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server.go
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server.go
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package osquery
import (
"context"
"fmt"
"sync"
"time"
"github.com/apache/thrift/lib/go/thrift"
"github.com/osquery/osquery-go/gen/osquery"
"github.com/osquery/osquery-go/traces"
"github.com/osquery/osquery-go/transport"
"github.com/pkg/errors"
)
type OsqueryPlugin interface {
// Name is the name used to refer to the plugin (eg. the name of the
// table the plugin implements).
Name() string
// RegistryName is which "registry" the plugin should be added to.
// Valid names are ["config", "logger", "table"].
RegistryName() string
// Routes returns the detailed information about the interface exposed
// by the plugin. See the example plugins for samples.
Routes() osquery.ExtensionPluginResponse
// Ping implements a health check for the plugin. If the plugin is in a
// healthy state, StatusOK should be returned.
Ping() osquery.ExtensionStatus
// Call requests the plugin to perform its defined behavior, returning
// a response containing the result.
Call(context.Context, osquery.ExtensionPluginRequest) osquery.ExtensionResponse
// Shutdown alerts the plugin to stop.
Shutdown()
}
type ExtensionManager interface {
Close()
Ping() (*osquery.ExtensionStatus, error)
Call(registry, item string, req osquery.ExtensionPluginRequest) (*osquery.ExtensionResponse, error)
Extensions() (osquery.InternalExtensionList, error)
RegisterExtension(info *osquery.InternalExtensionInfo, registry osquery.ExtensionRegistry) (*osquery.ExtensionStatus, error)
DeregisterExtension(uuid osquery.ExtensionRouteUUID) (*osquery.ExtensionStatus, error)
Options() (osquery.InternalOptionList, error)
Query(sql string) (*osquery.ExtensionResponse, error)
GetQueryColumns(sql string) (*osquery.ExtensionResponse, error)
}
const defaultTimeout = 1 * time.Second
const defaultPingInterval = 5 * time.Second
// ExtensionManagerServer is an implementation of the full ExtensionManager
// API. Plugins can register with an extension manager, which handles the
// communication with the osquery process.
type ExtensionManagerServer struct {
name string
version string
sockPath string
serverClient ExtensionManager
serverClientShouldShutdown bool // Whether to shutdown the client during server shutdown
registry map[string](map[string]OsqueryPlugin)
server thrift.TServer
transport thrift.TServerTransport
timeout time.Duration
pingInterval time.Duration // How often to ping osquery server
mutex sync.Mutex
uuid osquery.ExtensionRouteUUID
started bool // Used to ensure tests wait until the server is actually started
}
// validRegistryNames contains the allowable RegistryName() values. If a plugin
// attempts to register with another value, the program will panic.
var validRegistryNames = map[string]bool{
"table": true,
"logger": true,
"config": true,
"distributed": true,
}
type ServerOption func(*ExtensionManagerServer)
func ExtensionVersion(version string) ServerOption {
return func(s *ExtensionManagerServer) {
s.version = version
}
}
func ServerTimeout(timeout time.Duration) ServerOption {
return func(s *ExtensionManagerServer) {
s.timeout = timeout
}
}
func ServerPingInterval(interval time.Duration) ServerOption {
return func(s *ExtensionManagerServer) {
s.pingInterval = interval
}
}
// ServerSideConnectivityCheckInterval Sets a thrift package variable for the ticker
// interval used by connectivity check in thrift compiled TProcessorFunc implementations.
// See the thrift docs for more information
func ServerConnectivityCheckInterval(interval time.Duration) ServerOption {
return func(s *ExtensionManagerServer) {
s.mutex.Lock()
defer s.mutex.Unlock()
thrift.ServerConnectivityCheckInterval = interval
}
}
// WithClient sets the server to use an existing ExtensionManagerClient
// instead of creating a new one.
func WithClient(client ExtensionManager) ServerOption {
return func(s *ExtensionManagerServer) {
s.serverClient = client
}
}
// MaxSocketPathCharacters is set to 97 because a ".12345" uuid is added to the socket down stream
// if the provided socket is greater than 97 we may exceed the limit of 103 (104 causes an error)
// why 103 limit? https://unix.stackexchange.com/questions/367008/why-is-socket-path-length-limited-to-a-hundred-chars
const MaxSocketPathCharacters = 97
// NewExtensionManagerServer creates a new extension management server
// communicating with osquery over the socket at the provided path. If
// resolving the address or connecting to the socket fails, this function will
// error.
func NewExtensionManagerServer(name string, sockPath string, opts ...ServerOption) (*ExtensionManagerServer, error) {
if len(sockPath) > MaxSocketPathCharacters {
return nil, errors.Errorf("socket path %s (%d characters) exceeded the maximum socket path character length of %d", sockPath, len(sockPath), MaxSocketPathCharacters)
}
// Initialize nested registry maps
registry := make(map[string](map[string]OsqueryPlugin))
for reg := range validRegistryNames {
registry[reg] = make(map[string]OsqueryPlugin)
}
manager := &ExtensionManagerServer{
name: name,
sockPath: sockPath,
registry: registry,
timeout: defaultTimeout,
pingInterval: defaultPingInterval,
}
for _, opt := range opts {
opt(manager)
}
if manager.serverClient == nil {
serverClient, err := NewClient(sockPath, manager.timeout)
if err != nil {
if serverClient != nil {
serverClient.Close()
}
return nil, err
}
manager.serverClient = serverClient
manager.serverClientShouldShutdown = true
}
return manager, nil
}
// RegisterPlugin adds one or more OsqueryPlugins to this extension manager.
func (s *ExtensionManagerServer) RegisterPlugin(plugins ...OsqueryPlugin) {
s.mutex.Lock()
defer s.mutex.Unlock()
for _, plugin := range plugins {
if !validRegistryNames[plugin.RegistryName()] {
panic("invalid registry name: " + plugin.RegistryName())
}
s.registry[plugin.RegistryName()][plugin.Name()] = plugin
}
}
func (s *ExtensionManagerServer) genRegistry() osquery.ExtensionRegistry {
registry := osquery.ExtensionRegistry{}
for regName := range s.registry {
registry[regName] = osquery.ExtensionRouteTable{}
for _, plugin := range s.registry[regName] {
registry[regName][plugin.Name()] = plugin.Routes()
}
}
return registry
}
// Start registers the extension plugins and begins listening on a unix socket
// for requests from the osquery process. All plugins should be registered with
// RegisterPlugin() before calling Start().
func (s *ExtensionManagerServer) Start() error {
var server thrift.TServer
err := func() error {
s.mutex.Lock()
defer s.mutex.Unlock()
// check after the lock the serverClient is present. It could have gone away on very short restart loops
if s.serverClient == nil {
return errors.New("cannot start, shutdown in progress")
}
registry := s.genRegistry()
stat, err := s.serverClient.RegisterExtension(
&osquery.InternalExtensionInfo{
Name: s.name,
Version: s.version,
},
registry,
)
if err != nil {
return errors.Wrap(err, "registering extension")
}
if stat.Code != 0 {
return errors.Errorf("status %d registering extension: %s", stat.Code, stat.Message)
}
s.uuid = stat.UUID
listenPath := fmt.Sprintf("%s.%d", s.sockPath, stat.UUID)
processor := osquery.NewExtensionProcessor(s)
s.transport, err = transport.OpenServer(listenPath, s.timeout)
if err != nil {
openError := errors.Wrapf(err, "opening server socket (%s)", listenPath)
_, err = s.serverClient.DeregisterExtension(stat.UUID)
if err != nil {
return errors.Wrapf(err, "deregistering extension - follows %s", openError.Error())
}
return openError
}
s.server = thrift.NewTSimpleServer2(processor, s.transport)
server = s.server
s.started = true
return nil
}()
if err != nil {
return err
}
return server.Serve()
}
// Run starts the extension manager and runs until osquery calls for a shutdown
// or the osquery instance goes away.
func (s *ExtensionManagerServer) Run() error {
errc := make(chan error)
go func() {
errc <- s.Start()
}()
// Watch for the osquery process going away. If so, initiate shutdown.
go func() {
for {
time.Sleep(s.pingInterval)
s.mutex.Lock()
serverClient := s.serverClient
s.mutex.Unlock()
// can't ping if s.Shutdown has already happened
if serverClient == nil {
break
}
status, err := serverClient.Ping()
if err != nil {
errc <- errors.Wrap(err, "extension ping failed")
break
}
if status.Code != 0 {
errc <- errors.Errorf("ping returned status %d", status.Code)
break
}
}
}()
err := <-errc
_ = s.Shutdown(context.Background())
return err
}
// Ping implements the basic health check.
func (s *ExtensionManagerServer) Ping(ctx context.Context) (*osquery.ExtensionStatus, error) {
return &osquery.ExtensionStatus{Code: 0, Message: "OK"}, nil
}
// Call routes a call from the osquery process to the appropriate registered
// plugin.
func (s *ExtensionManagerServer) Call(ctx context.Context, registry string, item string, request osquery.ExtensionPluginRequest) (*osquery.ExtensionResponse, error) {
ctx, span := traces.StartSpan(ctx, "ExtensionManagerServer.Call",
"registry", registry,
"item", item,
)
defer span.End()
subreg, ok := s.registry[registry]
if !ok {
return &osquery.ExtensionResponse{
Status: &osquery.ExtensionStatus{
Code: 1,
Message: "Unknown registry: " + registry,
},
}, nil
}
plugin, ok := subreg[item]
if !ok {
return &osquery.ExtensionResponse{
Status: &osquery.ExtensionStatus{
Code: 1,
Message: "Unknown registry item: " + item,
},
}, nil
}
response := plugin.Call(ctx, request)
return &response, nil
}
// Shutdown deregisters the extension, stops the server and closes all sockets.
func (s *ExtensionManagerServer) Shutdown(ctx context.Context) (err error) {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.serverClient != nil {
var stat *osquery.ExtensionStatus
stat, err = s.serverClient.DeregisterExtension(s.uuid)
err = errors.Wrap(err, "deregistering extension")
if err == nil && stat.Code != 0 {
err = errors.Errorf("status %d deregistering extension: %s", stat.Code, stat.Message)
}
}
if s.server != nil {
server := s.server
s.server = nil
// Stop the server asynchronously so that the current request
// can complete. Otherwise, this is vulnerable to deadlock if a
// shutdown request is being processed when Shutdown is
// explicitly called.
go func() {
server.Stop()
}()
}
// Shutdown the client, if appropriate
if s.serverClientShouldShutdown && s.serverClient != nil {
s.serverClient.Close()
s.serverClient = nil
}
return
}
// Useful for testing
func (s *ExtensionManagerServer) waitStarted() {
for {
s.mutex.Lock()
started := s.started
s.mutex.Unlock()
if started {
time.Sleep(10 * time.Millisecond)
break
}
}
}