pki/vendor/gopkg.in/square/go-jose.v2/signing.go
Paul Lecuq a7d4f06285
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2020-11-25 20:36:07 +01:00

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/*-
* Copyright 2014 Square Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jose
import (
"bytes"
"crypto/ecdsa"
"crypto/rsa"
"encoding/base64"
"errors"
"fmt"
"golang.org/x/crypto/ed25519"
"gopkg.in/square/go-jose.v2/json"
)
// NonceSource represents a source of random nonces to go into JWS objects
type NonceSource interface {
Nonce() (string, error)
}
// Signer represents a signer which takes a payload and produces a signed JWS object.
type Signer interface {
Sign(payload []byte) (*JSONWebSignature, error)
Options() SignerOptions
}
// SigningKey represents an algorithm/key used to sign a message.
type SigningKey struct {
Algorithm SignatureAlgorithm
Key interface{}
}
// SignerOptions represents options that can be set when creating signers.
type SignerOptions struct {
NonceSource NonceSource
EmbedJWK bool
// Optional map of additional keys to be inserted into the protected header
// of a JWS object. Some specifications which make use of JWS like to insert
// additional values here. All values must be JSON-serializable.
ExtraHeaders map[HeaderKey]interface{}
}
// WithHeader adds an arbitrary value to the ExtraHeaders map, initializing it
// if necessary. It returns itself and so can be used in a fluent style.
func (so *SignerOptions) WithHeader(k HeaderKey, v interface{}) *SignerOptions {
if so.ExtraHeaders == nil {
so.ExtraHeaders = map[HeaderKey]interface{}{}
}
so.ExtraHeaders[k] = v
return so
}
// WithContentType adds a content type ("cty") header and returns the updated
// SignerOptions.
func (so *SignerOptions) WithContentType(contentType ContentType) *SignerOptions {
return so.WithHeader(HeaderContentType, contentType)
}
// WithType adds a type ("typ") header and returns the updated SignerOptions.
func (so *SignerOptions) WithType(typ ContentType) *SignerOptions {
return so.WithHeader(HeaderType, typ)
}
// WithCritical adds the given names to the critical ("crit") header and returns
// the updated SignerOptions.
func (so *SignerOptions) WithCritical(names ...string) *SignerOptions {
if so.ExtraHeaders[headerCritical] == nil {
so.WithHeader(headerCritical, make([]string, 0, len(names)))
}
crit := so.ExtraHeaders[headerCritical].([]string)
so.ExtraHeaders[headerCritical] = append(crit, names...)
return so
}
// WithBase64 adds a base64url-encode payload ("b64") header and returns the updated
// SignerOptions. When the "b64" value is "false", the payload is not base64 encoded.
func (so *SignerOptions) WithBase64(b64 bool) *SignerOptions {
if !b64 {
so.WithHeader(headerB64, b64)
so.WithCritical(headerB64)
}
return so
}
type payloadSigner interface {
signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error)
}
type payloadVerifier interface {
verifyPayload(payload []byte, signature []byte, alg SignatureAlgorithm) error
}
type genericSigner struct {
recipients []recipientSigInfo
nonceSource NonceSource
embedJWK bool
extraHeaders map[HeaderKey]interface{}
}
type recipientSigInfo struct {
sigAlg SignatureAlgorithm
publicKey func() *JSONWebKey
signer payloadSigner
}
func staticPublicKey(jwk *JSONWebKey) func() *JSONWebKey {
return func() *JSONWebKey {
return jwk
}
}
// NewSigner creates an appropriate signer based on the key type
func NewSigner(sig SigningKey, opts *SignerOptions) (Signer, error) {
return NewMultiSigner([]SigningKey{sig}, opts)
}
// NewMultiSigner creates a signer for multiple recipients
func NewMultiSigner(sigs []SigningKey, opts *SignerOptions) (Signer, error) {
signer := &genericSigner{recipients: []recipientSigInfo{}}
if opts != nil {
signer.nonceSource = opts.NonceSource
signer.embedJWK = opts.EmbedJWK
signer.extraHeaders = opts.ExtraHeaders
}
for _, sig := range sigs {
err := signer.addRecipient(sig.Algorithm, sig.Key)
if err != nil {
return nil, err
}
}
return signer, nil
}
// newVerifier creates a verifier based on the key type
func newVerifier(verificationKey interface{}) (payloadVerifier, error) {
switch verificationKey := verificationKey.(type) {
case ed25519.PublicKey:
return &edEncrypterVerifier{
publicKey: verificationKey,
}, nil
case *rsa.PublicKey:
return &rsaEncrypterVerifier{
publicKey: verificationKey,
}, nil
case *ecdsa.PublicKey:
return &ecEncrypterVerifier{
publicKey: verificationKey,
}, nil
case []byte:
return &symmetricMac{
key: verificationKey,
}, nil
case JSONWebKey:
return newVerifier(verificationKey.Key)
case *JSONWebKey:
return newVerifier(verificationKey.Key)
}
if ov, ok := verificationKey.(OpaqueVerifier); ok {
return &opaqueVerifier{verifier: ov}, nil
}
return nil, ErrUnsupportedKeyType
}
func (ctx *genericSigner) addRecipient(alg SignatureAlgorithm, signingKey interface{}) error {
recipient, err := makeJWSRecipient(alg, signingKey)
if err != nil {
return err
}
ctx.recipients = append(ctx.recipients, recipient)
return nil
}
func makeJWSRecipient(alg SignatureAlgorithm, signingKey interface{}) (recipientSigInfo, error) {
switch signingKey := signingKey.(type) {
case ed25519.PrivateKey:
return newEd25519Signer(alg, signingKey)
case *rsa.PrivateKey:
return newRSASigner(alg, signingKey)
case *ecdsa.PrivateKey:
return newECDSASigner(alg, signingKey)
case []byte:
return newSymmetricSigner(alg, signingKey)
case JSONWebKey:
return newJWKSigner(alg, signingKey)
case *JSONWebKey:
return newJWKSigner(alg, *signingKey)
}
if signer, ok := signingKey.(OpaqueSigner); ok {
return newOpaqueSigner(alg, signer)
}
return recipientSigInfo{}, ErrUnsupportedKeyType
}
func newJWKSigner(alg SignatureAlgorithm, signingKey JSONWebKey) (recipientSigInfo, error) {
recipient, err := makeJWSRecipient(alg, signingKey.Key)
if err != nil {
return recipientSigInfo{}, err
}
if recipient.publicKey != nil && recipient.publicKey() != nil {
// recipient.publicKey is a JWK synthesized for embedding when recipientSigInfo
// was created for the inner key (such as a RSA or ECDSA public key). It contains
// the pub key for embedding, but doesn't have extra params like key id.
publicKey := signingKey
publicKey.Key = recipient.publicKey().Key
recipient.publicKey = staticPublicKey(&publicKey)
// This should be impossible, but let's check anyway.
if !recipient.publicKey().IsPublic() {
return recipientSigInfo{}, errors.New("square/go-jose: public key was unexpectedly not public")
}
}
return recipient, nil
}
func (ctx *genericSigner) Sign(payload []byte) (*JSONWebSignature, error) {
obj := &JSONWebSignature{}
obj.payload = payload
obj.Signatures = make([]Signature, len(ctx.recipients))
for i, recipient := range ctx.recipients {
protected := map[HeaderKey]interface{}{
headerAlgorithm: string(recipient.sigAlg),
}
if recipient.publicKey != nil && recipient.publicKey() != nil {
// We want to embed the JWK or set the kid header, but not both. Having a protected
// header that contains an embedded JWK while also simultaneously containing the kid
// header is confusing, and at least in ACME the two are considered to be mutually
// exclusive. The fact that both can exist at the same time is a somewhat unfortunate
// result of the JOSE spec. We've decided that this library will only include one or
// the other to avoid this confusion.
//
// See https://github.com/square/go-jose/issues/157 for more context.
if ctx.embedJWK {
protected[headerJWK] = recipient.publicKey()
} else {
keyID := recipient.publicKey().KeyID
if keyID != "" {
protected[headerKeyID] = keyID
}
}
}
if ctx.nonceSource != nil {
nonce, err := ctx.nonceSource.Nonce()
if err != nil {
return nil, fmt.Errorf("square/go-jose: Error generating nonce: %v", err)
}
protected[headerNonce] = nonce
}
for k, v := range ctx.extraHeaders {
protected[k] = v
}
serializedProtected := mustSerializeJSON(protected)
needsBase64 := true
if b64, ok := protected[headerB64]; ok {
if needsBase64, ok = b64.(bool); !ok {
return nil, errors.New("square/go-jose: Invalid b64 header parameter")
}
}
var input bytes.Buffer
input.WriteString(base64.RawURLEncoding.EncodeToString(serializedProtected))
input.WriteByte('.')
if needsBase64 {
input.WriteString(base64.RawURLEncoding.EncodeToString(payload))
} else {
input.Write(payload)
}
signatureInfo, err := recipient.signer.signPayload(input.Bytes(), recipient.sigAlg)
if err != nil {
return nil, err
}
signatureInfo.protected = &rawHeader{}
for k, v := range protected {
b, err := json.Marshal(v)
if err != nil {
return nil, fmt.Errorf("square/go-jose: Error marshalling item %#v: %v", k, err)
}
(*signatureInfo.protected)[k] = makeRawMessage(b)
}
obj.Signatures[i] = signatureInfo
}
return obj, nil
}
func (ctx *genericSigner) Options() SignerOptions {
return SignerOptions{
NonceSource: ctx.nonceSource,
EmbedJWK: ctx.embedJWK,
ExtraHeaders: ctx.extraHeaders,
}
}
// Verify validates the signature on the object and returns the payload.
// This function does not support multi-signature, if you desire multi-sig
// verification use VerifyMulti instead.
//
// Be careful when verifying signatures based on embedded JWKs inside the
// payload header. You cannot assume that the key received in a payload is
// trusted.
func (obj JSONWebSignature) Verify(verificationKey interface{}) ([]byte, error) {
err := obj.DetachedVerify(obj.payload, verificationKey)
if err != nil {
return nil, err
}
return obj.payload, nil
}
// UnsafePayloadWithoutVerification returns the payload without
// verifying it. The content returned from this function cannot be
// trusted.
func (obj JSONWebSignature) UnsafePayloadWithoutVerification() []byte {
return obj.payload
}
// DetachedVerify validates a detached signature on the given payload. In
// most cases, you will probably want to use Verify instead. DetachedVerify
// is only useful if you have a payload and signature that are separated from
// each other.
func (obj JSONWebSignature) DetachedVerify(payload []byte, verificationKey interface{}) error {
verifier, err := newVerifier(verificationKey)
if err != nil {
return err
}
if len(obj.Signatures) > 1 {
return errors.New("square/go-jose: too many signatures in payload; expecting only one")
}
signature := obj.Signatures[0]
headers := signature.mergedHeaders()
critical, err := headers.getCritical()
if err != nil {
return err
}
for _, name := range critical {
if !supportedCritical[name] {
return ErrCryptoFailure
}
}
input, err := obj.computeAuthData(payload, &signature)
if err != nil {
return ErrCryptoFailure
}
alg := headers.getSignatureAlgorithm()
err = verifier.verifyPayload(input, signature.Signature, alg)
if err == nil {
return nil
}
return ErrCryptoFailure
}
// VerifyMulti validates (one of the multiple) signatures on the object and
// returns the index of the signature that was verified, along with the signature
// object and the payload. We return the signature and index to guarantee that
// callers are getting the verified value.
func (obj JSONWebSignature) VerifyMulti(verificationKey interface{}) (int, Signature, []byte, error) {
idx, sig, err := obj.DetachedVerifyMulti(obj.payload, verificationKey)
if err != nil {
return -1, Signature{}, nil, err
}
return idx, sig, obj.payload, nil
}
// DetachedVerifyMulti validates a detached signature on the given payload with
// a signature/object that has potentially multiple signers. This returns the index
// of the signature that was verified, along with the signature object. We return
// the signature and index to guarantee that callers are getting the verified value.
//
// In most cases, you will probably want to use Verify or VerifyMulti instead.
// DetachedVerifyMulti is only useful if you have a payload and signature that are
// separated from each other, and the signature can have multiple signers at the
// same time.
func (obj JSONWebSignature) DetachedVerifyMulti(payload []byte, verificationKey interface{}) (int, Signature, error) {
verifier, err := newVerifier(verificationKey)
if err != nil {
return -1, Signature{}, err
}
outer:
for i, signature := range obj.Signatures {
headers := signature.mergedHeaders()
critical, err := headers.getCritical()
if err != nil {
continue
}
for _, name := range critical {
if !supportedCritical[name] {
continue outer
}
}
input, err := obj.computeAuthData(payload, &signature)
if err != nil {
continue
}
alg := headers.getSignatureAlgorithm()
err = verifier.verifyPayload(input, signature.Signature, alg)
if err == nil {
return i, signature, nil
}
}
return -1, Signature{}, ErrCryptoFailure
}