package acme import ( "bytes" "crypto" "crypto/ecdsa" "crypto/elliptic" "crypto/rsa" "fmt" "net/http" "sync" "gopkg.in/square/go-jose.v1" ) type jws struct { directoryURL string privKey crypto.PrivateKey nonces []string sync.Mutex } func keyAsJWK(key interface{}) *jose.JsonWebKey { switch k := key.(type) { case *ecdsa.PublicKey: return &jose.JsonWebKey{Key: k, Algorithm: "EC"} case *rsa.PublicKey: return &jose.JsonWebKey{Key: k, Algorithm: "RSA"} default: return nil } } // Posts a JWS signed message to the specified URL func (j *jws) post(url string, content []byte) (*http.Response, error) { signedContent, err := j.signContent(content) if err != nil { return nil, err } resp, err := httpPost(url, "application/jose+json", bytes.NewBuffer([]byte(signedContent.FullSerialize()))) if err != nil { return nil, err } j.Lock() defer j.Unlock() j.getNonceFromResponse(resp) return resp, err } func (j *jws) signContent(content []byte) (*jose.JsonWebSignature, error) { var alg jose.SignatureAlgorithm switch k := j.privKey.(type) { case *rsa.PrivateKey: alg = jose.RS256 case *ecdsa.PrivateKey: if k.Curve == elliptic.P256() { alg = jose.ES256 } else if k.Curve == elliptic.P384() { alg = jose.ES384 } } signer, err := jose.NewSigner(alg, j.privKey) if err != nil { return nil, err } signer.SetNonceSource(j) signed, err := signer.Sign(content) if err != nil { return nil, err } return signed, nil } func (j *jws) getNonceFromResponse(resp *http.Response) error { nonce := resp.Header.Get("Replay-Nonce") if nonce == "" { return fmt.Errorf("Server did not respond with a proper nonce header.") } j.nonces = append(j.nonces, nonce) return nil } func (j *jws) getNonce() error { resp, err := httpHead(j.directoryURL) if err != nil { return err } return j.getNonceFromResponse(resp) } func (j *jws) Nonce() (string, error) { j.Lock() defer j.Unlock() nonce := "" if len(j.nonces) == 0 { err := j.getNonce() if err != nil { return nonce, err } } if len(j.nonces) == 0 { return "", fmt.Errorf("Can't get nonce") } nonce, j.nonces = j.nonces[len(j.nonces)-1], j.nonces[:len(j.nonces)-1] return nonce, nil }