forked from edgelesssys/edgelessdb
/
key.go
205 lines (170 loc) · 5.71 KB
/
key.go
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/* Copyright (c) Edgeless Systems GmbH
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
package core
import (
"crypto/rand"
"encoding/hex"
"errors"
"os"
"path/filepath"
"time"
"github.com/edgelesssys/edgelessdb/edb/rt"
"github.com/edgelesssys/ego/ecrypto"
)
// PersistenceDir holds the directory name where we store the seal key on the host filesystem when running standalone
const PersistenceDir = "edb-persistence"
// ERocksDBMasterKeyVar is the name of the environment variable holding the master key for eRocksDB.
// Needs to be kept in sync with 3rdparty/edgeless-rocksdb/file/encrypted_file.cc
const ERocksDBMasterKeyVar = "EROCKSDB_MASTERKEY"
// sealedKeyFname is the filename where the key used for the database is stored encrypted on the disk with the SGX product key
const sealedKeyFname = "sealed_key"
// ErrKeyIncorrectSize is an error type returned when the key used by ERocksDB is not 16 bytes (= 128 bit) long
var ErrKeyIncorrectSize = errors.New("key is not 16 bytes long")
// ErrKeyNotProvidedMarblerun is an error type thrown when edb was run as a Marble, but Marblerun did not provide a key in the environment
var ErrKeyNotProvidedMarblerun = errors.New("marblerun did not set required key for edb")
// ErrKeyNotAllowedToChangeMarblerun is an error type thrown when edb attempts to change the sealing key provided by Marblerun
var ErrKeyNotAllowedToChangeMarblerun = errors.New("cannot change sealing key when running under marblerun")
func (c *Core) loadMasterKeyFromEnv() ([]byte, error) {
keyHex, ok := os.LookupEnv(ERocksDBMasterKeyVar)
if !ok {
return nil, nil
}
key, err := hex.DecodeString(keyHex)
if err != nil {
return nil, err
} else if len(key) != 16 {
return nil, errors.New("key in environment has incorrect size")
}
return key, nil
}
func (c *Core) loadMasterKey() ([]byte, error) {
// If key was already set, return it from env
key, err := c.loadMasterKeyFromEnv()
if err != nil {
return nil, err
}
if key != nil {
return key, nil
}
// If running as a Marble, we force Marblerun to provide the key & handle recovery
if c.isMarble {
return nil, ErrKeyNotProvidedMarblerun
}
// If no key was set yet, try to read from disk
key, err = c.fs.ReadFile(filepath.Join(c.cfg.DataPath, PersistenceDir, sealedKeyFname))
if err != nil {
return nil, err
}
// If key was set, unseal from disk
if c.rt.IsEnclave() {
key, err = ecrypto.Unseal(key, nil)
if err != nil {
return nil, err
}
}
// This should not happen as it should have been only stored on disk when it was 16 bytes long, but let's be safe here...
if len(key) != 16 {
return nil, ErrKeyIncorrectSize
}
if err := c.storeMasterKeyToEnv(key); err != nil {
return nil, err
}
// Return unsealed key
return key, nil
}
func (c *Core) newMasterKey() ([]byte, error) {
// Generate new random key
key := make([]byte, 16)
n, err := rand.Read(key)
if err != nil {
return nil, err
} else if n != 16 {
return nil, ErrKeyIncorrectSize
}
// Save & set new key
if err := c.storeMasterKey(key); err != nil {
return nil, err
}
return key, nil
}
func (c *Core) storeMasterKeyToEnv(key []byte) error {
// Set newly generated key for eRocksDB
if len(key) != 16 {
return ErrKeyIncorrectSize
}
return os.Setenv(ERocksDBMasterKeyVar, hex.EncodeToString(key))
}
func (c *Core) storeMasterKey(key []byte) error {
// Set newly generated key for eRocksDB
if err := c.storeMasterKeyToEnv(key); err != nil {
return err
}
// Save master key
if c.rt.IsEnclave() {
var err error
key, err = ecrypto.SealWithProductKey(key, nil)
if err != nil {
return err
}
}
// Create dir
if err := os.MkdirAll(filepath.Join(c.cfg.DataPath, PersistenceDir), 0o700); err != nil {
return err
}
// If there already is an existing key file stored on disk, save it
fname := filepath.Join(c.cfg.DataPath, PersistenceDir, sealedKeyFname)
if sealedKeyData, err := c.fs.ReadFile(fname); err == nil {
t := time.Now()
newFileName := fname + "_" + t.Format("20060102150405") + ".bak"
c.fs.WriteFile(newFileName, sealedKeyData, 0o600)
}
// Write the sealed encryption key to disk
if err := c.fs.WriteFile(fname, key, 0o600); err != nil {
return err
}
return nil
}
func (c *Core) setMasterKey(key []byte) error {
// Not allowed to change keys when running under Marblerun
if c.isMarble {
return ErrKeyNotAllowedToChangeMarblerun
}
c.masterKey = key
return c.storeMasterKey(key)
}
func (c *Core) mustInitMasterKey() {
// Check if RocksDB has already been initialized
rocksDBAlreadyInitialized, err := c.fs.Exists(filepath.Join(c.cfg.DataPath, "#rocksdb"))
if err != nil {
panic(err)
}
// Try to load from env or file.
key, err := c.loadMasterKey()
// Does not exist? Generate a new one.
if os.IsNotExist(err) && !rocksDBAlreadyInitialized {
key, err = c.newMasterKey()
if err != nil {
panic(err)
}
} else if err == ErrKeyNotProvidedMarblerun {
panic(err)
}
// Failed to read/decrypt? Enter recovery.
if err != nil {
rt.Log.Println("Failed to initialize master key:", err)
rt.Log.Println("Entering recovery mode...")
c.advanceState(stateRecovery)
return
}
c.advanceState(stateInitialized)
c.masterKey = key
}