aboutsummaryrefslogtreecommitdiff
path: root/cli_args.go
blob: 1314ed73a9f75200712d756a32f6aca5b37fa68d (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
package main

import (
	"flag"
	"fmt"
	"net"
	"os"
	"strconv"
	"strings"

	"github.com/hanwen/go-fuse/fuse"
	"github.com/rfjakob/gocryptfs/internal/configfile"
	"github.com/rfjakob/gocryptfs/internal/exitcodes"
	"github.com/rfjakob/gocryptfs/internal/prefer_openssl"
	"github.com/rfjakob/gocryptfs/internal/stupidgcm"
	"github.com/rfjakob/gocryptfs/internal/tlog"
)

// argContainer stores the parsed CLI options and arguments
type argContainer struct {
	debug, init, zerokey, fusedebug, openssl, passwd, fg, version,
	plaintextnames, quiet, nosyslog, wpanic,
	longnames, allow_other, reverse, aessiv, nonempty, raw64,
	noprealloc, speed, hkdf, serialize_reads, forcedecode, hh, info,
	sharedstorage, devrandom, fsck, trezor bool
	// Mount options with opposites
	dev, nodev, suid, nosuid, exec, noexec, rw, ro bool
	masterkey, mountpoint, cipherdir, cpuprofile, extpass,
	memprofile, ko, passfile, ctlsock, fsname, force_owner, trace string
	// Configuration file name override
	config             string
	notifypid, scryptn int
	// Helper variables that are NOT cli options all start with an underscore
	// _configCustom is true when the user sets a custom config file name.
	_configCustom bool
	// _ctlsockFd stores the control socket file descriptor (ctlsock stores the path)
	_ctlsockFd net.Listener
	// _forceOwner is, if non-nil, a parsed, validated Owner (as opposed to the string above)
	_forceOwner *fuse.Owner
}

type multipleStrings []string

func (s *multipleStrings) String() string {
	s2 := []string(*s)
	return fmt.Sprint(s2)
}

func (s *multipleStrings) Set(val string) error {
	*s = append(*s, val)
	return nil
}

var flagSet *flag.FlagSet

// prefixOArgs transform options passed via "-o foo,bar" into regular options
// like "-foo -bar" and prefixes them to the command line.
// Testcases in TestPrefixOArgs().
func prefixOArgs(osArgs []string) ([]string, error) {
	// Need at least 3, example: gocryptfs -o    foo,bar
	//                               ^ 0    ^ 1    ^ 2
	if len(osArgs) < 3 {
		return osArgs, nil
	}
	// Passing "--" disables "-o" parsing. Ignore element 0 (program name).
	for _, v := range osArgs[1:] {
		if v == "--" {
			return osArgs, nil
		}
	}
	// Find and extract "-o foo,bar"
	var otherArgs, oOpts []string
	for i := 1; i < len(osArgs); i++ {
		if osArgs[i] == "-o" {
			// Last argument?
			if i+1 >= len(osArgs) {
				return nil, fmt.Errorf("The \"-o\" option requires an argument")
			}
			oOpts = strings.Split(osArgs[i+1], ",")
			// Skip over the arguments to "-o"
			i++
		} else if strings.HasPrefix(osArgs[i], "-o=") {
			oOpts = strings.Split(osArgs[i][3:], ",")
		} else {
			otherArgs = append(otherArgs, osArgs[i])
		}
	}
	// Start with program name
	newArgs := []string{osArgs[0]}
	// Add options from "-o"
	for _, o := range oOpts {
		if o == "" {
			continue
		}
		if o == "o" || o == "-o" {
			tlog.Fatal.Printf("You can't pass \"-o\" to \"-o\"")
			os.Exit(exitcodes.Usage)
		}
		newArgs = append(newArgs, "-"+o)
	}
	// Add other arguments
	newArgs = append(newArgs, otherArgs...)
	return newArgs, nil
}

// parseCliOpts - parse command line options (i.e. arguments that start with "-")
func parseCliOpts() (args argContainer) {
	var err error
	var opensslAuto string

	os.Args, err = prefixOArgs(os.Args)
	if err != nil {
		tlog.Fatal.Println(err)
		os.Exit(exitcodes.Usage)
	}

	flagSet = flag.NewFlagSet(tlog.ProgramName, flag.ContinueOnError)
	flagSet.Usage = func() {}
	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.fg, "f", false, "")
	flagSet.BoolVar(&args.fg, "fg", 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.reverse, "reverse", false, "Reverse mode")
	flagSet.BoolVar(&args.aessiv, "aessiv", false, "AES-SIV encryption")
	flagSet.BoolVar(&args.nonempty, "nonempty", false, "Allow mounting over non-empty directories")
	flagSet.BoolVar(&args.raw64, "raw64", true, "Use unpadded base64 for file names")
	flagSet.BoolVar(&args.noprealloc, "noprealloc", false, "Disable preallocation before writing")
	flagSet.BoolVar(&args.speed, "speed", false, "Run crypto speed test")
	flagSet.BoolVar(&args.hkdf, "hkdf", true, "Use HKDF as an additional key derivation step")
	flagSet.BoolVar(&args.serialize_reads, "serialize_reads", false, "Try to serialize read operations")
	flagSet.BoolVar(&args.forcedecode, "forcedecode", false, "Force decode of files even if integrity check fails."+
		" Requires gocryptfs to be compiled with openssl support and implies -openssl true")
	flagSet.BoolVar(&args.hh, "hh", false, "Show this long help text")
	flagSet.BoolVar(&args.info, "info", false, "Display information about CIPHERDIR")
	flagSet.BoolVar(&args.sharedstorage, "sharedstorage", false, "Make concurrent access to a shared CIPHERDIR safer")
	flagSet.BoolVar(&args.devrandom, "devrandom", false, "Use /dev/random for generating master key")
	flagSet.BoolVar(&args.fsck, "fsck", false, "Run a filesystem check on CIPHERDIR")
	flagSet.BoolVar(&args.trezor, "trezor", false, "Protect the masterkey using a SatoshiLabs Trezor instead of a password")

	// Mount options with opposites
	flagSet.BoolVar(&args.dev, "dev", false, "Allow device files")
	flagSet.BoolVar(&args.nodev, "nodev", false, "Deny device files")
	flagSet.BoolVar(&args.suid, "suid", false, "Allow suid binaries")
	flagSet.BoolVar(&args.nosuid, "nosuid", false, "Deny suid binaries")
	flagSet.BoolVar(&args.exec, "exec", false, "Allow executables")
	flagSet.BoolVar(&args.noexec, "noexec", false, "Deny executables")
	flagSet.BoolVar(&args.rw, "rw", false, "Mount the filesystem read-write")
	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.passfile, "passfile", "", "Read password from file")
	flagSet.StringVar(&args.ko, "ko", "", "Pass additional options directly to the kernel, comma-separated list")
	flagSet.StringVar(&args.ctlsock, "ctlsock", "", "Create control socket at specified path")
	flagSet.StringVar(&args.fsname, "fsname", "", "Override the filesystem name")
	flagSet.StringVar(&args.force_owner, "force_owner", "", "uid:gid pair to coerce ownership")
	flagSet.StringVar(&args.trace, "trace", "", "Write execution trace to file")
	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. Possible values: 10-28. "+
		"A lower value speeds up mounting and reduces its memory needs, but makes the password susceptible to brute-force attacks")
	var dummyString string
	flagSet.StringVar(&dummyString, "o", "", "For compatibility with mount(1), options can be also passed as a comma-separated list to -o on the end.")
	// Actual parsing
	err = flagSet.Parse(os.Args[1:])
	if err == flag.ErrHelp {
		helpShort()
		os.Exit(0)
	}
	if err != nil {
		tlog.Fatal.Printf("Invalid command line: %s. Try '%s -help'.", prettyArgs(), tlog.ProgramName)
		os.Exit(exitcodes.Usage)
	}
	// "-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(exitcodes.Usage)
		}
	}
	// "-forcedecode" only works with openssl. Check compilation and command line parameters
	if args.forcedecode == true {
		if stupidgcm.BuiltWithoutOpenssl == true {
			tlog.Fatal.Printf("The -forcedecode flag requires openssl support, but gocryptfs was compiled without it!")
			os.Exit(exitcodes.Usage)
		}
		if args.aessiv == true {
			tlog.Fatal.Printf("The -forcedecode and -aessiv flags are incompatible because they use different crypto libs (openssl vs native Go)")
			os.Exit(exitcodes.Usage)
		}
		if args.reverse == true {
			tlog.Fatal.Printf("The reverse mode and the -forcedecode option are not compatible")
			os.Exit(exitcodes.Usage)
		}
		// Has the user explicitly disabled openssl using "-openssl=false/0"?
		if !args.openssl && opensslAuto != "auto" {
			tlog.Fatal.Printf("-forcedecode requires openssl, but is disabled via command-line option")
			os.Exit(exitcodes.Usage)
		}
		args.openssl = true

		// Try to make it harder for the user to shoot himself in the foot.
		args.ro = true
		args.allow_other = false
		args.ko = "noexec"
	}
	// '-passfile FILE' is a shortcut for -extpass='/bin/cat -- FILE'
	if args.passfile != "" {
		args.extpass = "/bin/cat -- " + args.passfile
	}
	if args.extpass != "" && args.masterkey != "" {
		tlog.Fatal.Printf("The options -extpass and -masterkey cannot be used at the same time")
		os.Exit(exitcodes.Usage)
	}
	if args.extpass != "" && args.trezor {
		tlog.Fatal.Printf("The options -extpass and -trezor cannot be used at the same time")
		os.Exit(exitcodes.Usage)
	}
	return args
}

// prettyArgs pretty-prints the command-line arguments.
func prettyArgs() string {
	pa := fmt.Sprintf("%v", os.Args)
	// Get rid of "[" and "]"
	pa = pa[1 : len(pa)-1]
	return pa
}

// countOpFlags counts the number of operation flags we were passed.
func countOpFlags(args *argContainer) int {
	var count int
	if args.info {
		count++
	}
	if args.passwd {
		count++
	}
	if args.init {
		count++
	}
	if args.fsck {
		count++
	}
	return count
}