301 lines
8.3 KiB
Go
301 lines
8.3 KiB
Go
// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information.
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package encryption
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import (
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"crypto/hmac"
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"crypto/sha512"
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"encoding/base64"
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"strings"
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"github.com/zeebo/errs"
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"storj.io/storj/pkg/paths"
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"storj.io/storj/pkg/storj"
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)
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// StoreEncryptPath encrypts the path using the provided cipher and looking up
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// keys from the provided store and bucket.
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func StoreEncryptPath(bucket string, path paths.Unencrypted, cipher storj.CipherSuite, store *Store) (
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encPath paths.Encrypted, err error) {
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// Invalid paths map to invalid paths
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if !path.Valid() {
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return paths.Encrypted{}, nil
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}
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if cipher == storj.EncNull {
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return paths.NewEncrypted(path.Raw()), nil
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}
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_, consumed, base := store.LookupUnencrypted(bucket, path)
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if base == nil {
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return paths.Encrypted{}, errs.New("unable to find encryption base for: %s/%q", bucket, path)
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}
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remaining, ok := path.Consume(consumed)
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if !ok {
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return paths.Encrypted{}, errs.New("unable to encrypt bucket path: %s/%q", bucket, path)
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}
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// if we didn't consume any path, we're at the root of the bucket, and so we have
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// to fold the bucket name into the key.
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key := &base.Key
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if !consumed.Valid() {
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key, err = derivePathKeyComponent(key, bucket)
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if err != nil {
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return paths.Encrypted{}, errs.Wrap(err)
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}
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}
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encrypted, err := EncryptPathRaw(remaining.Raw(), cipher, key)
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if err != nil {
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return paths.Encrypted{}, errs.Wrap(err)
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}
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var builder strings.Builder
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builder.WriteString(base.Encrypted.Raw())
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if len(encrypted) > 0 {
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if builder.Len() > 0 {
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builder.WriteByte('/')
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}
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builder.WriteString(encrypted)
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}
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return paths.NewEncrypted(builder.String()), nil
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}
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// EncryptPathRaw encrypts the path using the provided key directly. EncryptPath should be
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// preferred if possible.
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func EncryptPathRaw(raw string, cipher storj.CipherSuite, key *storj.Key) (string, error) {
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if cipher == storj.EncNull {
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return raw, nil
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}
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var builder strings.Builder
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for iter, i := paths.NewIterator(raw), 0; !iter.Done(); i++ {
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component := iter.Next()
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encComponent, err := storeEncryptPathComponent(component, cipher, key)
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if err != nil {
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return "", errs.Wrap(err)
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}
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key, err = derivePathKeyComponent(key, component)
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if err != nil {
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return "", errs.Wrap(err)
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}
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if i > 0 {
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builder.WriteByte('/')
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}
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builder.WriteString(encComponent)
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}
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return builder.String(), nil
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}
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// StoreDecryptPath decrypts the path using the provided cipher and looking up
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// keys from the provided store and bucket.
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func StoreDecryptPath(bucket string, path paths.Encrypted, cipher storj.CipherSuite, store *Store) (
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unencPath paths.Unencrypted, err error) {
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// Invalid paths map to invalid paths
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if !path.Valid() {
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return paths.Unencrypted{}, nil
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}
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if cipher == storj.EncNull {
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return paths.NewUnencrypted(path.Raw()), nil
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}
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_, consumed, base := store.LookupEncrypted(bucket, path)
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if base == nil {
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return paths.Unencrypted{}, errs.New("unable to find decryption base for: %q", path)
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}
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remaining, ok := path.Consume(consumed)
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if !ok {
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return paths.Unencrypted{}, errs.New("unable to decrypt bucket path: %q", path)
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}
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// if we didn't consume any path, we're at the root of the bucket, and so we have
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// to fold the bucket name into the key.
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key := &base.Key
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if !consumed.Valid() {
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key, err = derivePathKeyComponent(key, bucket)
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if err != nil {
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return paths.Unencrypted{}, errs.Wrap(err)
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}
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}
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decrypted, err := DecryptPathRaw(remaining.Raw(), cipher, key)
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if err != nil {
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return paths.Unencrypted{}, errs.Wrap(err)
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}
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var builder strings.Builder
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builder.WriteString(base.Unencrypted.Raw())
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if len(decrypted) > 0 {
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if builder.Len() > 0 {
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builder.WriteByte('/')
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}
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builder.WriteString(decrypted)
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}
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return paths.NewUnencrypted(builder.String()), nil
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}
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// DecryptPathRaw decrypts the path using the provided key directly. DecryptPath should be
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// preferred if possible.
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func DecryptPathRaw(raw string, cipher storj.CipherSuite, key *storj.Key) (string, error) {
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if cipher == storj.EncNull {
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return raw, nil
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}
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var builder strings.Builder
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for iter, i := paths.NewIterator(raw), 0; !iter.Done(); i++ {
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component := iter.Next()
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unencComponent, err := storeDecryptPathComponent(component, cipher, key)
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if err != nil {
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return "", errs.Wrap(err)
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}
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key, err = derivePathKeyComponent(key, unencComponent)
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if err != nil {
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return "", errs.Wrap(err)
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}
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if i > 0 {
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builder.WriteByte('/')
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}
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builder.WriteString(unencComponent)
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}
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return builder.String(), nil
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}
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// StoreDeriveContentKey returns the content key for the passed in path by looking up
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// the appropriate base key from the store and bucket and deriving the rest.
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func StoreDeriveContentKey(bucket string, path paths.Unencrypted, store *Store) (key *storj.Key, err error) {
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key, err = StoreDerivePathKey(bucket, path, store)
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if err != nil {
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return nil, errs.Wrap(err)
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}
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key, err = DeriveKey(key, "content")
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return key, errs.Wrap(err)
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}
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// StoreDerivePathKey returns the path key for the passed in path by looking up the
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// appropriate base key from the store and bucket and deriving the rest.
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func StoreDerivePathKey(bucket string, path paths.Unencrypted, store *Store) (key *storj.Key, err error) {
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_, consumed, base := store.LookupUnencrypted(bucket, path)
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if base == nil {
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return nil, errs.New("unable to find encryption base for: %s/%q", bucket, path)
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}
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// If asking for the key at the bucket, do that and return.
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if !path.Valid() {
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key, err = derivePathKeyComponent(&base.Key, bucket)
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if err != nil {
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return nil, errs.Wrap(err)
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}
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return key, nil
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}
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remaining, ok := path.Consume(consumed)
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if !ok {
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return nil, errs.New("unable to derive path key for: %s/%q", bucket, path)
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}
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// if we didn't consume any path, we're at the root of the bucket, and so we have
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// to fold the bucket name into the key.
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key = &base.Key
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if !consumed.Valid() {
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key, err = derivePathKeyComponent(key, bucket)
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if err != nil {
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return nil, errs.Wrap(err)
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}
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}
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for iter := remaining.Iterator(); !iter.Done(); {
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key, err = derivePathKeyComponent(key, iter.Next())
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if err != nil {
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return nil, errs.Wrap(err)
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}
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}
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return key, nil
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}
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// derivePathKeyComponent derives a new key from the provided one using the component. It
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// should be preferred over DeriveKey when adding path components as it performs the
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// necessary transformation to the component.
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func derivePathKeyComponent(key *storj.Key, component string) (*storj.Key, error) {
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return DeriveKey(key, "path:"+component)
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}
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// storeEncryptPathComponent encrypts a single path component with the provided cipher and key.
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func storeEncryptPathComponent(comp string, cipher storj.CipherSuite, key *storj.Key) (string, error) {
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if comp == "" {
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return "", nil
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}
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// derive the key for the next path component. this is so that
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// every encrypted component has a unique nonce.
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derivedKey, err := derivePathKeyComponent(key, comp)
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if err != nil {
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return "", err
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}
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// use the derived key to derive the nonce
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mac := hmac.New(sha512.New, derivedKey[:])
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_, err = mac.Write([]byte("nonce"))
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if err != nil {
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return "", Error.Wrap(err)
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}
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nonce := new(storj.Nonce)
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copy(nonce[:], mac.Sum(nil))
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// encrypt the path components with the parent's key and the derived nonce
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cipherText, err := Encrypt([]byte(comp), cipher, key, nonce)
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if err != nil {
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return "", Error.Wrap(err)
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}
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nonceSize := storj.NonceSize
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if cipher == storj.EncAESGCM {
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nonceSize = AESGCMNonceSize
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}
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// keep the nonce together with the cipher text
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return base64.RawURLEncoding.EncodeToString(append(nonce[:nonceSize], cipherText...)), nil
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}
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// storeDecryptPathComponent decrypts a single path component with the provided cipher and key.
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func storeDecryptPathComponent(comp string, cipher storj.CipherSuite, key *storj.Key) (string, error) {
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if comp == "" {
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return "", nil
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}
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data, err := base64.RawURLEncoding.DecodeString(comp)
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if err != nil {
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return "", Error.Wrap(err)
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}
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nonceSize := storj.NonceSize
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if cipher == storj.EncAESGCM {
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nonceSize = AESGCMNonceSize
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}
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if len(data) < nonceSize || nonceSize < 0 {
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return "", errs.New("component did not contain enough nonce bytes")
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}
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// extract the nonce from the cipher text
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nonce := new(storj.Nonce)
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copy(nonce[:], data[:nonceSize])
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decrypted, err := Decrypt(data[nonceSize:], cipher, key, nonce)
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if err != nil {
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return "", Error.Wrap(err)
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}
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return string(decrypted), nil
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}
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