package readpassword import ( "fmt" "io" "os" "os/exec" "strings" "golang.org/x/crypto/ssh/terminal" "github.com/rfjakob/gocryptfs/internal/tlog" ) const ( exitCode = 9 ) // Once() tries to get a password from the user, either from the terminal, // extpass or stdin. func Once(extpass string) string { if extpass != "" { return readPasswordExtpass(extpass) } if !terminal.IsTerminal(int(os.Stdin.Fd())) { return readPasswordStdin() } return readPasswordTerminal("Password: ") } // Twice() is the same as Once but will prompt twice if we get // the password from the terminal. func Twice(extpass string) string { if extpass != "" { return readPasswordExtpass(extpass) } if !terminal.IsTerminal(int(os.Stdin.Fd())) { return readPasswordStdin() } p1 := readPasswordTerminal("Password: ") p2 := readPasswordTerminal("Repeat: ") if p1 != p2 { tlog.Fatal.Println("Passwords do not match") os.Exit(exitCode) } return p1 } // readPasswordTerminal reads a line from the terminal. // Exits on read error or empty result. func readPasswordTerminal(prompt string) string { fd := int(os.Stdin.Fd()) fmt.Fprintf(os.Stderr, prompt) // terminal.ReadPassword removes the trailing newline p, err := terminal.ReadPassword(fd) if err != nil { tlog.Fatal.Printf("Could not read password from terminal: %v\n", err) os.Exit(exitCode) } fmt.Fprintf(os.Stderr, "\n") if len(p) == 0 { tlog.Fatal.Println("Password is empty") os.Exit(exitCode) } return string(p) } // readPasswordStdin reads a line from stdin // Exits on read error or empty result. func readPasswordStdin() string { tlog.Info.Println("Reading password from stdin") p := readLineUnbuffered(os.Stdin) if len(p) == 0 { tlog.Fatal.Println("Got empty password from stdin") os.Exit(exitCode) } return p } // readPasswordExtpass executes the "extpass" program and returns the first line // of the output. // Exits on read error or empty result. func readPasswordExtpass(extpass string) string { tlog.Info.Println("Reading password from extpass program") parts := strings.Split(extpass, " ") cmd := exec.Command(parts[0], parts[1:]...) cmd.Stderr = os.Stderr pipe, err := cmd.StdoutPipe() if err != nil { tlog.Fatal.Printf("extpass pipe setup failed: %v", err) os.Exit(exitCode) } err = cmd.Start() if err != nil { tlog.Fatal.Printf("extpass cmd start failed: %v", err) os.Exit(exitCode) } p := readLineUnbuffered(pipe) pipe.Close() cmd.Wait() if len(p) == 0 { tlog.Fatal.Println("extpass: password is empty") os.Exit(exitCode) } return p } // readLineUnbuffered reads single bytes from "r" util it gets "\n" or EOF. // The returned string does NOT contain the trailing "\n". func readLineUnbuffered(r io.Reader) (l string) { b := make([]byte, 1) for { n, err := r.Read(b) if err == io.EOF { return l } if err != nil { tlog.Fatal.Printf("readLineUnbuffered: %v", err) os.Exit(exitCode) } if n == 0 { continue } if b[0] == '\n' { return l } l = l + string(b) } }