tetragon: Add killer tests

Adding test for killer sensor and testing both killing
application matching the selector and overriding syscall
that matches the selector.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>

contrib/tester-progs/Makefile

@@ -15,7 +15,8 @@ PROGS = sigkill-tester \
 	uprobe-test-1 \
 	uprobe-test-2 \
 	lseek-pipe \
-	threads-tester
+	threads-tester \
+	killer-tester
 
 all: $(PROGS)
 

contrib/tester-progs/killer-tester.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include <sys/prctl.h>
+#include <errno.h>
+
+int main(void)
+{
+	prctl(0xffff, 0, 0, 0, 0);
+	return errno;
+}

pkg/sensors/tracing/killer_test.go

@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Authors of Tetragon
+
+package tracing
+
+import (
+	"context"
+	"os"
+	"os/exec"
+	"sync"
+	"syscall"
+	"testing"
+
+	"github.com/cilium/tetragon/api/v1/tetragon/codegen/eventchecker"
+	ec "github.com/cilium/tetragon/api/v1/tetragon/codegen/eventchecker"
+	"github.com/cilium/tetragon/pkg/bpf"
+	"github.com/cilium/tetragon/pkg/jsonchecker"
+	lc "github.com/cilium/tetragon/pkg/matchers/listmatcher"
+	"github.com/cilium/tetragon/pkg/observer/observertesthelper"
+	"github.com/cilium/tetragon/pkg/testutils"
+	tus "github.com/cilium/tetragon/pkg/testutils/sensors"
+	"github.com/stretchr/testify/assert"
+)
+
+func test_killer(t *testing.T, configHook string, test string,
+	checker *eventchecker.UnorderedEventChecker,
+	checkerFunc func(err error, rc int)) {
+
+	var doneWG, readyWG sync.WaitGroup
+	defer doneWG.Wait()
+
+	ctx, cancel := context.WithTimeout(context.Background(), tus.Conf().CmdWaitTime)
+	defer cancel()
+
+	err := os.WriteFile(testConfigFile, []byte(configHook), 0644)
+	if err != nil {
+		t.Fatalf("writeFile(%s): err %s", testConfigFile, err)
+	}
+
+	obs, err := observertesthelper.GetDefaultObserverWithFile(t, ctx, testConfigFile, tus.Conf().TetragonLib, observertesthelper.WithMyPid())
+	if err != nil {
+		t.Fatalf("GetDefaultObserverWithFile error: %s", err)
+	}
+	observertesthelper.LoopEvents(ctx, t, &doneWG, &readyWG, obs)
+	readyWG.Wait()
+
+	cmd := exec.Command(test)
+	err = cmd.Run()
+
+	checkerFunc(err, cmd.ProcessState.ExitCode())
+
+	err = jsonchecker.JsonTestCheck(t, checker)
+	assert.NoError(t, err)
+}
+
+func TestKillerOverride(t *testing.T) {
+	if !bpf.HasOverrideHelper() {
+		t.Skip("skipping killer test, bpf_override_return helper not available")
+	}
+
+	test := testutils.RepoRootPath("contrib/tester-progs/killer-tester")
+	configHook := `
+apiVersion: cilium.io/v1alpha1
+kind: TracingPolicy
+metadata:
+  name: "kill-syscalls"
+spec:
+  lists:
+  - name: "mine"
+    type: "syscalls"
+    values:
+    - "sys_prctl"
+  killers:
+  - syscalls:
+    - "list:mine"
+  tracepoints:
+  - subsystem: "raw_syscalls"
+    event: "sys_enter"
+    args:
+    - index: 4
+      type: "uint64"
+    selectors:
+    - matchArgs:
+      - index: 0
+        operator: "InMap"
+        values:
+        - "list:mine"
+      matchBinaries:
+      - operator: "In"
+        values:
+        - "` + test + `"
+      matchActions:
+      - action: "NotifyKiller"
+        argError: -17 # EEXIST
+`
+
+	tpChecker := ec.NewProcessTracepointChecker("").
+		WithArgs(ec.NewKprobeArgumentListMatcher().
+			WithOperator(lc.Ordered).
+			WithValues(
+				ec.NewKprobeArgumentChecker().WithSizeArg(syscall.SYS_PRCTL),
+			))
+
+	checker := ec.NewUnorderedEventChecker(tpChecker)
+
+	checkerFunc := func(err error, rc int) {
+		if rc != int(syscall.EEXIST) {
+			t.Fatalf("Wrong exit code %d expected %d", rc, int(syscall.EEXIST))
+		}
+	}
+
+	test_killer(t, configHook, test, checker, checkerFunc)
+}
+
+func TestKillerSignal(t *testing.T) {
+	if !bpf.HasOverrideHelper() {
+		t.Skip("skipping killer test, bpf_override_return helper not available")
+	}
+
+	test := testutils.RepoRootPath("contrib/tester-progs/killer-tester")
+	configHook := `
+apiVersion: cilium.io/v1alpha1
+kind: TracingPolicy
+metadata:
+  name: "kill-syscalls"
+spec:
+  lists:
+  - name: "mine"
+    type: "syscalls"
+    values:
+    - "sys_prctl"
+  killers:
+  - syscalls:
+    - "list:mine"
+  tracepoints:
+  - subsystem: "raw_syscalls"
+    event: "sys_enter"
+    args:
+    - index: 4
+      type: "uint64"
+    selectors:
+    - matchArgs:
+      - index: 0
+        operator: "InMap"
+        values:
+        - "list:mine"
+      matchBinaries:
+      - operator: "In"
+        values:
+        - "` + test + `"
+      matchActions:
+      - action: "NotifyKiller"
+        argSig: 9 # SIGKILL
+`
+
+	tpChecker := ec.NewProcessTracepointChecker("").
+		WithArgs(ec.NewKprobeArgumentListMatcher().
+			WithOperator(lc.Ordered).
+			WithValues(
+				ec.NewKprobeArgumentChecker().WithSizeArg(syscall.SYS_PRCTL),
+			))
+
+	checker := ec.NewUnorderedEventChecker(tpChecker)
+
+	checkerFunc := func(err error, rc int) {
+		if err == nil || err.Error() != "signal: killed" {
+			t.Fatalf("Wrong error '%v' expected 'killed'", err)
+		}
+	}
+
+	test_killer(t, configHook, test, checker, checkerFunc)
+}