cloaking: Generate and check for cloak keys appropriately

irc/cloaking/cloak.go

@@ -0,0 +1,177 @@
+// Copyright (c) 2017 Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+// Package cloak implements IP address cloaking for IRC.
+package cloak
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+
+	"encoding/base32"
+)
+
+const (
+	// MinKeyLength determines how many bytes our cloak keys should be, minimum.
+	// This MUST NOT be higher in future releases, or else it will break existing,
+	// working cloaking for everyone using key lengths this long.
+	MinKeyLength = 32
+	// partLength is how long each octet is after being base32'd.
+	partLength = 10
+)
+
+var (
+	errNetName             = errors.New("NetName is not the right size (must be 1-10 characters long)")
+	errNotIPv4             = errors.New("The given address is not an IPv4 address")
+	errConfigDisabled      = errors.New("Config has disabled IP cloaking")
+	errKeysTooShort        = errors.New("Cloaking keys too short")
+	errKeysNotRandomEnough = errors.New("Cloaking keys aren't random enough")
+)
+
+// Config controls whether we cloak, and if we do what values are used to do so.
+type Config struct {
+	// Enabled controls whether cloaking is performed.
+	Enabled bool
+	// NetName is the name used for the network in cloaked addresses.
+	NetName string
+	// IPv4KeyString is used to cloak the `a`, `b`, `c` and `d` parts of the IP address.
+	// it is split up into the separate A/B/C/D keys below.
+	IPv4KeysString []string `yaml:"ipv4-keys"`
+	IPv4KeyA       []byte
+	IPv4KeyB       []byte
+	IPv4KeyC       []byte
+	IPv4KeyD       []byte
+}
+
+// CheckConfig checks whether we're configured correctly.
+func (config *Config) CheckConfig() error {
+	if config.Enabled {
+		// IPv4 cloak keys
+		if len(config.IPv4KeysString) < 4 {
+			return errKeysTooShort
+		}
+
+		keyA, errA := base64.StdEncoding.DecodeString(config.IPv4KeysString[0])
+		keyB, errB := base64.StdEncoding.DecodeString(config.IPv4KeysString[1])
+		keyC, errC := base64.StdEncoding.DecodeString(config.IPv4KeysString[2])
+		keyD, errD := base64.StdEncoding.DecodeString(config.IPv4KeysString[3])
+
+		if errA != nil || errB != nil || errC != nil || errD != nil {
+			return fmt.Errorf("Could not decode IPv4 cloak keys")
+		}
+		if len(keyA) < MinKeyLength || len(keyB) < MinKeyLength || len(keyC) < MinKeyLength || len(keyD) < MinKeyLength {
+			return errKeysTooShort
+		}
+
+		config.IPv4KeyA = keyA
+		config.IPv4KeyB = keyB
+		config.IPv4KeyC = keyC
+		config.IPv4KeyD = keyD
+
+		// try cloaking IPs to confirm everything works properly
+		_, err := IPv4(net.ParseIP("8.8.8.8"), config)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// GenerateCloakKey generates one cloak key.
+func GenerateCloakKey() (string, error) {
+	keyBytes := make([]byte, MinKeyLength)
+	_, err := rand.Read(keyBytes)
+	if err != nil {
+		return "", fmt.Errorf("Could not generate random bytes for cloak key: %s", err.Error())
+	}
+
+	return base64.StdEncoding.EncodeToString(keyBytes), nil
+}
+
+// IsRandomEnough makes sure people are using keys that are random enough.
+func IsRandomEnough(key []byte) bool {
+	//TODO(dan): actually find out how to calc this
+	return true
+}
+
+// toByteSlice is used for converting sha512 output from [64]byte to []byte.
+func toByteSlice(orig [64]byte) []byte {
+	var new []byte
+	for _, val := range orig {
+		new = append(new, val)
+	}
+	return new
+}
+
+// hashOctet does the heavy lifting in terms of hashing and returned an appropriate hashed octet
+func hashOctet(key []byte, data string) string {
+	sig := hmac.New(sha256.New, key)
+	sig.Write([]byte(data))
+	raw := sig.Sum(nil)
+	return strings.ToLower(base32.StdEncoding.EncodeToString(raw))
+}
+
+// IPv4 returns a cloaked IPv4 address
+//
+// IPv4 addresses can be represented as a.b.c.d, where `a` is the least unique
+// part of the address and `d` is the most unique part.
+//
+// `a` is unique for a given a.*.*.*, and `d` is unique for a given, specific
+// a.b.c.d address. That is, if you have 1.2.3.4 and 2.3.4.4, the `d` part of
+// both addresses should differ to prevent discoverability. In the same way,
+// if you have 4.5.6.7 and 4.3.2.1 then the `a` part of those addresses will
+// be the same value. This ensures chanops can properly ban dodgy people as
+// they need to do so.
+func IPv4(address net.IP, config *Config) (string, error) {
+	if !config.Enabled {
+		return "", errConfigDisabled
+	}
+	if len(config.NetName) < 1 || 10 < len(config.NetName) {
+		return "", errNetName
+	}
+
+	// make sure the IP address is an IPv4 address.
+	// from this point on we can assume `address` is a 4-byte slice
+	if address.To4() == nil {
+		return "", errNotIPv4
+	}
+
+	// check randomness of cloak keys
+	if len(config.IPv4KeyA) < MinKeyLength || len(config.IPv4KeyB) < MinKeyLength || len(config.IPv4KeyC) < MinKeyLength || len(config.IPv4KeyD) < MinKeyLength {
+		return "", errKeysTooShort
+	}
+	if !IsRandomEnough(config.IPv4KeyA) || !IsRandomEnough(config.IPv4KeyB) || !IsRandomEnough(config.IPv4KeyC) || !IsRandomEnough(config.IPv4KeyD) {
+		return "", errKeysNotRandomEnough
+	}
+
+	// get IP parts
+	address = address.To4()
+	partA := address[0]
+	partB := address[1]
+	partC := address[2]
+	partD := address[3]
+
+	// cloak `a` part of IP address.
+	data := fmt.Sprintf("%d", partA)
+	partAHashed := hashOctet(config.IPv4KeyA, data)[:partLength]
+
+	// cloak `b` part of IP address.
+	data = fmt.Sprintf("%d%d", partB, partA)
+	partBHashed := hashOctet(config.IPv4KeyB, data)[:partLength]
+
+	// cloak `c` part of IP address.
+	data = fmt.Sprintf("%d%d%d", partC, partB, partA)
+	partCHashed := hashOctet(config.IPv4KeyC, data)[:partLength]
+
+	// cloak `d` part of IP address.
+	data = fmt.Sprintf("%d%d%d%d", partD, partC, partB, partA)
+	partDHashed := hashOctet(config.IPv4KeyD, data)[:partLength]
+
+	return fmt.Sprintf("%s.%s.%s.%s.%s-cloaked", partAHashed, partBHashed, partCHashed, partDHashed, strings.ToLower(config.NetName)), nil
+}

irc/config.go

@@ -14,6 +14,7 @@ import (
 	"strings"
 	"time"
 
+	cloak "github.com/oragono/oragono/irc/cloaking"
 	"github.com/oragono/oragono/irc/custime"
 	"github.com/oragono/oragono/irc/logger"
 
@@ -188,6 +189,7 @@ type StackImpactConfig struct {
 type Config struct {
 	Network struct {
 		Name       string
+		IPCloaking cloak.Config `yaml:"ip-cloaking"`
 	}
 
 	Server struct {
@@ -418,6 +420,10 @@ func LoadConfig(filename string) (config *Config, err error) {
 			return nil, fmt.Errorf("STS port is incorrect, should be 0 if disabled: %d", config.Server.STS.Port)
 		}
 	}
+	err = config.Network.IPCloaking.CheckConfig()
+	if err != nil {
+		return nil, fmt.Errorf("Could not parse IP cloaking: %s", err.Error())
+	}
 	if config.Server.ConnectionThrottle.Enabled {
 		config.Server.ConnectionThrottle.Duration, err = time.ParseDuration(config.Server.ConnectionThrottle.DurationString)
 		if err != nil {

oragono.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/docopt/docopt-go"
 	"github.com/oragono/oragono/irc"
+	cloak "github.com/oragono/oragono/irc/cloaking"
 	"github.com/oragono/oragono/irc/logger"
 	"github.com/oragono/oragono/mkcerts"
 	stackimpact "github.com/stackimpact/stackimpact-go"
@@ -28,6 +29,7 @@ Usage:
 	oragono initdb [--conf <filename>] [--quiet]
 	oragono upgradedb [--conf <filename>] [--quiet]
 	oragono genpasswd [--conf <filename>] [--quiet]
+	oragono genkeys
 	oragono mkcerts [--conf <filename>] [--quiet]
 	oragono run [--conf <filename>] [--quiet]
 	oragono -h | --help
@@ -40,8 +42,13 @@ Options:
 
 	arguments, _ := docopt.Parse(usage, nil, true, version, false)
 
+	// load config and logger for everything but genkeys
+	var err error
 	configfile := arguments["--conf"].(string)
-	config, err := irc.LoadConfig(configfile)
+	var config *irc.Config
+	var logman *logger.Manager
+	if !arguments["genkeys"].(bool) {
+		config, err = irc.LoadConfig(configfile)
 		if err != nil {
 			log.Fatal("Config file did not load successfully:", err.Error())
 		}
@@ -60,10 +67,11 @@ Options:
 			})
 		}
 
-	logger, err := logger.NewManager(logConfigs...)
+		logman, err = logger.NewManager(logConfigs...)
 		if err != nil {
 			log.Fatal("Logger did not load successfully:", err.Error())
 		}
+	}
 
 	if arguments["genpasswd"].(bool) {
 		fmt.Print("Enter Password: ")
@@ -78,6 +86,65 @@ Options:
 		}
 		fmt.Print("\n")
 		fmt.Println(encoded)
+	} else if arguments["genkeys"].(bool) {
+		fmt.Println("Here are your cloak keys:")
+
+		// generate IPv4 keys
+		keyA, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyB, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyC, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyD, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+
+		fmt.Println(fmt.Sprintf(`ipv4-keys: ["%s", "%s", "%s", "%s"]`, keyA, keyB, keyC, keyD))
+
+		// generate IPv6 keys
+		keyA, err = cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyB, err = cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyC, err = cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyD, err = cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyE, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyF, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyG, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+		keyH, err := cloak.GenerateCloakKey()
+		if err != nil {
+			log.Fatal("Error generating cloak keys:", err)
+		}
+
+		fmt.Println(fmt.Sprintf(`ipv6-keys: ["%s", "%s", "%s", "%s", "%s", "%s", "%s", "%s"]`, keyA, keyB, keyC, keyD, keyE, keyF, keyG, keyH))
+
 	} else if arguments["initdb"].(bool) {
 		irc.InitDB(config.Datastore.Path)
 		if !arguments["--quiet"].(bool) {
@@ -108,13 +175,13 @@ Options:
 	} else if arguments["run"].(bool) {
 		rand.Seed(time.Now().UTC().UnixNano())
 		if !arguments["--quiet"].(bool) {
-			logger.Info("startup", fmt.Sprintf("Oragono v%s starting", irc.SemVer))
+			logman.Info("startup", fmt.Sprintf("Oragono v%s starting", irc.SemVer))
 		}
 
 		// profiling
 		if config.Debug.StackImpact.Enabled {
 			if config.Debug.StackImpact.AgentKey == "" || config.Debug.StackImpact.AppName == "" {
-				logger.Error("startup", "Could not start StackImpact - agent-key or app-name are undefined")
+				logman.Error("startup", "Could not start StackImpact - agent-key or app-name are undefined")
 				return
 			}
 
@@ -122,22 +189,22 @@ Options:
 			agent.Start(stackimpact.Options{AgentKey: config.Debug.StackImpact.AgentKey, AppName: config.Debug.StackImpact.AppName})
 			defer agent.RecordPanic()
 
-			logger.Info("startup", fmt.Sprintf("StackImpact profiling started as %s", config.Debug.StackImpact.AppName))
+			logman.Info("startup", fmt.Sprintf("StackImpact profiling started as %s", config.Debug.StackImpact.AppName))
 		}
 
 		// warning if running a non-final version
 		if strings.Contains(irc.SemVer, "unreleased") {
-			logger.Warning("startup", "You are currently running an unreleased beta version of Oragono that may be unstable and could corrupt your database.\nIf you are running a production network, please download the latest build from https://oragono.io/downloads.html and run that instead.")
+			logman.Warning("startup", "You are currently running an unreleased beta version of Oragono that may be unstable and could corrupt your database.\nIf you are running a production network, please download the latest build from https://oragono.io/downloads.html and run that instead.")
 		}
 
-		server, err := irc.NewServer(configfile, config, logger)
+		server, err := irc.NewServer(configfile, config, logman)
 		if err != nil {
-			logger.Error("startup", fmt.Sprintf("Could not load server: %s", err.Error()))
+			logman.Error("startup", fmt.Sprintf("Could not load server: %s", err.Error()))
 			return
 		}
 		if !arguments["--quiet"].(bool) {
-			logger.Info("startup", "Server running")
-			defer logger.Info("shutdown", fmt.Sprintf("Oragono v%s exiting", irc.SemVer))
+			logman.Info("startup", "Server running")
+			defer logman.Info("shutdown", fmt.Sprintf("Oragono v%s exiting", irc.SemVer))
 		}
 		server.Run()
 	}

oragono.yaml

@@ -5,6 +5,26 @@ network:
     # name of the network
     name: OragonoTest
 
+    # cloaking IP addresses and hostnames
+    ip-cloaking:
+        # enable the cloaking
+        enabled: false
+
+        # short name to use in cloaked hostnames
+        netname: "testnet"
+
+        # ipv4 cloak keys
+        # to generate these keys, run "oragono genkeys"
+        ipv4-keys: ["keyhere", "keyhere", "keyhere", "keyhere"]
+
+        # ipv6 cloak keys
+        # to generate these keys, run "oragono genkeys"
+        ipv6-keys: ["keyhere", "keyhere", "keyhere", "keyhere", "keyhere", "keyhere", "keyhere", "keyhere"]
+
+        # hostname cloaking keys
+        # to generate these keys, run "oragono genkeys"
+        hostname-keys: ["keyhere", "keyhere", "keyhere", "keyhere"]
+
 # server configuration
 server:
     # server name