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[WRONG BRANCH] fix(lab): reject symlinked purge directories #245

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[WRONG BRANCH] fix(lab): reject symlinked purge directories #245

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8 changes: 8 additions & 0 deletions src/lab/ledger/purge.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ import {
closeSync,
existsSync,
fsyncSync,
lstatSync,
openSync,
readdirSync,
renameSync,
Expand Down Expand Up @@ -128,6 +129,13 @@ function deleteArtifactsFailClosed(dir: TrustedArtifactDir, digests: string[]):

function purgeBoundedDirectory(dirPath: string): void {
if (!existsSync(dirPath)) return;
const metadata = lstatSync(dirPath);

@chatgpt-codex-connector chatgpt-codex-connector Bot Aug 11, 2026

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P2 Badge Pin the purge directory before deleting its contents

When another process can modify the Lab directory concurrently, this lstatSync() check is subject to a TOCTOU race: after validation, the real scratch or export directory can be renamed and replaced with a symlink before readdirSync(dirPath), causing the subsequent path-based rmSync() calls to delete children of the symlink target. Open the directory without following links, retain and verify its descriptor/identity, and perform enumeration and deletion relative to that pinned directory (as the artifact secure-fs code does) so replacing the pathname cannot redirect the purge.

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if (metadata.isSymbolicLink() || !metadata.isDirectory()) {
throw new PurgeError(
"scratch_export_unsafe_directory",
`refusing to purge non-directory or symbolic-link path: ${dirPath}`,
);
}
const entries = readdirSync(dirPath, { withFileTypes: true });
for (const entry of entries) {
const full = join(dirPath, entry.name);
Expand Down
10 changes: 8 additions & 2 deletions src/lab/paths.ts
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Original file line number Diff line number Diff line change
@@ -1,11 +1,15 @@
import { chmodSync, mkdirSync, statSync } from "node:fs";
import { chmodSync, lstatSync, mkdirSync } from "node:fs";
import { join } from "node:path";
import { getConfigDir } from "../config";

function ensureRestrictedDir(dir: string): void {
mkdirSync(dir, { recursive: true, mode: 0o700 });
const metadata = lstatSync(dir);
if (metadata.isSymbolicLink() || !metadata.isDirectory()) {
throw new Error(`lab state path must be a real directory: ${dir}`);
}
if (process.platform === "win32") return;
const mode = statSync(dir).mode & 0o777;
const mode = metadata.mode & 0o777;
if (mode !== 0o700) chmodSync(dir, 0o700);
}

Expand Down Expand Up @@ -54,6 +58,8 @@ export function ensureLabDirs(configDir = getConfigDir()): {
const exportDir = labExportDir(configDir);
ensureRestrictedDir(root);
ensureRestrictedDir(artifactsDir);
ensureRestrictedDir(scratchDir);
ensureRestrictedDir(exportDir);
return {
root,
ledgerPath: labLedgerPath(configDir),
Expand Down
35 changes: 34 additions & 1 deletion tests/lab-evidence-ledger.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1138,6 +1138,39 @@ describe("CL-02 phase-2 review regressions", () => {
});
});

test.each(["scratch", "export"] as const)(
"%s purge refuses a symbolic-link directory root",
(action) => {
withHome((home) => {
const authority = loadCaseAuthority();
const caseRecord = discoverScenarios(authority, ["responses-core"])[0]!;
const { event } = persistConformanceResult(
syntheticPassResult(caseRecord),
caseRecord,
authority,
{ configDir: home, recordedAt: 1000 },
);
const outside = join(home, `outside-${action}`);
const labDir = join(home, "lab", action);
mkdirSync(outside);
writeFileSync(join(outside, "keep.txt"), "keep");
rmSync(labDir, { recursive: true });
symlinkSync(outside, labDir, process.platform === "win32" ? "junction" : "dir");

expect(() =>
purgeSensitiveEvidence({
configDir: home,
targetEventIds: [event.eventId],
targetArtifactDigests: [],
purgeActions: [action],
recordedAt: 5000,
}),
).toThrow(/must be a real directory/);
expect(existsSync(join(outside, "keep.txt"))).toBe(true);
});
},
);

test("behavior fingerprint includes frozen runtime keys deterministically", () => {
const authority = loadCaseAuthority();
const caseRecord = discoverScenarios(authority, ["responses-core"])[0]!;
Expand All @@ -1158,4 +1191,4 @@ describe("CL-02 phase-2 review regressions", () => {
closeTrustedArtifactDir(dir);
});
});
});
});
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