[auditbeat] fim: implement kprobes backend

CHANGELOG.next.asciidoc

@@ -18,6 +18,7 @@ you can achieve this by overwriting the value using an `add_fields` processor. {
 
 *Auditbeat*
 
+- Add opt-in `KProbes` backend for file_integrity module. {pull}37796[37796]
 
 *Filebeat*
 

NOTICE.txt

@@ -15825,6 +15825,218 @@ Contents of probable licence file $GOMODCACHE/github.com/elastic/mito@v1.8.0/LIC
    limitations under the License.
 
 
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+Dependency : github.com/elastic/tk-btf
+Version: v0.1.0
+Licence type (autodetected): Apache-2.0
+--------------------------------------------------------------------------------
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 --------------------------------------------------------------------------------
 Dependency : github.com/elastic/toutoumomoma
 Version: v0.0.0-20221026030040-594ef30cb640

auditbeat/auditbeat.reference.yml

@@ -92,6 +92,10 @@ auditbeat.modules:
   # Auditbeat will ignore files unless they match a pattern.
   #include_files:
   #- '/\.ssh($|/)'
+  # Select the backend which will be used to source events.
+  # Valid values: ebpf, kprobes, fsnotify.
+  # Default: fsnotify.
+  force_backend: fsnotify
 
   # Scan over the configured file paths at startup and send events for new or
   # modified files since the last time Auditbeat was running.

auditbeat/docker-compose.yml

@@ -14,6 +14,7 @@ services:
       - KIBANA_PORT=5601
     volumes:
       - ${PWD}/..:/go/src/github.com/elastic/beats/
+      - /sys:/sys
     command: make
     privileged: true
     pid: host

auditbeat/docs/modules/file_integrity.asciidoc

@@ -28,8 +28,12 @@ to only send events for new or modified files.
 
 The operating system features that power this feature are as follows.
 
-* Linux - `inotify` is used, and therefore the kernel must have inotify support.
-Inotify was initially merged into the 2.6.13 Linux kernel.
+* Linux - As of now, three kernel backends are supported: `ebpf`, `kprobes` and `fsnotify`.
+By default, `fsnotify` is used, and therefore the kernel must have inotify support.
+`Inotify` was initially merged into the 2.6.13 Linux kernel.
+The `Kprobes` backend uses tracefs and supports 3.10+ kernels.
+The `eBPF` backend uses modern eBPF features and supports 5.10.16+ kernels.
+The preferred backend can be selected by specifying the `force_backend` config option.
 * macOS (Darwin) - Uses the `FSEvents` API, present since macOS 10.5. This API
 coalesces multiple changes to a file into a single event. {beatname_uc} translates
 this coalesced changes into a meaningful sequence of actions. However,

auditbeat/module/file_integrity/_meta/config.yml.tmpl

@@ -55,6 +55,13 @@
   #- '/\.ssh($|/)'
   {{- end }}
 
+  {{- if eq .GOOS "linux" }}
+  # Select the backend which will be used to source events.
+  # Valid values: ebpf, kprobes, fsnotify.
+  # Default: fsnotify.
+  force_backend: fsnotify
+  {{- end }}
+
   # Scan over the configured file paths at startup and send events for new or
   # modified files since the last time Auditbeat was running.
   scan_at_start: true

auditbeat/module/file_integrity/_meta/docs.asciidoc

@@ -21,8 +21,12 @@ to only send events for new or modified files.
 
 The operating system features that power this feature are as follows.
 
-* Linux - `inotify` is used, and therefore the kernel must have inotify support.
-Inotify was initially merged into the 2.6.13 Linux kernel.
+* Linux - As of now, three kernel backends are supported: `ebpf`, `kprobes` and `fsnotify`.
+By default, `fsnotify` is used, and therefore the kernel must have inotify support.
+`Inotify` was initially merged into the 2.6.13 Linux kernel.
+The `Kprobes` backend uses tracefs and supports 3.10+ kernels.
+The `eBPF` backend uses modern eBPF features and supports 5.10.16+ kernels.
+The preferred backend can be selected by specifying the `force_backend` config option.
 * macOS (Darwin) - Uses the `FSEvents` API, present since macOS 10.5. This API
 coalesces multiple changes to a file into a single event. {beatname_uc} translates
 this coalesced changes into a meaningful sequence of actions. However,

auditbeat/module/file_integrity/config.go

@@ -18,10 +18,12 @@
 package file_integrity
 
 import (
+	"errors"
 	"fmt"
 	"math"
 	"path/filepath"
 	"regexp"
+	"runtime"
 	"sort"
 	"strings"
 
@@ -72,6 +74,19 @@ const (
 	XXH64       HashType = "xxh64"
 )
 
+type Backend string
+
+const (
+	BackendFSNotify Backend = "fsnotify"
+	BackendEBPF     Backend = "ebpf"
+	BackendKProbes  Backend = "kprobes"
+)
+
+func (b *Backend) Unpack(v string) error {
+	*b = Backend(v)
+	return nil
+}
+
 // Config contains the configuration parameters for the file integrity
 // metricset.
 type Config struct {
@@ -86,6 +101,7 @@ type Config struct {
 	Recursive           bool            `config:"recursive"` // Recursive enables recursive monitoring of directories.
 	ExcludeFiles        []match.Matcher `config:"exclude_files"`
 	IncludeFiles        []match.Matcher `config:"include_files"`
+	ForceBackend        Backend         `config:"force_backend"`
 }
 
 // Validate validates the config data and return an error explaining all the
@@ -160,6 +176,19 @@ nextHash:
 	if err != nil {
 		errs = append(errs, fmt.Errorf("invalid scan_rate_per_sec value: %w", err))
 	}
+
+	if len(c.ForceBackend) > 0 {
+		if runtime.GOOS != "linux" {
+			errs = append(errs, errors.New("force_backend can only be specified on linux"))
+		}
+
+		switch c.ForceBackend {
+		case BackendEBPF, BackendKProbes, BackendFSNotify:
+		default:
+			errs = append(errs, errors.New("force_backend can only be 'ebpf', 'kprobes' or 'fsnotify'"))
+		}
+	}
+
 	return errs.Err()
 }
 

auditbeat/module/file_integrity/event.go

@@ -62,14 +62,19 @@ func (s Source) MarshalText() ([]byte, error) { return []byte(s.String()), nil }
 const (
 	// SourceScan identifies events triggered by a file system scan.
 	SourceScan Source = iota
-	// SourceFSNotify identifies events triggered by a notification from the
-	// file system.
+	// SourceFSNotify identifies file integrity events triggered by fsnotify backend.
 	SourceFSNotify
+	// SourceEBPF identifies file integrity events triggered by eBPF backend.
+	SourceEBPF
+	// SourceKProbes identifies file integrity events triggered by KProbes backend.
+	SourceKProbes
 )
 
 var sourceNames = map[Source]string{
 	SourceScan:     "scan",
 	SourceFSNotify: "fsnotify",
+	SourceEBPF:     "ebpf",
+	SourceKProbes:  "kprobes",
 }
 
 // Type identifies the file type (e.g. dir, file, symlink).