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// 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.
// syz-bisect runs bisection to find cause/fix commit for a crash.
//
// The tool is originally created to test pkg/bisect logic,
// the interface is not particularly handy to use.
//
// The tool requires a config file passed in -config flag, see Config type below for details,
// and a directory with info about the crash passed in -crash flag).
// If -fix flag is specified, it does fix bisection. Otherwise it does cause bisection.
//
// The crash dir should contain the following files:
// - repro.c: C reproducer for the crash (optional)
// - repro.syz: syzkaller reproducer for the crash
// - repro.opts: syzkaller reproducer options (e.g. {"procs":1,"sandbox":"none",...})
// - syzkaller.commit: hash of syzkaller commit which was used to trigger the crash
// - kernel.commit: hash of kernel commit on which the crash was triggered
// - kernel.config: kernel config file
package main
import (
"encoding/json"
"flag"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"github.com/google/syzkaller/pkg/bisect"
"github.com/google/syzkaller/pkg/config"
"github.com/google/syzkaller/pkg/mgrconfig"
"github.com/google/syzkaller/pkg/osutil"
)
var (
flagConfig = flag.String("config", "", "bisect config file")
flagCrash = flag.String("crash", "", "dir with crash info")
flagFix = flag.Bool("fix", false, "search for crash fix")
)
type Config struct {
// BinDir must point to a dir that contains compilers required to build
// older versions of the kernel. For linux, it needs to include several
// gcc versions. A working archive can be downloaded from:
// https://storage.googleapis.com/syzkaller/bisect_bin.tar.gz
BinDir string `json:"bin_dir"`
Ccache string `json:"ccache"`
KernelRepo string `json:"kernel_repo"`
KernelBranch string `json:"kernel_branch"`
SyzkallerRepo string `json:"syzkaller_repo"`
// Directory with user-space system for building kernel images
// (for linux that's the input to tools/create-gce-image.sh).
Userspace string `json:"userspace"`
// Sysctl/cmdline files used to build the image which was used to crash the kernel, e.g. see:
// dashboard/config/upstream.sysctl
// dashboard/config/upstream-selinux.cmdline
Sysctl string `json:"sysctl"`
Cmdline string `json:"cmdline"`
// Manager config that was used to obtain the crash.
Manager json.RawMessage `json:"manager"`
}
func main() {
flag.Parse()
os.Setenv("SYZ_DISABLE_SANDBOXING", "yes")
mycfg := new(Config)
if err := config.LoadFile(*flagConfig, mycfg); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
mgrcfg, err := mgrconfig.LoadData(mycfg.Manager)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
if mgrcfg.Workdir == "" {
mgrcfg.Workdir, err = ioutil.TempDir("", "syz-bisect")
if err != nil {
fmt.Fprintf(os.Stderr, "failed to create temp dir: %v\n", err)
os.Exit(1)
}
defer os.RemoveAll(mgrcfg.Workdir)
}
cfg := &bisect.Config{
Trace: os.Stdout,
Fix: *flagFix,
BinDir: mycfg.BinDir,
Ccache: mycfg.Ccache,
DebugDir: *flagCrash,
Kernel: bisect.KernelConfig{
Repo: mycfg.KernelRepo,
Branch: mycfg.KernelBranch,
Userspace: mycfg.Userspace,
Sysctl: mycfg.Sysctl,
Cmdline: mycfg.Cmdline,
},
Syzkaller: bisect.SyzkallerConfig{
Repo: mycfg.SyzkallerRepo,
},
Manager: mgrcfg,
}
loadString("syzkaller.commit", &cfg.Syzkaller.Commit)
loadString("kernel.commit", &cfg.Kernel.Commit)
loadFile("kernel.config", &cfg.Kernel.Config, true)
loadFile("kernel.baseline_config", &cfg.Kernel.BaselineConfig, false)
loadFile("repro.syz", &cfg.Repro.Syz, false)
loadFile("repro.c", &cfg.Repro.C, false)
loadFile("repro.opts", &cfg.Repro.Opts, true)
if _, err := bisect.Run(cfg); err != nil {
fmt.Fprintf(os.Stderr, "bisection failed: %v\n", err)
os.Exit(1)
}
}
func loadString(file string, dst *string) {
data, err := ioutil.ReadFile(filepath.Join(*flagCrash, file))
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
*dst = strings.TrimSpace(string(data))
}
func loadFile(file string, dst *[]byte, mandatory bool) {
filename := filepath.Join(*flagCrash, file)
if !mandatory && !osutil.IsExist(filename) {
return
}
data, err := ioutil.ReadFile(filename)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
*dst = data
}
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