2 Aug
2017
2 Aug
'17
9:51 a.m.
Module: check_mk
Branch: master
Commit: e55afe0e4ac4a79a6f8f4e7f70ac04698b037746
URL:
http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=e55afe0e4ac4a7…
Author: Lars Michelsen <lm(a)mathias-kettner.de>
Date: Wed Aug 2 16:36:41 2017 +0200
5051 FIX Fixed backup/restore of encrypted backups
It was not possible to perform encrypted backups since version 1.4.0b5. An error
message "NotImplementedError("Use module Crypto.Cipher.PKCS1_OAEP
instead“)" was
displayed in the log when trying to create such a backup.
Workaround: Disable encrypted backups and perform unencrypted ones.
Encrypted backups created with previous versions need to be restored with 1.4.0b4
or older.
Change-Id: Ib3bd6798cc104b0ee1b1a5e9a7872223df7fe78b
---
.werks/5051 | 18 ++++++++++++++++++
bin/mkbackup | 39 +++++++++++++++++++++++----------------
2 files changed, 41 insertions(+), 16 deletions(-)
diff --git a/.werks/5051 b/.werks/5051
new file mode 100644
index 0000000..3254b81
--- /dev/null
+++ b/.werks/5051
@@ -0,0 +1,18 @@
+Title: Fixed backup/restore of encrypted backups
+Level: 1
+Component: wato
+Class: fix
+Compatible: compat
+Edition: cre
+State: unknown
+Version: 1.5.0i1
+Date: 1501684381
+
+It was not possible to perform encrypted backups since version 1.4.0b5. An error
+message "NotImplementedError("Use module Crypto.Cipher.PKCS1_OAEP
instead“)" was
+displayed in the log when trying to create such a backup.
+
+Workaround: Disable encrypted backups and perform unencrypted ones.
+
+Encrypted backups created with previous versions need to be restored with 1.4.0b4
+or older.
diff --git a/bin/mkbackup b/bin/mkbackup
index c9d1a36..96010a4 100755
--- a/bin/mkbackup
+++ b/bin/mkbackup
@@ -53,7 +53,7 @@ from tarfile import TarFile, ReadError
from hashlib import md5
from OpenSSL import crypto
-from Crypto.Cipher import AES
+from Crypto.Cipher import AES, PKCS1_OAEP
from Crypto.PublicKey import RSA
import Crypto.Util.number
@@ -836,7 +836,10 @@ class BackupStream(MKBackupStream):
# Write out a file version marker and the encrypted secret key, preceded by
# a length indication. All separated by \0.
- return "%d\0%d\0%s\0" % (1, len(encrypted_secret_key),
encrypted_secret_key)
+ # Version 1: Encrypted secret key written with pubkey.encrypt(). Worked with
+ # early versions of 1.4 until moving from PyCryto to PyCryptodome
+ # Version 2: Use PKCS1_OAEP for encrypting the encrypted_secret_key.
+ return "%d\0%d\0%s\0" % (2, len(encrypted_secret_key),
encrypted_secret_key)
def _read_chunk(self):
@@ -878,16 +881,13 @@ class BackupStream(MKBackupStream):
# logic from
http://stackoverflow.com/questions/6309958/encrypting-a-file-with-rsa-in-py…
+ # Since our packages moved from PyCrypto to PyCryptodome we need to change this to
use PKCS1_OAEP.
def _derive_key(self, pubkey, key_length):
secret_key = os.urandom(key_length)
- # Padding (see explanations below)
- plaintext_length = (Crypto.Util.number.size(pubkey.n) - 2) / 8
- padding = '\xff' + os.urandom(16)
- padding += '\0' * (plaintext_length - len(padding) - len(secret_key))
-
# Encrypt the secret key with the RSA public key
- encrypted_secret_key = pubkey.encrypt(padding + secret_key, None)[0]
+ cipher_rsa = PKCS1_OAEP.new(pubkey)
+ encrypted_secret_key = cipher_rsa.encrypt(secret_key)
return secret_key, encrypted_secret_key
@@ -898,8 +898,8 @@ class RestoreStream(MKBackupStream):
if not self._encrypt():
return
- encrypted_secret_key = self._read_encrypted_secret_key()
- secret_key = self._decrypt_secret_key(encrypted_secret_key)
+ file_version, encrypted_secret_key = self._read_encrypted_secret_key()
+ secret_key = self._decrypt_secret_key(file_version, encrypted_secret_key)
self._cipher = AES.new(secret_key, AES.MODE_CBC, self._iv)
@@ -945,8 +945,8 @@ class RestoreStream(MKBackupStream):
return buf
file_version = read_field()
- if file_version != "1":
- raise MKGeneralException("Failed to process backup file (invalid
version)")
+ if file_version not in [ "1", "2" ]:
+ raise MKGeneralException("Failed to process backup file (invalid version
%r)" % file_version)
try:
key_len = int(read_field())
@@ -961,7 +961,7 @@ class RestoreStream(MKBackupStream):
if self._stream.read(1) != "\0":
raise MKGeneralException("Failed to parse the encrypted backup file
(header broken)")
- return encrypted_secret_key
+ return file_version, encrypted_secret_key
def _get_encryption_private_key(self):
@@ -988,10 +988,17 @@ class RestoreStream(MKBackupStream):
raise MKGeneralException("Failed to load private key (wrong
passphrase?)")
- def _decrypt_secret_key(self, encrypted_secret_key):
+ def _decrypt_secret_key(self, file_version, encrypted_secret_key):
private_key = self._get_encryption_private_key()
- secret_key_with_padding = private_key.decrypt(encrypted_secret_key)
- return secret_key_with_padding[-32:]
+
+ if file_version == "1":
+ raise MKGeneralException("You can not restore this backup using your
current Check_MK "
+ "version. You need to use a Check_MK 1.4
version that has "
+ "been released before 2017-03-24. The last
compatible "
+ "release is 1.4.0b4.")
+ else:
+ cipher_rsa = PKCS1_OAEP.new(private_key)
+ return cipher_rsa.decrypt(encrypted_secret_key)
# Returns the base path for the backup to work with. In backup mode, this is