package gpgbin import ( "bufio" "bytes" "errors" "fmt" "io" "io/ioutil" "log" "os" "os/exec" "strconv" "strings" "git.sr.ht/~rjarry/aerc/models" "github.com/mattn/go-isatty" ) // gpg represents a gpg command with buffers attached to stdout and stderr type gpg struct { cmd *exec.Cmd stdout bytes.Buffer stderr bytes.Buffer } // newGpg creates a new gpg command with buffers attached func newGpg(stdin io.Reader, args []string) *gpg { g := new(gpg) g.cmd = exec.Command("gpg", "--status-fd", "1", "--batch") g.cmd.Args = append(g.cmd.Args, args...) g.cmd.Stdin = stdin g.cmd.Stdout = &g.stdout g.cmd.Stderr = &g.stderr return g } // parseError parses errors returned by gpg that don't show up with a [GNUPG:] // prefix func parseError(s string) error { lines := strings.Split(s, "\n") for _, line := range lines { line = strings.ToLower(line) if GPGErrors[line] > 0 { return errors.New(line) } } return errors.New(strings.Join(lines, ", ")) } // fields returns the field name from --status-fd output. See: // https://github.com/gpg/gnupg/blob/master/doc/DETAILS func field(s string) string { tokens := strings.SplitN(s, " ", 3) if tokens[0] == "[GNUPG:]" { return tokens[1] } return "" } // getIdentity returns the identity of the given key func getIdentity(key uint64) string { fpr := fmt.Sprintf("%X", key) cmd := exec.Command("gpg", "--with-colons", "--batch", "--list-keys", fpr) var outbuf strings.Builder cmd.Stdout = &outbuf cmd.Run() out := strings.Split(outbuf.String(), "\n") for _, line := range out { if strings.HasPrefix(line, "uid") { flds := strings.Split(line, ":") return flds[9] } } return "" } // getKeyId returns the 16 digit key id, if key exists func getKeyId(s string, private bool) string { cmd := exec.Command("gpg", "--with-colons", "--batch") listArg := "--list-keys" if private { listArg = "--list-secret-keys" } cmd.Args = append(cmd.Args, listArg, s) var outbuf strings.Builder cmd.Stdout = &outbuf cmd.Run() out := strings.Split(outbuf.String(), "\n") for _, line := range out { if strings.HasPrefix(line, "fpr") { flds := strings.Split(line, ":") id := flds[9] return id[len(id)-16:] } } return "" } // longKeyToUint64 returns a uint64 version of the given key func longKeyToUint64(key string) (uint64, error) { fpr := string(key[len(key)-16:]) fprUint64, err := strconv.ParseUint(fpr, 16, 64) if err != nil { return 0, err } return fprUint64, nil } // parse parses the output of gpg --status-fd func parse(r io.Reader, md *models.MessageDetails) error { var ( logOut io.Writer logger *log.Logger ) if !isatty.IsTerminal(os.Stdout.Fd()) { logOut = os.Stdout } else { logOut = ioutil.Discard os.Stdout, _ = os.Open(os.DevNull) } logger = log.New(logOut, "", log.LstdFlags) var err error var msgContent []byte var msgCollecting bool newLine := []byte("\r\n") scanner := bufio.NewScanner(r) for scanner.Scan() { line := scanner.Text() if field(line) == "PLAINTEXT_LENGTH" { continue } if strings.HasPrefix(line, "[GNUPG:]") { msgCollecting = false logger.Println(line) } if msgCollecting { msgContent = append(msgContent, scanner.Bytes()...) msgContent = append(msgContent, newLine...) } switch field(line) { case "ENC_TO": md.IsEncrypted = true case "DECRYPTION_KEY": md.DecryptedWithKeyId, err = parseDecryptionKey(line) md.DecryptedWith = getIdentity(md.DecryptedWithKeyId) if err != nil { return err } case "DECRYPTION_FAILED": return fmt.Errorf("gpg: decryption failed") case "PLAINTEXT": msgCollecting = true case "NEWSIG": md.IsSigned = true case "GOODSIG": t := strings.SplitN(line, " ", 4) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } md.SignedBy = t[3] case "BADSIG": t := strings.SplitN(line, " ", 4) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } md.SignatureError = "gpg: invalid signature" md.SignedBy = t[3] case "EXPSIG": t := strings.SplitN(line, " ", 4) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } md.SignatureError = "gpg: expired signature" md.SignedBy = t[3] case "EXPKEYSIG": t := strings.SplitN(line, " ", 4) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } md.SignatureError = "gpg: signature made with expired key" md.SignedBy = t[3] case "REVKEYSIG": t := strings.SplitN(line, " ", 4) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } md.SignatureError = "gpg: signature made with revoked key" md.SignedBy = t[3] case "ERRSIG": t := strings.SplitN(line, " ", 9) md.SignedByKeyId, err = longKeyToUint64(t[2]) if err != nil { return err } if t[7] == "9" { md.SignatureError = "gpg: missing public key" } if t[7] == "4" { md.SignatureError = "gpg: unsupported algorithm" } md.SignedBy = "(unknown signer)" case "BEGIN_ENCRYPTION": msgCollecting = true case "SIG_CREATED": fields := strings.Split(line, " ") micalg, err := strconv.Atoi(fields[4]) if err != nil { return fmt.Errorf("gpg: micalg not found") } md.Micalg = micalgs[micalg] msgCollecting = true case "VALIDSIG": fields := strings.Split(line, " ") micalg, err := strconv.Atoi(fields[9]) if err != nil { return fmt.Errorf("gpg: micalg not found") } md.Micalg = micalgs[micalg] case "NODATA": md.SignatureError = "gpg: no signature packet found" case "FAILURE": return fmt.Errorf(strings.TrimPrefix(line, "[GNUPG:] ")) } } md.Body = bytes.NewReader(msgContent) return nil } // parseDecryptionKey returns primary key from DECRYPTION_KEY line func parseDecryptionKey(l string) (uint64, error) { key := strings.Split(l, " ")[3] fpr := string(key[len(key)-16:]) fprUint64, err := longKeyToUint64(fpr) if err != nil { return 0, err } getIdentity(fprUint64) return fprUint64, nil } type GPGError int32 const ( ERROR_NO_PGP_DATA_FOUND GPGError = iota + 1 ) var GPGErrors = map[string]GPGError{ "gpg: no valid openpgp data found.": ERROR_NO_PGP_DATA_FOUND, } // micalgs represent hash algorithms for signatures. These are ignored by many // email clients, but can be used as an additional verification so are sent. // Both gpgmail and pgpmail implementations in aerc check for matching micalgs var micalgs = map[int]string{ 1: "pgp-md5", 2: "pgp-sha1", 3: "pgp-ripemd160", 8: "pgp-sha256", 9: "pgp-sha384", 10: "pgp-sha512", 11: "pgp-sha224", } func logger(s string) { var ( logOut io.Writer logger *log.Logger ) if !isatty.IsTerminal(os.Stdout.Fd()) { logOut = os.Stdout } else { logOut = ioutil.Discard os.Stdout, _ = os.Open(os.DevNull) } logger = log.New(logOut, "", log.LstdFlags) logger.Println(s) }