[client] Rebuild the overlay listeners when the TUN is renewed (#7397)

client/ssh/auth/auth.go

@@ -3,6 +3,7 @@ package auth
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"sync"
 
 	log "github.com/sirupsen/logrus"
@@ -155,6 +156,24 @@ func (a *Authorizer) GetUserIDClaim() string {
 	return a.userIDClaim
 }
 
+// Config returns the authorization currently in force. The user list and the
+// machine-user map are copies; the originals stay in use here.
+func (a *Authorizer) Config() *Config {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+
+	machineUsers := make(map[string][]uint32, len(a.machineUsers))
+	for osUser, indexes := range a.machineUsers {
+		machineUsers[osUser] = slices.Clone(indexes)
+	}
+
+	return &Config{
+		UserIDClaim:     a.userIDClaim,
+		AuthorizedUsers: slices.Clone(a.authorizedUsers),
+		MachineUsers:    machineUsers,
+	}
+}
+
 // findUserIndex finds the index of a hashed user ID in the authorized users list
 // Returns the index and true if found, 0 and false if not found
 func (a *Authorizer) findUserIndex(hashedUserID sshuserhash.UserIDHash) (int, bool) {

client/ssh/server/server.go

@@ -197,6 +197,12 @@ type Config struct {
 
 	// HostKey is the SSH server host key in PEM format
 	HostKeyPEM []byte
+
+	// Auth is the fine-grained authorization to open with. Nil starts with an
+	// empty authorizer, which authorizes nobody until UpdateSSHAuth is called.
+	// Setting it here rather than afterwards means the server never accepts a
+	// login before it knows who is allowed.
+	Auth *sshauth.Config
 }
 
 // SessionInfo contains information about an active SSH session
@@ -220,7 +226,11 @@ func New(config *Config) *Server {
 		connections:            make(map[connKey]*connState),
 		jwtEnabled:             config.JWT != nil,
 		jwtConfig:              config.JWT,
-		authorizer:             sshauth.NewAuthorizer(), // Initialize with empty config
+		authorizer:             sshauth.NewAuthorizer(),
+	}
+
+	if config.Auth != nil {
+		s.authorizer.Update(config.Auth)
 	}
 
 	return s
@@ -461,6 +471,27 @@ func (s *Server) UpdateSSHAuth(config *sshauth.Config) {
 	s.authorizer.Update(config)
 }
 
+// JWTConfig returns the JWT authentication this server was built with, or nil
+// when JWT authentication is disabled.
+func (s *Server) JWTConfig() *JWTConfig {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.jwtConfig
+}
+
+// AuthConfig returns the fine-grained authorization currently in force, or nil
+// when the server has no authorizer.
+func (s *Server) AuthConfig() *sshauth.Config {
+	s.mu.RLock()
+	authorizer := s.authorizer
+	s.mu.RUnlock()
+
+	if authorizer == nil {
+		return nil
+	}
+	return authorizer.Config()
+}
+
 // ensureJWTValidator initializes the JWT validator and extractor if not already initialized
 func (s *Server) ensureJWTValidator() error {
 	s.mu.RLock()