libgocryptfs/main.go
Jakob Unterwurzacher adf7d75d31 main: changePassword: zero masterkey
Overwrite the masterkey with zeros once we
have encrypted it, and let it run out of scope.

Also get rid of the password duplicate in
readpassword.Twice.
2018-02-18 15:36:14 +01:00

289 lines
8.5 KiB
Go

package main
import (
"fmt"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"github.com/hanwen/go-fuse/fuse"
"github.com/rfjakob/gocryptfs/internal/configfile"
"github.com/rfjakob/gocryptfs/internal/contentenc"
"github.com/rfjakob/gocryptfs/internal/exitcodes"
"github.com/rfjakob/gocryptfs/internal/readpassword"
"github.com/rfjakob/gocryptfs/internal/speed"
"github.com/rfjakob/gocryptfs/internal/stupidgcm"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
// GitVersion is the gocryptfs version according to git, set by build.bash
var GitVersion = "[GitVersion not set - please compile using ./build.bash]"
// GitVersionFuse is the go-fuse library version, set by build.bash
var GitVersionFuse = "[GitVersionFuse not set - please compile using ./build.bash]"
// BuildDate is a date string like "2017-09-06", set by build.bash
var BuildDate = "0000-00-00"
// raceDetector is set to true by race.go if we are compiled with "go build -race"
var raceDetector bool
// loadConfig loads the config file "args.config", prompting the user for the password
func loadConfig(args *argContainer) (masterkey []byte, confFile *configfile.ConfFile, err error) {
// Check if the file can be opened at all before prompting for a password
fd, err := os.Open(args.config)
if err != nil {
tlog.Fatal.Printf("Cannot open config file: %v", err)
return nil, nil, exitcodes.NewErr(err.Error(), exitcodes.OpenConf)
}
fd.Close()
// The user has passed the master key (probably because he forgot the
// password).
if args.masterkey != "" {
masterkey = parseMasterKey(args.masterkey)
_, confFile, err = configfile.LoadConfFile(args.config, nil)
} else {
pw := readpassword.Once(args.extpass)
tlog.Info.Println("Decrypting master key")
masterkey, confFile, err = configfile.LoadConfFile(args.config, pw)
for i := range pw {
pw[i] = 0
}
}
if err != nil {
tlog.Fatal.Println(err)
return nil, nil, err
}
return masterkey, confFile, nil
}
// changePassword - change the password of config file "filename"
// Does not return (calls os.Exit both on success and on error).
func changePassword(args *argContainer) {
var confFile *configfile.ConfFile
var err error
{
var masterkey []byte
masterkey, confFile, err = loadConfig(args)
if err != nil {
exitcodes.Exit(err)
}
tlog.Info.Println("Please enter your new password.")
newPw := readpassword.Twice(args.extpass)
readpassword.CheckTrailingGarbage()
confFile.EncryptKey(masterkey, newPw, confFile.ScryptObject.LogN())
for i := range newPw {
newPw[i] = 0
}
for i := range masterkey {
masterkey[i] = 0
}
// masterkey and newPw run out of scope here
}
// Are we resetting the password without knowing the old one using
// "-masterkey"?
if args.masterkey != "" {
bak := args.config + ".bak"
err = os.Link(args.config, bak)
if err != nil {
tlog.Fatal.Printf("Could not create backup file: %v", err)
os.Exit(exitcodes.Init)
}
tlog.Info.Printf(tlog.ColorGrey+
"A copy of the old config file has been created at %q.\n"+
"Delete it after you have verified that you can access your files with the new password."+
tlog.ColorReset, bak)
}
err = confFile.WriteFile()
if err != nil {
tlog.Fatal.Println(err)
os.Exit(exitcodes.WriteConf)
}
tlog.Info.Printf(tlog.ColorGreen + "Password changed." + tlog.ColorReset)
os.Exit(0)
}
// printVersion prints a version string like this:
// gocryptfs v0.12-36-ge021b9d-dirty; go-fuse a4c968c; 2016-07-03 go1.6.2
func printVersion() {
buildFlags := ""
if stupidgcm.BuiltWithoutOpenssl {
buildFlags = " without_openssl"
}
built := fmt.Sprintf("%s %s", BuildDate, runtime.Version())
if raceDetector {
built += " -race"
}
fmt.Printf("%s %s%s; go-fuse %s; %s\n",
tlog.ProgramName, GitVersion, buildFlags, GitVersionFuse, built)
}
func main() {
mxp := runtime.GOMAXPROCS(0)
if mxp < 4 {
// On a 2-core machine, setting maxprocs to 4 gives 10% better performance
runtime.GOMAXPROCS(4)
}
var err error
// Parse all command-line options (i.e. arguments starting with "-")
// into "args". Path arguments are parsed below.
args := parseCliOpts()
// Fork a child into the background if "-fg" is not set AND we are mounting
// a filesystem. The child will do all the work.
if !args.fg && flagSet.NArg() == 2 {
ret := forkChild()
os.Exit(ret)
}
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)
}
// "-hh"
if args.hh {
helpLong()
os.Exit(0)
}
// "-speed"
if args.speed {
speed.Run()
os.Exit(0)
}
if args.wpanic {
tlog.Warn.Wpanic = true
tlog.Debug.Printf("Panicking on warnings")
}
// Every operation below requires CIPHERDIR. Exit if we don't have it.
if flagSet.NArg() == 0 {
if flagSet.NFlag() == 0 {
// Naked call to "gocryptfs". Just print the help text.
helpShort()
} else {
// The user has passed some flags, but CIPHERDIR is missing. State
// what is wrong.
tlog.Fatal.Printf("CIPHERDIR argument is missing")
}
os.Exit(exitcodes.Usage)
}
// Check that CIPHERDIR exists
args.cipherdir, _ = filepath.Abs(flagSet.Arg(0))
err = checkDir(args.cipherdir)
if err != nil {
tlog.Fatal.Printf("Invalid cipherdir: %v", err)
os.Exit(exitcodes.CipherDir)
}
// "-q"
if args.quiet {
tlog.Info.Enabled = false
}
// "-reverse" implies "-aessiv"
if args.reverse {
args.aessiv = true
}
// "-config"
if args.config != "" {
args.config, err = filepath.Abs(args.config)
if err != nil {
tlog.Fatal.Printf("Invalid \"-config\" setting: %v", err)
os.Exit(exitcodes.Init)
}
tlog.Info.Printf("Using config file at custom location %s", args.config)
args._configCustom = true
} else if args.reverse {
args.config = filepath.Join(args.cipherdir, configfile.ConfReverseName)
} else {
args.config = filepath.Join(args.cipherdir, configfile.ConfDefaultName)
}
// "-force_owner"
if args.force_owner != "" {
var uidNum, gidNum int64
ownerPieces := strings.SplitN(args.force_owner, ":", 2)
if len(ownerPieces) != 2 {
tlog.Fatal.Printf("force_owner must be in form UID:GID")
os.Exit(exitcodes.Usage)
}
uidNum, err = strconv.ParseInt(ownerPieces[0], 0, 32)
if err != nil || uidNum < 0 {
tlog.Fatal.Printf("force_owner: Unable to parse UID %v as positive integer", ownerPieces[0])
os.Exit(exitcodes.Usage)
}
gidNum, err = strconv.ParseInt(ownerPieces[1], 0, 32)
if err != nil || gidNum < 0 {
tlog.Fatal.Printf("force_owner: Unable to parse GID %v as positive integer", ownerPieces[1])
os.Exit(exitcodes.Usage)
}
args._forceOwner = &fuse.Owner{Uid: uint32(uidNum), Gid: uint32(gidNum)}
}
// "-cpuprofile"
if args.cpuprofile != "" {
onExitFunc := setupCpuprofile(args.cpuprofile)
defer onExitFunc()
}
// "-memprofile"
if args.memprofile != "" {
onExitFunc := setupMemprofile(args.memprofile)
defer onExitFunc()
}
// "-trace"
if args.trace != "" {
onExitFunc := setupTrace(args.trace)
defer onExitFunc()
}
if args.cpuprofile != "" || args.memprofile != "" || args.trace != "" {
tlog.Info.Printf("Note: You must unmount gracefully, otherwise the profile file(s) will stay empty!\n")
}
// "-openssl"
if !args.openssl {
tlog.Debug.Printf("OpenSSL disabled, using Go GCM")
} else {
tlog.Debug.Printf("OpenSSL enabled")
}
// Operation flags
if args.info && args.init || args.info && args.passwd || args.passwd && args.init {
tlog.Fatal.Printf("At most one of -info, -init, -passwd is allowed")
os.Exit(exitcodes.Usage)
}
// "-info"
if args.info {
if flagSet.NArg() > 1 {
tlog.Fatal.Printf("Usage: %s -info CIPHERDIR", tlog.ProgramName)
os.Exit(exitcodes.Usage)
}
info(args.config) // does not return
}
// "-init"
if args.init {
if flagSet.NArg() > 1 {
tlog.Fatal.Printf("Usage: %s -init [OPTIONS] CIPHERDIR", tlog.ProgramName)
os.Exit(exitcodes.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(exitcodes.Usage)
}
changePassword(&args) // does not return
}
// Default operation: mount.
if flagSet.NArg() != 2 {
prettyArgs := prettyArgs()
tlog.Info.Printf("Wrong number of arguments (have %d, want 2). You passed: %s",
flagSet.NArg(), prettyArgs)
tlog.Fatal.Printf("Usage: %s [OPTIONS] CIPHERDIR MOUNTPOINT [-o COMMA-SEPARATED-OPTIONS]", tlog.ProgramName)
os.Exit(exitcodes.Usage)
}
doMount(&args)
// Don't call os.Exit to give deferred functions a chance to run
}