Files
bsky-social-app/bskyweb/cmd/bskyweb/passtoken.go
T

63 lines
1.6 KiB
Go

// bskyweb/cmd/bskyweb/passtoken.go
package main
import (
"crypto/hmac"
"crypto/sha256"
"encoding/base64"
"encoding/json"
"errors"
"strings"
"time"
)
var (
ErrTokenExpired = errors.New("invite pass token expired")
ErrTokenInvalid = errors.New("invite pass token invalid")
)
type passTokenPayload struct {
Did string `json:"d"`
Theme string `json:"t"`
PDS string `json:"p,omitempty"`
Exp int64 `json:"e"`
}
func MintPassToken(secret []byte, did, theme, pdsHost string, now time.Time, ttl time.Duration) (string, error) {
p := passTokenPayload{Did: did, Theme: theme, PDS: pdsHost, Exp: now.Add(ttl).Unix()}
body, err := json.Marshal(p)
if err != nil {
return "", err
}
bodyB64 := base64.RawURLEncoding.EncodeToString(body)
mac := hmac.New(sha256.New, secret)
mac.Write([]byte(bodyB64))
sig := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
return bodyB64 + "." + sig, nil
}
func VerifyPassToken(secret []byte, token string, now time.Time) (did, theme, pdsHost string, err error) {
parts := strings.SplitN(token, ".", 2)
if len(parts) != 2 {
return "", "", "", ErrTokenInvalid
}
mac := hmac.New(sha256.New, secret)
mac.Write([]byte(parts[0]))
want := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
if !hmac.Equal([]byte(want), []byte(parts[1])) {
return "", "", "", ErrTokenInvalid
}
body, perr := base64.RawURLEncoding.DecodeString(parts[0])
if perr != nil {
return "", "", "", ErrTokenInvalid
}
var p passTokenPayload
if uerr := json.Unmarshal(body, &p); uerr != nil {
return "", "", "", ErrTokenInvalid
}
if now.Unix() > p.Exp {
return "", "", "", ErrTokenExpired
}
return p.Did, p.Theme, p.PDS, nil
}