[tor-commits] [stem/master] Move digest contants into base descriptor module

[atagar at torproject.org]

commit 10b6ce3fc5b129dbe30714ba1c63f2b2e190bb7f
Author: Damian Johnson <atagar at torproject.org>
Date:   Mon Jun 19 12:31:00 2017 -0700

    Move digest contants into base descriptor module
    
    Ah. On reflection we already used these a little for signature validation.
---
 stem/descriptor/__init__.py          | 8 ++++++--
 stem/descriptor/server_descriptor.py | 7 +++----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/stem/descriptor/__init__.py b/stem/descriptor/__init__.py
index 82b71d5..e18dfd2 100644
--- a/stem/descriptor/__init__.py
+++ b/stem/descriptor/__init__.py
@@ -81,6 +81,10 @@ PGP_BLOCK_START = re.compile('^-----BEGIN ([%s%s]+)-----$' % (KEYWORD_CHAR, WHIT
 PGP_BLOCK_END = '-----END %s-----'
 EMPTY_COLLECTION = ([], {}, set())
 
+DIGEST_TYPE_INFO = b'\x00\x01'
+DIGEST_PADDING = b'\xFF'
+DIGEST_SEPARATOR = b'\x00'
+
 CRYPTO_BLOB = """
 MIGJAoGBAJv5IIWQ+WDWYUdyA/0L8qbIkEVH/cwryZWoIaPAzINfrw1WfNZGtBmg
 skFtXhOHHqTRN4GPPrZsAIUOQGzQtGb66IQgT4tO/pj+P6QmSCCdTfhvGfgTCsC+
@@ -720,7 +724,7 @@ class Descriptor(object):
     ############################################################################
 
     try:
-      if decrypted_bytes.index(b'\x00\x01') != 0:
+      if decrypted_bytes.index(DIGEST_TYPE_INFO) != 0:
         raise ValueError('Verification failed, identifier missing')
     except ValueError:
       raise ValueError('Verification failed, malformed data')
@@ -729,7 +733,7 @@ class Descriptor(object):
       identifier_offset = 2
 
       # find the separator
-      seperator_index = decrypted_bytes.index(b'\x00', identifier_offset)
+      seperator_index = decrypted_bytes.index(DIGEST_SEPARATOR, identifier_offset)
     except ValueError:
       raise ValueError('Verification failed, seperator not found')
 
diff --git a/stem/descriptor/server_descriptor.py b/stem/descriptor/server_descriptor.py
index 2ff42e7..30599a8 100644
--- a/stem/descriptor/server_descriptor.py
+++ b/stem/descriptor/server_descriptor.py
@@ -52,6 +52,9 @@ from stem.util import str_type
 from stem.descriptor import (
   CRYPTO_BLOB,
   PGP_BLOCK_END,
+  DIGEST_TYPE_INFO,
+  DIGEST_PADDING,
+  DIGEST_SEPARATOR,
   Descriptor,
   _descriptor_content,
   _descriptor_components,
@@ -76,10 +79,6 @@ except ImportError:
 
 SigningKey = collections.namedtuple('SigningKey', ['public', 'private', 'descriptor_signing_key'])
 
-DIGEST_TYPE_INFO = b'\x00\x01'
-DIGEST_PADDING = b'\xFF'
-DIGEST_SEPARATOR = b'\x00'
-
 # relay descriptors must have exactly one of the following
 REQUIRED_FIELDS = (
   'router',