mirror of
https://github.com/crowdsecurity/crowdsec.git
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320 lines
8.9 KiB
Go
320 lines
8.9 KiB
Go
package wineventlogacquisition
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import (
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"encoding/xml"
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"errors"
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"fmt"
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"runtime"
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"strings"
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"syscall"
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"time"
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"github.com/crowdsecurity/crowdsec/pkg/acquisition/configuration"
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leaky "github.com/crowdsecurity/crowdsec/pkg/leakybucket"
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"github.com/crowdsecurity/crowdsec/pkg/types"
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"github.com/google/winops/winlog"
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"github.com/google/winops/winlog/wevtapi"
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"github.com/prometheus/client_golang/prometheus"
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log "github.com/sirupsen/logrus"
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"golang.org/x/sys/windows"
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"gopkg.in/tomb.v2"
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"gopkg.in/yaml.v2"
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)
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type WinEventLogConfiguration struct {
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configuration.DataSourceCommonCfg `yaml:",inline"`
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EventChannel string `yaml:"event_channel"`
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EventLevel string `yaml:"event_level"`
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EventIDs []int `yaml:"event_ids"`
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XPathQuery string `yaml:"xpath_query"`
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EventFile string `yaml:"event_file"`
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PrettyName string `yaml:"pretty_name"`
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}
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type WinEventLogSource struct {
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config WinEventLogConfiguration
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logger *log.Entry
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evtConfig *winlog.SubscribeConfig
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query string
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name string
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}
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type QueryList struct {
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Select Select `xml:"Query>Select"`
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}
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type Select struct {
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Path string `xml:"Path,attr"`
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Query string `xml:",chardata"`
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}
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var linesRead = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "cs_winevtlogsource_hits_total",
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Help: "Total event that were read.",
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},
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[]string{"source"})
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func logLevelToInt(logLevel string) ([]string, error) {
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switch strings.ToUpper(logLevel) {
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case "CRITICAL":
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return []string{"1"}, nil
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case "ERROR":
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return []string{"2"}, nil
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case "WARNING":
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return []string{"3"}, nil
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case "INFORMATION":
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return []string{"0", "4"}, nil
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case "VERBOSE":
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return []string{"5"}, nil
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default:
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return nil, errors.New("invalid log level")
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}
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}
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//This is lifted from winops/winlog, but we only want to render the basic XML string, we don't need the extra fluff
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func (w *WinEventLogSource) getXMLEvents(config *winlog.SubscribeConfig, publisherCache map[string]windows.Handle, resultSet windows.Handle, maxEvents int) ([]string, error) {
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var events = make([]windows.Handle, maxEvents)
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var returned uint32
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// Get handles to events from the result set.
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err := wevtapi.EvtNext(
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resultSet, // Handle to query or subscription result set.
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uint32(len(events)), // The number of events to attempt to retrieve.
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&events[0], // Pointer to the array of event handles.
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2000, // Timeout in milliseconds to wait.
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0, // Reserved. Must be zero.
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&returned) // The number of handles in the array that are set by the API.
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if err == windows.ERROR_NO_MORE_ITEMS {
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return nil, err
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} else if err != nil {
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return nil, fmt.Errorf("wevtapi.EvtNext failed: %v", err)
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}
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// Event handles must be closed after they are returned by EvtNext whether or not we use them.
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defer func() {
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for _, event := range events[:returned] {
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winlog.Close(event)
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}
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}()
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// Render events.
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var renderedEvents []string
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for _, event := range events[:returned] {
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// Render the basic XML representation of the event.
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fragment, err := winlog.RenderFragment(event, wevtapi.EvtRenderEventXml)
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if err != nil {
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w.logger.Errorf("Failed to render event with RenderFragment, skipping: %v", err)
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continue
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}
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w.logger.Tracef("Rendered event: %s", fragment)
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renderedEvents = append(renderedEvents, fragment)
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}
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return renderedEvents, err
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}
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func (w *WinEventLogSource) buildXpathQuery() (string, error) {
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var query string
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queryComponents := [][]string{}
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if w.config.EventIDs != nil {
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eventIds := []string{}
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for _, id := range w.config.EventIDs {
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eventIds = append(eventIds, fmt.Sprintf("EventID=%d", id))
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}
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queryComponents = append(queryComponents, eventIds)
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}
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if w.config.EventLevel != "" {
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levels, err := logLevelToInt(w.config.EventLevel)
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logLevels := []string{}
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if err != nil {
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return "", err
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}
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for _, level := range levels {
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logLevels = append(logLevels, fmt.Sprintf("Level=%s", level))
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}
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queryComponents = append(queryComponents, logLevels)
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}
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if len(queryComponents) > 0 {
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andList := []string{}
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for _, component := range queryComponents {
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andList = append(andList, fmt.Sprintf("(%s)", strings.Join(component, " or ")))
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}
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query = fmt.Sprintf("*[System[%s]]", strings.Join(andList, " and "))
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} else {
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query = "*"
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}
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queryList := QueryList{Select: Select{Path: w.config.EventChannel, Query: query}}
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xpathQuery, err := xml.Marshal(queryList)
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if err != nil {
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w.logger.Errorf("Marshal failed: %v", err)
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return "", err
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}
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w.logger.Debugf("xpathQuery: %s", xpathQuery)
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return string(xpathQuery), nil
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}
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func (w *WinEventLogSource) getEvents(out chan types.Event, t *tomb.Tomb) error {
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subscription, err := winlog.Subscribe(w.evtConfig)
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if err != nil {
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w.logger.Errorf("Failed to subscribe to event log: %s", err)
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return err
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}
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defer winlog.Close(subscription)
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publisherCache := make(map[string]windows.Handle)
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defer func() {
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for _, h := range publisherCache {
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winlog.Close(h)
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}
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}()
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for {
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select {
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case <-t.Dying():
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w.logger.Infof("wineventlog is dying")
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return nil
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default:
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status, err := windows.WaitForSingleObject(w.evtConfig.SignalEvent, 1000)
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if err != nil {
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w.logger.Errorf("WaitForSingleObject failed: %s", err)
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return err
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}
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if status == syscall.WAIT_OBJECT_0 {
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renderedEvents, err := w.getXMLEvents(w.evtConfig, publisherCache, subscription, 500)
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if err == windows.ERROR_NO_MORE_ITEMS {
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windows.ResetEvent(w.evtConfig.SignalEvent)
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} else if err != nil {
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w.logger.Errorf("getXMLEvents failed: %v", err)
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continue
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}
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for _, event := range renderedEvents {
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linesRead.With(prometheus.Labels{"source": w.name}).Inc()
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l := types.Line{}
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l.Raw = event
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l.Module = w.GetName()
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l.Labels = w.config.Labels
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l.Time = time.Now()
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l.Src = w.name
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l.Process = true
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if !w.config.UseTimeMachine {
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out <- types.Event{Line: l, Process: true, Type: types.LOG, ExpectMode: leaky.LIVE}
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} else {
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out <- types.Event{Line: l, Process: true, Type: types.LOG, ExpectMode: leaky.TIMEMACHINE}
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}
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}
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}
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}
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}
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}
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func (w *WinEventLogSource) generateConfig(query string) (*winlog.SubscribeConfig, error) {
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var config winlog.SubscribeConfig
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var err error
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// Create a subscription signaler.
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config.SignalEvent, err = windows.CreateEvent(
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nil, // Default security descriptor.
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1, // Manual reset.
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1, // Initial state is signaled.
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nil) // Optional name.
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if err != nil {
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return &config, fmt.Errorf("windows.CreateEvent failed: %v", err)
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}
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config.Flags = wevtapi.EvtSubscribeToFutureEvents
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config.Query, err = syscall.UTF16PtrFromString(query)
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if err != nil {
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return &config, fmt.Errorf("syscall.UTF16PtrFromString failed: %v", err)
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}
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return &config, nil
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}
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func (w *WinEventLogSource) Configure(yamlConfig []byte, logger *log.Entry) error {
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config := WinEventLogConfiguration{}
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w.logger = logger
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err := yaml.UnmarshalStrict(yamlConfig, &config)
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if err != nil {
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return fmt.Errorf("unable to parse configuration: %v", err)
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}
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if config.EventChannel != "" && config.XPathQuery != "" {
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return fmt.Errorf("event_channel and xpath_query are mutually exclusive")
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}
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if config.EventChannel == "" && config.XPathQuery == "" {
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return fmt.Errorf("event_channel or xpath_query must be set")
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}
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config.Mode = configuration.TAIL_MODE
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w.config = config
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if config.XPathQuery != "" {
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w.query = config.XPathQuery
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} else {
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w.query, err = w.buildXpathQuery()
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if err != nil {
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return fmt.Errorf("buildXpathQuery failed: %v", err)
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}
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}
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w.evtConfig, err = w.generateConfig(w.query)
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if err != nil {
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return err
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}
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if config.PrettyName != "" {
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w.name = config.PrettyName
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} else {
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w.name = w.query
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}
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return nil
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}
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func (w *WinEventLogSource) ConfigureByDSN(dsn string, labels map[string]string, logger *log.Entry) error {
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return nil
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}
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func (w *WinEventLogSource) GetMode() string {
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return w.config.Mode
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}
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func (w *WinEventLogSource) SupportedModes() []string {
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return []string{configuration.TAIL_MODE}
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}
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func (w *WinEventLogSource) OneShotAcquisition(out chan types.Event, t *tomb.Tomb) error {
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return nil
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}
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func (w *WinEventLogSource) GetMetrics() []prometheus.Collector {
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return []prometheus.Collector{linesRead}
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}
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func (w *WinEventLogSource) GetAggregMetrics() []prometheus.Collector {
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return []prometheus.Collector{linesRead}
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}
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func (w *WinEventLogSource) GetName() string {
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return "wineventlog"
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}
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func (w *WinEventLogSource) CanRun() error {
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if runtime.GOOS != "windows" {
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return errors.New("windows event log acquisition is only supported on Windows")
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}
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return nil
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}
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func (w *WinEventLogSource) StreamingAcquisition(out chan types.Event, t *tomb.Tomb) error {
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t.Go(func() error {
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defer types.CatchPanic("crowdsec/acquis/wineventlog/streaming")
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return w.getEvents(out, t)
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})
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return nil
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}
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func (w *WinEventLogSource) Dump() interface{} {
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return w
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}
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