cwinfo/yggdrasil-go
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Merge pull request #432 from neilalexander/gatekeeper

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Implement session gatekeeper functions
This commit is contained in:
Neil Alexander 2019-06-13 23:41:42 +01:00 committed by GitHub
commit 2fd3ac6837
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3 changed files with 113 additions and 86 deletions
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85
cmd/yggdrasil/main.go
View File

@ -2,6 +2,7 @@ package main
import (
"bytes"
"encoding/hex"
"encoding/json"
"flag"
"fmt"
@ -20,22 +21,21 @@ import (
"github.com/yggdrasil-network/yggdrasil-go/src/admin"
"github.com/yggdrasil-network/yggdrasil-go/src/config"
"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
"github.com/yggdrasil-network/yggdrasil-go/src/multicast"
"github.com/yggdrasil-network/yggdrasil-go/src/tuntap"
"github.com/yggdrasil-network/yggdrasil-go/src/yggdrasil"
)
type nodeConfig = config.NodeConfig
type Core = yggdrasil.Core
type node struct {
core Core
core yggdrasil.Core
state *config.NodeState
tuntap tuntap.TunAdapter
multicast multicast.Multicast
admin admin.AdminSocket
}
func readConfig(useconf *bool, useconffile *string, normaliseconf *bool) *nodeConfig {
func readConfig(useconf *bool, useconffile *string, normaliseconf *bool) *config.NodeConfig {
// Use a configuration file. If -useconf, the configuration will be read
// from stdin. If -useconffile, the configuration will be read from the
// filesystem.
@ -116,7 +116,7 @@ func main() {
logging := flag.String("logging", "info,warn,error", "comma-separated list of logging levels to enable")
flag.Parse()
var cfg *nodeConfig
var cfg *config.NodeConfig
var err error
switch {
case *version:
@ -181,18 +181,20 @@ func main() {
n := node{}
// Now start Yggdrasil - this starts the DHT, router, switch and other core
// components needed for Yggdrasil to operate
state, err := n.core.Start(cfg, logger)
n.state, err = n.core.Start(cfg, logger)
if err != nil {
logger.Errorln("An error occurred during startup")
panic(err)
}
// Register the session firewall gatekeeper function
n.core.SetSessionGatekeeper(n.sessionFirewall)
// Start the admin socket
n.admin.Init(&n.core, state, logger, nil)
n.admin.Init(&n.core, n.state, logger, nil)
if err := n.admin.Start(); err != nil {
logger.Errorln("An error occurred starting admin socket:", err)
}
// Start the multicast interface
n.multicast.Init(&n.core, state, logger, nil)
n.multicast.Init(&n.core, n.state, logger, nil)
if err := n.multicast.Start(); err != nil {
logger.Errorln("An error occurred starting multicast:", err)
}
@ -200,7 +202,7 @@ func main() {
// Start the TUN/TAP interface
if listener, err := n.core.ConnListen(); err == nil {
if dialer, err := n.core.ConnDialer(); err == nil {
n.tuntap.Init(state, logger, listener, dialer)
n.tuntap.Init(n.state, logger, listener, dialer)
if err := n.tuntap.Start(); err != nil {
logger.Errorln("An error occurred starting TUN/TAP:", err)
}
@ -251,3 +253,66 @@ func main() {
}
exit:
}
func (n *node) sessionFirewall(pubkey *crypto.BoxPubKey, initiator bool) bool {
n.state.Mutex.RLock()
defer n.state.Mutex.RUnlock()
// Allow by default if the session firewall is disabled
if !n.state.Current.SessionFirewall.Enable {
return true
}
// Prepare for checking whitelist/blacklist
var box crypto.BoxPubKey
// Reject blacklisted nodes
for _, b := range n.state.Current.SessionFirewall.BlacklistEncryptionPublicKeys {
key, err := hex.DecodeString(b)
if err == nil {
copy(box[:crypto.BoxPubKeyLen], key)
if box == *pubkey {
return false
}
}
}
// Allow whitelisted nodes
for _, b := range n.state.Current.SessionFirewall.WhitelistEncryptionPublicKeys {
key, err := hex.DecodeString(b)
if err == nil {
copy(box[:crypto.BoxPubKeyLen], key)
if box == *pubkey {
return true
}
}
}
// Allow outbound sessions if appropriate
if n.state.Current.SessionFirewall.AlwaysAllowOutbound {
if initiator {
return true
}
}
// Look and see if the pubkey is that of a direct peer
var isDirectPeer bool
for _, peer := range n.core.GetPeers() {
if peer.PublicKey == *pubkey {
isDirectPeer = true
break
}
}
// Allow direct peers if appropriate
if n.state.Current.SessionFirewall.AllowFromDirect && isDirectPeer {
return true
}
// Allow remote nodes if appropriate
if n.state.Current.SessionFirewall.AllowFromRemote && !isDirectPeer {
return true
}
// Finally, default-deny if not matching any of the above rules
return false
}

13
src/yggdrasil/api.go
View File

@ -395,6 +395,19 @@ func (c *Core) GetNodeInfo(keyString, coordString string, nocache bool) (NodeInf
return NodeInfoPayload{}, errors.New(fmt.Sprintf("getNodeInfo timeout: %s", keyString))
}
// SetSessionGatekeeper allows you to configure a handler function for deciding
// whether a session should be allowed or not. The default session firewall is
// implemented in this way. The function receives the public key of the remote
// side and a boolean which is true if we initiated the session or false if we
// received an incoming session request. The function should return true to
// allow the session or false to reject it.
func (c *Core) SetSessionGatekeeper(f func(pubkey *crypto.BoxPubKey, initiator bool) bool) {
c.sessions.isAllowedMutex.Lock()
defer c.sessions.isAllowedMutex.Unlock()
c.sessions.isAllowedHandler = f
}
// SetLogger sets the output logger of the Yggdrasil node after startup. This
// may be useful if you want to redirect the output later.
func (c *Core) SetLogger(log *log.Logger) {

101
src/yggdrasil/session.go
View File

@ -6,7 +6,6 @@ package yggdrasil
import (
"bytes"
"encoding/hex"
"sync"
"time"
@ -111,18 +110,20 @@ func (s *sessionInfo) update(p *sessionPing) bool {
// Sessions are indexed by handle.
// Additionally, stores maps of address/subnet onto keys, and keys onto handles.
type sessions struct {
core *Core
listener *Listener
listenerMutex sync.Mutex
reconfigure chan chan error
lastCleanup time.Time
permShared map[crypto.BoxPubKey]*crypto.BoxSharedKey // Maps known permanent keys to their shared key, used by DHT a lot
sinfos map[crypto.Handle]*sessionInfo // Maps (secret) handle onto session info
conns map[crypto.Handle]*Conn // Maps (secret) handle onto connections
byMySes map[crypto.BoxPubKey]*crypto.Handle // Maps mySesPub onto handle
byTheirPerm map[crypto.BoxPubKey]*crypto.Handle // Maps theirPermPub onto handle
addrToPerm map[address.Address]*crypto.BoxPubKey
subnetToPerm map[address.Subnet]*crypto.BoxPubKey
core *Core
listener *Listener
listenerMutex sync.Mutex
reconfigure chan chan error
lastCleanup time.Time
isAllowedHandler func(pubkey *crypto.BoxPubKey, initiator bool) bool // Returns true or false if session setup is allowed
isAllowedMutex sync.RWMutex // Protects the above
permShared map[crypto.BoxPubKey]*crypto.BoxSharedKey // Maps known permanent keys to their shared key, used by DHT a lot
sinfos map[crypto.Handle]*sessionInfo // Maps (secret) handle onto session info
conns map[crypto.Handle]*Conn // Maps (secret) handle onto connections
byMySes map[crypto.BoxPubKey]*crypto.Handle // Maps mySesPub onto handle
byTheirPerm map[crypto.BoxPubKey]*crypto.Handle // Maps theirPermPub onto handle
addrToPerm map[address.Address]*crypto.BoxPubKey
subnetToPerm map[address.Subnet]*crypto.BoxPubKey
}
// Initializes the session struct.
@ -155,70 +156,17 @@ func (ss *sessions) init(core *Core) {
ss.lastCleanup = time.Now()
}
// Determines whether the session firewall is enabled.
func (ss *sessions) isSessionFirewallEnabled() bool {
ss.core.config.Mutex.RLock()
defer ss.core.config.Mutex.RUnlock()
return ss.core.config.Current.SessionFirewall.Enable
}
// Determines whether the session with a given publickey is allowed based on
// session firewall rules.
func (ss *sessions) isSessionAllowed(pubkey *crypto.BoxPubKey, initiator bool) bool {
ss.core.config.Mutex.RLock()
defer ss.core.config.Mutex.RUnlock()
ss.isAllowedMutex.RLock()
defer ss.isAllowedMutex.RUnlock()
// Allow by default if the session firewall is disabled
if !ss.isSessionFirewallEnabled() {
if ss.isAllowedHandler == nil {
return true
}
// Prepare for checking whitelist/blacklist
var box crypto.BoxPubKey
// Reject blacklisted nodes
for _, b := range ss.core.config.Current.SessionFirewall.BlacklistEncryptionPublicKeys {
key, err := hex.DecodeString(b)
if err == nil {
copy(box[:crypto.BoxPubKeyLen], key)
if box == *pubkey {
return false
}
}
}
// Allow whitelisted nodes
for _, b := range ss.core.config.Current.SessionFirewall.WhitelistEncryptionPublicKeys {
key, err := hex.DecodeString(b)
if err == nil {
copy(box[:crypto.BoxPubKeyLen], key)
if box == *pubkey {
return true
}
}
}
// Allow outbound sessions if appropriate
if ss.core.config.Current.SessionFirewall.AlwaysAllowOutbound {
if initiator {
return true
}
}
// Look and see if the pubkey is that of a direct peer
var isDirectPeer bool
for _, peer := range ss.core.peers.ports.Load().(map[switchPort]*peer) {
if peer.box == *pubkey {
isDirectPeer = true
break
}
}
// Allow direct peers if appropriate
if ss.core.config.Current.SessionFirewall.AllowFromDirect && isDirectPeer {
return true
}
// Allow remote nodes if appropriate
if ss.core.config.Current.SessionFirewall.AllowFromRemote && !isDirectPeer {
return true
}
// Finally, default-deny if not matching any of the above rules
return false
return ss.isAllowedHandler(pubkey, initiator)
}
// Gets the session corresponding to a given handle.
@ -271,6 +219,7 @@ func (ss *sessions) getByTheirSubnet(snet *address.Subnet) (*sessionInfo, bool)
// includse initializing session info to sane defaults (e.g. lowest supported
// MTU).
func (ss *sessions) createSession(theirPermKey *crypto.BoxPubKey) *sessionInfo {
// TODO: this check definitely needs to be moved
if !ss.isSessionAllowed(theirPermKey, true) {
return nil
}
@ -444,12 +393,12 @@ func (ss *sessions) sendPingPong(sinfo *sessionInfo, isPong bool) {
func (ss *sessions) handlePing(ping *sessionPing) {
// Get the corresponding session (or create a new session)
sinfo, isIn := ss.getByTheirPerm(&ping.SendPermPub)
// Check the session firewall
if !isIn && ss.isSessionFirewallEnabled() {
if !ss.isSessionAllowed(&ping.SendPermPub, false) {
return
}
// Check if the session is allowed
// TODO: this check may need to be moved
if !isIn && !ss.isSessionAllowed(&ping.SendPermPub, false) {
return
}
// Create the session if it doesn't already exist
if !isIn {
ss.createSession(&ping.SendPermPub)
sinfo, isIn = ss.getByTheirPerm(&ping.SendPermPub)