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1#!/usr/bin/env python3
2
3# translate_ciphers.py
4#
5# Copyright The Mbed TLS Contributors
6# SPDX-License-Identifier: Apache-2.0
7#
8# Licensed under the Apache License, Version 2.0 (the "License"); you may
9# not use this file except in compliance with the License.
10# You may obtain a copy of the License at
11#
12# http://www.apache.org/licenses/LICENSE-2.0
13#
14# Unless required by applicable law or agreed to in writing, software
15# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
16# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17# See the License for the specific language governing permissions and
18# limitations under the License.
19
20"""
21Translate ciphersuite names in Mbed TLS format to OpenSSL and GNUTLS
22standards.
23
24To test the translation functions run:
25python3 -m unittest translate_cipher.py
26"""
27
28import re
29import argparse
30import unittest
31
32class TestTranslateCiphers(unittest.TestCase):
33    """
34    Ensure translate_ciphers.py translates and formats ciphersuite names
35    correctly
36    """
37    def test_translate_all_cipher_names(self):
38        """
39        Translate MbedTLS ciphersuite names to their OpenSSL and
40        GnuTLS counterpart. Use only a small subset of ciphers
41        that exercise each step of the translate functions
42        """
43        ciphers = [
44            ("TLS-ECDHE-ECDSA-WITH-NULL-SHA",
45             "+ECDHE-ECDSA:+NULL:+SHA1",
46             "ECDHE-ECDSA-NULL-SHA"),
47            ("TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256",
48             "+ECDHE-ECDSA:+AES-128-GCM:+AEAD",
49             "ECDHE-ECDSA-AES128-GCM-SHA256"),
50            ("TLS-DHE-RSA-WITH-3DES-EDE-CBC-SHA",
51             "+DHE-RSA:+3DES-CBC:+SHA1",
52             "EDH-RSA-DES-CBC3-SHA"),
53            ("TLS-RSA-WITH-AES-256-CBC-SHA",
54             "+RSA:+AES-256-CBC:+SHA1",
55             "AES256-SHA"),
56            ("TLS-PSK-WITH-3DES-EDE-CBC-SHA",
57             "+PSK:+3DES-CBC:+SHA1",
58             "PSK-3DES-EDE-CBC-SHA"),
59            ("TLS-ECDHE-ECDSA-WITH-CHACHA20-POLY1305-SHA256",
60             None,
61             "ECDHE-ECDSA-CHACHA20-POLY1305"),
62            ("TLS-ECDHE-ECDSA-WITH-AES-128-CCM",
63             "+ECDHE-ECDSA:+AES-128-CCM:+AEAD",
64             None),
65            ("TLS-ECDHE-RSA-WITH-ARIA-256-GCM-SHA384",
66             None,
67             "ECDHE-ARIA256-GCM-SHA384"),
68        ]
69
70        for m, g_exp, o_exp in ciphers:
71
72            if g_exp is not None:
73                g = translate_gnutls(m)
74                self.assertEqual(g, g_exp)
75
76            if o_exp is not None:
77                o = translate_ossl(m)
78                self.assertEqual(o, o_exp)
79
80def translate_gnutls(m_cipher):
81    """
82    Translate m_cipher from Mbed TLS ciphersuite naming convention
83    and return the GnuTLS naming convention
84    """
85
86    m_cipher = re.sub(r'\ATLS-', '+', m_cipher)
87    m_cipher = m_cipher.replace("-WITH-", ":+")
88    m_cipher = m_cipher.replace("-EDE", "")
89
90    # SHA in Mbed TLS == SHA1 GnuTLS,
91    # if the last 3 chars are SHA append 1
92    if m_cipher[-3:] == "SHA":
93        m_cipher = m_cipher+"1"
94
95    # CCM or CCM-8 should be followed by ":+AEAD"
96    # Replace "GCM:+SHAxyz" with "GCM:+AEAD"
97    if "CCM" in m_cipher or "GCM" in m_cipher:
98        m_cipher = re.sub(r"GCM-SHA\d\d\d", "GCM", m_cipher)
99        m_cipher = m_cipher+":+AEAD"
100
101    # Replace the last "-" with ":+"
102    else:
103        index = m_cipher.rindex("-")
104        m_cipher = m_cipher[:index] + ":+" + m_cipher[index+1:]
105
106    return m_cipher
107
108def translate_ossl(m_cipher):
109    """
110    Translate m_cipher from Mbed TLS ciphersuite naming convention
111    and return the OpenSSL naming convention
112    """
113
114    m_cipher = re.sub(r'^TLS-', '', m_cipher)
115    m_cipher = m_cipher.replace("-WITH", "")
116
117    # Remove the "-" from "ABC-xyz"
118    m_cipher = m_cipher.replace("AES-", "AES")
119    m_cipher = m_cipher.replace("CAMELLIA-", "CAMELLIA")
120    m_cipher = m_cipher.replace("ARIA-", "ARIA")
121
122    # Remove "RSA" if it is at the beginning
123    m_cipher = re.sub(r'^RSA-', r'', m_cipher)
124
125    # For all circumstances outside of PSK
126    if "PSK" not in m_cipher:
127        m_cipher = m_cipher.replace("-EDE", "")
128        m_cipher = m_cipher.replace("3DES-CBC", "DES-CBC3")
129
130        # Remove "CBC" if it is not prefixed by DES
131        m_cipher = re.sub(r'(?<!DES-)CBC-', r'', m_cipher)
132
133    # ECDHE-RSA-ARIA does not exist in OpenSSL
134    m_cipher = m_cipher.replace("ECDHE-RSA-ARIA", "ECDHE-ARIA")
135
136    # POLY1305 should not be followed by anything
137    if "POLY1305" in m_cipher:
138        index = m_cipher.rindex("POLY1305")
139        m_cipher = m_cipher[:index+8]
140
141    # If DES is being used, Replace DHE with EDH
142    if "DES" in m_cipher and "DHE" in m_cipher and "ECDHE" not in m_cipher:
143        m_cipher = m_cipher.replace("DHE", "EDH")
144
145    return m_cipher
146
147def format_ciphersuite_names(mode, names):
148    t = {"g": translate_gnutls, "o": translate_ossl}[mode]
149    return " ".join(t(c) for c in names)
150
151def main(target, names):
152    print(format_ciphersuite_names(target, names))
153
154if __name__ == "__main__":
155    PARSER = argparse.ArgumentParser()
156    PARSER.add_argument('target', metavar='TARGET', choices=['o', 'g'])
157    PARSER.add_argument('names', metavar='NAMES', nargs='+')
158    ARGS = PARSER.parse_args()
159    main(ARGS.target, ARGS.names)
160