| 1 | package keyless |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "net/http" |
| 9 | "strings" |
| 10 | "time" |
| 11 | |
| 12 | ksigner "github.com/gosuda/keyless_tls/relay/signer" |
| 13 | "github.com/gosuda/keyless_tls/relay/signrpc" |
| 14 | ) |
| 15 | |
| 16 | const ( |
| 17 | RelayKeyID = "relay-cert" |
| 18 | defaultAllowedSkew = 5 * time.Minute |
| 19 | ) |
| 20 | |
| 21 | type Signer struct { |
| 22 | service *ksigner.Service |
| 23 | keyID string |
| 24 | } |
| 25 | |
| 26 | func NewSigner(keyPEM []byte) (*Signer, error) { |
| 27 | signingKey, err := ksigner.ParsePrivateKeyPEM(keyPEM) |
| 28 | if err != nil { |
| 29 | return nil, fmt.Errorf("parse keyless signing key: %w", err) |
| 30 | } |
| 31 | |
| 32 | store := ksigner.NewStaticKeyStore() |
| 33 | if err := store.Put(RelayKeyID, signingKey); err != nil { |
| 34 | return nil, fmt.Errorf("register keyless signing key: %w", err) |
| 35 | } |
| 36 | |
| 37 | return &Signer{ |
| 38 | service: &ksigner.Service{ |
| 39 | Store: store, |
| 40 | AllowedSkew: defaultAllowedSkew, |
| 41 | }, |
| 42 | keyID: RelayKeyID, |
| 43 | }, nil |
| 44 | } |
| 45 | |
| 46 | func (s *Signer) KeyID() string { |
| 47 | if s == nil { |
| 48 | return "" |
| 49 | } |
| 50 | return s.keyID |
| 51 | } |
| 52 | |
| 53 | func (s *Signer) Sign(ctx context.Context, req *signrpc.SignRequest) (*signrpc.SignResponse, error) { |
| 54 | if s == nil || s.service == nil { |
| 55 | return nil, errors.New("keyless signer is disabled") |
| 56 | } |
| 57 | return s.service.Sign(ctx, req) |
| 58 | } |
| 59 | |
| 60 | func (s *Signer) Handler() http.Handler { |
| 61 | mux := http.NewServeMux() |
| 62 | mux.HandleFunc(signrpc.SignPath, func(w http.ResponseWriter, r *http.Request) { |
| 63 | if r.Method != http.MethodPost { |
| 64 | w.Header().Set("Allow", http.MethodPost) |
| 65 | writeJSONError(w, http.StatusMethodNotAllowed, "method not allowed") |
| 66 | return |
| 67 | } |
| 68 | if ct := r.Header.Get("Content-Type"); ct != "" && !strings.HasPrefix(ct, "application/json") { |
| 69 | writeJSONError(w, http.StatusUnsupportedMediaType, "content type must be application/json") |
| 70 | return |
| 71 | } |
| 72 | |
| 73 | r.Body = http.MaxBytesReader(w, r.Body, 4<<10) |
| 74 | defer r.Body.Close() |
| 75 | |
| 76 | var req signrpc.SignRequest |
| 77 | if err := json.NewDecoder(r.Body).Decode(&req); err != nil { |
| 78 | writeJSONError(w, http.StatusBadRequest, "invalid json body") |
| 79 | return |
| 80 | } |
| 81 | |
| 82 | resp, err := s.Sign(r.Context(), &req) |
| 83 | if err != nil { |
| 84 | status := http.StatusInternalServerError |
| 85 | switch { |
| 86 | case errors.Is(err, ksigner.ErrInvalidArgument): |
| 87 | status = http.StatusBadRequest |
| 88 | case errors.Is(err, ksigner.ErrPermissionDenied): |
| 89 | status = http.StatusForbidden |
| 90 | } |
| 91 | writeJSONError(w, status, err.Error()) |
| 92 | return |
| 93 | } |
| 94 | |
| 95 | w.Header().Set("Content-Type", "application/json") |
| 96 | _ = json.NewEncoder(w).Encode(resp) |
| 97 | }) |
| 98 | return mux |
| 99 | } |
| 100 | |
| 101 | func writeJSONError(w http.ResponseWriter, status int, message string) { |
| 102 | w.Header().Set("Content-Type", "application/json") |
| 103 | w.WriteHeader(status) |
| 104 | _ = json.NewEncoder(w).Encode(signrpc.ErrorResponse{Error: message}) |
| 105 | } |