| 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "encoding/base64" |
| 5 | "encoding/hex" |
| 6 | "errors" |
| 7 | "flag" |
| 8 | "fmt" |
| 9 | "io" |
| 10 | "os" |
| 11 | "strings" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/FelineStateMachine/tinyrelay/internal/event" |
| 15 | "github.com/FelineStateMachine/tinyrelay/protocol/auth" |
| 16 | ) |
| 17 | |
| 18 | // gitToken mints the GRASP-08 repository-root proof that private Git hosting |
| 19 | // expects, so plain git and agents can clone and push with one header. The |
| 20 | // key never leaves the process: it is read from an environment variable and |
| 21 | // used once to sign a kind 27235 event. |
| 22 | func gitToken(args []string, out io.Writer) error { |
| 23 | fs := flag.NewFlagSet("tiny git-token" , flag.ContinueOnError) |
| 24 | fs.SetOutput(out) |
| 25 | repo := fs.String("repo" , "" , "repository URL ending in .git, or any URL beneath it" ) |
| 26 | keyEnv := fs.String("key-env" , "TINY_AGENT_KEY" , "environment variable holding the signing key as hex or nsec" ) |
| 27 | format := fs.String("format" , "header" , "output: header (Authorization line), value (token only) or git (http.extraHeader config value)" ) |
| 28 | if err := fs.Parse(args); err != nil { |
| 29 | return err |
| 30 | } |
| 31 | root, ok := auth.GRASP08RepositoryRoot(*repo) |
| 32 | if !ok { |
| 33 | return errors.New("git-token: --repo must be an HTTP or HTTPS repository URL ending in .git" ) |
| 34 | } |
| 35 | secret, err := secretKey(os.Getenv(*keyEnv)) |
| 36 | if err != nil { |
| 37 | return fmt.Errorf("git-token: %s: %w" , *keyEnv, err) |
| 38 | } |
| 39 | e := event.Event{Kind: 27235, CreatedAt: time.Now().Unix(), Tags: [][]string{{"u" , root}, {"method" , "GET" }}} |
| 40 | if err := event.Sign(&e, secret); err != nil { |
| 41 | return err |
| 42 | } |
| 43 | raw, err := event.Canonical(e) |
| 44 | if err != nil { |
| 45 | return err |
| 46 | } |
| 47 | token := base64.StdEncoding.EncodeToString(raw) |
| 48 | switch *format { |
| 49 | case "value" : |
| 50 | _, err = fmt.Fprintln(out, token) |
| 51 | case "git" : |
| 52 | _, err = fmt.Fprintf(out, "http.extraHeader=Authorization: Nostr %s\n" , token) |
| 53 | case "header" : |
| 54 | _, err = fmt.Fprintf(out, "Authorization: Nostr %s\n" , token) |
| 55 | default: |
| 56 | return fmt.Errorf("git-token: unknown --format %q" , *format) |
| 57 | } |
| 58 | return err |
| 59 | } |
| 60 | |
| 61 | // secretKey accepts a 64-character hex key or an nsec. |
| 62 | func secretKey(value string) (string, error) { |
| 63 | value = strings.TrimSpace(value) |
| 64 | if value == "" { |
| 65 | return "" , errors.New("no key set" ) |
| 66 | } |
| 67 | if len(value) == 64 && strings.Trim(strings.ToLower(value), "0123456789abcdef" ) == "" { |
| 68 | return strings.ToLower(value), nil |
| 69 | } |
| 70 | if strings.HasPrefix(strings.ToLower(value), "nsec1" ) { |
| 71 | data, ok := bech32Data(strings.ToLower(value)) |
| 72 | if !ok || len(data) != 32 { |
| 73 | return "" , errors.New("invalid nsec" ) |
| 74 | } |
| 75 | return hex.EncodeToString(data), nil |
| 76 | } |
| 77 | return "" , errors.New("expected a hex key or an nsec" ) |
| 78 | } |
| 79 | |
| 80 | const bech32Alphabet = "qpzry9x8gf2tvdw0s3jn54khce6mua7l" |
| 81 | |
| 82 | // bech32Data decodes a bech32 string and returns its 8-bit payload. |
| 83 | func bech32Data(value string) ([]byte, bool) { |
| 84 | separator := strings.LastIndexByte(value, '1' ) |
| 85 | if separator < 1 || separator+7 > len(value) { |
| 86 | return nil, false |
| 87 | } |
| 88 | hrp, encoded := value[:separator], value[separator+1:] |
| 89 | values := make([]byte, len(encoded)) |
| 90 | for i, char := range encoded { |
| 91 | position := strings.IndexRune(bech32Alphabet, char) |
| 92 | if position < 0 { |
| 93 | return nil, false |
| 94 | } |
| 95 | values[i] = byte(position) |
| 96 | } |
| 97 | expanded := make([]byte, 0, len(hrp)*2+1+len(values)) |
| 98 | for _, c := range hrp { |
| 99 | expanded = append(expanded, byte(c)>>5) |
| 100 | } |
| 101 | expanded = append(expanded, 0) |
| 102 | for _, c := range hrp { |
| 103 | expanded = append(expanded, byte(c)&31) |
| 104 | } |
| 105 | expanded = append(expanded, values...) |
| 106 | generators := [...]uint32{0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3} |
| 107 | checksum := uint32(1) |
| 108 | for _, v := range expanded { |
| 109 | top := checksum >> 25 |
| 110 | checksum = (checksum&0x1ffffff)<<5 ^ uint32(v) |
| 111 | for i, generator := range generators { |
| 112 | if top>>i&1 == 1 { |
| 113 | checksum ^= generator |
| 114 | } |
| 115 | } |
| 116 | } |
| 117 | if checksum != 1 { |
| 118 | return nil, false |
| 119 | } |
| 120 | data := values[:len(values)-6] |
| 121 | accumulator, bits := 0, 0 |
| 122 | var result []byte |
| 123 | for _, v := range data { |
| 124 | accumulator = accumulator<<5 | int(v) |
| 125 | bits += 5 |
| 126 | if bits >= 8 { |
| 127 | bits -= 8 |
| 128 | result = append(result, byte(accumulator>>bits&255)) |
| 129 | } |
| 130 | } |
| 131 | return result, true |
| 132 | } |