pkg/instance: add package for testing of images/patches/bisection

Move helper image/patch testing code from syz-ci/testing.go
to a separate package so that it can be reused during bisection.

Update #501

pkg/instance/instance.go

@@ -0,0 +1,337 @@
+// Copyright 2018 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+// Package instance provides helper functions for creation of temporal instances
+// used for testing of images, patches and bisection.
+package instance
+
+import (
+	"bytes"
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/google/syzkaller/pkg/csource"
+	"github.com/google/syzkaller/pkg/git"
+	"github.com/google/syzkaller/pkg/kernel"
+	"github.com/google/syzkaller/pkg/log"
+	"github.com/google/syzkaller/pkg/osutil"
+	"github.com/google/syzkaller/pkg/report"
+	"github.com/google/syzkaller/prog"
+	"github.com/google/syzkaller/syz-manager/mgrconfig"
+	"github.com/google/syzkaller/vm"
+)
+
+type Env struct {
+	cfg    *mgrconfig.Config
+	gopath string
+}
+
+func NewEnv(cfg *mgrconfig.Config) (*Env, error) {
+	switch cfg.Type {
+	case "gce", "qemu":
+	default:
+		return nil, fmt.Errorf("test instances can only work with qemu/gce")
+	}
+	if cfg.Workdir == "" {
+		return nil, fmt.Errorf("workdir path is empty")
+	}
+	if cfg.KernelSrc == "" {
+		return nil, fmt.Errorf("kernel src path is empty")
+	}
+	if cfg.Syzkaller == "" {
+		return nil, fmt.Errorf("syzkaller path is empty")
+	}
+	srcIndex := strings.LastIndex(cfg.Syzkaller, "/src/")
+	if srcIndex == -1 {
+		return nil, fmt.Errorf("syzkaller path %q is not in GOPATH", cfg.Syzkaller)
+	}
+	if err := osutil.MkdirAll(cfg.Workdir); err != nil {
+		return nil, fmt.Errorf("failed to create tmp dir: %v", err)
+	}
+	env := &Env{
+		cfg:    cfg,
+		gopath: cfg.Syzkaller[:srcIndex],
+	}
+	return env, nil
+}
+
+func (env *Env) BuildSyzkaller(repo, commit string) error {
+	if _, err := git.CheckoutCommit(env.cfg.Syzkaller, repo, commit); err != nil {
+		return fmt.Errorf("failed to checkout syzkaller repo: %v", err)
+	}
+	cmd := osutil.Command("make", "target")
+	cmd.Dir = env.cfg.Syzkaller
+	cmd.Env = append([]string{}, os.Environ()...)
+	cmd.Env = append(cmd.Env,
+		"GOPATH="+env.gopath,
+		"TARGETOS="+env.cfg.TargetOS,
+		"TARGETVMARCH="+env.cfg.TargetVMArch,
+		"TARGETARCH="+env.cfg.TargetArch,
+	)
+	if _, err := osutil.Run(time.Hour, cmd); err != nil {
+		return fmt.Errorf("syzkaller build failed: %v", err)
+	}
+	return nil
+}
+
+func (env *Env) BuildKernel(compilerBin, userspaceDir, cmdlineFile, sysctlFile string, kernelConfig []byte) error {
+	if err := kernel.Build(env.cfg.KernelSrc, compilerBin, kernelConfig); err != nil {
+		return fmt.Errorf("kernel build failed: %v", err)
+	}
+	env.cfg.Vmlinux = filepath.Join(env.cfg.KernelSrc, "vmlinux")
+	env.cfg.Image = filepath.Join(env.cfg.Workdir, "syz-image")
+	env.cfg.SSHKey = filepath.Join(env.cfg.Workdir, "syz-key")
+	if err := kernel.CreateImage(env.cfg.KernelSrc, userspaceDir,
+		cmdlineFile, sysctlFile, env.cfg.Image, env.cfg.SSHKey); err != nil {
+		return fmt.Errorf("image build failed: %v", err)
+	}
+	return nil
+}
+
+type TestError struct {
+	Boot   bool // says if the error happened during booting or during instance testing
+	Title  string
+	Output []byte
+	Report *report.Report
+}
+
+func (err *TestError) Error() string {
+	return err.Title
+}
+
+type CrashError struct {
+	Report *report.Report
+}
+
+func (err *CrashError) Error() string {
+	return err.Report.Title
+}
+
+// Test boots numVMs VMs, tests basic kernel operation, and optionally tests the provided reproducer.
+// TestError is returned if there is a problem with kernel/image (crash, reboot loop, etc).
+// CrashError is returned if the reproducer crashes kernel.
+func (env *Env) Test(numVMs int, reproSyz, reproOpts, reproC []byte) ([]error, error) {
+	if err := mgrconfig.Complete(env.cfg); err != nil {
+		return nil, err
+	}
+	reporter, err := report.NewReporter(env.cfg.TargetOS, env.cfg.KernelSrc,
+		filepath.Dir(env.cfg.Vmlinux), nil, env.cfg.ParsedIgnores)
+	if err != nil {
+		return nil, err
+	}
+	vmEnv := mgrconfig.CreateVMEnv(env.cfg, false)
+	vmPool, err := vm.Create(env.cfg.Type, vmEnv)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create VM pool: %v", err)
+	}
+	if n := vmPool.Count(); numVMs > n {
+		numVMs = n
+	}
+	res := make(chan error, numVMs)
+	for i := 0; i < numVMs; i++ {
+		inst := &inst{
+			cfg:       env.cfg,
+			reporter:  reporter,
+			vmPool:    vmPool,
+			vmIndex:   i,
+			reproSyz:  reproSyz,
+			reproOpts: reproOpts,
+			reproC:    reproC,
+		}
+		go func() { res <- inst.test() }()
+	}
+	var errors []error
+	for i := 0; i < numVMs; i++ {
+		errors = append(errors, <-res)
+	}
+	return errors, nil
+}
+
+type inst struct {
+	cfg       *mgrconfig.Config
+	reporter  report.Reporter
+	vmPool    *vm.Pool
+	vm        *vm.Instance
+	vmIndex   int
+	reproSyz  []byte
+	reproOpts []byte
+	reproC    []byte
+}
+
+func (inst *inst) test() error {
+	vmInst, err := inst.vmPool.Create(inst.vmIndex)
+	if err != nil {
+		testErr := &TestError{
+			Boot:  true,
+			Title: err.Error(),
+		}
+		if bootErr, ok := err.(vm.BootErrorer); ok {
+			testErr.Title, testErr.Output = bootErr.BootError()
+			// This linux-ism avoids detecting any crash during boot as "unexpected kernel reboot".
+			output := testErr.Output
+			if pos := bytes.Index(output, []byte("Booting the kernel.")); pos != -1 {
+				output = output[pos+1:]
+			}
+			testErr.Report = inst.reporter.Parse(output)
+			if testErr.Report != nil {
+				testErr.Title = testErr.Report.Title
+			} else {
+				testErr.Report = &report.Report{
+					Title:  testErr.Title,
+					Output: testErr.Output,
+				}
+			}
+			if err := inst.reporter.Symbolize(testErr.Report); err != nil {
+				// TODO(dvyukov): send such errors to dashboard.
+				log.Logf(0, "failed to symbolize report: %v", err)
+			}
+		}
+		return testErr
+	}
+	defer vmInst.Close()
+	inst.vm = vmInst
+	if err := inst.testInstance(); err != nil {
+		return err
+	}
+	if len(inst.reproSyz) != 0 {
+		if err := inst.testRepro(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// testInstance tests basic operation of the provided VM
+// (that we can copy binaries, run binaries, they can connect to host, run syzkaller programs, etc).
+// TestError is returned if there is a problem with the kernel (e.g. crash).
+func (inst *inst) testInstance() error {
+	ln, err := net.Listen("tcp", ":")
+	if err != nil {
+		return fmt.Errorf("failed to open listening socket: %v", err)
+	}
+	defer ln.Close()
+	var gotConn uint32
+	go func() {
+		conn, err := ln.Accept()
+		if err == nil {
+			conn.Close()
+			atomic.StoreUint32(&gotConn, 1)
+		}
+	}()
+	fwdAddr, err := inst.vm.Forward(ln.Addr().(*net.TCPAddr).Port)
+	if err != nil {
+		return fmt.Errorf("failed to setup port forwarding: %v", err)
+	}
+	fuzzerBin, err := inst.vm.Copy(inst.cfg.SyzFuzzerBin)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	executorBin, err := inst.vm.Copy(inst.cfg.SyzExecutorBin)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	cmd := fmt.Sprintf("%v -test -executor=%v -name=test -arch=%v -manager=%v -cover=0 -sandbox=%v",
+		fuzzerBin, executorBin, inst.cfg.TargetArch, fwdAddr, inst.cfg.Sandbox)
+	outc, errc, err := inst.vm.Run(5*time.Minute, nil, cmd)
+	if err != nil {
+		return fmt.Errorf("failed to run binary in VM: %v", err)
+	}
+	rep := vm.MonitorExecution(outc, errc, inst.reporter, true)
+	if rep != nil {
+		if err := inst.reporter.Symbolize(rep); err != nil {
+			// TODO(dvyukov): send such errors to dashboard.
+			log.Logf(0, "failed to symbolize report: %v", err)
+		}
+		return &TestError{
+			Title:  rep.Title,
+			Report: rep,
+		}
+	}
+	if atomic.LoadUint32(&gotConn) == 0 {
+		return fmt.Errorf("test machine failed to connect to host")
+	}
+	return nil
+}
+
+func (inst *inst) testRepro() error {
+	cfg := inst.cfg
+	execprogBin, err := inst.vm.Copy(cfg.SyzExecprogBin)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	executorBin, err := inst.vm.Copy(cfg.SyzExecutorBin)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	progFile := filepath.Join(cfg.Workdir, "repro.prog")
+	if err := osutil.WriteFile(progFile, inst.reproSyz); err != nil {
+		return fmt.Errorf("failed to write temp file: %v", err)
+	}
+	vmProgFile, err := inst.vm.Copy(progFile)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	opts, err := csource.DeserializeOptions(inst.reproOpts)
+	if err != nil {
+		return err
+	}
+	// Combine repro options and default options in a way that increases chances to reproduce the crash.
+	// First, we always enable threaded/collide as it should be [almost] strictly better.
+	// Executor does not support empty sandbox, so we use none instead.
+	// Finally, always use repeat and multiple procs.
+	if opts.Sandbox == "" {
+		opts.Sandbox = "none"
+	}
+	if !opts.Fault {
+		opts.FaultCall = -1
+	}
+	cmdSyz := fmt.Sprintf("%v -executor %v -arch=%v -procs=%v -sandbox=%v"+
+		" -fault_call=%v -fault_nth=%v -repeat=0 -cover=0 %v",
+		execprogBin, executorBin, cfg.TargetArch, cfg.Procs, opts.Sandbox,
+		opts.FaultCall, opts.FaultNth, vmProgFile)
+	if err := inst.testProgram(cmdSyz, 7*time.Minute); err != nil {
+		return err
+	}
+	if len(inst.reproC) == 0 {
+		return nil
+	}
+	cFile := filepath.Join(cfg.Workdir, "repro.c")
+	if err := osutil.WriteFile(cFile, inst.reproC); err != nil {
+		return fmt.Errorf("failed to write temp file: %v", err)
+	}
+	target, err := prog.GetTarget(cfg.TargetOS, cfg.TargetArch)
+	if err != nil {
+		return err
+	}
+	bin, err := csource.Build(target, "c", cFile)
+	if err != nil {
+		return err
+	}
+	vmBin, err := inst.vm.Copy(bin)
+	if err != nil {
+		return &TestError{Title: fmt.Sprintf("failed to copy test binary to VM: %v", err)}
+	}
+	// We should test for longer (e.g. 5 mins), but the problem is that
+	// reproducer does not print anything, so after 3 mins we detect "no output".
+	return inst.testProgram(vmBin, time.Minute)
+}
+
+func (inst *inst) testProgram(command string, testTime time.Duration) error {
+	outc, errc, err := inst.vm.Run(testTime, nil, command)
+	if err != nil {
+		return fmt.Errorf("failed to run binary in VM: %v", err)
+	}
+	rep := vm.MonitorExecution(outc, errc, inst.reporter, true)
+	if rep == nil {
+		return nil
+	}
+	if err := inst.reporter.Symbolize(rep); err != nil {
+		log.Logf(0, "failed to symbolize report: %v", err)
+	}
+	return &CrashError{Report: rep}
+}