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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 standard ciphersuite names to GnuTLS, OpenSSL and Mbed TLS standards.
22
23To test the translation functions run:
24python3 -m unittest translate_cipher.py
25"""
26
27import re
28import argparse
29import unittest
30
31class TestTranslateCiphers(unittest.TestCase):
32    """
33    Ensure translate_ciphers.py translates and formats ciphersuite names
34    correctly
35    """
36    def test_translate_all_cipher_names(self):
37        """
38        Translate standard ciphersuite names to GnuTLS, OpenSSL and
39        Mbed TLS counterpart. Use only a small subset of ciphers
40        that exercise each step of the translation functions
41        """
42        ciphers = [
43            ("TLS_ECDHE_ECDSA_WITH_NULL_SHA",
44             "+ECDHE-ECDSA:+NULL:+SHA1",
45             "ECDHE-ECDSA-NULL-SHA",
46             "TLS-ECDHE-ECDSA-WITH-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-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256"),
51            ("TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA",
52             "+DHE-RSA:+3DES-CBC:+SHA1",
53             "EDH-RSA-DES-CBC3-SHA",
54             "TLS-DHE-RSA-WITH-3DES-EDE-CBC-SHA"),
55            ("TLS_RSA_WITH_AES_256_CBC_SHA",
56             "+RSA:+AES-256-CBC:+SHA1",
57             "AES256-SHA",
58             "TLS-RSA-WITH-AES-256-CBC-SHA"),
59            ("TLS_PSK_WITH_3DES_EDE_CBC_SHA",
60             "+PSK:+3DES-CBC:+SHA1",
61             "PSK-3DES-EDE-CBC-SHA",
62             "TLS-PSK-WITH-3DES-EDE-CBC-SHA"),
63            ("TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
64             None,
65             "ECDHE-ECDSA-CHACHA20-POLY1305",
66             "TLS-ECDHE-ECDSA-WITH-CHACHA20-POLY1305-SHA256"),
67            ("TLS_ECDHE_ECDSA_WITH_AES_128_CCM",
68             "+ECDHE-ECDSA:+AES-128-CCM:+AEAD",
69             None,
70             "TLS-ECDHE-ECDSA-WITH-AES-128-CCM"),
71            ("TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384",
72             None,
73             "ECDHE-ARIA256-GCM-SHA384",
74             "TLS-ECDHE-RSA-WITH-ARIA-256-GCM-SHA384"),
75        ]
76
77        for s, g_exp, o_exp, m_exp in ciphers:
78
79            if g_exp is not None:
80                g = translate_gnutls(s)
81                self.assertEqual(g, g_exp)
82
83            if o_exp is not None:
84                o = translate_ossl(s)
85                self.assertEqual(o, o_exp)
86
87            if m_exp is not None:
88                m = translate_mbedtls(s)
89                self.assertEqual(m, m_exp)
90
91def translate_gnutls(s_cipher):
92    """
93    Translate s_cipher from standard ciphersuite naming convention
94    and return the GnuTLS naming convention
95    """
96
97    # Replace "_" with "-" to handle ciphersuite names based on Mbed TLS
98    # naming convention
99    s_cipher = s_cipher.replace("_", "-")
100
101    s_cipher = re.sub(r'\ATLS-', '+', s_cipher)
102    s_cipher = s_cipher.replace("-WITH-", ":+")
103    s_cipher = s_cipher.replace("-EDE", "")
104
105    # SHA in Mbed TLS == SHA1 GnuTLS,
106    # if the last 3 chars are SHA append 1
107    if s_cipher[-3:] == "SHA":
108        s_cipher = s_cipher+"1"
109
110    # CCM or CCM-8 should be followed by ":+AEAD"
111    # Replace "GCM:+SHAxyz" with "GCM:+AEAD"
112    if "CCM" in s_cipher or "GCM" in s_cipher:
113        s_cipher = re.sub(r"GCM-SHA\d\d\d", "GCM", s_cipher)
114        s_cipher = s_cipher+":+AEAD"
115
116    # Replace the last "-" with ":+"
117    else:
118        index = s_cipher.rindex("-")
119        s_cipher = s_cipher[:index] + ":+" + s_cipher[index+1:]
120
121    return s_cipher
122
123def translate_ossl(s_cipher):
124    """
125    Translate s_cipher from standard ciphersuite naming convention
126    and return the OpenSSL naming convention
127    """
128
129    # Replace "_" with "-" to handle ciphersuite names based on Mbed TLS
130    # naming convention
131    s_cipher = s_cipher.replace("_", "-")
132
133    s_cipher = re.sub(r'^TLS-', '', s_cipher)
134    s_cipher = s_cipher.replace("-WITH", "")
135
136    # Remove the "-" from "ABC-xyz"
137    s_cipher = s_cipher.replace("AES-", "AES")
138    s_cipher = s_cipher.replace("CAMELLIA-", "CAMELLIA")
139    s_cipher = s_cipher.replace("ARIA-", "ARIA")
140
141    # Remove "RSA" if it is at the beginning
142    s_cipher = re.sub(r'^RSA-', r'', s_cipher)
143
144    # For all circumstances outside of PSK
145    if "PSK" not in s_cipher:
146        s_cipher = s_cipher.replace("-EDE", "")
147        s_cipher = s_cipher.replace("3DES-CBC", "DES-CBC3")
148
149        # Remove "CBC" if it is not prefixed by DES
150        s_cipher = re.sub(r'(?<!DES-)CBC-', r'', s_cipher)
151
152    # ECDHE-RSA-ARIA does not exist in OpenSSL
153    s_cipher = s_cipher.replace("ECDHE-RSA-ARIA", "ECDHE-ARIA")
154
155    # POLY1305 should not be followed by anything
156    if "POLY1305" in s_cipher:
157        index = s_cipher.rindex("POLY1305")
158        s_cipher = s_cipher[:index+8]
159
160    # If DES is being used, Replace DHE with EDH
161    if "DES" in s_cipher and "DHE" in s_cipher and "ECDHE" not in s_cipher:
162        s_cipher = s_cipher.replace("DHE", "EDH")
163
164    return s_cipher
165
166def translate_mbedtls(s_cipher):
167    """
168    Translate s_cipher from standard ciphersuite naming convention
169    and return Mbed TLS ciphersuite naming convention
170    """
171
172    # Replace "_" with "-"
173    s_cipher = s_cipher.replace("_", "-")
174
175    return s_cipher
176
177def format_ciphersuite_names(mode, names):
178    t = {"g": translate_gnutls,
179         "o": translate_ossl,
180         "m": translate_mbedtls
181        }[mode]
182    return " ".join(c + '=' + t(c) for c in names)
183
184def main(target, names):
185    print(format_ciphersuite_names(target, names))
186
187if __name__ == "__main__":
188    PARSER = argparse.ArgumentParser()
189    PARSER.add_argument('target', metavar='TARGET', choices=['o', 'g', 'm'])
190    PARSER.add_argument('names', metavar='NAMES', nargs='+')
191    ARGS = PARSER.parse_args()
192    main(ARGS.target, ARGS.names)
193