fix(security): materialize complete skill packages

tests/unit/skill-materialize.test.ts

@@ -0,0 +1,84 @@
+import { existsSync, statSync } from "node:fs";
+import { mkdtemp, readFile, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { MAX_SKILL_FILE_BYTES, MAX_TOTAL_BYTES } from "@main/skill-github";
+import { materializeSkillFiles } from "@main/skills/materialize";
+
+describe("skill materialization", () => {
+  let tempDir: string;
+
+  beforeEach(async () => {
+    tempDir = await mkdtemp(join(tmpdir(), "agentcompany-skill-materialize-"));
+  });
+
+  afterEach(async () => {
+    await rm(tempDir, { recursive: true, force: true });
+  });
+
+  it("materializes every inventory file and preserves script executability", async () => {
+    const dir = join(tempDir, "skills", "company", "review");
+
+    await materializeSkillFiles(dir, [
+      { path: "SKILL.md", kind: "skill", content: "---\nname: Review\n---\n" },
+      { path: "references/api.md", kind: "reference", content: "API notes" },
+      { path: "assets/logo.bin", kind: "asset", content: new Uint8Array([1, 2, 3]) },
+      { path: "scripts/run.sh", kind: "script", content: "echo review\n" },
+    ]);
+
+    await expect(readFile(join(dir, "SKILL.md"), "utf-8")).resolves.toContain("Review");
+    await expect(readFile(join(dir, "references", "api.md"), "utf-8")).resolves.toBe("API notes");
+    await expect(readFile(join(dir, "assets", "logo.bin"))).resolves.toEqual(Buffer.from([1, 2, 3]));
+    await expect(readFile(join(dir, "scripts", "run.sh"), "utf-8")).resolves.toBe("echo review\n");
+    expect(statSync(join(dir, "scripts", "run.sh")).mode & 0o100).toBe(0o100);
+    expect(statSync(join(dir, "scripts", "run.sh")).mode & 0o011).toBe(0);
+    expect(statSync(join(dir, "references", "api.md")).mode & 0o111).toBe(0);
+  });
+
+  it("replaces stale files when a skill is re-materialized", async () => {
+    const dir = join(tempDir, "skills", "company", "review");
+    await materializeSkillFiles(dir, [
+      { path: "SKILL.md", kind: "skill", content: "old" },
+      { path: "references/stale.md", kind: "reference", content: "stale" },
+    ]);
+
+    await materializeSkillFiles(dir, [
+      { path: "SKILL.md", kind: "skill", content: "new" },
+    ]);
+
+    await expect(readFile(join(dir, "SKILL.md"), "utf-8")).resolves.toBe("new");
+    expect(existsSync(join(dir, "references", "stale.md"))).toBe(false);
+  });
+
+  it("rejects traversal paths before writing the package", async () => {
+    const dir = join(tempDir, "skills", "company", "bad");
+
+    await expect(materializeSkillFiles(dir, [
+      { path: "SKILL.md", kind: "skill", content: "ok" },
+      { path: "../escape.md", kind: "markdown", content: "bad" },
+    ])).rejects.toThrow("Skill file path contains traversal segments: ../escape.md");
+    expect(existsSync(dir)).toBe(false);
+  });
+
+  it("enforces single-file and aggregate package byte limits", async () => {
+    const dir = join(tempDir, "skills", "company", "large");
+
+    await expect(materializeSkillFiles(dir, [
+      { path: "SKILL.md", kind: "skill", content: "ok" },
+      { path: "assets/too-large.bin", kind: "asset", content: new Uint8Array(MAX_SKILL_FILE_BYTES + 1) },
+    ])).rejects.toThrow(`assets/too-large.bin exceeds ${MAX_SKILL_FILE_BYTES}-byte limit`);
+
+    const packageFiles = [
+      { path: "SKILL.md", kind: "skill" as const, content: "ok" },
+      ...Array.from({ length: Math.ceil(MAX_TOTAL_BYTES / MAX_SKILL_FILE_BYTES) }, (_, index) => ({
+        path: `assets/chunk-${index}.bin`,
+        kind: "asset" as const,
+        content: new Uint8Array(MAX_SKILL_FILE_BYTES),
+      })),
+    ];
+    await expect(materializeSkillFiles(dir, packageFiles)).rejects.toThrow(
+      `Skill package exceeded aggregate limit of ${MAX_TOTAL_BYTES} bytes`,
+    );
+  });
+});