510 lines
17 KiB
Python
Executable File
510 lines
17 KiB
Python
Executable File
# Copyright 2013 Red Hat, Inc.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
# not use this file except in compliance with the License. You may obtain
|
|
# a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
# License for the specific language governing permissions and limitations
|
|
# under the License.
|
|
|
|
|
|
"""
|
|
PEM formatted data is used frequently in conjunction with X509 PKI as
|
|
a data exchange mechanism for binary data. The acronym PEM stands for
|
|
Privacy Enhanced Mail as defined in RFC-1421. Contrary to expectation
|
|
the PEM format in common use has little to do with RFC-1421. Instead
|
|
what we know as PEM format grew out of the need for a data exchange
|
|
mechanism largely by the influence of OpenSSL. Other X509
|
|
implementations have adopted it.
|
|
|
|
Unfortunately PEM format has never been officially standarized. It's
|
|
basic format is as follows:
|
|
|
|
1) A header consisting of 5 hyphens followed by the word BEGIN and a
|
|
single space. Then an upper case string describing the contents of the
|
|
PEM block, this is followed by 5 hyphens and a newline.
|
|
|
|
2) Binary data (typically in DER ASN.1 format) encoded in base64. The
|
|
base64 text is line wrapped so that each line of base64 is 64
|
|
characters long and terminated with a newline. The last line of base64
|
|
text may be less than 64 characters. The content and format of the
|
|
binary data is entirely dependent upon the type of data announced in
|
|
the header and footer.
|
|
|
|
3) A footer in the exact same as the header except the word BEGIN is
|
|
replaced by END. The content name in both the header and footer should
|
|
exactly match.
|
|
|
|
The above is called a PEM block. It is permissible for multiple PEM
|
|
blocks to appear in a single file or block of text. This is often used
|
|
when specifying multiple X509 certificates.
|
|
|
|
An example PEM block for a certificate is:
|
|
|
|
-----BEGIN CERTIFICATE-----
|
|
MIIC0TCCAjqgAwIBAgIJANsHKV73HYOwMA0GCSqGSIb3DQEBBQUAMIGeMQowCAYD
|
|
VQQFEwE1MQswCQYDVQQGEwJVUzELMAkGA1UECBMCQ0ExEjAQBgNVBAcTCVN1bm55
|
|
dmFsZTESMBAGA1UEChMJT3BlblN0YWNrMREwDwYDVQQLEwhLZXlzdG9uZTElMCMG
|
|
CSqGSIb3DQEJARYWa2V5c3RvbmVAb3BlbnN0YWNrLm9yZzEUMBIGA1UEAxMLU2Vs
|
|
ZiBTaWduZWQwIBcNMTIxMTA1MTgxODI0WhgPMjA3MTA0MzAxODE4MjRaMIGeMQow
|
|
CAYDVQQFEwE1MQswCQYDVQQGEwJVUzELMAkGA1UECBMCQ0ExEjAQBgNVBAcTCVN1
|
|
bm55dmFsZTESMBAGA1UEChMJT3BlblN0YWNrMREwDwYDVQQLEwhLZXlzdG9uZTEl
|
|
MCMGCSqGSIb3DQEJARYWa2V5c3RvbmVAb3BlbnN0YWNrLm9yZzEUMBIGA1UEAxML
|
|
U2VsZiBTaWduZWQwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBALzI17ExCaqd
|
|
r7xY2Q5CBZ1bW1lsrXxS8eNJRdQtskDuQVAluY03/OGZd8HQYiiY/ci2tYy7BNIC
|
|
bh5GaO95eqTDykJR3liOYE/tHbY6puQlj2ZivmhlSd2d5d7lF0/H28RQsLu9VktM
|
|
uw6q9DpDm35jfrr8LgSeA3MdVqcS/4OhAgMBAAGjEzARMA8GA1UdEwEB/wQFMAMB
|
|
Af8wDQYJKoZIhvcNAQEFBQADgYEAjSQND7i1dNZtLKpWgX+JqMr3BdVlM15mFeVr
|
|
C26ZspZjZVY5okdozO9gU3xcwRe4Cg30sKFOe6EBQKpkTZucFOXwBtD3h6dWJrdD
|
|
c+m/CL/rs0GatDavbaIT2vv405SQUQooCdVh72LYel+4/a6xmRd7fQx3iEXN9QYj
|
|
vmHJUcA=
|
|
-----END CERTIFICATE-----
|
|
|
|
PEM format is safe for transmission in 7-bit ASCII systems
|
|
(i.e. standard email). Since 7-bit ASCII is a proper subset of UTF-8
|
|
and Latin-1 it is not affected by transcoding between those
|
|
charsets. Nor is PEM format affected by the choice of line
|
|
endings. This makes PEM format particularity attractive for transport
|
|
and storage of binary data.
|
|
|
|
This module provides a number of utilities supporting the generation
|
|
and consumption of PEM formatted data including:
|
|
|
|
* parse text and find all PEM blocks contained in the
|
|
text. Information on the location of the block in the text, the
|
|
type of PEM block, and it's base64 and binary data contents.
|
|
|
|
* parse text assumed to contain PEM data and return the binary
|
|
data.
|
|
|
|
* test if a block of text is a PEM block
|
|
|
|
* convert base64 text into a formatted PEM block
|
|
|
|
* convert binary data into a formatted PEM block
|
|
|
|
* access to the valid PEM types and their headers
|
|
|
|
"""
|
|
|
|
import base64
|
|
from keystone.common import base64utils
|
|
import re
|
|
|
|
import six
|
|
|
|
|
|
PEM_TYPE_TO_HEADER = {
|
|
u'cms': u'CMS',
|
|
u'dsa-private': u'DSA PRIVATE KEY',
|
|
u'dsa-public': u'DSA PUBLIC KEY',
|
|
u'ecdsa-public': u'ECDSA PUBLIC KEY',
|
|
u'ec-private': u'EC PRIVATE KEY',
|
|
u'pkcs7': u'PKCS7',
|
|
u'pkcs7-signed': u'PKCS',
|
|
u'pkcs8': u'ENCRYPTED PRIVATE KEY',
|
|
u'private-key': u'PRIVATE KEY',
|
|
u'public-key': u'PUBLIC KEY',
|
|
u'rsa-private': u'RSA PRIVATE KEY',
|
|
u'rsa-public': u'RSA PUBLIC KEY',
|
|
u'cert': u'CERTIFICATE',
|
|
u'crl': u'X509 CRL',
|
|
u'cert-pair': u'CERTIFICATE PAIR',
|
|
u'csr': u'CERTIFICATE REQUEST',
|
|
}
|
|
|
|
# This is not a 1-to-1 reverse map of PEM_TYPE_TO_HEADER
|
|
# because it includes deprecated headers that map to 1 pem_type.
|
|
PEM_HEADER_TO_TYPE = {
|
|
u'CMS': u'cms',
|
|
u'DSA PRIVATE KEY': u'dsa-private',
|
|
u'DSA PUBLIC KEY': u'dsa-public',
|
|
u'ECDSA PUBLIC KEY': u'ecdsa-public',
|
|
u'EC PRIVATE KEY': u'ec-private',
|
|
u'PKCS7': u'pkcs7',
|
|
u'PKCS': u'pkcs7-signed',
|
|
u'ENCRYPTED PRIVATE KEY': u'pkcs8',
|
|
u'PRIVATE KEY': u'private-key',
|
|
u'PUBLIC KEY': u'public-key',
|
|
u'RSA PRIVATE KEY': u'rsa-private',
|
|
u'RSA PUBLIC KEY': u'rsa-public',
|
|
u'CERTIFICATE': u'cert',
|
|
u'X509 CERTIFICATE': u'cert',
|
|
u'CERTIFICATE PAIR': u'cert-pair',
|
|
u'X509 CRL': u'crl',
|
|
u'CERTIFICATE REQUEST': u'csr',
|
|
u'NEW CERTIFICATE REQUEST': u'csr',
|
|
}
|
|
|
|
# List of valid pem_types
|
|
pem_types = sorted(PEM_TYPE_TO_HEADER.keys())
|
|
|
|
# List of valid pem_headers
|
|
pem_headers = sorted(PEM_TYPE_TO_HEADER.values())
|
|
|
|
_pem_begin_re = re.compile(r'^-{5}BEGIN\s+([^-]+)-{5}\s*$', re.MULTILINE)
|
|
_pem_end_re = re.compile(r'^-{5}END\s+([^-]+)-{5}\s*$', re.MULTILINE)
|
|
|
|
|
|
class PEMParseResult(object):
|
|
"""Information returned when a PEM block is found in text.
|
|
|
|
PEMParseResult contains information about a PEM block discovered
|
|
while parsing text. The following properties are defined:
|
|
|
|
pem_type
|
|
A short hand name for the type of the PEM data, e.g. cert,
|
|
csr, crl, cms, key. Valid pem_types are listed in pem_types.
|
|
When the pem_type is set the pem_header is updated to match it.
|
|
|
|
pem_header
|
|
The text following '-----BEGIN ' in the PEM header.
|
|
Common examples are:
|
|
|
|
-----BEGIN CERTIFICATE-----
|
|
-----BEGIN CMS-----
|
|
|
|
Thus the pem_header would be CERTIFICATE and CMS respectively.
|
|
When the pem_header is set the pem_type is updated to match it.
|
|
|
|
pem_start, pem_end
|
|
The beginning and ending positions of the PEM block
|
|
including the PEM header and footer.
|
|
|
|
base64_start, base64_end
|
|
The beginning and ending positions of the base64 data
|
|
contained inside the PEM header and footer. Includes trailing
|
|
new line
|
|
|
|
binary_data
|
|
The decoded base64 data. None if not decoded.
|
|
|
|
"""
|
|
|
|
def __init__(self, pem_type=None, pem_header=None,
|
|
pem_start=None, pem_end=None,
|
|
base64_start=None, base64_end=None,
|
|
binary_data=None):
|
|
|
|
self._pem_type = None
|
|
self._pem_header = None
|
|
|
|
if pem_type is not None:
|
|
self.pem_type = pem_type
|
|
|
|
if pem_header is not None:
|
|
self.pem_header = pem_header
|
|
|
|
self.pem_start = pem_start
|
|
self.pem_end = pem_end
|
|
self.base64_start = base64_start
|
|
self.base64_end = base64_end
|
|
self.binary_data = binary_data
|
|
|
|
@property
|
|
def pem_type(self):
|
|
return self._pem_type
|
|
|
|
@pem_type.setter
|
|
def pem_type(self, pem_type):
|
|
if pem_type is None:
|
|
self._pem_type = None
|
|
self._pem_header = None
|
|
else:
|
|
pem_header = PEM_TYPE_TO_HEADER.get(pem_type)
|
|
if pem_header is None:
|
|
raise ValueError(_('unknown pem_type "%(pem_type)s", '
|
|
'valid types are: %(valid_pem_types)s') %
|
|
{'pem_type': pem_type,
|
|
'valid_pem_types': ', '.join(pem_types)})
|
|
self._pem_type = pem_type
|
|
self._pem_header = pem_header
|
|
|
|
@property
|
|
def pem_header(self):
|
|
return self._pem_header
|
|
|
|
@pem_header.setter
|
|
def pem_header(self, pem_header):
|
|
if pem_header is None:
|
|
self._pem_type = None
|
|
self._pem_header = None
|
|
else:
|
|
pem_type = PEM_HEADER_TO_TYPE.get(pem_header)
|
|
if pem_type is None:
|
|
raise ValueError(_('unknown pem header "%(pem_header)s", '
|
|
'valid headers are: '
|
|
'%(valid_pem_headers)s') %
|
|
{'pem_header': pem_header,
|
|
'valid_pem_headers':
|
|
', '.join("'%s'" %
|
|
[x for x in pem_headers])})
|
|
|
|
self._pem_type = pem_type
|
|
self._pem_header = pem_header
|
|
|
|
#------------------------------------------------------------------------------
|
|
|
|
|
|
def pem_search(text, start=0):
|
|
"""Search for a block of PEM formatted data
|
|
|
|
Search for a PEM block in a text string. The search begins at
|
|
start. If a PEM block is found a PEMParseResult object is
|
|
returned, otherwise if no PEM block is found None is returned.
|
|
|
|
If the pem_type is not the same in both the header and footer
|
|
a ValueError is raised.
|
|
|
|
The start and end positions are suitable for use as slices into
|
|
the text. To search for multiple PEM blocks pass pem_end as the
|
|
start position for the next iteration. Terminate the iteration
|
|
when None is returned. Example::
|
|
|
|
start = 0
|
|
while True:
|
|
block = pem_search(text, start)
|
|
if block is None:
|
|
break
|
|
base64_data = text[block.base64_start : block.base64_end]
|
|
start = block.pem_end
|
|
|
|
:param text: the text to search for PEM blocks
|
|
:type text: string
|
|
:param start: the position in text to start searching from (default: 0)
|
|
:type start: int
|
|
:returns: PEMParseResult or None if not found
|
|
:raises: ValueError
|
|
"""
|
|
|
|
match = _pem_begin_re.search(text, pos=start)
|
|
if match:
|
|
pem_start = match.start()
|
|
begin_text = match.group(0)
|
|
base64_start = min(len(text), match.end() + 1)
|
|
begin_pem_header = match.group(1).strip()
|
|
|
|
match = _pem_end_re.search(text, pos=base64_start)
|
|
if match:
|
|
pem_end = min(len(text), match.end() + 1)
|
|
base64_end = match.start()
|
|
end_pem_header = match.group(1).strip()
|
|
else:
|
|
raise ValueError(_('failed to find end matching "%s"') %
|
|
begin_text)
|
|
|
|
if begin_pem_header != end_pem_header:
|
|
raise ValueError(_('beginning & end PEM headers do not match '
|
|
'(%(begin_pem_header)s'
|
|
'!= '
|
|
'%(end_pem_header)s)') %
|
|
{'begin_pem_header': begin_pem_header,
|
|
'end_pem_header': end_pem_header})
|
|
else:
|
|
return None
|
|
|
|
result = PEMParseResult(pem_header=begin_pem_header,
|
|
pem_start=pem_start, pem_end=pem_end,
|
|
base64_start=base64_start, base64_end=base64_end)
|
|
|
|
return result
|
|
|
|
|
|
def parse_pem(text, pem_type=None, max_items=None):
|
|
"""Scan text for PEM data, return list of PEM items
|
|
|
|
The input text is scanned for PEM blocks, for each one found a
|
|
PEMParseResult is contructed and added to the return list.
|
|
|
|
pem_type operates as a filter on the type of PEM desired. If
|
|
pem_type is specified only those PEM blocks which match will be
|
|
included. The pem_type is a logical name, not the actual text in
|
|
the pem header (e.g. 'cert'). If the pem_type is None all PEM
|
|
blocks are returned.
|
|
|
|
If max_items is specified the result is limited to that number of
|
|
items.
|
|
|
|
The return value is a list of PEMParseResult objects. The
|
|
PEMParseResult provides complete information about the PEM block
|
|
including the decoded binary data for the PEM block. The list is
|
|
ordered in the same order as found in the text.
|
|
|
|
Examples::
|
|
|
|
# Get all certs
|
|
certs = parse_pem(text, 'cert')
|
|
|
|
# Get the first cert
|
|
try:
|
|
binary_cert = parse_pem(text, 'cert', 1)[0].binary_data
|
|
except IndexError:
|
|
raise ValueError('no cert found')
|
|
|
|
:param text: The text to search for PEM blocks
|
|
:type text: string
|
|
:param pem_type: Only return data for this pem_type.
|
|
Valid types are: csr, cert, crl, cms, key.
|
|
If pem_type is None no filtering is performed.
|
|
(default: None)
|
|
:type pem_type: string or None
|
|
:param max_items: Limit the number of blocks returned. (default: None)
|
|
:type max_items: int or None
|
|
:return: List of PEMParseResult, one for each PEM block found
|
|
:raises: ValueError, InvalidBase64Error
|
|
"""
|
|
|
|
pem_blocks = []
|
|
start = 0
|
|
|
|
while True:
|
|
block = pem_search(text, start)
|
|
if block is None:
|
|
break
|
|
start = block.pem_end
|
|
if pem_type is None:
|
|
pem_blocks.append(block)
|
|
else:
|
|
try:
|
|
if block.pem_type == pem_type:
|
|
pem_blocks.append(block)
|
|
except KeyError:
|
|
raise ValueError(_('unknown pem_type: "%s"') % (pem_type))
|
|
|
|
if max_items is not None and len(pem_blocks) >= max_items:
|
|
break
|
|
|
|
for block in pem_blocks:
|
|
base64_data = text[block.base64_start:block.base64_end]
|
|
try:
|
|
binary_data = base64.b64decode(base64_data)
|
|
except Exception as e:
|
|
block.binary_data = None
|
|
raise base64utils.InvalidBase64Error(
|
|
_('failed to base64 decode %(pem_type)s PEM at position'
|
|
'%(position)d: %(err_msg)s') %
|
|
{'pem_type': block.pem_type,
|
|
'position': block.pem_start,
|
|
'err_msg': six.text_type(e)})
|
|
else:
|
|
block.binary_data = binary_data
|
|
|
|
return pem_blocks
|
|
|
|
|
|
def get_pem_data(text, pem_type='cert'):
|
|
"""Scan text for PEM data, return binary contents
|
|
|
|
The input text is scanned for a PEM block which matches the pem_type.
|
|
If found the binary data contained in the PEM block is returned.
|
|
If no PEM block is found or it does not match the specified pem type
|
|
None is returned.
|
|
|
|
:param text: The text to search for the PEM block
|
|
:type text: string
|
|
:param pem_type: Only return data for this pem_type.
|
|
Valid types are: csr, cert, crl, cms, key.
|
|
(default: 'cert')
|
|
:type pem_type: string
|
|
:return: binary data or None if not found.
|
|
"""
|
|
|
|
blocks = parse_pem(text, pem_type, 1)
|
|
if not blocks:
|
|
return None
|
|
return blocks[0].binary_data
|
|
|
|
|
|
def is_pem(text, pem_type='cert'):
|
|
"""Does this text contain a PEM block.
|
|
|
|
Check for the existence of a PEM formatted block in the
|
|
text, if one is found verify it's contents can be base64
|
|
decoded, if so return True. Return False otherwise.
|
|
|
|
:param text: The text to search for PEM blocks
|
|
:type text: string
|
|
:param pem_type: Only return data for this pem_type.
|
|
Valid types are: csr, cert, crl, cms, key.
|
|
(default: 'cert')
|
|
:type pem_type: string
|
|
:returns: bool -- True if text contains PEM matching the pem_type,
|
|
False otherwise.
|
|
"""
|
|
|
|
try:
|
|
pem_blocks = parse_pem(text, pem_type, max_items=1)
|
|
except base64utils.InvalidBase64Error:
|
|
return False
|
|
|
|
if pem_blocks:
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
|
|
def base64_to_pem(base64_text, pem_type='cert'):
|
|
"""Format string of base64 text into PEM format
|
|
|
|
Input is assumed to consist only of members of the base64 alphabet
|
|
(i.e no whitepace). Use one of the filter functions from
|
|
base64utils to assure the input is clean
|
|
(i.e. strip_whitespace()).
|
|
|
|
:param base64_text: text containing ONLY base64 alphabet
|
|
characters to be inserted into PEM output.
|
|
:type base64_text: string
|
|
:param pem_type: Produce a PEM block for this type.
|
|
Valid types are: csr, cert, crl, cms, key.
|
|
(default: 'cert')
|
|
:type pem_type: string
|
|
:returns: string -- PEM formatted text
|
|
|
|
|
|
"""
|
|
pem_header = PEM_TYPE_TO_HEADER[pem_type]
|
|
buf = six.StringIO()
|
|
|
|
buf.write(u'-----BEGIN %s-----' % pem_header)
|
|
buf.write(u'\n')
|
|
|
|
for line in base64utils.base64_wrap_iter(base64_text, width=64):
|
|
buf.write(line)
|
|
buf.write(u'\n')
|
|
|
|
buf.write(u'-----END %s-----' % pem_header)
|
|
buf.write(u'\n')
|
|
|
|
text = buf.getvalue()
|
|
buf.close()
|
|
return text
|
|
|
|
|
|
def binary_to_pem(binary_data, pem_type='cert'):
|
|
"""Format binary data into PEM format
|
|
|
|
Example:
|
|
|
|
# get the certificate binary data in DER format
|
|
der_data = certificate.der
|
|
# convert the DER binary data into a PEM
|
|
pem = binary_to_pem(der_data, 'cert')
|
|
|
|
|
|
:param binary_data: binary data to encapsulate into PEM
|
|
:type binary_data: buffer
|
|
:param pem_type: Produce a PEM block for this type.
|
|
Valid types are: csr, cert, crl, cms, key.
|
|
(default: 'cert')
|
|
:type pem_type: string
|
|
:returns: string -- PEM formatted text
|
|
|
|
"""
|
|
base64_text = base64.b64encode(binary_data)
|
|
return base64_to_pem(base64_text, pem_type)
|