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fix(llm-security): scanner robustness — ReDoS, MCP-stdout DoS, redirect loop, atomic writes (#24,#53,#31,#25,#51)

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#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
This commit is contained in:
Kjell Tore Guttormsen 2026-07-18 10:15:11 +02:00
commit 207385fbbe
10 changed files with 251 additions and 19 deletions
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7
scanners/lib/vsix-fetch.mjs
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@ -266,7 +266,7 @@ export async function fetchDirectVsix(url) {
};
}
async function httpsFetchSameHost(url, sourceHost) {
async function httpsFetchSameHost(url, sourceHost, depth = 0) {
const u = new URL(url);
if (u.protocol !== 'https:') {
throw new Error(`refusing non-HTTPS URL: ${url}`);
@ -282,7 +282,10 @@ async function httpsFetchSameHost(url, sourceHost) {
const loc = res.headers.get('location');
if (!loc) throw new Error(`HTTP ${res.status} without Location header`);
const next = new URL(loc, url).toString();
return httpsFetchSameHost(next, sourceHost);
// Cap redirect depth — mirrors httpsFetch (v7.8.3 #31): a same-host
// redirect loop would otherwise recurse forever.
if (depth >= 5) throw new Error('too many redirects');
return httpsFetchSameHost(next, sourceHost, depth + 1);
}
if (!res.ok) throw new Error(`HTTP ${res.status} ${res.statusText} for ${url}`);
const out = await readBodyCapped(res, controller);