1.1.00

convex/authGuard.ts

@@ -0,0 +1,63 @@
+"use node";
+
+import crypto from "crypto";
+import type { ActionCtx } from "./_generated/server";
+import { internal } from "./_generated/api";
+import type { Id } from "./_generated/dataModel";
+
+const MAX_CLOCK_SKEW_MS = 5 * 60 * 1000;
+
+/**
+ * Detached Ed25519 check: caller must sign `canonicalMessage` with the
+ * Ed25519 private key that pairs with the userProfile's stored
+ * `publicSigningKey`. Matches `voice.getToken` and
+ * `recovery.resetPasswordAction` — same window, same SPKI/PEM encoding,
+ * same hex signature format — so client-side signing code looks
+ * identical across every sensitive call.
+ *
+ * Throws on failure. Sensitive mutations that previously trusted a raw
+ * `userId` arg should now route through a "use node" action that calls
+ * this helper before running the internal mutation.
+ */
+export async function requireAuth(
+  ctx: ActionCtx,
+  userId: Id<"userProfiles">,
+  timestamp: number,
+  signature: string,
+  canonicalMessage: string,
+): Promise<void> {
+  if (
+    !Number.isFinite(timestamp) ||
+    Math.abs(Date.now() - timestamp) > MAX_CLOCK_SKEW_MS
+  ) {
+    throw new Error("Request expired. Please try again.");
+  }
+
+  const user = await ctx.runQuery(internal.auth.getUserForVoiceToken, {
+    userId,
+  });
+  if (!user) {
+    throw new Error("User not found");
+  }
+
+  let isValid = false;
+  try {
+    const publicKeyObj = crypto.createPublicKey({
+      key: user.publicSigningKey,
+      format: "pem",
+      type: "spki",
+    });
+    isValid = crypto.verify(
+      null,
+      Buffer.from(canonicalMessage),
+      publicKeyObj,
+      Buffer.from(signature, "hex"),
+    );
+  } catch {
+    throw new Error("Signature verification failed");
+  }
+
+  if (!isValid) {
+    throw new Error("Invalid signature");
+  }
+}