| 1 | package release |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "crypto/ed25519" |
| 6 | "encoding/base64" |
| 7 | "encoding/json" |
| 8 | "errors" |
| 9 | "io" |
| 10 | ) |
| 11 | |
| 12 | // MaxRootEnvelopeBytes bounds both the signed wire object and its decoded |
| 13 | // payload. Loss declarations can contain timer snapshots, so the worker |
| 14 | // control record's smaller bound is not suitable here. |
| 15 | const MaxRootEnvelopeBytes = 1 << 20 |
| 16 | |
| 17 | var ErrRootEnvelope = errors.New("release: root envelope refused") |
| 18 | |
| 19 | // RootPublicKey returns a copy of the verification anchor carried by a |
| 20 | // signer. It lets create-only callers resolve an ambiguous retry by reading |
| 21 | // and verifying the object they may already have created. |
| 22 | func (s Signer) RootPublicKey() ed25519.PublicKey { |
| 23 | return append(ed25519.PublicKey(nil), s.root...) |
| 24 | } |
| 25 | |
| 26 | // SignRootEnvelope writes the existing root-signed {payload,sig} envelope. |
| 27 | // Scoped release keys are deliberately refused: these records are deployment |
| 28 | // control authority, not channel publication. |
| 29 | func SignRootEnvelope(sg Signer, payload any) ([]byte, error) { |
| 30 | if sg.usable() != nil || sg.scope != nil || sg.grant != nil { |
| 31 | return nil, ErrRootEnvelope |
| 32 | } |
| 33 | raw, err := json.Marshal(payload) |
| 34 | if err != nil || len(raw) == 0 || len(raw) > MaxRootEnvelopeBytes/2 { |
| 35 | return nil, ErrRootEnvelope |
| 36 | } |
| 37 | b64 := base64.StdEncoding.EncodeToString(raw) |
| 38 | sig := ed25519.Sign(sg.key, []byte(b64)) |
| 39 | wire, err := json.Marshal(signedWrapper{Payload: b64, Sig: base64.StdEncoding.EncodeToString(sig)}) |
| 40 | if err != nil || len(wire) > MaxRootEnvelopeBytes { |
| 41 | return nil, ErrRootEnvelope |
| 42 | } |
| 43 | return wire, nil |
| 44 | } |
| 45 | |
| 46 | // VerifyRootEnvelope verifies an envelope against the deployment root and |
| 47 | // requires canonical JSON for both wrapper and typed payload. dst must be a |
| 48 | // non-nil pointer to the exact expected payload type. |
| 49 | func VerifyRootEnvelope(pub ed25519.PublicKey, wire []byte, dst any) error { |
| 50 | if len(pub) != ed25519.PublicKeySize || len(wire) == 0 || len(wire) > MaxRootEnvelopeBytes || dst == nil { |
| 51 | return ErrRootEnvelope |
| 52 | } |
| 53 | var wrapper signedWrapper |
| 54 | if strictCanonicalJSON(wire, &wrapper) != nil || wrapper.Grant != nil { |
| 55 | return ErrRootEnvelope |
| 56 | } |
| 57 | sig, err := base64.StdEncoding.Strict().DecodeString(wrapper.Sig) |
| 58 | if err != nil || base64.StdEncoding.EncodeToString(sig) != wrapper.Sig || len(sig) != ed25519.SignatureSize || |
| 59 | !ed25519.Verify(pub, []byte(wrapper.Payload), sig) { |
| 60 | return ErrRootEnvelope |
| 61 | } |
| 62 | raw, err := base64.StdEncoding.Strict().DecodeString(wrapper.Payload) |
| 63 | if err != nil || base64.StdEncoding.EncodeToString(raw) != wrapper.Payload || len(raw) == 0 || len(raw) > MaxRootEnvelopeBytes/2 { |
| 64 | return ErrRootEnvelope |
| 65 | } |
| 66 | if strictCanonicalJSON(raw, dst) != nil { |
| 67 | return ErrRootEnvelope |
| 68 | } |
| 69 | return nil |
| 70 | } |
| 71 | |
| 72 | func strictCanonicalJSON(raw []byte, dst any) error { |
| 73 | dec := json.NewDecoder(bytes.NewReader(raw)) |
| 74 | dec.DisallowUnknownFields() |
| 75 | if err := dec.Decode(dst); err != nil { |
| 76 | return err |
| 77 | } |
| 78 | var trailing any |
| 79 | if err := dec.Decode(&trailing); err != io.EOF { |
| 80 | return ErrRootEnvelope |
| 81 | } |
| 82 | canonical, err := json.Marshal(dst) |
| 83 | if err != nil { |
| 84 | return err |
| 85 | } |
| 86 | var compact bytes.Buffer |
| 87 | if err := json.Compact(&compact, raw); err != nil || !bytes.Equal(compact.Bytes(), canonical) { |
| 88 | return ErrRootEnvelope |
| 89 | } |
| 90 | return nil |
| 91 | } |
| 92 | |
amadan