edg

Documentation

Index

• Constants
• func DecryptOptions(ciphertext []byte, fileNum base.FileNum, keyManager *KeyManager) ([]byte, error)
• func EncryptOptions(serializedOpts []byte, fileNum base.DiskFileNum, keyManager *KeyManager) ([]byte, error)
• func GetCipher(key []byte) (cipher.AEAD, error)
• func TestEnableRandomKey()
• type ApprovedWriter
  • func (w *ApprovedWriter) Write(p []byte) (int, error)
• type KeyManager
  • func NewKeyManager(fs vfs.FS, dirname string, masterKey []byte) (*KeyManager, error)
  • func (m *KeyManager) Close() error
  • func (m *KeyManager) Create(fileNum base.FileNum) ([]byte, error)
  • func (m *KeyManager) Get(fileNum base.FileNum) ([]byte, error)
• type Writer

Constants

const GCMTagSize = 16

GCMTagSize is the AES-GCM tag size.

const (
	// SaltChainFilename is the name of the salt chain file.
	SaltChainFilename = "SALTCHAIN"
)

Functions

func DecryptOptions

func DecryptOptions(
	ciphertext []byte, fileNum base.FileNum, keyManager *KeyManager,
) ([]byte, error)

DecryptOptions decrypts the contents of an OPTIONS file.

func EncryptOptions

func EncryptOptions(
	serializedOpts []byte, fileNum base.DiskFileNum, keyManager *KeyManager,
) ([]byte, error)

EncryptOptions encrypts the contents of an OPTIONS file.

func GetCipher

func GetCipher(key []byte) (cipher.AEAD, error)

GetCipher returns an AES-GCM cipher for key.

func TestEnableRandomKey

func TestEnableRandomKey()

TestEnableRandomKey enables the use of a random key in case no key has been set. This reduces required changes to existing tests.

Types

type ApprovedWriter

type ApprovedWriter struct {
	Writer interface {
		WriteApproved([]byte) (int, error)
	}
}

ApprovedWriter wraps an edg.Writer and provides an io.Writer interface. Use this to pass an edg.Writer to functions that expect an io.Writer.

func (*ApprovedWriter) Write

func (w *ApprovedWriter) Write(p []byte) (int, error)

type KeyManager

type KeyManager struct {
	// contains filtered or unexported fields
}

KeyManager manages the encryption keys for database files.

Call Create(fileNum) to create a new key when writing a file. Call Get(fileNum) to get the key when reading a file.

Internally, KeyManager maps file numbers to unique salts. File keys are derived with hkdf(masterKey, salt). The salts are stored integrity-protected in the SALTCHAIN file. The file is an append-only chain of saltBlocks, linked by HMACs.

As the encrypted files are file-level integrity-protected, together with key management via the salt chain we achieve "snapshot integrity" for the entire database.

func NewKeyManager

func NewKeyManager(fs vfs.FS, dirname string, masterKey []byte) (*KeyManager, error)

NewKeyManager creates a new KeyManager.

func (*KeyManager) Close

func (m *KeyManager) Close() error

Close closes the KeyManager.

func (*KeyManager) Create

func (m *KeyManager) Create(fileNum base.FileNum) ([]byte, error)

Create creates a new key for writing a file.

func (*KeyManager) Get

func (m *KeyManager) Get(fileNum base.FileNum) ([]byte, error)

Get gets the key for reading a file.

type Writer

type Writer interface {
	Write([]byte) (int, error)
	WriteApproved([]byte) (int, error)
}

Writer is an interface for Write and WriteApproved.

var Discard Writer = discard{}

Discard is a Writer on which all Write calls succeed without doing anything.