new plugin signing and checking

Overlord-Server/src/server/plugin-signature.ts

@@ -0,0 +1,169 @@
+import fs from "fs/promises";
+import path from "path";
+import AdmZip from "adm-zip";
+import type { PluginSignatureInfo } from "../protocol";
+import { logger } from "../logger";
+import { getConfig } from "../config";
+
+export const BUILTIN_TRUSTED_KEYS: string[] = [
+  "c0f7b94f9678425d08d2408fd92494c419a5ea6819ee4dbcebc41d86c22c61fa",
+];
+
+export async function computeContentDigest(zip: InstanceType<typeof AdmZip>): Promise<string> {
+  const entries = zip.getEntries();
+  const fileHashes: Array<{ name: string; hash: string }> = [];
+
+  for (const entry of entries) {
+    if (entry.isDirectory) continue;
+    if (entry.entryName === "signature.json") continue;
+
+    const data = entry.getData();
+    const hashBuf = await crypto.subtle.digest("SHA-256", data);
+    const hash = Buffer.from(hashBuf).toString("hex");
+    fileHashes.push({ name: entry.entryName, hash });
+  }
+
+  fileHashes.sort((a, b) => a.name.localeCompare(b.name));
+  return fileHashes.map((f) => `${f.name}:${f.hash}\n`).join("");
+}
+
+export function extractSignatureFromZip(
+  zip: InstanceType<typeof AdmZip>,
+): { algorithm: string; publicKey: string; signature: string } | null {
+  const entry = zip.getEntry("signature.json");
+  if (!entry) return null;
+
+  try {
+    const raw = entry.getData().toString("utf-8");
+    const parsed = JSON.parse(raw);
+    if (
+      typeof parsed.algorithm === "string" &&
+      typeof parsed.publicKey === "string" &&
+      typeof parsed.signature === "string"
+    ) {
+      return {
+        algorithm: parsed.algorithm,
+        publicKey: parsed.publicKey,
+        signature: parsed.signature,
+      };
+    }
+    return null;
+  } catch {
+    return null;
+  }
+}
+
+export async function computeKeyFingerprint(publicKeyBase64: string): Promise<string> {
+  const pubBytes = Buffer.from(publicKeyBase64, "base64");
+  const hashBuf = await crypto.subtle.digest("SHA-256", pubBytes);
+  return Buffer.from(hashBuf).toString("hex");
+}
+
+export function isKeyTrusted(fingerprint: string, trustedKeys: string[]): boolean {
+  const normalized = fingerprint.toLowerCase();
+  const allTrusted = [...BUILTIN_TRUSTED_KEYS, ...trustedKeys];
+  return allTrusted.some((k) => k.toLowerCase() === normalized);
+}
+
+export async function verifyPluginSignature(zipPath: string): Promise<PluginSignatureInfo> {
+  let zip: InstanceType<typeof AdmZip>;
+  try {
+    zip = new AdmZip(zipPath);
+  } catch (err) {
+    logger.warn(`[plugin-signature] failed to read ZIP ${zipPath}: ${(err as Error).message}`);
+    return { signed: false, trusted: false, valid: false };
+  }
+
+  const sigData = extractSignatureFromZip(zip);
+  if (!sigData) {
+    return { signed: false, trusted: false, valid: false };
+  }
+
+  if (sigData.algorithm !== "ed25519") {
+    logger.warn(`[plugin-signature] unsupported algorithm: ${sigData.algorithm}`);
+    return { signed: true, trusted: false, valid: false, algorithm: sigData.algorithm };
+  }
+
+  try {
+    const pubBytes = Buffer.from(sigData.publicKey, "base64");
+    if (pubBytes.length !== 32) {
+      return { signed: true, trusted: false, valid: false, algorithm: sigData.algorithm };
+    }
+
+    const publicKey = await crypto.subtle.importKey(
+      "raw",
+      pubBytes,
+      { name: "Ed25519" },
+      false,
+      ["verify"],
+    );
+
+    const digest = await computeContentDigest(zip);
+    const digestBytes = new TextEncoder().encode(digest);
+
+    const sigBytes = Buffer.from(sigData.signature, "base64");
+    if (sigBytes.length !== 64) {
+      return { signed: true, trusted: false, valid: false, algorithm: sigData.algorithm };
+    }
+
+    const valid = await crypto.subtle.verify("Ed25519", publicKey, sigBytes, digestBytes);
+
+    const fingerprint = await computeKeyFingerprint(sigData.publicKey);
+
+    const config = getConfig();
+    const trusted = valid && isKeyTrusted(fingerprint, config.plugins.trustedKeys);
+
+    return {
+      signed: true,
+      valid,
+      trusted,
+      fingerprint,
+      algorithm: sigData.algorithm,
+    };
+  } catch (err) {
+    logger.warn(`[plugin-signature] verification error: ${(err as Error).message}`);
+    return { signed: true, trusted: false, valid: false, algorithm: sigData.algorithm };
+  }
+}
+
+export async function getOrVerifySignature(
+  pluginRoot: string,
+  pluginId: string,
+): Promise<PluginSignatureInfo> {
+  const sigInfoPath = path.join(pluginRoot, pluginId, "signature-info.json");
+  const zipPath = path.join(pluginRoot, `${pluginId}.zip`);
+
+  try {
+    const [zipStat, sigInfoStat] = await Promise.all([
+      fs.stat(zipPath),
+      fs.stat(sigInfoPath),
+    ]);
+    if (sigInfoStat.mtimeMs >= zipStat.mtimeMs) {
+      const raw = await fs.readFile(sigInfoPath, "utf-8");
+      const cached = JSON.parse(raw) as PluginSignatureInfo;
+      if (cached.signed && cached.valid && cached.fingerprint) {
+        const config = getConfig();
+        cached.trusted = isKeyTrusted(cached.fingerprint, config.plugins.trustedKeys);
+      }
+      return cached;
+    }
+  } catch {
+  }
+
+  try {
+    await fs.stat(zipPath);
+  } catch {
+    return { signed: false, trusted: false, valid: false };
+  }
+
+  const info = await verifyPluginSignature(zipPath);
+
+  try {
+    await fs.mkdir(path.join(pluginRoot, pluginId), { recursive: true });
+    await fs.writeFile(sigInfoPath, JSON.stringify(info, null, 2));
+  } catch (err) {
+    logger.warn(`[plugin-signature] failed to cache signature info: ${(err as Error).message}`);
+  }
+
+  return info;
+}

Overlord-Server/src/server/plugin-state-bundle.ts

@@ -4,7 +4,8 @@ import AdmZip from "adm-zip";
 import { v4 as uuidv4 } from "uuid";
 import type { ClientInfo } from "../types";
 import { logger } from "../logger";
-import { encodeMessage, type PluginManifest } from "../protocol";
+import { encodeMessage, type PluginManifest, type PluginSignatureInfo } from "../protocol";
+import { verifyPluginSignature, getOrVerifySignature } from "./plugin-signature";
 
 export type PluginState = {
   enabled: Record<string, boolean>;
@@ -126,6 +127,14 @@ export async function ensurePluginExtracted(
     },
   };
   await fs.writeFile(manifestPath, JSON.stringify(manifest, null, 2));
+
+  try {
+    const sigInfo = await verifyPluginSignature(zipPath);
+    const sigInfoPath = path.join(pluginDir, "signature-info.json");
+    await fs.writeFile(sigInfoPath, JSON.stringify(sigInfo, null, 2));
+  } catch (err) {
+    logger.warn(`[plugin] failed to verify signature for ${safeId}: ${(err as Error).message}`);
+  }
 }
 
 export async function syncPluginBundles(
@@ -146,16 +155,20 @@ export async function syncPluginBundles(
   }
 }
 
+export type PluginManifestWithSignature = PluginManifest & {
+  signature?: PluginSignatureInfo;
+};
+
 export async function listPluginManifests(
   pluginRoot: string,
   pluginState: PluginState,
   saveState: () => Promise<void>,
   ensureExtracted: (pluginId: string) => Promise<void>,
-): Promise<PluginManifest[]> {
+): Promise<PluginManifestWithSignature[]> {
   try {
     await syncPluginBundles(pluginRoot, ensureExtracted);
     const entries = await fs.readdir(pluginRoot, { withFileTypes: true });
-    const manifests: PluginManifest[] = [];
+    const manifests: PluginManifestWithSignature[] = [];
     for (const ent of entries) {
       if (!ent.isDirectory()) continue;
       const manifestPath = path.join(pluginRoot, ent.name, "manifest.json");
@@ -167,7 +180,8 @@ export async function listPluginManifests(
         if (pluginState.enabled[id] === undefined) {
           pluginState.enabled[id] = true;
         }
-        manifests.push({ ...manifest, id, name });
+        const sigInfo = await getOrVerifySignature(pluginRoot, id);
+        manifests.push({ ...manifest, id, name, signature: sigInfo });
       } catch {}
     }
     await saveState();

Overlord-Server/src/server/routes/plugin-routes.ts

@@ -6,11 +6,14 @@ import { requirePermission } from "../../rbac";
 import { canUserAccessClient } from "../../users";
 import * as clientManager from "../../clientManager";
 import { metrics } from "../../metrics";
-import { encodeMessage } from "../../protocol";
+import { encodeMessage, type PluginSignatureInfo } from "../../protocol";
+import { getConfig, updatePluginsConfig } from "../../config";
+import { getOrVerifySignature, BUILTIN_TRUSTED_KEYS } from "../plugin-signature";
 
 type PluginManifest = {
   id: string;
   name: string;
+  signature?: PluginSignatureInfo;
 };
 
 type PluginBundle = {
@@ -71,10 +74,57 @@ export async function handlePluginRoutes(
       lastError: deps.pluginState.lastError[p.id] || "",
       autoLoad: deps.pluginState.autoLoad[p.id] === true,
       autoStartEvents: deps.pluginState.autoStartEvents[p.id] || [],
+      signature: p.signature || { signed: false, trusted: false, valid: false },
     }));
     return Response.json({ plugins: enriched });
   }
 
+  if (req.method === "GET" && url.pathname === "/api/plugins/trusted-keys") {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+    if (user.role !== "admin") {
+      return new Response("Forbidden: Admin access required", { status: 403 });
+    }
+    const config = getConfig();
+    const allKeys = Array.from(new Set([...BUILTIN_TRUSTED_KEYS, ...config.plugins.trustedKeys]));
+    return Response.json({ trustedKeys: allKeys, builtinKeys: BUILTIN_TRUSTED_KEYS });
+  }
+
+  if (req.method === "POST" && url.pathname === "/api/plugins/trusted-keys") {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+    if (user.role !== "admin") {
+      return new Response("Forbidden: Admin access required", { status: 403 });
+    }
+    let body: any = {};
+    try { body = await req.json(); } catch {}
+    const fingerprint = typeof body.fingerprint === "string" ? body.fingerprint.trim().toLowerCase() : "";
+    if (!fingerprint || !/^[a-f0-9]{64}$/.test(fingerprint)) {
+      return Response.json({ ok: false, error: "Invalid fingerprint (expected 64-char hex SHA-256)" }, { status: 400 });
+    }
+    const config = getConfig();
+    const keys = [...config.plugins.trustedKeys];
+    if (!keys.includes(fingerprint)) {
+      keys.push(fingerprint);
+      await updatePluginsConfig({ trustedKeys: keys });
+    }
+    return Response.json({ ok: true, trustedKeys: keys });
+  }
+
+  const trustedKeyDeleteMatch = url.pathname.match(/^\/api\/plugins\/trusted-keys\/([a-f0-9]{64})$/);
+  if (req.method === "DELETE" && trustedKeyDeleteMatch) {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+    if (user.role !== "admin") {
+      return new Response("Forbidden: Admin access required", { status: 403 });
+    }
+    const fingerprint = trustedKeyDeleteMatch[1].toLowerCase();
+    const config = getConfig();
+    const keys = config.plugins.trustedKeys.filter((k) => k.toLowerCase() !== fingerprint);
+    await updatePluginsConfig({ trustedKeys: keys });
+    return Response.json({ ok: true, trustedKeys: keys });
+  }
+
   const clientPluginsMatch = url.pathname.match(/^\/api\/clients\/(.+)\/plugins$/);
   if (req.method === "GET" && clientPluginsMatch) {
     const user = await authenticateRequest(req);
@@ -100,6 +150,7 @@ export async function handlePluginRoutes(
       loaded: loaded.has(manifest.id),
       enabled: deps.pluginState.enabled[manifest.id] !== false,
       lastError: deps.pluginState.lastError[manifest.id] || "",
+      signature: manifest.signature || { signed: false, trusted: false, valid: false },
     }));
     return Response.json({ plugins });
   }
@@ -149,12 +200,14 @@ export async function handlePluginRoutes(
       return Response.json({ ok: false, error: (err as Error).message }, { status: 400 });
     }
 
+    const sigInfo = await getOrVerifySignature(deps.PLUGIN_ROOT, pluginId);
+
     if (deps.pluginState.enabled[pluginId] === undefined) {
-      deps.pluginState.enabled[pluginId] = true;
+      deps.pluginState.enabled[pluginId] = sigInfo.trusted === true;
       await deps.savePluginState();
     }
 
-    return Response.json({ ok: true, id: pluginId });
+    return Response.json({ ok: true, id: pluginId, enabled: deps.pluginState.enabled[pluginId], signature: sigInfo });
   }
 
   const pluginEnableMatch = url.pathname.match(/^\/api\/plugins\/(.+)\/enable$/);
@@ -177,6 +230,19 @@ export async function handlePluginRoutes(
       body = await req.json();
     } catch {}
     const enabled = !!body.enabled;
+
+    if (enabled) {
+      const sigInfo = await getOrVerifySignature(deps.PLUGIN_ROOT, pluginId);
+      if (!sigInfo.trusted) {
+        if (body.confirmed !== true) {
+          return Response.json(
+            { ok: false, error: "confirmation_required", signature: sigInfo },
+            { status: 428 },
+          );
+        }
+      }
+    }
+
     deps.pluginState.enabled[pluginId] = enabled;
     await deps.savePluginState();
     return Response.json({ ok: true, id: pluginId, enabled });
@@ -202,6 +268,14 @@ export async function handlePluginRoutes(
       body = await req.json();
     } catch {}
     const autoLoad = !!body.autoLoad;
+
+    if (autoLoad && deps.pluginState.enabled[pluginId] === false) {
+      return Response.json(
+        { ok: false, error: "Plugin must be enabled before auto-load can be turned on" },
+        { status: 400 },
+      );
+    }
+
     deps.pluginState.autoLoad[pluginId] = autoLoad;
 
     if (Array.isArray(body.autoStartEvents)) {
@@ -474,12 +548,35 @@ export async function handlePluginRoutes(
     if (deps.isPluginLoading(targetId, pluginId)) {
       return Response.json({ ok: true, loading: true });
     }
+
+    const sigInfo = await getOrVerifySignature(deps.PLUGIN_ROOT, pluginId);
+
+    if (sigInfo.signed && !sigInfo.valid) {
+      return Response.json(
+        { ok: false, error: "Plugin signature is invalid — the plugin may have been tampered with", signature: sigInfo },
+        { status: 403 },
+      );
+    }
+
+    if (!sigInfo.trusted) {
+      let body: any = {};
+      try {
+        body = await req.json();
+      } catch {}
+      if (body.confirmed !== true) {
+        return Response.json(
+          { ok: false, error: "confirmation_required", signature: sigInfo },
+          { status: 428 },
+        );
+      }
+    }
+
     try {
       const bundle = await deps.loadPluginBundle(pluginId, target.os, target.arch);
       deps.markPluginLoading(targetId, pluginId);
       deps.sendPluginBundle(target, bundle);
       metrics.recordCommand("plugin_load");
-      return Response.json({ ok: true });
+      return Response.json({ ok: true, signature: sigInfo });
     } catch (err) {
       return Response.json({ ok: false, error: (err as Error).message }, { status: 400 });
     }