DockerCLI/vendor/github.com/docker/libtrust/jsonsign.go

658 lines
17 KiB
Go

package libtrust
import (
"bytes"
"crypto"
"crypto/x509"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"sort"
"time"
"unicode"
)
var (
// ErrInvalidSignContent is used when the content to be signed is invalid.
ErrInvalidSignContent = errors.New("invalid sign content")
// ErrInvalidJSONContent is used when invalid json is encountered.
ErrInvalidJSONContent = errors.New("invalid json content")
// ErrMissingSignatureKey is used when the specified signature key
// does not exist in the JSON content.
ErrMissingSignatureKey = errors.New("missing signature key")
)
type jsHeader struct {
JWK PublicKey `json:"jwk,omitempty"`
Algorithm string `json:"alg"`
Chain []string `json:"x5c,omitempty"`
}
type jsSignature struct {
Header jsHeader `json:"header"`
Signature string `json:"signature"`
Protected string `json:"protected,omitempty"`
}
type jsSignaturesSorted []jsSignature
func (jsbkid jsSignaturesSorted) Swap(i, j int) { jsbkid[i], jsbkid[j] = jsbkid[j], jsbkid[i] }
func (jsbkid jsSignaturesSorted) Len() int { return len(jsbkid) }
func (jsbkid jsSignaturesSorted) Less(i, j int) bool {
ki, kj := jsbkid[i].Header.JWK.KeyID(), jsbkid[j].Header.JWK.KeyID()
si, sj := jsbkid[i].Signature, jsbkid[j].Signature
if ki == kj {
return si < sj
}
return ki < kj
}
type signKey struct {
PrivateKey
Chain []*x509.Certificate
}
// JSONSignature represents a signature of a json object.
type JSONSignature struct {
payload string
signatures []jsSignature
indent string
formatLength int
formatTail []byte
}
func newJSONSignature() *JSONSignature {
return &JSONSignature{
signatures: make([]jsSignature, 0, 1),
}
}
// Payload returns the encoded payload of the signature. This
// payload should not be signed directly
func (js *JSONSignature) Payload() ([]byte, error) {
return joseBase64UrlDecode(js.payload)
}
func (js *JSONSignature) protectedHeader() (string, error) {
protected := map[string]interface{}{
"formatLength": js.formatLength,
"formatTail": joseBase64UrlEncode(js.formatTail),
"time": time.Now().UTC().Format(time.RFC3339),
}
protectedBytes, err := json.Marshal(protected)
if err != nil {
return "", err
}
return joseBase64UrlEncode(protectedBytes), nil
}
func (js *JSONSignature) signBytes(protectedHeader string) ([]byte, error) {
buf := make([]byte, len(js.payload)+len(protectedHeader)+1)
copy(buf, protectedHeader)
buf[len(protectedHeader)] = '.'
copy(buf[len(protectedHeader)+1:], js.payload)
return buf, nil
}
// Sign adds a signature using the given private key.
func (js *JSONSignature) Sign(key PrivateKey) error {
protected, err := js.protectedHeader()
if err != nil {
return err
}
signBytes, err := js.signBytes(protected)
if err != nil {
return err
}
sigBytes, algorithm, err := key.Sign(bytes.NewReader(signBytes), crypto.SHA256)
if err != nil {
return err
}
js.signatures = append(js.signatures, jsSignature{
Header: jsHeader{
JWK: key.PublicKey(),
Algorithm: algorithm,
},
Signature: joseBase64UrlEncode(sigBytes),
Protected: protected,
})
return nil
}
// SignWithChain adds a signature using the given private key
// and setting the x509 chain. The public key of the first element
// in the chain must be the public key corresponding with the sign key.
func (js *JSONSignature) SignWithChain(key PrivateKey, chain []*x509.Certificate) error {
// Ensure key.Chain[0] is public key for key
//key.Chain.PublicKey
//key.PublicKey().CryptoPublicKey()
// Verify chain
protected, err := js.protectedHeader()
if err != nil {
return err
}
signBytes, err := js.signBytes(protected)
if err != nil {
return err
}
sigBytes, algorithm, err := key.Sign(bytes.NewReader(signBytes), crypto.SHA256)
if err != nil {
return err
}
header := jsHeader{
Chain: make([]string, len(chain)),
Algorithm: algorithm,
}
for i, cert := range chain {
header.Chain[i] = base64.StdEncoding.EncodeToString(cert.Raw)
}
js.signatures = append(js.signatures, jsSignature{
Header: header,
Signature: joseBase64UrlEncode(sigBytes),
Protected: protected,
})
return nil
}
// Verify verifies all the signatures and returns the list of
// public keys used to sign. Any x509 chains are not checked.
func (js *JSONSignature) Verify() ([]PublicKey, error) {
keys := make([]PublicKey, len(js.signatures))
for i, signature := range js.signatures {
signBytes, err := js.signBytes(signature.Protected)
if err != nil {
return nil, err
}
var publicKey PublicKey
if len(signature.Header.Chain) > 0 {
certBytes, err := base64.StdEncoding.DecodeString(signature.Header.Chain[0])
if err != nil {
return nil, err
}
cert, err := x509.ParseCertificate(certBytes)
if err != nil {
return nil, err
}
publicKey, err = FromCryptoPublicKey(cert.PublicKey)
if err != nil {
return nil, err
}
} else if signature.Header.JWK != nil {
publicKey = signature.Header.JWK
} else {
return nil, errors.New("missing public key")
}
sigBytes, err := joseBase64UrlDecode(signature.Signature)
if err != nil {
return nil, err
}
err = publicKey.Verify(bytes.NewReader(signBytes), signature.Header.Algorithm, sigBytes)
if err != nil {
return nil, err
}
keys[i] = publicKey
}
return keys, nil
}
// VerifyChains verifies all the signatures and the chains associated
// with each signature and returns the list of verified chains.
// Signatures without an x509 chain are not checked.
func (js *JSONSignature) VerifyChains(ca *x509.CertPool) ([][]*x509.Certificate, error) {
chains := make([][]*x509.Certificate, 0, len(js.signatures))
for _, signature := range js.signatures {
signBytes, err := js.signBytes(signature.Protected)
if err != nil {
return nil, err
}
var publicKey PublicKey
if len(signature.Header.Chain) > 0 {
certBytes, err := base64.StdEncoding.DecodeString(signature.Header.Chain[0])
if err != nil {
return nil, err
}
cert, err := x509.ParseCertificate(certBytes)
if err != nil {
return nil, err
}
publicKey, err = FromCryptoPublicKey(cert.PublicKey)
if err != nil {
return nil, err
}
intermediates := x509.NewCertPool()
if len(signature.Header.Chain) > 1 {
intermediateChain := signature.Header.Chain[1:]
for i := range intermediateChain {
certBytes, err := base64.StdEncoding.DecodeString(intermediateChain[i])
if err != nil {
return nil, err
}
intermediate, err := x509.ParseCertificate(certBytes)
if err != nil {
return nil, err
}
intermediates.AddCert(intermediate)
}
}
verifyOptions := x509.VerifyOptions{
Intermediates: intermediates,
Roots: ca,
}
verifiedChains, err := cert.Verify(verifyOptions)
if err != nil {
return nil, err
}
chains = append(chains, verifiedChains...)
sigBytes, err := joseBase64UrlDecode(signature.Signature)
if err != nil {
return nil, err
}
err = publicKey.Verify(bytes.NewReader(signBytes), signature.Header.Algorithm, sigBytes)
if err != nil {
return nil, err
}
}
}
return chains, nil
}
// JWS returns JSON serialized JWS according to
// http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-31#section-7.2
func (js *JSONSignature) JWS() ([]byte, error) {
if len(js.signatures) == 0 {
return nil, errors.New("missing signature")
}
sort.Sort(jsSignaturesSorted(js.signatures))
jsonMap := map[string]interface{}{
"payload": js.payload,
"signatures": js.signatures,
}
return json.MarshalIndent(jsonMap, "", " ")
}
func notSpace(r rune) bool {
return !unicode.IsSpace(r)
}
func detectJSONIndent(jsonContent []byte) (indent string) {
if len(jsonContent) > 2 && jsonContent[0] == '{' && jsonContent[1] == '\n' {
quoteIndex := bytes.IndexRune(jsonContent[1:], '"')
if quoteIndex > 0 {
indent = string(jsonContent[2 : quoteIndex+1])
}
}
return
}
type jsParsedHeader struct {
JWK json.RawMessage `json:"jwk"`
Algorithm string `json:"alg"`
Chain []string `json:"x5c"`
}
type jsParsedSignature struct {
Header jsParsedHeader `json:"header"`
Signature string `json:"signature"`
Protected string `json:"protected"`
}
// ParseJWS parses a JWS serialized JSON object into a Json Signature.
func ParseJWS(content []byte) (*JSONSignature, error) {
type jsParsed struct {
Payload string `json:"payload"`
Signatures []jsParsedSignature `json:"signatures"`
}
parsed := &jsParsed{}
err := json.Unmarshal(content, parsed)
if err != nil {
return nil, err
}
if len(parsed.Signatures) == 0 {
return nil, errors.New("missing signatures")
}
payload, err := joseBase64UrlDecode(parsed.Payload)
if err != nil {
return nil, err
}
js, err := NewJSONSignature(payload)
if err != nil {
return nil, err
}
js.signatures = make([]jsSignature, len(parsed.Signatures))
for i, signature := range parsed.Signatures {
header := jsHeader{
Algorithm: signature.Header.Algorithm,
}
if signature.Header.Chain != nil {
header.Chain = signature.Header.Chain
}
if signature.Header.JWK != nil {
publicKey, err := UnmarshalPublicKeyJWK([]byte(signature.Header.JWK))
if err != nil {
return nil, err
}
header.JWK = publicKey
}
js.signatures[i] = jsSignature{
Header: header,
Signature: signature.Signature,
Protected: signature.Protected,
}
}
return js, nil
}
// NewJSONSignature returns a new unsigned JWS from a json byte array.
// JSONSignature will need to be signed before serializing or storing.
// Optionally, one or more signatures can be provided as byte buffers,
// containing serialized JWS signatures, to assemble a fully signed JWS
// package. It is the callers responsibility to ensure uniqueness of the
// provided signatures.
func NewJSONSignature(content []byte, signatures ...[]byte) (*JSONSignature, error) {
var dataMap map[string]interface{}
err := json.Unmarshal(content, &dataMap)
if err != nil {
return nil, err
}
js := newJSONSignature()
js.indent = detectJSONIndent(content)
js.payload = joseBase64UrlEncode(content)
// Find trailing } and whitespace, put in protected header
closeIndex := bytes.LastIndexFunc(content, notSpace)
if content[closeIndex] != '}' {
return nil, ErrInvalidJSONContent
}
lastRuneIndex := bytes.LastIndexFunc(content[:closeIndex], notSpace)
if content[lastRuneIndex] == ',' {
return nil, ErrInvalidJSONContent
}
js.formatLength = lastRuneIndex + 1
js.formatTail = content[js.formatLength:]
if len(signatures) > 0 {
for _, signature := range signatures {
var parsedJSig jsParsedSignature
if err := json.Unmarshal(signature, &parsedJSig); err != nil {
return nil, err
}
// TODO(stevvooe): A lot of the code below is repeated in
// ParseJWS. It will require more refactoring to fix that.
jsig := jsSignature{
Header: jsHeader{
Algorithm: parsedJSig.Header.Algorithm,
},
Signature: parsedJSig.Signature,
Protected: parsedJSig.Protected,
}
if parsedJSig.Header.Chain != nil {
jsig.Header.Chain = parsedJSig.Header.Chain
}
if parsedJSig.Header.JWK != nil {
publicKey, err := UnmarshalPublicKeyJWK([]byte(parsedJSig.Header.JWK))
if err != nil {
return nil, err
}
jsig.Header.JWK = publicKey
}
js.signatures = append(js.signatures, jsig)
}
}
return js, nil
}
// NewJSONSignatureFromMap returns a new unsigned JSONSignature from a map or
// struct. JWS will need to be signed before serializing or storing.
func NewJSONSignatureFromMap(content interface{}) (*JSONSignature, error) {
switch content.(type) {
case map[string]interface{}:
case struct{}:
default:
return nil, errors.New("invalid data type")
}
js := newJSONSignature()
js.indent = " "
payload, err := json.MarshalIndent(content, "", js.indent)
if err != nil {
return nil, err
}
js.payload = joseBase64UrlEncode(payload)
// Remove '\n}' from formatted section, put in protected header
js.formatLength = len(payload) - 2
js.formatTail = payload[js.formatLength:]
return js, nil
}
func readIntFromMap(key string, m map[string]interface{}) (int, bool) {
value, ok := m[key]
if !ok {
return 0, false
}
switch v := value.(type) {
case int:
return v, true
case float64:
return int(v), true
default:
return 0, false
}
}
func readStringFromMap(key string, m map[string]interface{}) (v string, ok bool) {
value, ok := m[key]
if !ok {
return "", false
}
v, ok = value.(string)
return
}
// ParsePrettySignature parses a formatted signature into a
// JSON signature. If the signatures are missing the format information
// an error is thrown. The formatted signature must be created by
// the same method as format signature.
func ParsePrettySignature(content []byte, signatureKey string) (*JSONSignature, error) {
var contentMap map[string]json.RawMessage
err := json.Unmarshal(content, &contentMap)
if err != nil {
return nil, fmt.Errorf("error unmarshalling content: %s", err)
}
sigMessage, ok := contentMap[signatureKey]
if !ok {
return nil, ErrMissingSignatureKey
}
var signatureBlocks []jsParsedSignature
err = json.Unmarshal([]byte(sigMessage), &signatureBlocks)
if err != nil {
return nil, fmt.Errorf("error unmarshalling signatures: %s", err)
}
js := newJSONSignature()
js.signatures = make([]jsSignature, len(signatureBlocks))
for i, signatureBlock := range signatureBlocks {
protectedBytes, err := joseBase64UrlDecode(signatureBlock.Protected)
if err != nil {
return nil, fmt.Errorf("base64 decode error: %s", err)
}
var protectedHeader map[string]interface{}
err = json.Unmarshal(protectedBytes, &protectedHeader)
if err != nil {
return nil, fmt.Errorf("error unmarshalling protected header: %s", err)
}
formatLength, ok := readIntFromMap("formatLength", protectedHeader)
if !ok {
return nil, errors.New("missing formatted length")
}
encodedTail, ok := readStringFromMap("formatTail", protectedHeader)
if !ok {
return nil, errors.New("missing formatted tail")
}
formatTail, err := joseBase64UrlDecode(encodedTail)
if err != nil {
return nil, fmt.Errorf("base64 decode error on tail: %s", err)
}
if js.formatLength == 0 {
js.formatLength = formatLength
} else if js.formatLength != formatLength {
return nil, errors.New("conflicting format length")
}
if len(js.formatTail) == 0 {
js.formatTail = formatTail
} else if bytes.Compare(js.formatTail, formatTail) != 0 {
return nil, errors.New("conflicting format tail")
}
header := jsHeader{
Algorithm: signatureBlock.Header.Algorithm,
Chain: signatureBlock.Header.Chain,
}
if signatureBlock.Header.JWK != nil {
publicKey, err := UnmarshalPublicKeyJWK([]byte(signatureBlock.Header.JWK))
if err != nil {
return nil, fmt.Errorf("error unmarshalling public key: %s", err)
}
header.JWK = publicKey
}
js.signatures[i] = jsSignature{
Header: header,
Signature: signatureBlock.Signature,
Protected: signatureBlock.Protected,
}
}
if js.formatLength > len(content) {
return nil, errors.New("invalid format length")
}
formatted := make([]byte, js.formatLength+len(js.formatTail))
copy(formatted, content[:js.formatLength])
copy(formatted[js.formatLength:], js.formatTail)
js.indent = detectJSONIndent(formatted)
js.payload = joseBase64UrlEncode(formatted)
return js, nil
}
// PrettySignature formats a json signature into an easy to read
// single json serialized object.
func (js *JSONSignature) PrettySignature(signatureKey string) ([]byte, error) {
if len(js.signatures) == 0 {
return nil, errors.New("no signatures")
}
payload, err := joseBase64UrlDecode(js.payload)
if err != nil {
return nil, err
}
payload = payload[:js.formatLength]
sort.Sort(jsSignaturesSorted(js.signatures))
var marshalled []byte
var marshallErr error
if js.indent != "" {
marshalled, marshallErr = json.MarshalIndent(js.signatures, js.indent, js.indent)
} else {
marshalled, marshallErr = json.Marshal(js.signatures)
}
if marshallErr != nil {
return nil, marshallErr
}
buf := bytes.NewBuffer(make([]byte, 0, len(payload)+len(marshalled)+34))
buf.Write(payload)
buf.WriteByte(',')
if js.indent != "" {
buf.WriteByte('\n')
buf.WriteString(js.indent)
buf.WriteByte('"')
buf.WriteString(signatureKey)
buf.WriteString("\": ")
buf.Write(marshalled)
buf.WriteByte('\n')
} else {
buf.WriteByte('"')
buf.WriteString(signatureKey)
buf.WriteString("\":")
buf.Write(marshalled)
}
buf.WriteByte('}')
return buf.Bytes(), nil
}
// Signatures provides the signatures on this JWS as opaque blobs, sorted by
// keyID. These blobs can be stored and reassembled with payloads. Internally,
// they are simply marshaled json web signatures but implementations should
// not rely on this.
func (js *JSONSignature) Signatures() ([][]byte, error) {
sort.Sort(jsSignaturesSorted(js.signatures))
var sb [][]byte
for _, jsig := range js.signatures {
p, err := json.Marshal(jsig)
if err != nil {
return nil, err
}
sb = append(sb, p)
}
return sb, nil
}
// Merge combines the signatures from one or more other signatures into the
// method receiver. If the payloads differ for any argument, an error will be
// returned and the receiver will not be modified.
func (js *JSONSignature) Merge(others ...*JSONSignature) error {
merged := js.signatures
for _, other := range others {
if js.payload != other.payload {
return fmt.Errorf("payloads differ from merge target")
}
merged = append(merged, other.signatures...)
}
js.signatures = merged
return nil
}