package main import ( "encoding/hex" "os" "strings" "github.com/rfjakob/gocryptfs/v2/internal/cryptocore" "github.com/rfjakob/gocryptfs/v2/internal/exitcodes" "github.com/rfjakob/gocryptfs/v2/internal/readpassword" "github.com/rfjakob/gocryptfs/v2/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 } // handleArgsMasterkey looks at `args.masterkey` and `args.zerokey`, gets the // masterkey from the source the user wanted (string on the command line, stdin, all-zero), // and returns it in binary. Returns nil if no masterkey source was specified. func handleArgsMasterkey(args *argContainer) (masterkey []byte) { // "-masterkey=stdin" if args.masterkey == "stdin" { in, err := readpassword.Once(nil, nil, "Masterkey") if err != nil { tlog.Fatal.Println(err) os.Exit(exitcodes.ReadPassword) } return unhexMasterKey(string(in), true) } // "-masterkey=941a6029-3adc6a1c-..." if args.masterkey != "" { return unhexMasterKey(args.masterkey, false) } // "-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) } // No master key source specified on the command line. Caller must parse // the config file. return nil }