aboutsummaryrefslogtreecommitdiff
path: root/main.go
blob: b5de95931ebb23f59b450d83998d1efeab818d86 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log/syslog"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"runtime"
	"runtime/pprof"
	"strconv"
	"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/fusefrontend"
	"github.com/rfjakob/gocryptfs/internal/nametransform"
	"github.com/rfjakob/gocryptfs/internal/prefer_openssl"
	"github.com/rfjakob/gocryptfs/internal/readpassword"
	"github.com/rfjakob/gocryptfs/internal/tlog"
)

const (
	// Exit codes
	ERREXIT_USAGE      = 1
	ERREXIT_MOUNT      = 3
	ERREXIT_CIPHERDIR  = 6
	ERREXIT_INIT       = 7
	ERREXIT_LOADCONF   = 8
	ERREXIT_MOUNTPOINT = 10
)

type argContainer struct {
	debug, init, zerokey, fusedebug, openssl, passwd, foreground, version,
	plaintextnames, quiet, nosyslog, wpanic,
	longnames, allow_other, ro bool
	masterkey, mountpoint, cipherdir, cpuprofile, config, extpass,
	memprofile, o string
	notifypid, scryptn int
}

var flagSet *flag.FlagSet

// GitVersion will be set by the build script "build.bash"
var GitVersion = "[version not set - please compile using ./build.bash]"
var GitVersionFuse = "[version not set - please compile using ./build.bash]"

// initDir initializes an empty directory for use as a gocryptfs cipherdir.
func initDir(args *argContainer) {
	err := checkDirEmpty(args.cipherdir)
	if err != nil {
		tlog.Fatal.Printf("Invalid cipherdir: %v", err)
		os.Exit(ERREXIT_INIT)
	}

	// Create gocryptfs.conf
	if args.extpass == "" {
		tlog.Info.Printf("Choose a password for protecting your files.")
	} else {
		tlog.Info.Printf("Using password provided via -extpass.")
	}
	password := readpassword.Twice(args.extpass)
	creator := tlog.ProgramName + " " + GitVersion
	err = configfile.CreateConfFile(args.config, password, args.plaintextnames, args.scryptn, creator)
	if err != nil {
		tlog.Fatal.Println(err)
		os.Exit(ERREXIT_INIT)
	}

	if !args.plaintextnames {
		// Create gocryptfs.diriv in the root dir
		err = nametransform.WriteDirIV(args.cipherdir)
		if err != nil {
			tlog.Fatal.Println(err)
			os.Exit(ERREXIT_INIT)
		}
	}

	tlog.Info.Printf(tlog.ColorGreen + "The filesystem has been created successfully." + tlog.ColorReset)
	wd, _ := os.Getwd()
	friendlyPath, _ := filepath.Rel(wd, args.cipherdir)
	if strings.HasPrefix(friendlyPath, "../") {
		// A relative path that starts with "../" is pretty unfriendly, just
		// keep the absolute path.
		friendlyPath = args.cipherdir
	}
	tlog.Info.Printf(tlog.ColorGrey+"You can now mount it using: %s %s MOUNTPOINT"+tlog.ColorReset,
		tlog.ProgramName, friendlyPath)
	os.Exit(0)
}

func usageText() {
	printVersion()
	fmt.Printf(`
Usage: %s -init|-passwd [OPTIONS] CIPHERDIR
  or   %s [OPTIONS] CIPHERDIR MOUNTPOINT

Options:
`, tlog.ProgramName, tlog.ProgramName)

	flagSet.PrintDefaults()
}

// loadConfig - load the config file "filename", prompting the user for the password
func loadConfig(args *argContainer) (masterkey []byte, confFile *configfile.ConfFile) {
	// Check if the file exists at all before prompting for a password
	_, err := os.Stat(args.config)
	if err != nil {
		tlog.Fatal.Printf("Config file not found: %v", err)
		os.Exit(ERREXIT_LOADCONF)
	}
	pw := readpassword.Once(args.extpass)
	tlog.Info.Println("Decrypting master key")
	masterkey, confFile, err = configfile.LoadConfFile(args.config, pw)
	if err != nil {
		tlog.Fatal.Println(err)
		os.Exit(ERREXIT_LOADCONF)
	}

	return masterkey, confFile
}

// changePassword - change the password of config file "filename"
func changePassword(args *argContainer) {
	masterkey, confFile := loadConfig(args)
	tlog.Info.Println("Please enter your new password.")
	newPw := readpassword.Twice(args.extpass)
	confFile.EncryptKey(masterkey, newPw, confFile.ScryptObject.LogN())
	err := confFile.WriteFile()
	if err != nil {
		tlog.Fatal.Println(err)
		os.Exit(ERREXIT_INIT)
	}
	tlog.Info.Printf("Password changed.")
	os.Exit(0)
}

// printVersion - print a version string like
// "gocryptfs v0.3.1-31-g6736212-dirty; on-disk format 2"
func printVersion() {
	fmt.Printf("%s %s; go-fuse %s; %s\n",
		tlog.ProgramName, GitVersion, GitVersionFuse, runtime.Version())
}

func main() {
	runtime.GOMAXPROCS(4)
	var err error
	var args argContainer

	// Parse command line arguments
	var opensslAuto string
	flagSet = flag.NewFlagSet(tlog.ProgramName, flag.ExitOnError)
	flagSet.Usage = usageText
	flagSet.BoolVar(&args.debug, "d", false, "")
	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")
	// Tri-state true/false/auto
	flagSet.StringVar(&opensslAuto, "openssl", "auto", "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")
	flagSet.BoolVar(&args.quiet, "q", false, "")
	flagSet.BoolVar(&args.quiet, "quiet", false, "Quiet - silence informational messages")
	flagSet.BoolVar(&args.nosyslog, "nosyslog", false, "Do not redirect output to syslog when running in the background")
	flagSet.BoolVar(&args.wpanic, "wpanic", false, "When encountering a warning, panic and exit immediately")
	flagSet.BoolVar(&args.longnames, "longnames", true, "Store names longer than 176 bytes in extra files")
	flagSet.BoolVar(&args.allow_other, "allow_other", false, "Allow other users to access the filesystem. "+
		"Only works if user_allow_other is set in /etc/fuse.conf.")
	flagSet.BoolVar(&args.ro, "ro", false, "Mount the filesystem read-only")
	flagSet.StringVar(&args.masterkey, "masterkey", "", "Mount with explicit master key")
	flagSet.StringVar(&args.cpuprofile, "cpuprofile", "", "Write cpu profile to specified file")
	flagSet.StringVar(&args.memprofile, "memprofile", "", "Write memory profile to specified file")
	flagSet.StringVar(&args.config, "config", "", "Use specified config file instead of CIPHERDIR/gocryptfs.conf")
	flagSet.StringVar(&args.extpass, "extpass", "", "Use external program for the password prompt")
	flagSet.StringVar(&args.o, "o", "", "Pass additional mount options to the kernel, comma-separated list")
	flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+
		"successful mount - used internally for daemonization")
	flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. "+
		"Setting this to a lower value speeds up mounting but makes the password susceptible to brute-force attacks")
	flagSet.Parse(os.Args[1:])

	// "-openssl" needs some post-processing
	if opensslAuto == "auto" {
		args.openssl = prefer_openssl.PreferOpenSSL()
	} else {
		args.openssl, err = strconv.ParseBool(opensslAuto)
		if err != nil {
			tlog.Fatal.Printf("Invalid \"-openssl\" setting: %v", err)
			os.Exit(ERREXIT_USAGE)
		}
	}

	// Fork a child into the background if "-f" is not set AND we are mounting a filesystem
	if !args.foreground && flagSet.NArg() == 2 {
		forkChild() // does not return
	}
	if args.debug {
		tlog.Debug.Enabled = true
	}
	// "-v"
	if args.version {
		tlog.Debug.Printf("openssl=%v\n", args.openssl)
		tlog.Debug.Printf("on-disk format %d\n", contentenc.CurrentVersion)
		printVersion()
		os.Exit(0)
	}
	if args.wpanic {
		tlog.Warn.Wpanic = true
		tlog.Debug.Printf("Panicing on warnings")
	}
	// Every operation below requires CIPHERDIR. Check that we have it.
	if flagSet.NArg() >= 1 {
		args.cipherdir, _ = filepath.Abs(flagSet.Arg(0))
		err = checkDir(args.cipherdir)
		if err != nil {
			tlog.Fatal.Printf("Invalid cipherdir: %v", err)
			os.Exit(ERREXIT_CIPHERDIR)
		}
	} else {
		usageText()
		os.Exit(ERREXIT_USAGE)
	}
	// "-q"
	if args.quiet {
		tlog.Info.Enabled = false
	}
	// "-config"
	if args.config != "" {
		args.config, err = filepath.Abs(args.config)
		if err != nil {
			tlog.Fatal.Printf("Invalid \"-config\" setting: %v", err)
			os.Exit(ERREXIT_INIT)
		}
		tlog.Info.Printf("Using config file at custom location %s", args.config)
	} else {
		args.config = filepath.Join(args.cipherdir, configfile.ConfDefaultName)
	}
	// "-cpuprofile"
	if args.cpuprofile != "" {
		tlog.Info.Printf("Writing CPU profile to %s", args.cpuprofile)
		var f *os.File
		f, err = os.Create(args.cpuprofile)
		if err != nil {
			tlog.Fatal.Println(err)
			os.Exit(ERREXIT_INIT)
		}
		pprof.StartCPUProfile(f)
		defer pprof.StopCPUProfile()
	}
	// "-memprofile"
	if args.memprofile != "" {
		tlog.Info.Printf("Writing mem profile to %s", args.memprofile)
		var f *os.File
		f, err = os.Create(args.memprofile)
		if err != nil {
			tlog.Fatal.Println(err)
			os.Exit(ERREXIT_INIT)
		}
		defer func() {
			pprof.WriteHeapProfile(f)
			f.Close()
			return
		}()
	}
	if args.cpuprofile != "" || args.memprofile != "" {
		tlog.Info.Printf("Note: You must unmount gracefully, otherwise the profile file(s) will stay empty!\n")
	}
	// "-openssl"
	if args.openssl == false {
		tlog.Debug.Printf("OpenSSL disabled, using Go GCM")
	} else {
		tlog.Debug.Printf("OpenSSL enabled")
	}
	// Operation flags: init, passwd or mount
	// "-init"
	if args.init {
		if flagSet.NArg() > 1 {
			tlog.Fatal.Printf("Usage: %s -init [OPTIONS] CIPHERDIR", tlog.ProgramName)
			os.Exit(ERREXIT_USAGE)
		}
		initDir(&args) // does not return
	}
	// "-passwd"
	if args.passwd {
		if flagSet.NArg() > 1 {
			tlog.Fatal.Printf("Usage: %s -passwd [OPTIONS] CIPHERDIR", tlog.ProgramName)
			os.Exit(ERREXIT_USAGE)
		}
		changePassword(&args) // does not return
	}
	// Mount
	// Check mountpoint
	if flagSet.NArg() != 2 {
		tlog.Fatal.Printf("Usage: %s [OPTIONS] CIPHERDIR MOUNTPOINT", tlog.ProgramName)
		os.Exit(ERREXIT_USAGE)
	}
	args.mountpoint, err = filepath.Abs(flagSet.Arg(1))
	if err != nil {
		tlog.Fatal.Printf("Invalid mountpoint: %v", err)
		os.Exit(ERREXIT_MOUNTPOINT)
	}
	err = checkDirEmpty(args.mountpoint)
	if err != nil {
		tlog.Fatal.Printf("Invalid mountpoint: %v", err)
		os.Exit(ERREXIT_MOUNTPOINT)
	}
	// Get master key
	var masterkey []byte
	var confFile *configfile.ConfFile
	if args.masterkey != "" {
		// "-masterkey"
		tlog.Info.Printf("Using explicit master key.")
		masterkey = parseMasterKey(args.masterkey)
		tlog.Info.Printf("THE MASTER KEY IS VISIBLE VIA \"ps -auxwww\", ONLY USE THIS MODE FOR EMERGENCIES.")
	} else if args.zerokey {
		// "-zerokey"
		tlog.Info.Printf("Using all-zero dummy master key.")
		tlog.Info.Printf("ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING.")
		masterkey = make([]byte, cryptocore.KeyLen)
	} else {
		// Load master key from config file
		masterkey, confFile = loadConfig(&args)
		printMasterKey(masterkey)
	}
	// Initialize FUSE server
	tlog.Debug.Printf("cli args: %v", args)
	srv := initFuseFrontend(masterkey, args, confFile)
	tlog.Info.Println(tlog.ColorGreen + "Filesystem mounted and ready." + tlog.ColorReset)
	// We are ready - send USR1 signal to our parent and switch to syslog
	if args.notifypid > 0 {
		sendUsr1(args.notifypid)

		if !args.nosyslog {
			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)
		}
	}
	// Wait for SIGINT 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 exits with code 0
}

// initFuseFrontend - initialize gocryptfs/fusefrontend
// Calls os.Exit on errors
func initFuseFrontend(key []byte, args argContainer, confFile *configfile.ConfFile) *fuse.Server {

	// Reconciliate CLI and config file arguments into a Args struct that is passed to the
	// filesystem implementation
	frontendArgs := fusefrontend.Args{
		Cipherdir:      args.cipherdir,
		Masterkey:      key,
		OpenSSL:        args.openssl,
		PlaintextNames: args.plaintextnames,
		LongNames:      args.longnames,
	}
	// 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)
	}
	// 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))

	finalFs := fusefrontend.NewFS(frontendArgs)
	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
	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")
	}
	// Set values shown in "df -T" and friends
	// First column, "Filesystem"
	mOpts.Options = append(mOpts.Options, "fsname="+args.cipherdir)
	// Second column, "Type", will be shown as "fuse." + Name
	mOpts.Name = "gocryptfs"

	// The kernel enforces read-only operation, we just have to pass "ro".
	if args.ro {
		mOpts.Options = append(mOpts.Options, "ro")
	}
	// Add additional mount options (if any) after the stock ones, so the user has
	// a chance to override them.
	if args.o != "" {
		parts := strings.Split(args.o, ",")
		tlog.Debug.Printf("Adding -o 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("Mount failed: %v", err)
		os.Exit(ERREXIT_MOUNT)
	}
	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.Print(err)
			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(1)
	}()
}