libgocryptfs/main.go

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Go
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package main
import (
"flag"
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"fmt"
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"os"
"os/exec"
"os/signal"
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"path/filepath"
"runtime"
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"runtime/pprof"
"syscall"
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"time"
"github.com/rfjakob/gocryptfs/cryptfs"
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"github.com/rfjakob/gocryptfs/pathfs_frontend"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/hanwen/go-fuse/fuse/pathfs"
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)
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const (
PROGRAM_NAME = "gocryptfs"
// Exit codes
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ERREXIT_USAGE = 1
ERREXIT_MOUNT = 3
ERREXIT_CIPHERDIR = 6
ERREXIT_INIT = 7
ERREXIT_LOADCONF = 8
ERREXIT_PASSWORD = 9
ERREXIT_MOUNTPOINT = 10
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)
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// GitVersion will be set by the build script "build.bash"
var GitVersion = "[version not set - please compile using ./build.bash]"
func initDir(dirArg string, plaintextNames bool) {
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dir, _ := filepath.Abs(dirArg)
err := checkDirEmpty(dir)
if err != nil {
fmt.Printf("Invalid CIPHERDIR: %v\n", err)
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os.Exit(ERREXIT_INIT)
}
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confName := filepath.Join(dir, cryptfs.ConfDefaultName)
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cryptfs.Info.Printf("Choose a password for protecting your files.\n")
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password := readPasswordTwice()
err = cryptfs.CreateConfFile(confName, password, plaintextNames)
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if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_INIT)
}
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cryptfs.Info.Printf("The filesystem is now ready for mounting.\n")
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os.Exit(0)
}
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func usageText() {
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fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] CIPHERDIR MOUNTPOINT\n", PROGRAM_NAME)
fmt.Fprintf(os.Stderr, "\nOptions:\n")
flagSet.PrintDefaults()
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}
type argContainer struct {
debug, init, zerokey, fusedebug, openssl, passwd, foreground, version,
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plaintextnames, quiet bool
masterkey, mountpoint, cipherdir string
cpuprofile *string
notifypid int
}
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var flagSet *flag.FlagSet
func main() {
runtime.GOMAXPROCS(4)
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// Parse command line arguments
var args argContainer
flagSet = flag.NewFlagSet(PROGRAM_NAME, flag.ExitOnError)
flagSet.Usage = usageText
flagSet.BoolVar(&args.debug, "debug", false, "Enable debug output")
flagSet.BoolVar(&args.fusedebug, "fusedebug", false, "Enable fuse library debug output")
flagSet.BoolVar(&args.init, "init", false, "Initialize encrypted directory")
flagSet.BoolVar(&args.zerokey, "zerokey", false, "Use all-zero dummy master key")
flagSet.BoolVar(&args.openssl, "openssl", true, "Use OpenSSL instead of built-in Go crypto")
flagSet.BoolVar(&args.passwd, "passwd", false, "Change password")
flagSet.BoolVar(&args.foreground, "f", false, "Stay in the foreground")
flagSet.BoolVar(&args.version, "version", false, "Print version and exit")
flagSet.BoolVar(&args.plaintextnames, "plaintextnames", false,
"Do not encrypt file names - can only be used together with -init")
flagSet.BoolVar(&args.quiet, "q", false, "Quiet - silence informational messages")
flagSet.StringVar(&args.masterkey, "masterkey", "", "Mount with explicit master key")
args.cpuprofile = flagSet.String("cpuprofile", "", "Write cpu profile to specified file")
flagSet.IntVar(&args.notifypid, "notifypid", 0,
"Send USR1 to the specified process after successful mount - used internally for daemonization")
flagSet.Parse(os.Args[1:])
if args.version {
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fmt.Printf("%s %s; on-disk format %d\n", PROGRAM_NAME, GitVersion, cryptfs.HEADER_CURRENT_VERSION)
os.Exit(0)
}
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if args.quiet {
cryptfs.Info.Disable()
}
if !args.foreground {
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daemonize() // does not return
}
if *args.cpuprofile != "" {
f, err := os.Create(*args.cpuprofile)
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if err != nil {
fmt.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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cryptfs.Info.Printf("Writing CPU profile to %s\n", *args.cpuprofile)
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pprof.StartCPUProfile(f)
defer pprof.StopCPUProfile()
}
if args.debug {
cryptfs.Debug.Enable()
cryptfs.Debug.Printf("Debug output enabled\n")
}
if args.openssl == false {
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cryptfs.Info.Printf("Openssl disabled\n")
}
if args.init {
if flagSet.NArg() != 1 && args.plaintextnames == false {
fmt.Printf("Usage: %s --init [--plaintextnames] CIPHERDIR\n", PROGRAM_NAME)
os.Exit(ERREXIT_USAGE)
}
initDir(flagSet.Arg(0), args.plaintextnames) // does not return
}
if args.passwd {
if flagSet.NArg() != 1 {
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fmt.Printf("Usage: %s --passwd CIPHERDIR\n", PROGRAM_NAME)
os.Exit(ERREXIT_USAGE)
}
} else {
// Normal mount
if flagSet.NArg() < 2 {
usageText()
os.Exit(ERREXIT_USAGE)
}
args.mountpoint, _ = filepath.Abs(flagSet.Arg(1))
err := checkDirEmpty(args.mountpoint)
if err != nil {
fmt.Printf("Invalid MOUNTPOINT: %v\n", err)
os.Exit(ERREXIT_MOUNTPOINT)
}
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}
args.cipherdir, _ = filepath.Abs(flagSet.Arg(0))
err := checkDir(args.cipherdir)
if err != nil {
fmt.Printf("Invalid CIPHERDIR: %v\n", err)
os.Exit(ERREXIT_CIPHERDIR)
}
var plaintextNames bool
var cf *cryptfs.ConfFile
var currentPassword string
key := make([]byte, cryptfs.KEY_LEN)
if args.zerokey {
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cryptfs.Info.Printf("Zerokey mode active: using all-zero dummy master key.\n")
plaintextNames = args.plaintextnames
} else if len(args.masterkey) > 0 {
key = parseMasterKey(args.masterkey)
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cryptfs.Info.Printf("Using explicit master key.\n")
} else {
// Load config file
cfname := filepath.Join(args.cipherdir, cryptfs.ConfDefaultName)
_, err = os.Stat(cfname)
if err != nil {
fmt.Printf("Error: %s not found in CIPHERDIR\n", cryptfs.ConfDefaultName)
fmt.Printf("Please run \"%s --init %s\" first\n", os.Args[0], flagSet.Arg(0))
os.Exit(ERREXIT_LOADCONF)
}
if args.passwd == true {
fmt.Printf("Old password: ")
} else {
fmt.Printf("Password: ")
}
currentPassword = readPassword()
cryptfs.Info.Printf("Decrypting master key... ")
cryptfs.Warn.Disable() // Silence DecryptBlock() error messages on incorrect password
key, cf, err = cryptfs.LoadConfFile(cfname, currentPassword)
cryptfs.Warn.Enable()
if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_LOADCONF)
}
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cryptfs.Info.Printf("done.\n")
}
if args.passwd == true {
fmt.Printf("Please enter the new password.\n")
newPassword := readPasswordTwice()
if newPassword == currentPassword {
fmt.Printf("New and old passwords are identical\n")
os.Exit(ERREXIT_PASSWORD)
}
cf.EncryptKey(key, newPassword)
err := cf.WriteFile()
if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_INIT)
}
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cryptfs.Info.Printf("Password changed.\n")
os.Exit(0)
}
if cf != nil {
plaintextNames = cf.PlaintextNames()
}
srv := pathfsFrontend(key, args.cipherdir, args.mountpoint, args.fusedebug, args.openssl, plaintextNames)
if args.zerokey == false && len(args.masterkey) == 0 {
printMasterKey(key)
} else if args.zerokey == true {
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cryptfs.Info.Printf("ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING.\n")
} else if len(args.masterkey) > 0 {
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cryptfs.Info.Printf("THE MASTER KEY IS VISIBLE VIA \"ps -auxwww\", ONLY USE THIS MODE FOR EMERGENCIES.\n")
}
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cryptfs.Info.Println("Filesystem ready.")
// Send USR1 notification
if args.notifypid > 0 {
sendUsr1(args.notifypid)
}
// Wait for SIGING in the background and unmount ourselves if we get it
// This prevents a dangling "Transport endpoint is not connected" mountpoint
handleSigint(srv, args.mountpoint)
// Jump into server loop. Returns when it gets an umount request from the kernel.
srv.Serve()
// main returns with code 0
}
func pathfsFrontend(key []byte, cipherdir string, mountpoint string,
debug bool, openssl bool, plaintextNames bool) *fuse.Server {
finalFs := pathfs_frontend.NewFS(key, cipherdir, openssl, plaintextNames)
pathFsOpts := &pathfs.PathNodeFsOptions{ClientInodes: true}
pathFs := pathfs.NewPathNodeFs(finalFs, pathFsOpts)
fuseOpts := &nodefs.Options{
// These options are to be compatible with libfuse defaults,
// making benchmarking easier.
NegativeTimeout: time.Second,
AttrTimeout: time.Second,
EntryTimeout: time.Second,
}
conn := nodefs.NewFileSystemConnector(pathFs.Root(), fuseOpts)
var mOpts fuse.MountOptions
mOpts.AllowOther = false
// Set values shown in "df -T" and friends
// First column, "Filesystem"
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mOpts.Options = append(mOpts.Options, "fsname="+cipherdir)
// Second column, "Type", will be shown as "fuse." + Name
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mOpts.Name = "gocryptfs"
srv, err := fuse.NewServer(conn.RawFS(), mountpoint, &mOpts)
if err != nil {
fmt.Printf("Mount failed: %v", err)
os.Exit(ERREXIT_MOUNT)
}
srv.SetDebug(debug)
return srv
}
func handleSigint(srv *fuse.Server, mountpoint string) {
ch := make(chan os.Signal, 1)
signal.Notify(ch, os.Interrupt)
signal.Notify(ch, syscall.SIGTERM)
go func() {
<-ch
err := srv.Unmount()
if err != nil {
fmt.Print(err)
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cryptfs.Info.Printf("Trying lazy unmount\n")
cmd := exec.Command("fusermount", "-u", "-z", mountpoint)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Run()
}
os.Exit(1)
}()
}