package main import ( "encoding/json" "fmt" "log" "log/syslog" "net" "os" "os/exec" "os/signal" "path" "path/filepath" "runtime" "runtime/debug" "strings" "syscall" "time" "github.com/hanwen/go-fuse/fuse" "github.com/hanwen/go-fuse/fuse/nodefs" "github.com/hanwen/go-fuse/fuse/pathfs" "github.com/rfjakob/gocryptfs/internal/configfile" "github.com/rfjakob/gocryptfs/internal/contentenc" "github.com/rfjakob/gocryptfs/internal/cryptocore" "github.com/rfjakob/gocryptfs/internal/ctlsock" "github.com/rfjakob/gocryptfs/internal/exitcodes" "github.com/rfjakob/gocryptfs/internal/fusefrontend" "github.com/rfjakob/gocryptfs/internal/fusefrontend_reverse" "github.com/rfjakob/gocryptfs/internal/nametransform" "github.com/rfjakob/gocryptfs/internal/tlog" ) // doMount mounts an encrypted directory. // Called from main. func doMount(args *argContainer) { // Check mountpoint var err error args.mountpoint, err = filepath.Abs(flagSet.Arg(1)) if err != nil { tlog.Fatal.Printf("Invalid mountpoint: %v", err) os.Exit(exitcodes.MountPoint) } // We cannot mount "/home/user/.cipher" at "/home/user" because the mount // will hide ".cipher" also for us. if args.cipherdir == args.mountpoint || strings.HasPrefix(args.cipherdir, args.mountpoint+"/") { tlog.Fatal.Printf("Mountpoint %q would shadow cipherdir %q, this is not supported", args.mountpoint, args.cipherdir) os.Exit(exitcodes.MountPoint) } // Reverse-mounting "/foo" at "/foo/mnt" means we would be recursively // encrypting ourselves. if strings.HasPrefix(args.mountpoint, args.cipherdir+"/") { tlog.Fatal.Printf("Mountpoint %q is contained in cipherdir %q, this is not supported", args.mountpoint, args.cipherdir) os.Exit(exitcodes.MountPoint) } if args.nonempty { err = isDir(args.mountpoint) } else { err = isDirEmpty(args.mountpoint) // OSXFuse will create the mountpoint for us ( https://github.com/rfjakob/gocryptfs/issues/194 ) if runtime.GOOS == "darwin" && os.IsNotExist(err) { tlog.Info.Printf("Mountpoint %q does not exist, but should be created by OSXFuse", args.mountpoint) err = nil } } if err != nil { tlog.Fatal.Printf("Invalid mountpoint: %v", err) os.Exit(exitcodes.MountPoint) } // Open control socket early so we can error out before asking the user // for the password if args.ctlsock != "" { // We must use an absolute path because we cd to / when daemonizing. // This messes up the delete-on-close logic in the unix socket object. args.ctlsock, _ = filepath.Abs(args.ctlsock) var sock net.Listener sock, err = net.Listen("unix", args.ctlsock) if err != nil { tlog.Fatal.Printf("ctlsock: %v", err) os.Exit(exitcodes.CtlSock) } args._ctlsockFd = sock // Close also deletes the socket file defer func() { err = sock.Close() if err != nil { tlog.Warn.Printf("ctlsock close: %v", err) } }() } // We cannot use JSON for pretty-printing as the fields are unexported tlog.Debug.Printf("cli args: %#v", args) // Initialize gocryptfs (read config file, ask for password, ...) fs, wipeKeys := initFuseFrontend(args) // Initialize go-fuse FUSE server srv := initGoFuse(fs, args) // Try to wipe secrect keys from memory after unmount defer wipeKeys() tlog.Info.Println(tlog.ColorGreen + "Filesystem mounted and ready." + tlog.ColorReset) // We have been forked into the background, as evidenced by the set // "notifypid". if args.notifypid > 0 { // Chdir to the root directory so we don't block unmounting the CWD os.Chdir("/") // Switch to syslog if !args.nosyslog { // Switch all of our logs and the generic logger to syslog tlog.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_INFO) tlog.Debug.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_DEBUG) tlog.Warn.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_WARNING) tlog.SwitchLoggerToSyslog(syslog.LOG_USER | syslog.LOG_WARNING) // Daemons should redirect stdin, stdout and stderr redirectStdFds() } // Disconnect from the controlling terminal by creating a new session. // This prevents us from getting SIGINT when the user presses Ctrl-C // to exit a running script that has called gocryptfs. _, err = syscall.Setsid() if err != nil { tlog.Warn.Printf("Setsid: %v", err) } // Send SIGUSR1 to our parent sendUsr1(args.notifypid) } // Increase the open file limit to 4096. This is not essential, so do it after // we have switched to syslog and don't bother the user with warnings. setOpenFileLimit() // Wait for SIGINT in the background and unmount ourselves if we get it. // This prevents a dangling "Transport endpoint is not connected" // mountpoint if the user hits CTRL-C. handleSigint(srv, args.mountpoint) // Return memory that was allocated for scrypt (64M by default!) and other // stuff that is no longer needed to the OS debug.FreeOSMemory() // Jump into server loop. Returns when it gets an umount request from the kernel. srv.Serve() } // setOpenFileLimit tries to increase the open file limit to 4096 (the default hard // limit on Linux). func setOpenFileLimit() { var lim syscall.Rlimit err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim) if err != nil { tlog.Warn.Printf("Getting RLIMIT_NOFILE failed: %v", err) return } if lim.Cur >= 4096 { return } lim.Cur = 4096 err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &lim) if err != nil { tlog.Warn.Printf("Setting RLIMIT_NOFILE to %+v failed: %v", lim, err) // %+v output: "{Cur:4097 Max:4096}" ^ } } // ctlsockFs satisfies both the pathfs.FileSystem and the ctlsock.Interface // interfaces type ctlsockFs interface { pathfs.FileSystem ctlsock.Interface } // initFuseFrontend - initialize gocryptfs/fusefrontend // Calls os.Exit on errors func initFuseFrontend(args *argContainer) (pfs pathfs.FileSystem, wipeKeys func()) { // Get master key (may prompt for the password) and read config file masterkey, confFile := getMasterKey(args) // Reconciliate CLI and config file arguments into a fusefrontend.Args struct // that is passed to the filesystem implementation cryptoBackend := cryptocore.BackendGoGCM if args.openssl { cryptoBackend = cryptocore.BackendOpenSSL } if args.aessiv { cryptoBackend = cryptocore.BackendAESSIV } // forceOwner implies allow_other, as documented. // Set this early, so args.allow_other can be relied on below this point. if args._forceOwner != nil { args.allow_other = true } frontendArgs := fusefrontend.Args{ Cipherdir: args.cipherdir, PlaintextNames: args.plaintextnames, LongNames: args.longnames, ConfigCustom: args._configCustom, NoPrealloc: args.noprealloc, SerializeReads: args.serialize_reads, ForceDecode: args.forcedecode, ForceOwner: args._forceOwner, Exclude: args.exclude, } // confFile is nil when "-zerokey" or "-masterkey" was used if confFile != nil { // Settings from the config file override command line args frontendArgs.PlaintextNames = confFile.IsFeatureFlagSet(configfile.FlagPlaintextNames) args.raw64 = confFile.IsFeatureFlagSet(configfile.FlagRaw64) args.hkdf = confFile.IsFeatureFlagSet(configfile.FlagHKDF) if confFile.IsFeatureFlagSet(configfile.FlagAESSIV) { cryptoBackend = cryptocore.BackendAESSIV } else if args.reverse { tlog.Fatal.Printf("AES-SIV is required by reverse mode, but not enabled in the config file") os.Exit(exitcodes.Usage) } } // If allow_other is set and we run as root, try to give newly created files to // the right user. if args.allow_other && os.Getuid() == 0 { frontendArgs.PreserveOwner = true } jsonBytes, _ := json.MarshalIndent(frontendArgs, "", "\t") tlog.Debug.Printf("frontendArgs: %s", string(jsonBytes)) // Init crypto backend cCore := cryptocore.New(masterkey, cryptoBackend, contentenc.DefaultIVBits, args.hkdf, args.forcedecode) cEnc := contentenc.New(cCore, contentenc.DefaultBS, args.forcedecode) nameTransform := nametransform.New(cCore.EMECipher, frontendArgs.LongNames, args.raw64) // After the crypto backend is initialized, // we can purge the master key from memory. for i := range masterkey { masterkey[i] = 0 } masterkey = nil // Spawn fusefrontend var fs ctlsockFs if args.reverse { if cryptoBackend != cryptocore.BackendAESSIV { log.Panic("reverse mode must use AES-SIV, everything else is insecure") } fs = fusefrontend_reverse.NewFS(frontendArgs, cEnc, nameTransform) } else { fs = fusefrontend.NewFS(frontendArgs, cEnc, nameTransform) } // We have opened the socket early so that we cannot fail here after // asking the user for the password if args._ctlsockFd != nil { go ctlsock.Serve(args._ctlsockFd, fs) } return fs, func() { cCore.Wipe() } } func initGoFuse(fs pathfs.FileSystem, args *argContainer) *fuse.Server { // pathFsOpts are passed into go-fuse/pathfs pathFsOpts := &pathfs.PathNodeFsOptions{ClientInodes: true} if args.sharedstorage { // shared storage mode disables hard link tracking as the backing inode // numbers may change behind our back: // https://github.com/rfjakob/gocryptfs/issues/156 pathFsOpts.ClientInodes = false } if args.reverse { // Reverse mode is read-only, so we don't need a working link(). // Disable hard link tracking to avoid strange breakage on duplicate // inode numbers ( https://github.com/rfjakob/gocryptfs/issues/149 ). pathFsOpts.ClientInodes = false } pathFs := pathfs.NewPathNodeFs(fs, pathFsOpts) var fuseOpts *nodefs.Options if args.sharedstorage { // sharedstorage mode sets all cache timeouts to zero so changes to the // backing shared storage show up immediately. fuseOpts = &nodefs.Options{} } else { 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) mOpts := fuse.MountOptions{ // Writes and reads are usually capped at 128kiB on Linux through // the FUSE_MAX_PAGES_PER_REQ kernel constant in fuse_i.h. Our // sync.Pool buffer pools are sized acc. to the default. Users may set // the kernel constant higher, and Synology NAS kernels are known to // have it >128kiB. We cannot handle more than 128kiB, so we tell // the kernel to limit the size explicitly. MaxWrite: fuse.MAX_KERNEL_WRITE, Options: []string{fmt.Sprintf("max_read=%d", fuse.MAX_KERNEL_WRITE)}, } if args.allow_other { tlog.Info.Printf(tlog.ColorYellow + "The option \"-allow_other\" is set. Make sure the file " + "permissions protect your data from unwanted access." + tlog.ColorReset) mOpts.AllowOther = true // Make the kernel check the file permissions for us mOpts.Options = append(mOpts.Options, "default_permissions") } if args.forcedecode { tlog.Info.Printf(tlog.ColorYellow + "THE OPTION \"-forcedecode\" IS ACTIVE. GOCRYPTFS WILL RETURN CORRUPT DATA!" + tlog.ColorReset) } if args.nonempty { mOpts.Options = append(mOpts.Options, "nonempty") } // Set values shown in "df -T" and friends // First column, "Filesystem" fsname := args.cipherdir if args.fsname != "" { fsname = args.fsname } mOpts.Options = append(mOpts.Options, "fsname="+fsname) // Second column, "Type", will be shown as "fuse." + Name mOpts.Name = "gocryptfs" if args.reverse { mOpts.Name += "-reverse" } // Add a volume name if running osxfuse. Otherwise the Finder will show it as // something like "osxfuse Volume 0 (gocryptfs)". if runtime.GOOS == "darwin" { mOpts.Options = append(mOpts.Options, "volname="+path.Base(args.mountpoint)) } // The kernel enforces read-only operation, we just have to pass "ro". // Reverse mounts are always read-only. if args.ro || args.reverse { mOpts.Options = append(mOpts.Options, "ro") } else if args.rw { mOpts.Options = append(mOpts.Options, "rw") } // If both "nosuid" and "suid" were passed, the safer option wins. if args.nosuid { mOpts.Options = append(mOpts.Options, "nosuid") } else if args.suid { mOpts.Options = append(mOpts.Options, "suid") } if args.nodev { mOpts.Options = append(mOpts.Options, "nodev") } else if args.dev { mOpts.Options = append(mOpts.Options, "dev") } if args.noexec { mOpts.Options = append(mOpts.Options, "noexec") } else if args.exec { mOpts.Options = append(mOpts.Options, "exec") } // Add additional mount options (if any) after the stock ones, so the user has // a chance to override them. if args.ko != "" { parts := strings.Split(args.ko, ",") tlog.Debug.Printf("Adding -ko mount options: %v", parts) mOpts.Options = append(mOpts.Options, parts...) } srv, err := fuse.NewServer(conn.RawFS(), args.mountpoint, &mOpts) if err != nil { tlog.Fatal.Printf("fuse.NewServer failed: %s", strings.TrimSpace(err.Error())) if runtime.GOOS == "darwin" { tlog.Info.Printf("Maybe you should run: /Library/Filesystems/osxfuse.fs/Contents/Resources/load_osxfuse") } os.Exit(exitcodes.FuseNewServer) } srv.SetDebug(args.fusedebug) // All FUSE file and directory create calls carry explicit permission // information. We need an unrestricted umask to create the files and // directories with the requested permissions. syscall.Umask(0000) 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 { tlog.Warn.Printf("handleSigint: srv.Unmount returned %v", err) if runtime.GOOS == "linux" { // MacOSX does not support lazy unmount tlog.Info.Printf("Trying lazy unmount") cmd := exec.Command("fusermount", "-u", "-z", mountpoint) cmd.Stdout = os.Stdout cmd.Stderr = os.Stderr cmd.Run() } } os.Exit(exitcodes.SigInt) }() }