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import { describe, it } from 'node:test';
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import assert from 'node:assert/strict';
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import { inspectServer } from '../../scanners/mcp-live-inspect.mjs';
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describe('inspectServer — stdout line byte cap (v7.8.3 #53)', () => {
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it('aborts on a giant newline-less stdout chunk instead of buffering unbounded', { timeout: 30_000 }, async () => {
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// Child writes ~10MB with no newline, then stays alive so stdout does
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// not close. Without a cap the inspector buffers everything and only
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// fails via the generic RPC timeout.
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const script = [
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'const b = Buffer.alloc(65536, 120);',
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'for (let i = 0; i < 160; i++) process.stdout.write(b);',
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'setInterval(() => {}, 1000);',
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].join(' ');
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const descriptor = {
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name: 'hostile-flood',
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command: process.execPath,
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args: ['-e', script],
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env: {},
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};
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const result = await inspectServer(descriptor, 20_000);
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assert.ok(result, 'expected a result object');
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assert.ok(result.error, `expected an error result, got: ${JSON.stringify(result).slice(0, 200)}`);
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assert.match(
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result.error,
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/stdout line exceeded/,
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`expected stdout cap error (not a generic timeout), got: ${result.error}`,
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);
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});
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});
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