open-vault/vault/seal/shamir/shamir.go

126 lines
2.8 KiB
Go

package shamir
import (
"context"
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"errors"
"fmt"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-uuid"
"github.com/hashicorp/vault/sdk/physical"
"github.com/hashicorp/vault/vault/seal"
)
// ShamirSeal implements the seal.Access interface for Shamir unseal
type ShamirSeal struct {
logger log.Logger
aead cipher.AEAD
}
// Ensure that we are implementing AutoSealAccess
var _ seal.Access = (*ShamirSeal)(nil)
// NewSeal creates a new ShamirSeal with the provided logger
func NewSeal(logger log.Logger) *ShamirSeal {
seal := &ShamirSeal{
logger: logger,
}
return seal
}
// SetConfig sets the fields on the ShamirSeal object based on
// values from the config parameter.
func (s *ShamirSeal) SetConfig(config map[string]string) (map[string]string, error) {
// Map that holds non-sensitive configuration info
sealInfo := make(map[string]string)
if config == nil || config["key"] == "" {
return sealInfo, nil
}
keyB64 := config["key"]
key, err := base64.StdEncoding.DecodeString(keyB64)
if err != nil {
return sealInfo, err
}
aesCipher, err := aes.NewCipher(key)
if err != nil {
return sealInfo, err
}
aead, err := cipher.NewGCM(aesCipher)
if err != nil {
return sealInfo, err
}
s.aead = aead
return sealInfo, nil
}
// Init is called during core.Initialize. No-op at the moment.
func (s *ShamirSeal) Init(_ context.Context) error {
return nil
}
// Finalize is called during shutdown. This is a no-op since
// ShamirSeal doesn't require any cleanup.
func (s *ShamirSeal) Finalize(_ context.Context) error {
return nil
}
// SealType returns the seal type for this particular seal implementation.
func (s *ShamirSeal) SealType() string {
return seal.Shamir
}
// KeyID returns the last known key id.
func (s *ShamirSeal) KeyID() string {
return ""
}
// Encrypt is used to encrypt the plaintext using the aead held by the seal.
func (s *ShamirSeal) Encrypt(_ context.Context, plaintext []byte) (*physical.EncryptedBlobInfo, error) {
if plaintext == nil {
return nil, fmt.Errorf("given plaintext for encryption is nil")
}
if s.aead == nil {
return nil, errors.New("aead is not configured in the seal")
}
iv, err := uuid.GenerateRandomBytes(12)
if err != nil {
return nil, err
}
ciphertext := s.aead.Seal(nil, iv, plaintext, nil)
return &physical.EncryptedBlobInfo{
Ciphertext: append(iv, ciphertext...),
}, nil
}
func (s *ShamirSeal) Decrypt(_ context.Context, in *physical.EncryptedBlobInfo) ([]byte, error) {
if in == nil {
return nil, fmt.Errorf("given plaintext for encryption is nil")
}
if s.aead == nil {
return nil, errors.New("aead is not configured in the seal")
}
iv, ciphertext := in.Ciphertext[:12], in.Ciphertext[12:]
plaintext, err := s.aead.Open(nil, iv, ciphertext, nil)
if err != nil {
return nil, err
}
return plaintext, nil
}