| # -*- coding: utf-8 -*- |
| # |
| # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> |
| # |
| # 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. |
| |
| '''Functions that load and write PEM-encoded files.''' |
| |
| import base64 |
| from rsa._compat import b, is_bytes |
| |
| def _markers(pem_marker): |
| ''' |
| Returns the start and end PEM markers |
| ''' |
| |
| if is_bytes(pem_marker): |
| pem_marker = pem_marker.decode('utf-8') |
| |
| return (b('-----BEGIN %s-----' % pem_marker), |
| b('-----END %s-----' % pem_marker)) |
| |
| def load_pem(contents, pem_marker): |
| '''Loads a PEM file. |
| |
| @param contents: the contents of the file to interpret |
| @param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY' |
| when your file has '-----BEGIN RSA PRIVATE KEY-----' and |
| '-----END RSA PRIVATE KEY-----' markers. |
| |
| @return the base64-decoded content between the start and end markers. |
| |
| @raise ValueError: when the content is invalid, for example when the start |
| marker cannot be found. |
| |
| ''' |
| |
| (pem_start, pem_end) = _markers(pem_marker) |
| |
| pem_lines = [] |
| in_pem_part = False |
| |
| for line in contents.splitlines(): |
| line = line.strip() |
| |
| # Skip empty lines |
| if not line: |
| continue |
| |
| # Handle start marker |
| if line == pem_start: |
| if in_pem_part: |
| raise ValueError('Seen start marker "%s" twice' % pem_start) |
| |
| in_pem_part = True |
| continue |
| |
| # Skip stuff before first marker |
| if not in_pem_part: |
| continue |
| |
| # Handle end marker |
| if in_pem_part and line == pem_end: |
| in_pem_part = False |
| break |
| |
| # Load fields |
| if b(':') in line: |
| continue |
| |
| pem_lines.append(line) |
| |
| # Do some sanity checks |
| if not pem_lines: |
| raise ValueError('No PEM start marker "%s" found' % pem_start) |
| |
| if in_pem_part: |
| raise ValueError('No PEM end marker "%s" found' % pem_end) |
| |
| # Base64-decode the contents |
| pem = b('').join(pem_lines) |
| return base64.decodestring(pem) |
| |
| |
| def save_pem(contents, pem_marker): |
| '''Saves a PEM file. |
| |
| @param contents: the contents to encode in PEM format |
| @param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY' |
| when your file has '-----BEGIN RSA PRIVATE KEY-----' and |
| '-----END RSA PRIVATE KEY-----' markers. |
| |
| @return the base64-encoded content between the start and end markers. |
| |
| ''' |
| |
| (pem_start, pem_end) = _markers(pem_marker) |
| |
| b64 = base64.encodestring(contents).replace(b('\n'), b('')) |
| pem_lines = [pem_start] |
| |
| for block_start in range(0, len(b64), 64): |
| block = b64[block_start:block_start + 64] |
| pem_lines.append(block) |
| |
| pem_lines.append(pem_end) |
| pem_lines.append(b('')) |
| |
| return b('\n').join(pem_lines) |
| |