libgocryptfs/Documentation/MANPAGE.md

5.5 KiB

% 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
-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.
-f
Stay in the foreground instead of forking away. Implies "-nosyslog".
-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.
-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.
-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
-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 v0.12-2; go-fuse a4c968c; go1.6.2". Field 1 is the gocryptfs version, field 2 is the version of the go-fuse library, field 3 is the Go version that was used to compile the binary.
-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.

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 "-q -zerokey".

EXAMPLES

Create and mount an encrypted filesystem:

mkdir /tmp/g1 /tmp/g2

gocryptfs -init /tmp/g1
gocryptfs /tmp/g1 /tmp/g2

SEE ALSO

fuse(8)