Add asymmetric JWT signing (#16010)
* Added asymmetric token signing. * Load signing key from settings. * Added optional kid parameter. * Updated documentation. * Add "kid" to token header.tokarchuk/v1.17
KN4CK3R
3 years ago
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29695cd6d5
@ -0,0 +1,378 @@ |
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// Copyright 2021 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package oauth2 |
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import ( |
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"crypto/ecdsa" |
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"crypto/elliptic" |
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"crypto/rand" |
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"crypto/rsa" |
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"crypto/sha256" |
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"crypto/x509" |
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"encoding/base64" |
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"encoding/pem" |
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"fmt" |
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"io/ioutil" |
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"math/big" |
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"os" |
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"path/filepath" |
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"strings" |
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"code.gitea.io/gitea/modules/generate" |
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"code.gitea.io/gitea/modules/log" |
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"code.gitea.io/gitea/modules/setting" |
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"code.gitea.io/gitea/modules/util" |
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"github.com/dgrijalva/jwt-go" |
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ini "gopkg.in/ini.v1" |
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) |
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// ErrInvalidAlgorithmType represents an invalid algorithm error.
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type ErrInvalidAlgorithmType struct { |
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Algorightm string |
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} |
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func (err ErrInvalidAlgorithmType) Error() string { |
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return fmt.Sprintf("JWT signing algorithm is not supported: %s", err.Algorightm) |
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} |
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// JWTSigningKey represents a algorithm/key pair to sign JWTs
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type JWTSigningKey interface { |
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IsSymmetric() bool |
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SigningMethod() jwt.SigningMethod |
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SignKey() interface{} |
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VerifyKey() interface{} |
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ToJWK() (map[string]string, error) |
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PreProcessToken(*jwt.Token) |
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} |
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type hmacSigningKey struct { |
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signingMethod jwt.SigningMethod |
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secret []byte |
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} |
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func (key hmacSigningKey) IsSymmetric() bool { |
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return true |
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} |
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func (key hmacSigningKey) SigningMethod() jwt.SigningMethod { |
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return key.signingMethod |
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} |
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func (key hmacSigningKey) SignKey() interface{} { |
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return key.secret |
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} |
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func (key hmacSigningKey) VerifyKey() interface{} { |
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return key.secret |
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} |
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func (key hmacSigningKey) ToJWK() (map[string]string, error) { |
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return map[string]string{ |
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"kty": "oct", |
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"alg": key.SigningMethod().Alg(), |
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}, nil |
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} |
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func (key hmacSigningKey) PreProcessToken(*jwt.Token) {} |
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type rsaSingingKey struct { |
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signingMethod jwt.SigningMethod |
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key *rsa.PrivateKey |
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id string |
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} |
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func newRSASingingKey(signingMethod jwt.SigningMethod, key *rsa.PrivateKey) (rsaSingingKey, error) { |
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kid, err := createPublicKeyFingerprint(key.Public().(*rsa.PublicKey)) |
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if err != nil { |
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return rsaSingingKey{}, err |
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} |
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return rsaSingingKey{ |
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signingMethod, |
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key, |
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base64.RawURLEncoding.EncodeToString(kid), |
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}, nil |
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} |
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func (key rsaSingingKey) IsSymmetric() bool { |
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return false |
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} |
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func (key rsaSingingKey) SigningMethod() jwt.SigningMethod { |
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return key.signingMethod |
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} |
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func (key rsaSingingKey) SignKey() interface{} { |
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return key.key |
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} |
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func (key rsaSingingKey) VerifyKey() interface{} { |
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return key.key.Public() |
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} |
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func (key rsaSingingKey) ToJWK() (map[string]string, error) { |
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pubKey := key.key.Public().(*rsa.PublicKey) |
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return map[string]string{ |
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"kty": "RSA", |
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"alg": key.SigningMethod().Alg(), |
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"kid": key.id, |
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"e": base64.RawURLEncoding.EncodeToString(big.NewInt(int64(pubKey.E)).Bytes()), |
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"n": base64.RawURLEncoding.EncodeToString(pubKey.N.Bytes()), |
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}, nil |
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} |
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func (key rsaSingingKey) PreProcessToken(token *jwt.Token) { |
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token.Header["kid"] = key.id |
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} |
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type ecdsaSingingKey struct { |
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signingMethod jwt.SigningMethod |
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key *ecdsa.PrivateKey |
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id string |
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} |
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func newECDSASingingKey(signingMethod jwt.SigningMethod, key *ecdsa.PrivateKey) (ecdsaSingingKey, error) { |
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kid, err := createPublicKeyFingerprint(key.Public().(*ecdsa.PublicKey)) |
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if err != nil { |
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return ecdsaSingingKey{}, err |
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} |
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return ecdsaSingingKey{ |
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signingMethod, |
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key, |
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base64.RawURLEncoding.EncodeToString(kid), |
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}, nil |
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} |
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func (key ecdsaSingingKey) IsSymmetric() bool { |
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return false |
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} |
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func (key ecdsaSingingKey) SigningMethod() jwt.SigningMethod { |
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return key.signingMethod |
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} |
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func (key ecdsaSingingKey) SignKey() interface{} { |
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return key.key |
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} |
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func (key ecdsaSingingKey) VerifyKey() interface{} { |
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return key.key.Public() |
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} |
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func (key ecdsaSingingKey) ToJWK() (map[string]string, error) { |
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pubKey := key.key.Public().(*ecdsa.PublicKey) |
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return map[string]string{ |
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"kty": "EC", |
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"alg": key.SigningMethod().Alg(), |
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"kid": key.id, |
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"crv": pubKey.Params().Name, |
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"x": base64.RawURLEncoding.EncodeToString(pubKey.X.Bytes()), |
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"y": base64.RawURLEncoding.EncodeToString(pubKey.Y.Bytes()), |
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}, nil |
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} |
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func (key ecdsaSingingKey) PreProcessToken(token *jwt.Token) { |
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token.Header["kid"] = key.id |
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} |
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// createPublicKeyFingerprint creates a fingerprint of the given key.
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// The fingerprint is the sha256 sum of the PKIX structure of the key.
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func createPublicKeyFingerprint(key interface{}) ([]byte, error) { |
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bytes, err := x509.MarshalPKIXPublicKey(key) |
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if err != nil { |
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return nil, err |
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} |
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checksum := sha256.Sum256(bytes) |
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return checksum[:], nil |
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} |
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// CreateJWTSingingKey creates a signing key from an algorithm / key pair.
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func CreateJWTSingingKey(algorithm string, key interface{}) (JWTSigningKey, error) { |
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var signingMethod jwt.SigningMethod |
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switch algorithm { |
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case "HS256": |
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signingMethod = jwt.SigningMethodHS256 |
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case "HS384": |
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signingMethod = jwt.SigningMethodHS384 |
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case "HS512": |
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signingMethod = jwt.SigningMethodHS512 |
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case "RS256": |
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signingMethod = jwt.SigningMethodRS256 |
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case "RS384": |
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signingMethod = jwt.SigningMethodRS384 |
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case "RS512": |
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signingMethod = jwt.SigningMethodRS512 |
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case "ES256": |
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signingMethod = jwt.SigningMethodES256 |
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case "ES384": |
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signingMethod = jwt.SigningMethodES384 |
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case "ES512": |
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signingMethod = jwt.SigningMethodES512 |
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default: |
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return nil, ErrInvalidAlgorithmType{algorithm} |
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} |
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switch signingMethod.(type) { |
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case *jwt.SigningMethodECDSA: |
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privateKey, ok := key.(*ecdsa.PrivateKey) |
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if !ok { |
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return nil, jwt.ErrInvalidKeyType |
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} |
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return newECDSASingingKey(signingMethod, privateKey) |
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case *jwt.SigningMethodRSA: |
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privateKey, ok := key.(*rsa.PrivateKey) |
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if !ok { |
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return nil, jwt.ErrInvalidKeyType |
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} |
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return newRSASingingKey(signingMethod, privateKey) |
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default: |
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secret, ok := key.([]byte) |
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if !ok { |
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return nil, jwt.ErrInvalidKeyType |
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} |
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return hmacSigningKey{signingMethod, secret}, nil |
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} |
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} |
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// DefaultSigningKey is the default signing key for JWTs.
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var DefaultSigningKey JWTSigningKey |
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// InitSigningKey creates the default signing key from settings or creates a random key.
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func InitSigningKey() error { |
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var err error |
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var key interface{} |
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switch setting.OAuth2.JWTSigningAlgorithm { |
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case "HS256": |
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fallthrough |
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case "HS384": |
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fallthrough |
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case "HS512": |
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key, err = loadOrCreateSymmetricKey() |
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case "RS256": |
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fallthrough |
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case "RS384": |
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fallthrough |
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case "RS512": |
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fallthrough |
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case "ES256": |
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fallthrough |
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case "ES384": |
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fallthrough |
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case "ES512": |
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key, err = loadOrCreateAsymmetricKey() |
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default: |
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return ErrInvalidAlgorithmType{setting.OAuth2.JWTSigningAlgorithm} |
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} |
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if err != nil { |
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return fmt.Errorf("Error while loading or creating symmetric key: %v", err) |
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} |
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signingKey, err := CreateJWTSingingKey(setting.OAuth2.JWTSigningAlgorithm, key) |
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if err != nil { |
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return err |
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} |
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DefaultSigningKey = signingKey |
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return nil |
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} |
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// loadOrCreateSymmetricKey checks if the configured secret is valid.
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// If it is not valid a new secret is created and saved in the configuration file.
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func loadOrCreateSymmetricKey() (interface{}, error) { |
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key := make([]byte, 32) |
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n, err := base64.RawURLEncoding.Decode(key, []byte(setting.OAuth2.JWTSecretBase64)) |
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if err != nil || n != 32 { |
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key, err = generate.NewJwtSecret() |
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if err != nil { |
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log.Fatal("error generating JWT secret: %v", err) |
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return nil, err |
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} |
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setting.CreateOrAppendToCustomConf(func(cfg *ini.File) { |
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secretBase64 := base64.RawURLEncoding.EncodeToString(key) |
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cfg.Section("oauth2").Key("JWT_SECRET").SetValue(secretBase64) |
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}) |
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} |
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return key, nil |
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} |
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// loadOrCreateAsymmetricKey checks if the configured private key exists.
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// If it does not exist a new random key gets generated and saved on the configured path.
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func loadOrCreateAsymmetricKey() (interface{}, error) { |
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keyPath := setting.OAuth2.JWTSigningPrivateKeyFile |
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isExist, err := util.IsExist(keyPath) |
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if err != nil { |
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log.Fatal("Unable to check if %s exists. Error: %v", keyPath, err) |
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} |
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if !isExist { |
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err := func() error { |
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key, err := func() (interface{}, error) { |
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if strings.HasPrefix(setting.OAuth2.JWTSigningAlgorithm, "RS") { |
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return rsa.GenerateKey(rand.Reader, 4096) |
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} |
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return ecdsa.GenerateKey(elliptic.P256(), rand.Reader) |
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}() |
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if err != nil { |
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return err |
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} |
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bytes, err := x509.MarshalPKCS8PrivateKey(key) |
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if err != nil { |
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return err |
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} |
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privateKeyPEM := &pem.Block{Type: "PRIVATE KEY", Bytes: bytes} |
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if err := os.MkdirAll(filepath.Dir(keyPath), os.ModePerm); err != nil { |
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return err |
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} |
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f, err := os.OpenFile(keyPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600) |
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if err != nil { |
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return err |
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} |
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defer func() { |
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if err = f.Close(); err != nil { |
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log.Error("Close: %v", err) |
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} |
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}() |
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return pem.Encode(f, privateKeyPEM) |
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}() |
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if err != nil { |
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log.Fatal("Error generating private key: %v", err) |
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return nil, err |
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} |
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} |
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bytes, err := ioutil.ReadFile(keyPath) |
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if err != nil { |
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return nil, err |
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} |
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block, _ := pem.Decode(bytes) |
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if block == nil { |
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return nil, fmt.Errorf("no valid PEM data found in %s", keyPath) |
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} else if block.Type != "PRIVATE KEY" { |
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return nil, fmt.Errorf("expected PRIVATE KEY, got %s in %s", block.Type, keyPath) |
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} |
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return x509.ParsePKCS8PrivateKey(block.Bytes) |
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} |
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