forked from mirror/jwt
80 lines
1.9 KiB
Go
80 lines
1.9 KiB
Go
package jwt
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import (
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"crypto"
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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/pem"
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"errors"
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)
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type SigningMethodRS256 struct{}
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func init() {
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RegisterSigningMethod("RS256", func() SigningMethod {
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return new(SigningMethodRS256)
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})
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}
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func (m *SigningMethodRS256) Alg() string {
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return "RS256"
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}
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func (m *SigningMethodRS256) Verify(signingString, signature string, key []byte) (err error) {
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// Key
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var sig []byte
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if sig, err = DecodeSegment(signature); err == nil {
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var block *pem.Block
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if block, _ = pem.Decode(key); block != nil {
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var parsedKey interface{}
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if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err == nil {
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if rsaKey, ok := parsedKey.(*rsa.PublicKey); ok {
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hasher := sha256.New()
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hasher.Write([]byte(signingString))
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err = rsa.VerifyPKCS1v15(rsaKey, crypto.SHA256, hasher.Sum(nil), sig)
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} else {
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err = errors.New("Key is not a valid RSA public key")
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}
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}
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} else {
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err = errors.New("Could not parse key data")
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}
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}
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return
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}
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func (m *SigningMethodRS256) Sign(signingString string, key []byte) (sig string, err error) {
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// Key
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var rsaKey *rsa.PrivateKey
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if rsaKey, err = m.parsePrivateKey(key); err == nil {
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hasher := sha256.New()
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hasher.Write([]byte(signingString))
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var sigBytes []byte
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if sigBytes, err = rsa.SignPKCS1v15(rand.Reader, rsaKey, crypto.SHA256, hasher.Sum(nil)); err == nil {
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sig = EncodeSegment(sigBytes)
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}
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}
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return
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}
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func (m *SigningMethodRS256) parsePrivateKey(key []byte) (pkey *rsa.PrivateKey, err error) {
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var block *pem.Block
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if block, _ = pem.Decode(key); block != nil {
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var parsedKey interface{}
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if parsedKey, err = x509.ParsePKCS1PrivateKey(block.Bytes); err != nil {
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if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
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return nil, err
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}
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}
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var ok bool
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if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
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err = errors.New("Key is not a valid RSA private key")
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}
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}
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return
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}
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