Bound checked candidate metadata and restricted invocation resources

src/execution-world/files.ts

@@ -13,6 +13,7 @@ import {
   type CheckedWorld,
 } from "./artifacts.js";
 import { type ExecutionPlan, ExecutionPlanError } from "./plan.js";
+import type { CandidateMetadataScope } from "./metadata.js";
 
 const maxFileBytes = 256 * 1024 * 1024;
 const metadataLimit = 16 * 1024 * 1024;
@@ -21,7 +22,10 @@ const fail = (where: string, message: string): never => {
 };
 /** Roots must be trusted immutable output directories. Refuse symlinks, including
  * interior directory links. Hash verification is still required before serving bytes. */
-export async function artifactFileReader(roots: Readonly<Record<string, string>>): Promise<ArtifactReader> {
+export async function artifactFileReader(
+  roots: Readonly<Record<string, string>>,
+  metadata?: CandidateMetadataScope,
+): Promise<ArtifactReader> {
   const directories = new Map<string, string>();
   for (const [revision, root] of Object.entries(roots)) {
     if (!path.isAbsolute(root) || path.normalize(root) !== root || (await realpath(root)) !== root)
@@ -47,6 +51,7 @@ export async function artifactFileReader(roots: Readonly<Record<string, string>>
     try {
       const stat = await handle.stat();
       if (!stat.isFile() || stat.size > limit) fail(relative, "File exceeds its declared bound");
+      if (relative === "share/quixos/package-artifacts.json") metadata?.charge((stat.size + 1) * 32);
       // A fixed allocation and one extra byte detect growth without readFile's unbounded allocation.
       const buffer = Buffer.alloc(stat.size + 1);
       let offset = 0;
@@ -72,8 +77,9 @@ export interface LoadedArtifactWorld {
 export async function loadArtifactWorld(
   plan: ExecutionPlan,
   roots: Readonly<Record<string, string>>,
+  metadata?: CandidateMetadataScope,
 ): Promise<LoadedArtifactWorld> {
-  const read = await artifactFileReader(roots),
+  const read = await artifactFileReader(roots, metadata),
     manifests: PackageArtifacts[] = [];
   const expected = plan.definition.packages.map((p) => p.revision).sort();
   if (JSON.stringify(Object.keys(roots).sort()) !== JSON.stringify(expected))