15b88756ad
Device files and suid binaries are often not needed when running gocryptfs as root. As they are potentially dangerous, let the user enable them explicitely via the new "-o" option instead of always enabling them when running as root.
456 lines
15 KiB
Go
456 lines
15 KiB
Go
package main
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import (
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"encoding/json"
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"flag"
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"fmt"
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"log/syslog"
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"os"
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"os/exec"
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"os/signal"
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"path/filepath"
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"runtime"
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"runtime/pprof"
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"strconv"
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"strings"
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"syscall"
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"time"
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"github.com/hanwen/go-fuse/fuse"
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"github.com/hanwen/go-fuse/fuse/nodefs"
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"github.com/hanwen/go-fuse/fuse/pathfs"
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"github.com/rfjakob/gocryptfs/internal/configfile"
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"github.com/rfjakob/gocryptfs/internal/contentenc"
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"github.com/rfjakob/gocryptfs/internal/cryptocore"
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"github.com/rfjakob/gocryptfs/internal/fusefrontend"
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"github.com/rfjakob/gocryptfs/internal/nametransform"
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"github.com/rfjakob/gocryptfs/internal/prefer_openssl"
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"github.com/rfjakob/gocryptfs/internal/readpassword"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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const (
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// Exit codes
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ERREXIT_USAGE = 1
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ERREXIT_MOUNT = 3
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ERREXIT_CIPHERDIR = 6
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ERREXIT_INIT = 7
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ERREXIT_LOADCONF = 8
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ERREXIT_MOUNTPOINT = 10
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)
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type argContainer struct {
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debug, init, zerokey, fusedebug, openssl, passwd, foreground, version,
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plaintextnames, quiet, nosyslog, wpanic,
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longnames, allow_other, ro bool
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masterkey, mountpoint, cipherdir, cpuprofile, config, extpass,
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memprofile, o string
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notifypid, scryptn int
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}
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var flagSet *flag.FlagSet
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// GitVersion will be set by the build script "build.bash"
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var GitVersion = "[version not set - please compile using ./build.bash]"
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var GitVersionFuse = "[version not set - please compile using ./build.bash]"
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// initDir initializes an empty directory for use as a gocryptfs cipherdir.
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func initDir(args *argContainer) {
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err := checkDirEmpty(args.cipherdir)
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if err != nil {
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tlog.Fatal.Printf("Invalid cipherdir: %v", err)
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os.Exit(ERREXIT_INIT)
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}
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// Create gocryptfs.conf
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if args.extpass == "" {
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tlog.Info.Printf("Choose a password for protecting your files.")
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} else {
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tlog.Info.Printf("Using password provided via -extpass.")
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}
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password := readpassword.Twice(args.extpass)
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creator := tlog.ProgramName + " " + GitVersion
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err = configfile.CreateConfFile(args.config, password, args.plaintextnames, args.scryptn, creator)
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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if !args.plaintextnames {
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// Create gocryptfs.diriv in the root dir
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err = nametransform.WriteDirIV(args.cipherdir)
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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}
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tlog.Info.Printf(tlog.ColorGreen + "The filesystem has been created successfully." + tlog.ColorReset)
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wd, _ := os.Getwd()
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friendlyPath, _ := filepath.Rel(wd, args.cipherdir)
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if strings.HasPrefix(friendlyPath, "../") {
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// A relative path that starts with "../" is pretty unfriendly, just
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// keep the absolute path.
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friendlyPath = args.cipherdir
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}
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tlog.Info.Printf(tlog.ColorGrey+"You can now mount it using: %s %s MOUNTPOINT"+tlog.ColorReset,
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tlog.ProgramName, friendlyPath)
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os.Exit(0)
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}
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func usageText() {
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printVersion()
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fmt.Printf(`
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Usage: %s -init|-passwd [OPTIONS] CIPHERDIR
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or %s [OPTIONS] CIPHERDIR MOUNTPOINT
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Options:
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`, tlog.ProgramName, tlog.ProgramName)
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flagSet.PrintDefaults()
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}
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// loadConfig - load the config file "filename", prompting the user for the password
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func loadConfig(args *argContainer) (masterkey []byte, confFile *configfile.ConfFile) {
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// Check if the file exists at all before prompting for a password
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_, err := os.Stat(args.config)
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if err != nil {
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tlog.Fatal.Printf("Config file not found: %v", err)
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os.Exit(ERREXIT_LOADCONF)
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}
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pw := readpassword.Once(args.extpass)
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tlog.Info.Println("Decrypting master key")
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masterkey, confFile, err = configfile.LoadConfFile(args.config, pw)
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_LOADCONF)
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}
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return masterkey, confFile
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}
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// changePassword - change the password of config file "filename"
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func changePassword(args *argContainer) {
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masterkey, confFile := loadConfig(args)
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tlog.Info.Println("Please enter your new password.")
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newPw := readpassword.Twice(args.extpass)
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confFile.EncryptKey(masterkey, newPw, confFile.ScryptObject.LogN())
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err := confFile.WriteFile()
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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tlog.Info.Printf("Password changed.")
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os.Exit(0)
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}
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// printVersion - print a version string like
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// "gocryptfs v0.3.1-31-g6736212-dirty; on-disk format 2"
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func printVersion() {
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fmt.Printf("%s %s; go-fuse %s; %s\n",
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tlog.ProgramName, GitVersion, GitVersionFuse, runtime.Version())
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}
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func main() {
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runtime.GOMAXPROCS(4)
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var err error
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var args argContainer
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// Parse command line arguments
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var opensslAuto string
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flagSet = flag.NewFlagSet(tlog.ProgramName, flag.ExitOnError)
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flagSet.Usage = usageText
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flagSet.BoolVar(&args.debug, "d", false, "")
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flagSet.BoolVar(&args.debug, "debug", false, "Enable debug output")
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flagSet.BoolVar(&args.fusedebug, "fusedebug", false, "Enable fuse library debug output")
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flagSet.BoolVar(&args.init, "init", false, "Initialize encrypted directory")
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flagSet.BoolVar(&args.zerokey, "zerokey", false, "Use all-zero dummy master key")
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// Tri-state true/false/auto
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flagSet.StringVar(&opensslAuto, "openssl", "auto", "Use OpenSSL instead of built-in Go crypto")
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flagSet.BoolVar(&args.passwd, "passwd", false, "Change password")
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flagSet.BoolVar(&args.foreground, "f", false, "Stay in the foreground")
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flagSet.BoolVar(&args.version, "version", false, "Print version and exit")
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flagSet.BoolVar(&args.plaintextnames, "plaintextnames", false, "Do not encrypt file names")
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flagSet.BoolVar(&args.quiet, "q", false, "")
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flagSet.BoolVar(&args.quiet, "quiet", false, "Quiet - silence informational messages")
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flagSet.BoolVar(&args.nosyslog, "nosyslog", false, "Do not redirect output to syslog when running in the background")
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flagSet.BoolVar(&args.wpanic, "wpanic", false, "When encountering a warning, panic and exit immediately")
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flagSet.BoolVar(&args.longnames, "longnames", true, "Store names longer than 176 bytes in extra files")
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flagSet.BoolVar(&args.allow_other, "allow_other", false, "Allow other users to access the filesystem. "+
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"Only works if user_allow_other is set in /etc/fuse.conf.")
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flagSet.BoolVar(&args.ro, "ro", false, "Mount the filesystem read-only")
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flagSet.StringVar(&args.masterkey, "masterkey", "", "Mount with explicit master key")
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flagSet.StringVar(&args.cpuprofile, "cpuprofile", "", "Write cpu profile to specified file")
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flagSet.StringVar(&args.memprofile, "memprofile", "", "Write memory profile to specified file")
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flagSet.StringVar(&args.config, "config", "", "Use specified config file instead of CIPHERDIR/gocryptfs.conf")
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flagSet.StringVar(&args.extpass, "extpass", "", "Use external program for the password prompt")
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flagSet.StringVar(&args.o, "o", "", "Pass additional mount options to the kernel, comma-separated list")
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flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+
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"successful mount - used internally for daemonization")
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flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. "+
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"Setting this to a lower value speeds up mounting but makes the password susceptible to brute-force attacks")
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flagSet.Parse(os.Args[1:])
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// "-openssl" needs some post-processing
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if opensslAuto == "auto" {
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args.openssl = prefer_openssl.PreferOpenSSL()
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} else {
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args.openssl, err = strconv.ParseBool(opensslAuto)
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if err != nil {
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tlog.Fatal.Printf("Invalid \"-openssl\" setting: %v", err)
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os.Exit(ERREXIT_USAGE)
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}
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}
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// Fork a child into the background if "-f" is not set AND we are mounting a filesystem
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if !args.foreground && flagSet.NArg() == 2 {
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forkChild() // does not return
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}
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if args.debug {
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tlog.Debug.Enabled = true
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}
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// "-v"
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if args.version {
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tlog.Debug.Printf("openssl=%v\n", args.openssl)
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tlog.Debug.Printf("on-disk format %d\n", contentenc.CurrentVersion)
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printVersion()
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os.Exit(0)
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}
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if args.wpanic {
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tlog.Warn.Wpanic = true
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tlog.Debug.Printf("Panicing on warnings")
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}
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// Every operation below requires CIPHERDIR. Check that we have it.
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if flagSet.NArg() >= 1 {
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args.cipherdir, _ = filepath.Abs(flagSet.Arg(0))
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err = checkDir(args.cipherdir)
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if err != nil {
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tlog.Fatal.Printf("Invalid cipherdir: %v", err)
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os.Exit(ERREXIT_CIPHERDIR)
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}
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} else {
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usageText()
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os.Exit(ERREXIT_USAGE)
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}
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// "-q"
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if args.quiet {
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tlog.Info.Enabled = false
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}
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// "-config"
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if args.config != "" {
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args.config, err = filepath.Abs(args.config)
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if err != nil {
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tlog.Fatal.Printf("Invalid \"-config\" setting: %v", err)
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os.Exit(ERREXIT_INIT)
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}
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tlog.Info.Printf("Using config file at custom location %s", args.config)
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} else {
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args.config = filepath.Join(args.cipherdir, configfile.ConfDefaultName)
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}
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// "-cpuprofile"
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if args.cpuprofile != "" {
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tlog.Info.Printf("Writing CPU profile to %s", args.cpuprofile)
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var f *os.File
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f, err = os.Create(args.cpuprofile)
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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pprof.StartCPUProfile(f)
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defer pprof.StopCPUProfile()
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}
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// "-memprofile"
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if args.memprofile != "" {
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tlog.Info.Printf("Writing mem profile to %s", args.memprofile)
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var f *os.File
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f, err = os.Create(args.memprofile)
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if err != nil {
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tlog.Fatal.Println(err)
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os.Exit(ERREXIT_INIT)
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}
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defer func() {
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pprof.WriteHeapProfile(f)
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f.Close()
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return
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}()
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}
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if args.cpuprofile != "" || args.memprofile != "" {
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tlog.Info.Printf("Note: You must unmount gracefully, otherwise the profile file(s) will stay empty!\n")
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}
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// "-openssl"
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if args.openssl == false {
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tlog.Debug.Printf("OpenSSL disabled, using Go GCM")
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} else {
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tlog.Debug.Printf("OpenSSL enabled")
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}
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// Operation flags: init, passwd or mount
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// "-init"
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if args.init {
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if flagSet.NArg() > 1 {
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tlog.Fatal.Printf("Usage: %s -init [OPTIONS] CIPHERDIR", tlog.ProgramName)
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os.Exit(ERREXIT_USAGE)
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}
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initDir(&args) // does not return
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}
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// "-passwd"
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if args.passwd {
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if flagSet.NArg() > 1 {
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tlog.Fatal.Printf("Usage: %s -passwd [OPTIONS] CIPHERDIR", tlog.ProgramName)
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os.Exit(ERREXIT_USAGE)
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}
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changePassword(&args) // does not return
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}
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// Mount
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// Check mountpoint
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if flagSet.NArg() != 2 {
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tlog.Fatal.Printf("Usage: %s [OPTIONS] CIPHERDIR MOUNTPOINT", tlog.ProgramName)
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os.Exit(ERREXIT_USAGE)
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}
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args.mountpoint, err = filepath.Abs(flagSet.Arg(1))
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if err != nil {
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tlog.Fatal.Printf("Invalid mountpoint: %v", err)
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os.Exit(ERREXIT_MOUNTPOINT)
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}
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err = checkDirEmpty(args.mountpoint)
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if err != nil {
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tlog.Fatal.Printf("Invalid mountpoint: %v", err)
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os.Exit(ERREXIT_MOUNTPOINT)
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}
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// Get master key
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var masterkey []byte
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var confFile *configfile.ConfFile
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if args.masterkey != "" {
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// "-masterkey"
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tlog.Info.Printf("Using explicit master key.")
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masterkey = parseMasterKey(args.masterkey)
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tlog.Info.Printf("THE MASTER KEY IS VISIBLE VIA \"ps -auxwww\", ONLY USE THIS MODE FOR EMERGENCIES.")
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} else if args.zerokey {
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// "-zerokey"
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tlog.Info.Printf("Using all-zero dummy master key.")
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tlog.Info.Printf("ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING.")
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masterkey = make([]byte, cryptocore.KeyLen)
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} else {
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// Load master key from config file
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masterkey, confFile = loadConfig(&args)
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printMasterKey(masterkey)
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}
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// Initialize FUSE server
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tlog.Debug.Printf("cli args: %v", args)
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srv := initFuseFrontend(masterkey, args, confFile)
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tlog.Info.Println(tlog.ColorGreen + "Filesystem mounted and ready." + tlog.ColorReset)
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// We are ready - send USR1 signal to our parent and switch to syslog
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if args.notifypid > 0 {
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sendUsr1(args.notifypid)
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if !args.nosyslog {
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tlog.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_INFO)
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tlog.Debug.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_DEBUG)
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tlog.Warn.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_WARNING)
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}
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}
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// Wait for SIGINT in the background and unmount ourselves if we get it.
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// This prevents a dangling "Transport endpoint is not connected" mountpoint.
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handleSigint(srv, args.mountpoint)
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// Jump into server loop. Returns when it gets an umount request from the kernel.
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srv.Serve()
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// main exits with code 0
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}
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// initFuseFrontend - initialize gocryptfs/fusefrontend
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// Calls os.Exit on errors
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func initFuseFrontend(key []byte, args argContainer, confFile *configfile.ConfFile) *fuse.Server {
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// Reconciliate CLI and config file arguments into a Args struct that is passed to the
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// filesystem implementation
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frontendArgs := fusefrontend.Args{
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Cipherdir: args.cipherdir,
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Masterkey: key,
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OpenSSL: args.openssl,
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PlaintextNames: args.plaintextnames,
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LongNames: args.longnames,
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}
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// confFile is nil when "-zerokey" or "-masterkey" was used
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if confFile != nil {
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// Settings from the config file override command line args
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frontendArgs.PlaintextNames = confFile.IsFeatureFlagSet(configfile.FlagPlaintextNames)
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}
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// If allow_other is set and we run as root, try to give newly created files to
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// the right user.
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if args.allow_other && os.Getuid() == 0 {
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frontendArgs.PreserveOwner = true
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}
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jsonBytes, _ := json.MarshalIndent(frontendArgs, "", "\t")
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tlog.Debug.Printf("frontendArgs: %s", string(jsonBytes))
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finalFs := fusefrontend.NewFS(frontendArgs)
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pathFsOpts := &pathfs.PathNodeFsOptions{ClientInodes: true}
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pathFs := pathfs.NewPathNodeFs(finalFs, pathFsOpts)
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fuseOpts := &nodefs.Options{
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// These options are to be compatible with libfuse defaults,
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// making benchmarking easier.
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NegativeTimeout: time.Second,
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AttrTimeout: time.Second,
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EntryTimeout: time.Second,
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}
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conn := nodefs.NewFileSystemConnector(pathFs.Root(), fuseOpts)
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var mOpts fuse.MountOptions
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mOpts.AllowOther = false
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if args.allow_other {
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tlog.Info.Printf(tlog.ColorYellow + "The option \"-allow_other\" is set. Make sure the file " +
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"permissions protect your data from unwanted access." + tlog.ColorReset)
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mOpts.AllowOther = true
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// Make the kernel check the file permissions for us
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mOpts.Options = append(mOpts.Options, "default_permissions")
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}
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// Set values shown in "df -T" and friends
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// First column, "Filesystem"
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mOpts.Options = append(mOpts.Options, "fsname="+args.cipherdir)
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// Second column, "Type", will be shown as "fuse." + Name
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mOpts.Name = "gocryptfs"
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// The kernel enforces read-only operation, we just have to pass "ro".
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if args.ro {
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mOpts.Options = append(mOpts.Options, "ro")
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}
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// Add additional mount options (if any) after the stock ones, so the user has
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// a chance to override them.
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if args.o != "" {
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parts := strings.Split(args.o, ",")
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tlog.Debug.Printf("Adding -o mount options: %v", parts)
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mOpts.Options = append(mOpts.Options, parts...)
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}
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srv, err := fuse.NewServer(conn.RawFS(), args.mountpoint, &mOpts)
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if err != nil {
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tlog.Fatal.Printf("Mount failed: %v", err)
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os.Exit(ERREXIT_MOUNT)
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}
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srv.SetDebug(args.fusedebug)
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// All FUSE file and directory create calls carry explicit permission
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// information. We need an unrestricted umask to create the files and
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// directories with the requested permissions.
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syscall.Umask(0000)
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return srv
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}
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func handleSigint(srv *fuse.Server, mountpoint string) {
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ch := make(chan os.Signal, 1)
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signal.Notify(ch, os.Interrupt)
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signal.Notify(ch, syscall.SIGTERM)
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go func() {
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<-ch
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err := srv.Unmount()
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if err != nil {
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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)
|
|
}()
|
|
}
|