Run integration test triggers in own PID (#2323)

This is a change to the integration tests so that the commands
which are meant to trigger events that the tests look for, are
actually picked up by tracee. In order for this to happen,
the events can't be the same PID as tracee. This is accomplished
using syscall.ForkExec() which runs functions in a shell script.

Signed-off-by: grantseltzer <[email protected]>

Author: grantseltzer

tests/integration/integration_test.go

@@ -2,9 +2,10 @@ package integration
 
 import (
 	"context"
+	"io/ioutil"
 	"os"
-	"os/exec"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 
@@ -16,49 +17,23 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// // small set of actions to trigger a magic write event
-// func checkMagicwrite(t *testing.T, gotOutput *[]trace.Event) {
-// 	// create a temp dir for testing
-// 	d, err := ioutil.TempDir("", "Test_MagicWrite-dir-*")
-// 	require.NoError(t, err)
-
-// 	// cp a file to trigger
-// 	f, err := os.CreateTemp(d, "Test_MagicWrite-file-*")
-// 	require.NoError(t, err)
-// 	defer func() {
-// 		os.Remove(d)
-// 	}()
-
-// 	f.WriteString(`foo.bar.baz`)
-// 	f.Close()
-
-// 	cpCmd := exec.Command("cp", f.Name(), filepath.Join(d+filepath.Base(f.Name())+"-new"))
-// 	fmt.Println("executing: ", cpCmd.String())
-// 	cpCmd.Stdout = os.Stdout
-// 	assert.NoError(t, cpCmd.Run())
-
-// 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
-
-// 	// check tracee output
-// 	expect := []byte{102, 111, 111, 46, 98, 97, 114, 46, 98, 97, 122}
-// 	fail := true
-// 	for _, evt := range *gotOutput {
-// 		arg := events.GetArg(&evt, "bytes")
-// 		argVal, ok := arg.Value.([]byte)
-// 		require.Equal(t, true, ok)
-// 		ok = assert.ElementsMatch(t, argVal, expect)
-// 		if ok {
-// 			fail = false
-// 		}
-// 	}
-// 	if fail {
-// 		t.Fail()
-// 	}
-// }
+// small set of actions to trigger a magic write event
+func checkMagicwrite(t *testing.T, gotOutput *[]trace.Event) {
+
+	_, err := forkAndExecFunction(doMagicWrite)
+	require.NoError(t, err)
+
+	waitForTraceeOutput(t, gotOutput, time.Now(), true)
+
+	// check tracee output
+	for _, evt := range *gotOutput {
+		assert.Equal(t, []byte(evt.EventName), []byte("magic_write"))
+	}
+}
 
 // execute a ls command
 func checkExeccommand(t *testing.T, gotOutput *[]trace.Event) {
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
@@ -77,8 +52,7 @@ func checkExeccommand(t *testing.T, gotOutput *[]trace.Event) {
 func checkPidnew(t *testing.T, gotOutput *[]trace.Event) {
 	traceePid := os.Getpid()
 
-	// run a command
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
@@ -97,7 +71,7 @@ func checkPidnew(t *testing.T, gotOutput *[]trace.Event) {
 
 // only capture uids of 0 that are run by comm ls
 func checkUidZero(t *testing.T, gotOutput *[]trace.Event) {
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
@@ -117,7 +91,7 @@ func checkUidZero(t *testing.T, gotOutput *[]trace.Event) {
 
 // trigger ls from uid 0 (tests run as root) and check if empty
 func checkUidNonZero(t *testing.T, gotOutput *[]trace.Event) {
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), false)
@@ -128,7 +102,7 @@ func checkUidNonZero(t *testing.T, gotOutput *[]trace.Event) {
 
 // check that execve event is called
 func checkExecve(t *testing.T, gotOutput *[]trace.Event) {
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
@@ -150,7 +124,7 @@ func checkExecve(t *testing.T, gotOutput *[]trace.Event) {
 
 // check for filesystem set when ls is invoked
 func checkSetFs(t *testing.T, gotOutput *[]trace.Event) {
-	err := exec.Command("/usr/bin/ls").Run()
+	_, err := forkAndExecFunction(doLs)
 	require.NoError(t, err)
 
 	waitForTraceeOutput(t, gotOutput, time.Now(), true)
@@ -171,11 +145,9 @@ func checkSetFs(t *testing.T, gotOutput *[]trace.Event) {
 }
 
 func checkNewContainers(t *testing.T, gotOutput *[]trace.Event) {
-	containerIdBytes, err := exec.Command("docker", "run", "-d", "--rm", "alpine").Output()
+	containerIdBytes, err := forkAndExecFunction(doDockerRun)
 	require.NoError(t, err)
-
 	containerId := strings.TrimSuffix(string(containerIdBytes), "\n")
-
 	containerIds := []string{}
 	for _, evt := range *gotOutput {
 		containerIds = append(containerIds, evt.ContainerID)
@@ -202,11 +174,11 @@ func Test_EventFilters(t *testing.T) {
 		filterArgs []string
 		eventFunc  func(*testing.T, *[]trace.Event)
 	}{
-		// {
-		// 	name:       "do a file write",
-		// 	filterArgs: []string{"event=magic_write"},
-		// 	eventFunc:  checkMagicwrite,
-		// },
+		{
+			name:       "do a file write",
+			filterArgs: []string{"event=magic_write"},
+			eventFunc:  checkMagicwrite,
+		},
 		{
 			name:       "execute a command",
 			filterArgs: []string{"comm=ls"},
@@ -291,3 +263,37 @@ func Test_EventFilters(t *testing.T) {
 		})
 	}
 }
+
+type testFunc string
+
+const (
+	doMagicWrite testFunc = "do_magic_write"
+	doLs         testFunc = "do_ls"
+	doDockerRun  testFunc = "do_docker_run"
+)
+
+// forkAndExecFunction runs a function in `tester.sh` in it's own system process.
+// This is so Tracee running in the current pid can pick the command up.
+// It returns the output of the process and a possible error.
+func forkAndExecFunction(funcName testFunc) ([]byte, error) {
+	tmpFile, err := os.CreateTemp("/tmp", "tracee-test*")
+	if err != nil {
+		return nil, err
+	}
+	_, err = syscall.ForkExec("./tester.sh", []string{"./tester.sh", string(funcName), tmpFile.Name()},
+		&syscall.ProcAttr{
+			Files: []uintptr{0, 1, 2, tmpFile.Fd()},
+		})
+	if err != nil {
+		return nil, err
+	}
+
+	// ForkExec doesn't block, wait for output
+	time.Sleep(time.Second)
+
+	output, err := ioutil.ReadAll(tmpFile)
+	if err != nil {
+		return nil, err
+	}
+	return output, nil
+}

tests/integration/tester.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+do_magic_write() {
+    tmpFileName=$1
+    echo "AAAAA" > $tmpFileName
+}
+
+do_ls() {
+    ls > /dev/null
+}
+
+do_docker_run() {
+    outputFileName=$1
+    output=$(docker run -d --rm alpine)
+    $(echo $output > $outputFileName)
+}
+
+# $1 is the function to call
+# $2 is the temp file to optionally output to
+$1 $2