authelia/internal/session/encrypting_serializer.go

68 lines
1.5 KiB
Go

package session
import (
"crypto/sha256"
"fmt"
"github.com/fasthttp/session"
"github.com/authelia/authelia/internal/utils"
)
// EncryptingSerializer a serializer encrypting the data with AES-GCM with 256-bit keys.
type EncryptingSerializer struct {
key [32]byte
}
// NewEncryptingSerializer return new encrypt instance.
func NewEncryptingSerializer(secret string) *EncryptingSerializer {
key := sha256.Sum256([]byte(secret))
return &EncryptingSerializer{key}
}
// Encode encode and encrypt session.
func (e *EncryptingSerializer) Encode(src session.Dict) ([]byte, error) {
if len(src.D) == 0 {
return nil, nil
}
dst, err := src.MarshalMsg(nil)
if err != nil {
return nil, fmt.Errorf("Unable to marshal session: %v", err)
}
encryptedDst, err := utils.Encrypt(dst, &e.key)
if err != nil {
return nil, fmt.Errorf("Unable to encrypt session: %v", err)
}
return encryptedDst, nil
}
// Decode decrypt and decode session.
func (e *EncryptingSerializer) Decode(dst *session.Dict, src []byte) error {
if len(src) == 0 {
return nil
}
dst.Reset()
decryptedSrc, err := utils.Decrypt(src, &e.key)
if err != nil {
// If an error is thrown while decrypting, it's probably an old unencrypted session
// so we just unmarshall it without decrypting. It's a way to avoid a breaking change
// requiring to flush redis.
// TODO(clems4ever): remove in few months
_, uerr := dst.UnmarshalMsg(src)
if uerr != nil {
return fmt.Errorf("Unable to decrypt session: %s", err)
}
return nil
}
_, err = dst.UnmarshalMsg(decryptedSrc)
return err
}