From 8885f14f1987173bcbcd83b20f886ce8efe928f7 Mon Sep 17 00:00:00 2001
From: Daniel Oaks <daniel@danieloaks.net>
Date: Thu, 21 Apr 2016 16:39:31 +1000
Subject: [PATCH] PROXY: Restrict to specified addresses/hostnames

---
 irc/client.go |  3 +--
 irc/config.go | 13 +++++-----
 irc/server.go | 69 ++++++++++++++++++++++++++++++---------------------
 oragono.yaml  |  5 ++++
 4 files changed, 54 insertions(+), 36 deletions(-)

diff --git a/irc/client.go b/irc/client.go
index 1cbdf73a..41bbe449 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -63,8 +63,7 @@ func (client *Client) run() {
 
 	// Set the hostname for this client. The client may later send a PROXY
 	// command from stunnel that sets the hostname to something more accurate.
-	client.send(NewProxyCommand(AddrLookupHostname(
-		client.socket.conn.RemoteAddr())))
+	client.hostname = AddrLookupHostname(client.socket.conn.RemoteAddr())
 
 	for err == nil {
 		//TODO(dan): does this read sockets correctly and split lines properly? (think that ZNC bug that kept happening with mammon)
diff --git a/irc/config.go b/irc/config.go
index 8072768e..571f0a58 100644
--- a/irc/config.go
+++ b/irc/config.go
@@ -46,12 +46,13 @@ type Config struct {
 
 	Server struct {
 		PassConfig
-		Name     string
-		Database string
-		Listen   []string
-		Wslisten string
-		Log      string
-		MOTD     string
+		Name             string
+		Database         string
+		Listen           []string
+		Wslisten         string
+		Log              string
+		MOTD             string
+		ProxyAllowedFrom []string `yaml:"proxy-allowed-from"`
 	}
 
 	SSLListener map[string]*SSLListenConfig
diff --git a/irc/server.go b/irc/server.go
index e8ba0fd0..925f8488 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -26,21 +26,22 @@ type RegServerCommand interface {
 }
 
 type Server struct {
-	channels  ChannelNameMap
-	clients   *ClientLookupSet
-	commands  chan Command
-	ctime     time.Time
-	db        *sql.DB
-	idle      chan *Client
-	motdLines []string
-	name      Name
-	newConns  chan net.Conn
-	operators map[Name][]byte
-	password  []byte
-	signals   chan os.Signal
-	whoWas    *WhoWasList
-	theaters  map[Name][]byte
-	isupport  *ISupportList
+	channels         ChannelNameMap
+	clients          *ClientLookupSet
+	commands         chan Command
+	ctime            time.Time
+	db               *sql.DB
+	idle             chan *Client
+	motdLines        []string
+	name             Name
+	newConns         chan net.Conn
+	operators        map[Name][]byte
+	password         []byte
+	signals          chan os.Signal
+	proxyAllowedFrom []string
+	whoWas           *WhoWasList
+	theaters         map[Name][]byte
+	isupport         *ISupportList
 }
 
 var (
@@ -50,18 +51,19 @@ var (
 
 func NewServer(config *Config) *Server {
 	server := &Server{
-		channels:  make(ChannelNameMap),
-		clients:   NewClientLookupSet(),
-		commands:  make(chan Command),
-		ctime:     time.Now(),
-		db:        OpenDB(config.Server.Database),
-		idle:      make(chan *Client),
-		name:      NewName(config.Server.Name),
-		newConns:  make(chan net.Conn),
-		operators: config.Operators(),
-		signals:   make(chan os.Signal, len(SERVER_SIGNALS)),
-		whoWas:    NewWhoWasList(100),
-		theaters:  config.Theaters(),
+		channels:         make(ChannelNameMap),
+		clients:          NewClientLookupSet(),
+		commands:         make(chan Command),
+		ctime:            time.Now(),
+		db:               OpenDB(config.Server.Database),
+		idle:             make(chan *Client),
+		name:             NewName(config.Server.Name),
+		newConns:         make(chan net.Conn),
+		operators:        config.Operators(),
+		signals:          make(chan os.Signal, len(SERVER_SIGNALS)),
+		proxyAllowedFrom: config.Server.ProxyAllowedFrom,
+		whoWas:           NewWhoWasList(100),
+		theaters:         config.Theaters(),
 	}
 
 	// ensure that there is a minimum number of args specified for every command
@@ -369,7 +371,18 @@ func (msg *PassCommand) HandleRegServer(server *Server) {
 }
 
 func (msg *ProxyCommand) HandleRegServer(server *Server) {
-	msg.Client().hostname = msg.hostname
+	client := msg.Client()
+	clientAddress := IPString(client.socket.conn.RemoteAddr()).String()
+	clientHostname := client.hostname.String()
+
+	for _, address := range server.proxyAllowedFrom {
+		if clientHostname == address || clientAddress == address {
+			client.hostname = msg.hostname
+			return
+		}
+	}
+
+	client.Quit("PROXY command is not usable from your address")
 }
 
 func (msg *UserCommand) HandleRegServer(server *Server) {
diff --git a/oragono.yaml b/oragono.yaml
index f3de0013..a16cdf4e 100644
--- a/oragono.yaml
+++ b/oragono.yaml
@@ -34,6 +34,11 @@ server:
     # if you change the motd, you should move it to ircd.motd
     motd: oragono.motd
 
+    # addresses/hostnames the PROXY command can be used from
+    proxy-allowed-from:
+        - "localhost"
+        - "127.0.0.1"
+
 # ssl listeners
 ssllistener:
     # listener on ":6697"