cwinfo/yggdrasil-go
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Add SetSessionGatekeeper

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This allows you to define a function which determines whether a session connection (either incoming or outgoing) is allowed based on the public key.
This commit is contained in:
Neil Alexander 2019-06-11 10:52:21 +01:00
parent d4a3b2bc76
commit 720a078a35
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GPG Key ID: A02A2019A2BB0944
2 changed files with 35 additions and 76 deletions
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12
src/yggdrasil/api.go
View File

@ -395,6 +395,18 @@ 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.
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) {

99
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.
@ -444,12 +392,11 @@ 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
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)