1 files changed, 46 insertions, 11 deletions
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/transport.js b/packages/meshbay-hub/src/meshbay_hub/static/transport.js
index ca9c60e..d636085 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/transport.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/transport.js
@@ -266,6 +266,39 @@ class MeshBayTransport {
     return msg;
   }
 
+  /**
+   * Authorize a privileged node operation with the user's Ed25519 identity key.
+   *
+   * The client rebuilds the signed transcript from the challenge fields and refuses
+   * to sign unless the operation and subject match what the user actually asked for.
+   * Previously the node sent 32 opaque random bytes and the client signed them
+   * blind, which let any peer obtain a signature over content of its choosing
+   * (finding H5).
+   */
+  async _authorizeAdminOp(challenge, expectedOp, expectedSubject, signFn) {
+    if (challenge.op !== expectedOp || challenge.subject !== expectedSubject) {
+      throw new Error(
+        `Refusing to sign: node asked to authorize "${challenge.op}" on ` +
+        `"${challenge.subject}", but the requested action was "${expectedOp}" ` +
+        `on "${expectedSubject}"`);
+    }
+    if (!signFn) throw new Error('Admin challenge received but no signing key available');
+
+    const transcript = window.MeshBayCrypto.adminTranscript(
+      challenge.op, challenge.node_pk, challenge.group_id,
+      challenge.subject, challenge.nonce, challenge.ts);
+
+    const signature = await signFn(transcript);
+    const ack = await this._sendAndWait({
+      type: 'admin_response',
+      v: '0.1',
+      op_id: challenge.op_id,
+      signature,
+    });
+    if (ack.type === 'error') throw new Error(ack.detail);
+    return ack;
+  }
+
   async deleteFile(fileId, signFn) {
     const msg = await this._sendAndWait({
       type: 'file_delete',
@@ -274,16 +307,7 @@ class MeshBayTransport {
     });
     if (msg.type === 'error') throw new Error(msg.detail);
     if (msg.type === 'admin_challenge') {
-      if (!signFn) throw new Error('Admin challenge received but no signing key available');
-      const signature = await signFn(msg.challenge);
-      const ack = await this._sendAndWait({
-        type: 'admin_response',
-        v: '0.1',
-        file_id: fileId,
-        signature,
-      });
-      if (ack.type === 'error') throw new Error(ack.detail);
-      return ack;
+      return this._authorizeAdminOp(msg, 'file_delete', fileId, signFn);
     }
     return msg;
   }
@@ -304,7 +328,15 @@ class MeshBayTransport {
     return msg;
   }
 
-  async storeGekBundle(userId, groupId, bundle) {
+  /**
+   * Store a wrapped GEK bundle on the node for a member.
+   *
+   * Node-operator operation: the node answers with an admin challenge and only the
+   * pinned operator key is accepted. Any member used to be able to write bundles —
+   * including one addressed to the operator, which the node then auto-adopted as the
+   * live group key (finding C5b).
+   */
+  async storeGekBundle(userId, groupId, bundle, signFn) {
     const msg = await this._sendAndWait({
       type: 'gek_bundle_store',
       v: '0.1',
@@ -315,6 +347,9 @@ class MeshBayTransport {
       wrapped_b64: bundle.wrapped_b64,
     });
     if (msg.type === 'error') throw new Error(msg.detail);
+    if (msg.type === 'admin_challenge') {
+      return this._authorizeAdminOp(msg, 'gek_bundle_store', userId, signFn);
+    }
     return msg;
   }