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|
// Package session manages secure communication sessions with Forward Secrecy
package session
import (
"crypto/rand"
"encoding/hex"
"fmt"
"sync"
"time"
"github.com/flynn/noise"
)
// Session represents a secure communication session
type Session struct {
ID string
RemotePubKey string // Remote peer's public key (hex)
HandshakeState *noise.HandshakeState
CipherState *noise.CipherState
CreatedAt time.Time
LastActivity time.Time
IsInitiator bool
}
// SessionManager manages multiple sessions
type SessionManager struct {
sessions map[string]*Session // key = session ID
mu sync.RWMutex
}
// NewSessionManager creates a new session manager
func NewSessionManager() *SessionManager {
return &SessionManager{
sessions: make(map[string]*Session),
}
}
// CreateSession creates a new Noise Protocol session
func (sm *SessionManager) CreateSession(remotePubKey string, isInitiator bool) (*Session, error) {
sm.mu.Lock()
defer sm.mu.Unlock()
// Generate session ID
sessionID := generateSessionID()
// Create Noise handshake configuration
// Using Noise_XX_25519_ChaChaPoly_BLAKE2b pattern for mutual authentication
var hs *noise.HandshakeState
var err error
config := noise.Config{
CipherSuite: noise.NewCipherSuite(noise.DH25519, noise.CipherChaChaPoly, noise.HashBLAKE2b),
Pattern: noise.HandshakeXX,
Initiator: isInitiator,
}
// Generate ephemeral keypair
keypair, err := noise.DH25519.GenerateKeypair(rand.Reader)
if err != nil {
return nil, fmt.Errorf("failed to generate keypair: %w", err)
}
config.KeyPair = keypair
hs, err = noise.NewHandshakeState(config)
if err != nil {
return nil, fmt.Errorf("failed to create handshake state: %w", err)
}
session := &Session{
ID: sessionID,
RemotePubKey: remotePubKey,
HandshakeState: hs,
CreatedAt: time.Now(),
LastActivity: time.Now(),
IsInitiator: isInitiator,
}
sm.sessions[sessionID] = session
return session, nil
}
// GetSession retrieves a session by ID
func (sm *SessionManager) GetSession(sessionID string) (*Session, bool) {
sm.mu.RLock()
defer sm.mu.RUnlock()
session, exists := sm.sessions[sessionID]
return session, exists
}
// RemoveSession removes a session and securely wipes it
func (sm *SessionManager) RemoveSession(sessionID string) {
sm.mu.Lock()
defer sm.mu.Unlock()
if session, exists := sm.sessions[sessionID]; exists {
session.SecureWipe()
delete(sm.sessions, sessionID)
}
}
// SecureWipeAll securely wipes all sessions
func (sm *SessionManager) SecureWipeAll() {
sm.mu.Lock()
defer sm.mu.Unlock()
for _, session := range sm.sessions {
session.SecureWipe()
}
sm.sessions = make(map[string]*Session)
}
// ListSessions returns all active sessions
func (sm *SessionManager) ListSessions() []*Session {
sm.mu.RLock()
defer sm.mu.RUnlock()
sessions := make([]*Session, 0, len(sm.sessions))
for _, session := range sm.sessions {
sessions = append(sessions, session)
}
return sessions
}
// CleanupExpiredSessions removes sessions older than the specified duration
func (sm *SessionManager) CleanupExpiredSessions(maxAge time.Duration) int {
sm.mu.Lock()
defer sm.mu.Unlock()
now := time.Now()
removed := 0
for id, session := range sm.sessions {
if now.Sub(session.LastActivity) > maxAge {
session.SecureWipe()
delete(sm.sessions, id)
removed++
}
}
return removed
}
// UpdateActivity updates the last activity timestamp
func (sm *SessionManager) UpdateActivity(sessionID string) {
sm.mu.Lock()
defer sm.mu.Unlock()
if session, exists := sm.sessions[sessionID]; exists {
session.LastActivity = time.Now()
}
}
// Count returns the number of active sessions
func (sm *SessionManager) Count() int {
sm.mu.RLock()
defer sm.mu.RUnlock()
return len(sm.sessions)
}
// SecureWipe zeros out sensitive session data
func (s *Session) SecureWipe() {
// Wipe cipher state if exists
if s.CipherState != nil {
// Noise library doesn't expose key wiping, but we can nil the reference
s.CipherState = nil
}
// Wipe handshake state
if s.HandshakeState != nil {
s.HandshakeState = nil
}
// Zero out session ID
s.ID = ""
s.RemotePubKey = ""
}
// generateSessionID generates a random session ID
func generateSessionID() string {
id := make([]byte, 16)
rand.Read(id)
return hex.EncodeToString(id)
}
// String returns a safe string representation
func (s *Session) String() string {
role := "responder"
if s.IsInitiator {
role = "initiator"
}
return fmt.Sprintf("Session(id=%s, role=%s, remote=%s...)",
s.ID[:8], role, s.RemotePubKey[:16])
}
// String returns session manager info
func (sm *SessionManager) String() string {
sm.mu.RLock()
defer sm.mu.RUnlock()
return fmt.Sprintf("SessionManager(active=%d)", len(sm.sessions))
}
|
