package main import ( "encoding/hex" "os" "strings" "github.com/rfjakob/gocryptfs/internal/configfile" "github.com/rfjakob/gocryptfs/internal/cryptocore" "github.com/rfjakob/gocryptfs/internal/exitcodes" "github.com/rfjakob/gocryptfs/internal/readpassword" "github.com/rfjakob/gocryptfs/internal/tlog" ) // unhexMasterKey - Convert a hex-encoded master key to binary. // Calls os.Exit on failure. func unhexMasterKey(masterkey string, fromStdin bool) []byte { masterkey = strings.Replace(masterkey, "-", "", -1) key, err := hex.DecodeString(masterkey) if err != nil { tlog.Fatal.Printf("Could not parse master key: %v", err) os.Exit(exitcodes.MasterKey) } if len(key) != cryptocore.KeyLen { tlog.Fatal.Printf("Master key has length %d but we require length %d", len(key), cryptocore.KeyLen) os.Exit(exitcodes.MasterKey) } tlog.Info.Printf("Using explicit master key.") if !fromStdin { tlog.Info.Printf(tlog.ColorYellow + "THE MASTER KEY IS VISIBLE VIA \"ps ax\" AND MAY BE STORED IN YOUR SHELL HISTORY!\n" + "ONLY USE THIS MODE FOR EMERGENCIES" + tlog.ColorReset) } return key } // getMasterKey looks at "args" to determine where the master key should come // from (-masterkey=a-b-c-d or stdin or from the config file). // If it comes from the config file, the user is prompted for the password // and a ConfFile instance is returned. // Calls os.Exit on failure. func getMasterKey(args *argContainer) (masterkey []byte, confFile *configfile.ConfFile) { masterkeyFromStdin := false // "-masterkey=stdin" if args.masterkey == "stdin" { args.masterkey = string(readpassword.Once(nil, "", "Masterkey")) masterkeyFromStdin = true } // "-masterkey=941a6029-3adc6a1c-..." if args.masterkey != "" { return unhexMasterKey(args.masterkey, masterkeyFromStdin), nil } // "-zerokey" if args.zerokey { tlog.Info.Printf("Using all-zero dummy master key.") tlog.Info.Printf(tlog.ColorYellow + "ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING." + tlog.ColorReset) return make([]byte, cryptocore.KeyLen), nil } var err error // Load master key from config file (normal operation). // Prompts the user for the password. masterkey, confFile, err = loadConfig(args) if err != nil { if args._ctlsockFd != nil { // Close the socket file (which also deletes it) args._ctlsockFd.Close() } exitcodes.Exit(err) } return masterkey, confFile }