Add support for alternative domains for Invidious cookies

config/config.example.yml

@@ -151,6 +151,20 @@ db:
 ##
 domain:
 
+##
+## List of alternative domains where the invidious instance is being served.
+## This needs to be set in order to be able to login and update user preferences
+## when using a domain that is not the same as the `domain` configuration,
+## like a .`onion` address, `.i2p` address, `.b32.i2p` address, etc.
+##
+## It will detect the alternative domain trough the `X-Forwarded-Host` header.
+## https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Host
+##
+## Accepted values: a list of fully qualified domain names (FQDN)
+## Default: <none>
+##
+alternative_domains:
+
 ##
 ## Tell Invidious that it is behind a proxy that provides only
 ## HTTPS, so all links must use the https:// scheme. This

src/invidious/config.cr

@@ -120,6 +120,8 @@ class Config
   property hmac_key : String = ""
   # Domain to be used for links to resources on the site where an absolute URL is required
   property domain : String?
+  # Additional domain list that is going to be used for cookie domain validation
+  property alternative_domains : Array(String) = [] of String
   # Subscribe to channels using PubSubHubbub (requires domain, hmac_key)
   property use_pubsub_feeds : Bool | Int32 = false
   property popular_enabled : Bool = true

src/invidious/routes/before_all.cr

@@ -32,6 +32,8 @@ module Invidious::Routes::BeforeAll
     env.response.headers["X-XSS-Protection"] = "1; mode=block"
     env.response.headers["X-Content-Type-Options"] = "nosniff"
 
+    env.set "header_x-forwarded-host", env.request.headers["X-Forwarded-Host"]?
+
     # Only allow the pages at /embed/* to be embedded
     if env.request.resource.starts_with?("/embed")
       frame_ancestors = "'self' file: http: https:"

src/invidious/routes/login.cr

@@ -26,6 +26,7 @@ module Invidious::Routes::Login
 
   def self.login(env)
     locale = env.get("preferences").as(Preferences).locale
+    host = env.get("header_x-forwarded-host")
 
     referer = get_referer(env, "/feed/subscriptions")
 
@@ -57,7 +58,11 @@ module Invidious::Routes::Login
           sid = Base64.urlsafe_encode(Random::Secure.random_bytes(32))
           Invidious::Database::SessionIDs.insert(sid, email)
 
+          if alt = CONFIG.alternative_domains.index(host)
+            env.response.cookies["SID"] = Invidious::User::Cookies.sid(CONFIG.alternative_domains[alt], sid)
+          else
             env.response.cookies["SID"] = Invidious::User::Cookies.sid(CONFIG.domain, sid)
+          end
         else
           return error_template(401, "Wrong username or password")
         end
@@ -123,7 +128,11 @@ module Invidious::Routes::Login
         view_name = "subscriptions_#{sha256(user.email)}"
         PG_DB.exec("CREATE MATERIALIZED VIEW #{view_name} AS #{MATERIALIZED_VIEW_SQL.call(user.email)}")
 
+        if alt = CONFIG.alternative_domains.index(host)
+          env.response.cookies["SID"] = Invidious::User::Cookies.sid(CONFIG.alternative_domains[alt], sid)
+        else
           env.response.cookies["SID"] = Invidious::User::Cookies.sid(CONFIG.domain, sid)
+        end
 
         if env.request.cookies["PREFS"]?
           user.preferences = env.get("preferences").as(Preferences)

src/invidious/routes/preferences.cr

@@ -225,9 +225,14 @@ module Invidious::Routes::PreferencesRoute
 
         File.write("config/config.yml", CONFIG.to_yaml)
       end
+    else
+      host = env.get("header_x-forwarded-host")
+      if alt = CONFIG.alternative_domains.index(host)
+        env.response.cookies["PREFS"] = Invidious::User::Cookies.prefs(CONFIG.alternative_domains[alt], preferences)
       else
         env.response.cookies["PREFS"] = Invidious::User::Cookies.prefs(CONFIG.domain, preferences)
       end
+    end
 
     env.redirect referer
   end
@@ -261,8 +266,13 @@ module Invidious::Routes::PreferencesRoute
         preferences.dark_mode = "dark"
       end
 
+      host = env.get("header_x-forwarded-host")
+      if alt = CONFIG.alternative_domains.index(host)
+        env.response.cookies["PREFS"] = Invidious::User::Cookies.prefs(CONFIG.alternative_domains[alt], preferences)
+      else
         env.response.cookies["PREFS"] = Invidious::User::Cookies.prefs(CONFIG.domain, preferences)
       end
+    end
 
     if redirect
       env.redirect referer

src/invidious/user/cookies.cr

@@ -6,17 +6,24 @@ struct Invidious::User
 
     # Note: we use ternary operator because the two variables
     # used in here are not booleans.
-    SECURE = (Kemal.config.ssl || CONFIG.https_only) ? true : false
+    @@secure = (Kemal.config.ssl || CONFIG.https_only) ? true : false
 
     # Session ID (SID) cookie
     # Parameter "domain" comes from the global config
     def sid(domain : String?, sid) : HTTP::Cookie
+      # Not secure if it's being accessed from I2P
+      # Browsers expect the domain to include https. On I2P there is no HTTPS
+      # Tor browser works fine with secure being true
+      if domain.try &.split(".").last == "i2p"
+        @@secure = false
+      end
+
       return HTTP::Cookie.new(
         name: "SID",
         domain: domain,
         value: sid,
         expires: Time.utc + 2.years,
-        secure: SECURE,
+        secure: @@secure,
         http_only: true,
         samesite: HTTP::Cookie::SameSite::Lax
       )
@@ -25,12 +32,19 @@ struct Invidious::User
     # Preferences (PREFS) cookie
     # Parameter "domain" comes from the global config
     def prefs(domain : String?, preferences : Preferences) : HTTP::Cookie
+      # Not secure if it's being accessed from I2P
+      # Browsers expect the domain to include https. On I2P there is no HTTPS
+      # Tor browser works fine with secure being true
+      if domain.try &.split(".").last == "i2p"
+        @@secure = false
+      end
+
       return HTTP::Cookie.new(
         name: "PREFS",
         domain: domain,
         value: URI.encode_www_form(preferences.to_json),
         expires: Time.utc + 2.years,
-        secure: SECURE,
+        secure: @@secure,
         http_only: false,
         samesite: HTTP::Cookie::SameSite::Lax
       )