fix(security): enforce trusted sender auth for discord moderation

src/discord/send.permissions.authz.test.ts

@@ -0,0 +1,128 @@
+import type { RequestClient } from "@buape/carbon";
+import { PermissionFlagsBits, Routes } from "discord-api-types/v10";
+import { describe, expect, it, vi } from "vitest";
+import {
+  fetchMemberGuildPermissionsDiscord,
+  hasGuildPermissionDiscord,
+} from "./send.permissions.js";
+
+const mockRest = vi.hoisted(() => ({
+  get: vi.fn(),
+}));
+
+vi.mock("./client.js", () => ({
+  resolveDiscordRest: () => mockRest as unknown as RequestClient,
+}));
+
+describe("discord guild permission authorization", () => {
+  describe("fetchMemberGuildPermissionsDiscord", () => {
+    it("returns null when user is not a guild member", async () => {
+      mockRest.get.mockRejectedValueOnce(new Error("404 Member not found"));
+
+      const result = await fetchMemberGuildPermissionsDiscord("guild-1", "user-1");
+      expect(result).toBeNull();
+    });
+
+    it("includes @everyone and member roles in computed permissions", async () => {
+      mockRest.get.mockImplementation(async (route: string) => {
+        if (route === Routes.guild("guild-1")) {
+          return {
+            id: "guild-1",
+            roles: [
+              { id: "guild-1", permissions: PermissionFlagsBits.ViewChannel.toString() },
+              { id: "role-mod", permissions: PermissionFlagsBits.KickMembers.toString() },
+            ],
+          };
+        }
+        if (route === Routes.guildMember("guild-1", "user-1")) {
+          return {
+            id: "user-1",
+            roles: ["role-mod"],
+          };
+        }
+        throw new Error(`Unexpected route: ${route}`);
+      });
+
+      const result = await fetchMemberGuildPermissionsDiscord("guild-1", "user-1");
+      expect(result).not.toBeNull();
+      expect((result! & PermissionFlagsBits.ViewChannel) === PermissionFlagsBits.ViewChannel).toBe(
+        true,
+      );
+      expect((result! & PermissionFlagsBits.KickMembers) === PermissionFlagsBits.KickMembers).toBe(
+        true,
+      );
+    });
+  });
+
+  describe("hasGuildPermissionDiscord", () => {
+    it("returns true when user has required permission", async () => {
+      mockRest.get.mockImplementation(async (route: string) => {
+        if (route === Routes.guild("guild-1")) {
+          return {
+            id: "guild-1",
+            roles: [
+              { id: "guild-1", permissions: "0" },
+              { id: "role-mod", permissions: PermissionFlagsBits.KickMembers.toString() },
+            ],
+          };
+        }
+        if (route === Routes.guildMember("guild-1", "user-1")) {
+          return { id: "user-1", roles: ["role-mod"] };
+        }
+        throw new Error(`Unexpected route: ${route}`);
+      });
+
+      const result = await hasGuildPermissionDiscord("guild-1", "user-1", [
+        PermissionFlagsBits.KickMembers,
+      ]);
+      expect(result).toBe(true);
+    });
+
+    it("returns true when user has ADMINISTRATOR", async () => {
+      mockRest.get.mockImplementation(async (route: string) => {
+        if (route === Routes.guild("guild-1")) {
+          return {
+            id: "guild-1",
+            roles: [
+              { id: "guild-1", permissions: "0" },
+              {
+                id: "role-admin",
+                permissions: PermissionFlagsBits.Administrator.toString(),
+              },
+            ],
+          };
+        }
+        if (route === Routes.guildMember("guild-1", "user-1")) {
+          return { id: "user-1", roles: ["role-admin"] };
+        }
+        throw new Error(`Unexpected route: ${route}`);
+      });
+
+      const result = await hasGuildPermissionDiscord("guild-1", "user-1", [
+        PermissionFlagsBits.KickMembers,
+      ]);
+      expect(result).toBe(true);
+    });
+
+    it("returns false when user lacks all required permissions", async () => {
+      mockRest.get.mockImplementation(async (route: string) => {
+        if (route === Routes.guild("guild-1")) {
+          return {
+            id: "guild-1",
+            roles: [{ id: "guild-1", permissions: PermissionFlagsBits.ViewChannel.toString() }],
+          };
+        }
+        if (route === Routes.guildMember("guild-1", "user-1")) {
+          return { id: "user-1", roles: [] };
+        }
+        throw new Error(`Unexpected route: ${route}`);
+      });
+
+      const result = await hasGuildPermissionDiscord("guild-1", "user-1", [
+        PermissionFlagsBits.BanMembers,
+        PermissionFlagsBits.KickMembers,
+      ]);
+      expect(result).toBe(false);
+    });
+  });
+});