336 lines
10 KiB
Go
336 lines
10 KiB
Go
package main
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import (
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"io/ioutil"
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"flag"
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"fmt"
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"os"
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"os/exec"
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"os/signal"
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"path/filepath"
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"runtime"
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"runtime/pprof"
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"syscall"
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"time"
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"github.com/rfjakob/gocryptfs/cryptfs"
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"github.com/rfjakob/gocryptfs/pathfs_frontend"
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"github.com/hanwen/go-fuse/fuse"
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"github.com/hanwen/go-fuse/fuse/nodefs"
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"github.com/hanwen/go-fuse/fuse/pathfs"
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)
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const (
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PROGRAM_NAME = "gocryptfs"
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// Exit codes
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ERREXIT_USAGE = 1
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ERREXIT_MOUNT = 3
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ERREXIT_CIPHERDIR = 6
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ERREXIT_INIT = 7
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ERREXIT_LOADCONF = 8
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ERREXIT_PASSWORD = 9
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ERREXIT_MOUNTPOINT = 10
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)
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// GitVersion will be set by the build script "build.bash"
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var GitVersion = "[version not set - please compile using ./build.bash]"
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func initDir(args *argContainer) {
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err := checkDirEmpty(args.cipherdir)
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if err != nil {
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fmt.Printf("Invalid CIPHERDIR: %v\n", err)
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os.Exit(ERREXIT_INIT)
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}
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// Create gocryptfs.diriv in the root dir
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diriv := cryptfs.RandBytes(cryptfs.DIRIV_LEN)
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dirivPath := filepath.Join(args.cipherdir, cryptfs.DIRIV_FILENAME)
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cryptfs.Debug.Printf("Creating %s\n", dirivPath)
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// 0444 permissions: the file is not secret but should not be written to
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err = ioutil.WriteFile(dirivPath, diriv, 0444)
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if err != nil {
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fmt.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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// Create gocryptfs.conf
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cryptfs.Info.Printf("Choose a password for protecting your files.\n")
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password := readPasswordTwice(args.extpass)
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err = cryptfs.CreateConfFile(args.config, password, args.plaintextnames)
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if err != nil {
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fmt.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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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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}
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func usageText() {
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printVersion()
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fmt.Printf("\n")
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fmt.Printf("Usage: %s -init|-passwd [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
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fmt.Printf(" or %s [OPTIONS] CIPHERDIR MOUNTPOINT\n", PROGRAM_NAME)
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fmt.Printf("\nOptions:\n")
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flagSet.PrintDefaults()
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}
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type argContainer struct {
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debug, init, zerokey, fusedebug, openssl, passwd, foreground, version,
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plaintextnames, quiet bool
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masterkey, mountpoint, cipherdir, cpuprofile, config, extpass string
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notifypid int
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}
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var flagSet *flag.FlagSet
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// loadConfig - load the config file "filename", prompting the user for the password
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func loadConfig(args *argContainer) (masterkey []byte, confFile *cryptfs.ConfFile) {
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// Check if the file exists at all before prompting for a password
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_, err := os.Stat(args.config)
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if err != nil {
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fmt.Println(err)
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os.Exit(ERREXIT_LOADCONF)
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}
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fmt.Printf("Password: ")
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pw := readPassword(args.extpass)
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cryptfs.Info.Printf("Decrypting master key... ")
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cryptfs.Warn.Disable() // Silence DecryptBlock() error messages on incorrect password
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masterkey, confFile, err = cryptfs.LoadConfFile(args.config, pw)
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cryptfs.Warn.Enable()
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if err != nil {
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fmt.Println(err)
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fmt.Println("Wrong password.")
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os.Exit(ERREXIT_LOADCONF)
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}
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cryptfs.Info.Printf("done.\n")
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return masterkey, confFile
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}
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// changePassword - change the password of config file "filename"
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func changePassword(args *argContainer) {
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masterkey, confFile := loadConfig(args)
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fmt.Printf("Please enter your new password.\n")
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newPw := readPasswordTwice(args.extpass)
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confFile.EncryptKey(masterkey, newPw)
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err := confFile.WriteFile()
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if err != nil {
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fmt.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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cryptfs.Info.Printf("Password changed.\n")
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os.Exit(0)
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}
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// printVersion - print a version string like
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// "gocryptfs v0.3.1-31-g6736212-dirty; on-disk format 2"
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func printVersion() {
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fmt.Printf("%s %s; on-disk format %d\n", PROGRAM_NAME, GitVersion, cryptfs.HEADER_CURRENT_VERSION)
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}
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func main() {
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runtime.GOMAXPROCS(4)
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var err error
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// Parse command line arguments
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var args argContainer
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flagSet = flag.NewFlagSet(PROGRAM_NAME, flag.ExitOnError)
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flagSet.Usage = usageText
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flagSet.BoolVar(&args.debug, "debug", false, "Enable debug output")
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flagSet.BoolVar(&args.fusedebug, "fusedebug", false, "Enable fuse library debug output")
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flagSet.BoolVar(&args.init, "init", false, "Initialize encrypted directory")
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flagSet.BoolVar(&args.zerokey, "zerokey", false, "Use all-zero dummy master key")
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flagSet.BoolVar(&args.openssl, "openssl", true, "Use OpenSSL instead of built-in Go crypto")
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flagSet.BoolVar(&args.passwd, "passwd", false, "Change password")
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flagSet.BoolVar(&args.foreground, "f", false, "Stay in the foreground")
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flagSet.BoolVar(&args.version, "version", false, "Print version and exit")
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flagSet.BoolVar(&args.plaintextnames, "plaintextnames", false, "Do not encrypt "+
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"file names")
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flagSet.BoolVar(&args.quiet, "q", false, "Quiet - silence informational messages")
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flagSet.StringVar(&args.masterkey, "masterkey", "", "Mount with explicit master key")
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flagSet.StringVar(&args.cpuprofile, "cpuprofile", "", "Write cpu profile to specified file")
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flagSet.StringVar(&args.config, "config", "", "Use specified config file instead of CIPHERDIR/gocryptfs.conf")
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flagSet.StringVar(&args.extpass, "extpass", "", "Use external program for the password prompt")
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flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+
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"successful mount - used internally for daemonization")
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flagSet.Parse(os.Args[1:])
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// By default, let the child handle everything.
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// The parent *could* handle operations that do not require backgrounding by
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// itself, but that would make the code paths more complicated.
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if !args.foreground {
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forkChild() // does not return
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}
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// Getting here means we *are* the child
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// "-v"
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if args.version {
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printVersion()
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os.Exit(0)
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}
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if args.debug {
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cryptfs.Debug.Enable()
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cryptfs.Debug.Printf("Debug output enabled\n")
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}
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// Every operation below requires CIPHERDIR. Check that we have it.
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if flagSet.NArg() >= 1 {
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args.cipherdir, _ = filepath.Abs(flagSet.Arg(0))
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err := checkDir(args.cipherdir)
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if err != nil {
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fmt.Printf("Invalid CIPHERDIR: %v\n", err)
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os.Exit(ERREXIT_CIPHERDIR)
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}
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} else {
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usageText()
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os.Exit(ERREXIT_USAGE)
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}
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// "-q"
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if args.quiet {
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cryptfs.Info.Disable()
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}
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// "-config"
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if args.config != "" {
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args.config, err = filepath.Abs(args.config)
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if err != nil {
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fmt.Printf("Invalid \"-config\" setting: %v\n", err)
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}
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cryptfs.Info.Printf("Using config file at custom location %s\n", args.config)
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} else {
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args.config = filepath.Join(args.cipherdir, cryptfs.ConfDefaultName)
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}
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// "-cpuprofile"
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if args.cpuprofile != "" {
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f, err := os.Create(args.cpuprofile)
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if err != nil {
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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)
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defer pprof.StopCPUProfile()
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}
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// "-openssl"
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if args.openssl == false {
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cryptfs.Info.Printf("Openssl disabled\n")
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}
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// Operation flags: init, passwd or mount
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// "-init"
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if args.init {
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if flagSet.NArg() > 1 {
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fmt.Printf("Usage: %s -init [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
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os.Exit(ERREXIT_USAGE)
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}
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initDir(&args) // does not return
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}
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// "-passwd"
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if args.passwd {
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if flagSet.NArg() > 1 {
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fmt.Printf("Usage: %s -passwd [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
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os.Exit(ERREXIT_USAGE)
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}
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changePassword(&args) // does not return
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}
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// Mount
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// Check mountpoint
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if flagSet.NArg() < 2 {
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usageText()
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os.Exit(ERREXIT_USAGE)
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}
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args.mountpoint, err = filepath.Abs(flagSet.Arg(1))
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if err != nil {
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fmt.Printf("Invalid MOUNTPOINT: %v\n", err)
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os.Exit(ERREXIT_MOUNTPOINT)
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}
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err = checkDirEmpty(args.mountpoint)
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if err != nil {
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fmt.Printf("Invalid MOUNTPOINT: %v\n", err)
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os.Exit(ERREXIT_MOUNTPOINT)
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}
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// Get master key
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var masterkey []byte
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if args.masterkey != "" {
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// "-masterkey"
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cryptfs.Info.Printf("Using explicit master key.\n")
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masterkey = parseMasterKey(args.masterkey)
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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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} else if args.zerokey {
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// "-zerokey"
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cryptfs.Info.Printf("Using all-zero dummy master key.\n")
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cryptfs.Info.Printf("ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING.\n")
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masterkey = make([]byte, cryptfs.KEY_LEN)
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} else {
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// Load master key from config file
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var confFile *cryptfs.ConfFile
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masterkey, confFile = loadConfig(&args)
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printMasterKey(masterkey)
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args.plaintextnames = confFile.PlaintextNames()
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}
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// Initialize FUSE server
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srv := pathfsFrontend(masterkey, args.cipherdir, args.mountpoint, args.fusedebug, args.openssl, args.plaintextnames)
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cryptfs.Info.Println("Filesystem ready.")
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// We are ready - send USR1 signal to our parent
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if args.notifypid > 0 {
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sendUsr1(args.notifypid)
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}
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// Wait for SIGINT in the background and unmount ourselves if we get it.
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// This prevents a dangling "Transport endpoint is not connected" mountpoint.
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handleSigint(srv, args.mountpoint)
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// Jump into server loop. Returns when it gets an umount request from the kernel.
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srv.Serve()
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// main exits with code 0
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}
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// pathfsFrontend - initialize FUSE server based on go-fuse's PathFS
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// Calls os.Exit on errors
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func pathfsFrontend(key []byte, cipherdir string, mountpoint string,
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debug bool, openssl bool, plaintextNames bool) *fuse.Server {
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finalFs := pathfs_frontend.NewFS(key, cipherdir, openssl, plaintextNames)
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pathFsOpts := &pathfs.PathNodeFsOptions{ClientInodes: true}
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pathFs := pathfs.NewPathNodeFs(finalFs, pathFsOpts)
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fuseOpts := &nodefs.Options{
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// These options are to be compatible with libfuse defaults,
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// making benchmarking easier.
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NegativeTimeout: time.Second,
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AttrTimeout: time.Second,
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EntryTimeout: time.Second,
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}
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conn := nodefs.NewFileSystemConnector(pathFs.Root(), fuseOpts)
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var mOpts fuse.MountOptions
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mOpts.AllowOther = false
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// Set values shown in "df -T" and friends
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// First column, "Filesystem"
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mOpts.Options = append(mOpts.Options, "fsname="+cipherdir)
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// Second column, "Type", will be shown as "fuse." + Name
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mOpts.Name = "gocryptfs"
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srv, err := fuse.NewServer(conn.RawFS(), mountpoint, &mOpts)
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if err != nil {
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fmt.Printf("Mount failed: %v", err)
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os.Exit(ERREXIT_MOUNT)
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}
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srv.SetDebug(debug)
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return srv
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}
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func handleSigint(srv *fuse.Server, mountpoint string) {
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ch := make(chan os.Signal, 1)
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signal.Notify(ch, os.Interrupt)
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signal.Notify(ch, syscall.SIGTERM)
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go func() {
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<-ch
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err := srv.Unmount()
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if err != nil {
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fmt.Print(err)
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cryptfs.Info.Printf("Trying lazy unmount\n")
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cmd := exec.Command("fusermount", "-u", "-z", mountpoint)
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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cmd.Run()
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}
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os.Exit(1)
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}()
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}
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