update to python3.7

lib/python3.7/site-packages/asn1crypto/pem.py

@@ -0,0 +1,222 @@
+# coding: utf-8
+
+"""
+Encoding DER to PEM and decoding PEM to DER. Exports the following items:
+
+ - armor()
+ - detect()
+ - unarmor()
+
+"""
+
+from __future__ import unicode_literals, division, absolute_import, print_function
+
+import base64
+import re
+import sys
+
+from ._errors import unwrap
+from ._types import type_name as _type_name, str_cls, byte_cls
+
+if sys.version_info < (3,):
+    from cStringIO import StringIO as BytesIO
+else:
+    from io import BytesIO
+
+
+def detect(byte_string):
+    """
+    Detect if a byte string seems to contain a PEM-encoded block
+
+    :param byte_string:
+        A byte string to look through
+
+    :return:
+        A boolean, indicating if a PEM-encoded block is contained in the byte
+        string
+    """
+
+    if not isinstance(byte_string, byte_cls):
+        raise TypeError(unwrap(
+            '''
+            byte_string must be a byte string, not %s
+            ''',
+            _type_name(byte_string)
+        ))
+
+    return byte_string.find(b'-----BEGIN') != -1 or byte_string.find(b'---- BEGIN') != -1
+
+
+def armor(type_name, der_bytes, headers=None):
+    """
+    Armors a DER-encoded byte string in PEM
+
+    :param type_name:
+        A unicode string that will be capitalized and placed in the header
+        and footer of the block. E.g. "CERTIFICATE", "PRIVATE KEY", etc. This
+        will appear as "-----BEGIN CERTIFICATE-----" and
+        "-----END CERTIFICATE-----".
+
+    :param der_bytes:
+        A byte string to be armored
+
+    :param headers:
+        An OrderedDict of the header lines to write after the BEGIN line
+
+    :return:
+        A byte string of the PEM block
+    """
+
+    if not isinstance(der_bytes, byte_cls):
+        raise TypeError(unwrap(
+            '''
+            der_bytes must be a byte string, not %s
+            ''' % _type_name(der_bytes)
+        ))
+
+    if not isinstance(type_name, str_cls):
+        raise TypeError(unwrap(
+            '''
+            type_name must be a unicode string, not %s
+            ''',
+            _type_name(type_name)
+        ))
+
+    type_name = type_name.upper().encode('ascii')
+
+    output = BytesIO()
+    output.write(b'-----BEGIN ')
+    output.write(type_name)
+    output.write(b'-----\n')
+    if headers:
+        for key in headers:
+            output.write(key.encode('ascii'))
+            output.write(b': ')
+            output.write(headers[key].encode('ascii'))
+            output.write(b'\n')
+        output.write(b'\n')
+    b64_bytes = base64.b64encode(der_bytes)
+    b64_len = len(b64_bytes)
+    i = 0
+    while i < b64_len:
+        output.write(b64_bytes[i:i + 64])
+        output.write(b'\n')
+        i += 64
+    output.write(b'-----END ')
+    output.write(type_name)
+    output.write(b'-----\n')
+
+    return output.getvalue()
+
+
+def _unarmor(pem_bytes):
+    """
+    Convert a PEM-encoded byte string into one or more DER-encoded byte strings
+
+    :param pem_bytes:
+        A byte string of the PEM-encoded data
+
+    :raises:
+        ValueError - when the pem_bytes do not appear to be PEM-encoded bytes
+
+    :return:
+        A generator of 3-element tuples in the format: (object_type, headers,
+        der_bytes). The object_type is a unicode string of what is between
+        "-----BEGIN " and "-----". Examples include: "CERTIFICATE",
+        "PUBLIC KEY", "PRIVATE KEY". The headers is a dict containing any lines
+        in the form "Name: Value" that are right after the begin line.
+    """
+
+    if not isinstance(pem_bytes, byte_cls):
+        raise TypeError(unwrap(
+            '''
+            pem_bytes must be a byte string, not %s
+            ''',
+            _type_name(pem_bytes)
+        ))
+
+    # Valid states include: "trash", "headers", "body"
+    state = 'trash'
+    headers = {}
+    base64_data = b''
+    object_type = None
+
+    found_start = False
+    found_end = False
+
+    for line in pem_bytes.splitlines(False):
+        if line == b'':
+            continue
+
+        if state == "trash":
+            # Look for a starting line since some CA cert bundle show the cert
+            # into in a parsed format above each PEM block
+            type_name_match = re.match(b'^(?:---- |-----)BEGIN ([A-Z0-9 ]+)(?: ----|-----)', line)
+            if not type_name_match:
+                continue
+            object_type = type_name_match.group(1).decode('ascii')
+
+            found_start = True
+            state = 'headers'
+            continue
+
+        if state == 'headers':
+            if line.find(b':') == -1:
+                state = 'body'
+            else:
+                decoded_line = line.decode('ascii')
+                name, value = decoded_line.split(':', 1)
+                headers[name] = value.strip()
+                continue
+
+        if state == 'body':
+            if line[0:5] in (b'-----', b'---- '):
+                der_bytes = base64.b64decode(base64_data)
+
+                yield (object_type, headers, der_bytes)
+
+                state = 'trash'
+                headers = {}
+                base64_data = b''
+                object_type = None
+                found_end = True
+                continue
+
+            base64_data += line
+
+    if not found_start or not found_end:
+        raise ValueError(unwrap(
+            '''
+            pem_bytes does not appear to contain PEM-encoded data - no
+            BEGIN/END combination found
+            '''
+        ))
+
+
+def unarmor(pem_bytes, multiple=False):
+    """
+    Convert a PEM-encoded byte string into a DER-encoded byte string
+
+    :param pem_bytes:
+        A byte string of the PEM-encoded data
+
+    :param multiple:
+        If True, function will return a generator
+
+    :raises:
+        ValueError - when the pem_bytes do not appear to be PEM-encoded bytes
+
+    :return:
+        A 3-element tuple (object_name, headers, der_bytes). The object_name is
+        a unicode string of what is between "-----BEGIN " and "-----". Examples
+        include: "CERTIFICATE", "PUBLIC KEY", "PRIVATE KEY". The headers is a
+        dict containing any lines in the form "Name: Value" that are right
+        after the begin line.
+    """
+
+    generator = _unarmor(pem_bytes)
+
+    if not multiple:
+        return next(generator)
+
+    return generator