From ceb997f6c1fa563a56fefe77cb5b77c9c8864159 Mon Sep 17 00:00:00 2001
From: rangoDJ <18576423+rangoDJ@users.noreply.github.com>
Date: Wed, 7 Oct 2026 18:48:21 -0400
Subject: [PATCH] Only let ConnectHub's own page open the stream

The base image sets SELKIES_ALLOWED_ORIGINS=*, disabling Selkies' check on
which pages may open the stream WebSocket. The SameSite=Lax session cookie
keeps out other sites, but SameSite is per site, so a page on a sibling
subdomain still got the cookie and could view and control the desktop.
Restore Selkies' same-origin default (empty). It compares the Origin's
hostname with the Host nginx forwards, so proxies, tunnels, LAN access and
localhost keep working; other origins can still be listed in compose.

Fixes #51

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Dockerfile         |  6 ++++++
 README.md          | 10 ++++++++++
 docker-compose.yml |  4 ++++
 3 files changed, 20 insertions(+)

diff --git a/Dockerfile b/Dockerfile
index 5330891..711a8f9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -54,6 +54,12 @@ COPY scripts/check_base_env.sh /tmp/check_base_env.sh
 RUN sh /tmp/check_base_env.sh /connecthub-base.env \
     && rm -f /tmp/check_base_env.sh /connecthub-base.env
 
+# The base's "*" lets any page open the stream WebSocket. The session cookie only keeps
+# out other *sites*, so a page on a sibling subdomain (other.example.com beside
+# hub.example.com) could still connect and control the desktop. Empty is Selkies'
+# same-origin default: the Origin's hostname must match the Host nginx forwards.
+ENV SELKIES_ALLOWED_ORIGINS=
+
 # Install FreeRDP 3, GPU drivers for VA-API, Python 3, and utilities
 RUN apt-get update && apt-get install -y --no-install-recommends \
     freerdp3-x11 \
diff --git a/README.md b/README.md
index 485d905..a20eb70 100644
--- a/README.md
+++ b/README.md
@@ -203,6 +203,16 @@ The application will automatically recognize the authenticated user and grant ac
 
 `FORWARD_AUTH_TRUSTED_PROXIES` is **required**: the header is only honoured when the request comes from one of these IPs/CIDRs (your proxy's address or Docker network). Otherwise anyone reaching the container port directly could forge the header. Also avoid publishing the container port publicly in this mode.
 
+### Which pages may open the stream
+
+Only ConnectHub's own page can open the remote desktop stream: Selkies checks that the browser's `Origin` matches the address you reached ConnectHub on, which keeps out pages on other sites, including other apps on sibling subdomains of the same domain. This works unchanged through a reverse proxy or tunnel, by LAN IP and on localhost. To allow another page (for example a portal that embeds ConnectHub from a different hostname), list its origin:
+
+```yaml
+SELKIES_ALLOWED_ORIGINS=https://portal.example.com
+```
+
+Avoid `*`, which lets any page connect if the browser sends your session cookie.
+
 ---
 
 ## Connection Types (RDP, VNC, SSH)
diff --git a/docker-compose.yml b/docker-compose.yml
index 6edc6a6..8354a84 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -60,6 +60,10 @@ services:
       # Session cookie Secure flag: auto (follows https), true, false
       - COOKIE_SECURE=${COOKIE_SECURE:-auto}
 
+      # Only ConnectHub's own page may open the stream. Add origins (comma-separated) only
+      # if another page must embed it, e.g. https://portal.example.com; avoid "*".
+      # - SELKIES_ALLOWED_ORIGINS=
+
       # Optional custom session secret key (auto-generated if omitted)
       - SECRET_KEY=${SECRET_KEY:-}