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
|
% GOCRYPTFS(1)
% github.com/rfjakob
% Oct 2016
NAME
====
gocryptfs - mount an encrypted directory
SYNOPSIS
========
Initialize encrypted filesystem
-------------------------------
gocryptfs -init [OPTIONS] CIPHERDIR
Mount
-----
gocryptfs [OPTIONS] CIPHERDIR MOUNTPOINT [-o COMMA-SEPARATED-OPTIONS]
Change password
---------------
gocryptfs -passwd [OPTIONS] CIPHERDIR
DESCRIPTION
===========
Options:
**-aessiv**
: Use the AES-SIV encryption mode. This is slower than GCM but is
secure with deterministic nonces as used in "-reverse" mode.
**-allow_other**
: By default, the Linux kernel prevents any other user (even root) to
access a mounted FUSE filesystem. Settings this option allows access for
other users, subject to file permission checking. Only works if
user_allow_other is set in /etc/fuse.conf. This option is equivalent to
"allow_other" plus "default_permissions" described in fuse(8).
**-config string**
: Use specified config file instead of CIPHERDIR/gocryptfs.conf
**-cpuprofile string**
: Write cpu profile to specified file
**-ctlsock string**
: Create a control socket at the specified location. The socket can be
used to decrypt and encrypt paths inside the filesystem. When using
this option, make sure that the direcory you place the socket in is
not world-accessible. For example, `/run/user/UID/my.socket` would
be suitable.
**-d, -debug**
: Enable debug output
**-extpass string**
: Use an external program (like ssh-askpass) for the password prompt.
The program should return the password on stdout, a trailing newline is
stripped by gocryptfs. Using something like "cat /mypassword.txt" allows
to mount the gocryptfs filesytem without user interaction.
**-fg, -f**
: Stay in the foreground instead of forking away. Implies "-nosyslog".
For compatability, "-f" is also accepted, but "-fg" is preferred.
**-fsname string**
: Override the filesystem name (first column in df -T). Can also be
passed as "-o fsname=" and is equivalent to libfuse's option of the
same name. By default, CIPHERDIR is used.
**-fusedebug**
: Enable fuse library debug output
**-init**
: Initialize encrypted directory
**-ko**
: Pass additonal mount options to the kernel (comma-separated list).
FUSE filesystems are mounted with "nodev,nosuid" by default. If gocryptfs
runs as root, you can enable device files by passing the opposite mount option,
"dev", and if you want to enable suid-binaries, pass "suid".
"ro" (equivalent to passing the "-ro" option) and "noexec" may also be
interesting. For a complete list see the section
`FILESYSTEM-INDEPENDENT MOUNT OPTIONS` in mount(8).
**-longnames**
: Store names longer than 176 bytes in extra files (default true)
This flag is useful when recovering old gocryptfs filesystems using
"-masterkey". It is ignored (stays at the default) otherwise.
**-masterkey string**
: Use a explicit master key specified on the command line. This
option can be used to mount a gocryptfs filesystem without a config file.
Note that the command line, and with it the master key, is visible to
anybody on the machine who can execute "ps -auxwww".
This is meant as a recovery option for emergencies, such as if you have
forgotten your password.
Example master key:
6f717d8b-6b5f8e8a-fd0aa206-778ec093-62c5669b-abd229cd-241e00cd-b4d6713d
**-memprofile string**
: Write memory profile to the specified file. This is useful when debugging
memory usage of gocryptfs.
**-nonempty**
: Allow mounting over non-empty directories. FUSE by default disallows
this to prevent accidential shadowing of files.
**-noprealloc**
: Disable preallocation before writing. By default, gocryptfs
preallocates the space the next write will take using fallocate(2)
in mode FALLOC_FL_KEEP_SIZE. The preallocation makes sure it cannot
run out of space in the middle of the write, which would cause the
last 4kB block to be corrupt and unreadable.
On ext4, preallocation is fast and does not cause a
noticeable performance hit. Unfortunately, on Btrfs, preallocation
is very slow, especially on rotational HDDs. The "-noprealloc"
option gives users the choice to trade robustness against
out-of-space errors for a massive speedup.
For benchmarks and more details of the issue see
https://github.com/rfjakob/gocryptfs/issues/63 .
**-nosyslog**
: Diagnostic messages are normally redirected to syslog once gocryptfs
daemonizes. This option disables the redirection and messages will
continue be printed to stdout and stderr.
**-notifypid int**
: Send USR1 to the specified process after successful mount. This is
used internally for daemonization.
**-o COMMA-SEPARATED-OPTIONS**
: For compatibility with mount(1), options are also accepted as
"-o COMMA-SEPARATED-OPTIONS" at the end of the command line.
For example, "-o q,zerokey" is equivalent to passing "-q -zerokey".
**-openssl bool/"auto"**
: Use OpenSSL instead of built-in Go crypto (default "auto"). Using
built-in crypto is 4x slower unless your CPU has AES instructions and
you are using Go 1.6+. In mode "auto", gocrypts chooses the faster
option.
**-passfile string**
: Read password from the specified file. This is a shortcut for
specifying '-extpass="/bin/cat -- FILE"'.
**-passwd**
: Change the password. Will ask for the old password, check if it is
correct, and ask for a new one.
This can be used together with `-masterkey` if
you forgot the password but know the master key. Note that without the
old password, gocryptfs cannot tell if the master key is correct and will
overwrite the old one without mercy. It will, however, create a backup copy
of the old config file as `gocryptfs.conf.bak`. Delete it after
you have verified that you can access your files with the
new password.
**-plaintextnames**
: Do not encrypt file names and symlink targets
**-q, -quiet**
: Quiet - silence informational messages
**-raw64**
: Use unpadded base64 encoding for file names. This gets rid of the
trailing "\\=\\=". A filesystem created with this option can only be
mounted using gocryptfs v1.2 and higher.
**-reverse**
: Reverse mode shows a read-only encrypted view of a plaintext
directory. Implies "-aessiv".
**-ro**
: Mount the filesystem read-only
**-scryptn int**
: scrypt cost parameter logN. Setting this to a lower value speeds up
mounting but makes the password susceptible to brute-force attacks
(default 16)
**-version**
: Print version and exit. The output contains three fields seperated by ";".
Example: "gocryptfs v1.1.1-5-g75b776c; go-fuse 6b801d3; 2016-11-01 go1.7.3".
Field 1 is the gocryptfs version, field 2 is the version of the go-fuse
library, field 3 is the compile date and the Go version that was
used.
**-wpanic**
: When encountering a warning, panic and exit immediately. This is
useful in regression testing.
**-zerokey**
: Use all-zero dummy master key. This options is only intended for
automated testing as it does not provide any security.
**--**
: Stop option parsing. Helpful when CIPHERDIR may start with a
dash "-".
EXAMPLES
========
Create an encrypted filesystem in directory "g1" and mount it on "g2":
mkdir g1 g2
gocryptfs -init g1
gocryptfs g1 g2
Mount an ecrypted view of joe's home directory using reverse mode:
mkdir /home/joe.crypt
gocryptfs -init -reverse /home/joe
gocryptfs -reverse /home/joe /home/joe.crypt
EXIT CODES
==========
0: success
12: password incorrect
other: please check the error message
SEE ALSO
========
fuse(8) fallocate(2)
|
