Security: Only trust local proxies unless overidden

config/defaults/settings.yml

@@ -695,6 +695,24 @@ throttling:
   # Environment Variable Override: PWP__THROTTLING__SECOND='20'
   second: 60
 
+### Trusted Proxies
+#
+# By default, Password Pusher will only proxy related headers from proxies on
+# the local network.  If you are using a proxy that is not on the local network,
+# you will need to add the IP address of the proxy to the list below.
+#
+# This is useful if you are using a remote reverse proxy such as Cloudflare to
+# serve the application.  If local, you can leave this setting as is.
+# 
+# Multiple IP addresses can be added by separating them with a comma.
+#
+# Environment Variable Override:
+# PWP__TRUSTED_PROXIES='<ipaddress>'
+# PWP__TRUSTED_PROXIES='<ipaddress1>,<ipaddress2>'
+#
+# trusted_proxies:
+#   - '1.2.3.4'
+#   - '2.3.4.5'
 
 ### Mail Server Configuration
 #

config/environments/development.rb

@@ -118,6 +118,19 @@
   # Raise error when a before_action's only/except options reference missing actions
   config.action_controller.raise_on_missing_callback_actions = true
 
+  # The list of trusted proxies from which we will accept proxy related headers.
+  config.action_dispatch.trusted_proxies = [
+    "127.0.0.1",         # Localhost
+    /^::1$/,             # IPv6 localhost
+    /192\.168\.\d{1,3}\.\d{1,3}/, # Local network
+    /10\.\d{1,3}\.\d{1,3}\.\d{1,3}/ # Private networks
+  ]
+
+  if Settings.trusted_proxies.present?
+    trusted_proxies = Settings.trusted_proxies.split(",").map(&:strip)
+    config.action_dispatch.trusted_proxies.concat(trusted_proxies)
+  end
+
   # If a user sets the allowed_hosts setting, we need to add the domain(s) to the list of allowed hosts
   if Settings.allowed_hosts.present?
     if Settings.allowed_hosts.is_a?(Array)

config/environments/production.rb

@@ -54,6 +54,19 @@
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
   config.force_ssl = ENV.key?("FORCE_SSL")
 
+  # The list of trusted proxies from which we will accept proxy related headers.
+  config.action_dispatch.trusted_proxies = [
+    "127.0.0.1",         # Localhost
+    /^::1$/,             # IPv6 localhost
+    /192\.168\.\d{1,3}\.\d{1,3}/, # Local network
+    /10\.\d{1,3}\.\d{1,3}\.\d{1,3}/ # Private networks
+  ]
+
+  if Settings.trusted_proxies.present?
+    trusted_proxies = Settings.trusted_proxies.split(",").map(&:strip)
+    config.action_dispatch.trusted_proxies.concat(trusted_proxies)
+  end
+
   # Logging
   config.logger = if ENV["RAILS_LOG_TO_STDOUT"].present? || Settings.log_to_stdout
     # Log to STDOUT by default

config/settings.yml

@@ -695,6 +695,24 @@ throttling:
   # Environment Variable Override: PWP__THROTTLING__SECOND='20'
   second: 60
 
+### Trusted Proxies
+#
+# By default, Password Pusher will only proxy related headers from proxies on
+# the local network.  If you are using a proxy that is not on the local network,
+# you will need to add the IP address of the proxy to the list below.
+#
+# This is useful if you are using a remote reverse proxy such as Cloudflare to
+# serve the application.  If local, you can leave this setting as is.
+# 
+# Multiple IP addresses can be added by separating them with a comma.
+#
+# Environment Variable Override:
+# PWP__TRUSTED_PROXIES='<ipaddress>'
+# PWP__TRUSTED_PROXIES='<ipaddress1>,<ipaddress2>'
+#
+# trusted_proxies:
+#   - '1.2.3.4'
+#   - '2.3.4.5'
 
 ### Mail Server Configuration
 #