Jan-Philip Gehrcke's answer 需要一个尚未发布的 python 版本才能使用（请参阅 cmets），这使得回答有关旧版本 python 的问题不切实际。但这段话启发了我：
...在套接字连接之前，您不能调用 sslsock.shared_ciphers()。否则，Python 的 _ssl 模块不会创建读取密码所需的低级 OpenSSL SSL 对象。
这让我想到了一个可能的解决方案。都在同一个python程序中：
- 创建一个接受任何密码 (
ciphers='ALL:aNULL:eNULL') 的服务器套接字。
- 使用配置了我们要检查的密码列表的客户端套接字连接到服务器套接字（如果我们想从 python 2.7.8 测试默认值，例如
'DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2'）
- 一旦建立连接，检查客户端实际选择的密码并打印它，例如
'AES256-GCM-SHA384'。客户端将从其配置的密码列表中选择与服务器提供的匹配的最高优先级密码。服务器接受任何密码并在具有相同 OpenSSL 库的相同 python 程序中运行，因此服务器的列表保证是客户端列表的超集。因此，使用的密码必须是提供给客户端套接字的扩展列表中优先级最高的密码。万岁。
- 现在重复一遍，再次连接到服务器套接字但是这次排除了上一轮选择的密码，将它的否定附加到客户端套接字的密码列表中，例如
'DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2:!AES256-GCM-SHA384')
- 重复直到 SSL 握手失败，因为我们已经用完了密码。
这里是代码（也可以作为a github gist）：
"""An attempt to produce similar output to "openssl ciphers -v", but for
python's built-in ssl.
To answer https://stackoverflow.com/q/28332448/445073
"""
from __future__ import print_function
import argparse
import logging
import multiprocessing
import os
import socket
import ssl
import sys
def server(log_level, queue):
logging.basicConfig(level=log_level)
logger = logging.getLogger("server")
logger.debug("Creating bind socket")
bind_sock = socket.socket()
bind_sock.bind(('127.0.0.1', 0))
bind_sock.listen(5)
bind_addr = bind_sock.getsockname()
logger.debug("Listening on %r", bind_addr)
queue.put(bind_addr)
while True:
logger.debug("Waiting for connection")
conn_sock, fromaddr = bind_sock.accept()
conn_sock = ssl.wrap_socket(conn_sock,
ssl_version=ssl.PROTOCOL_SSLv23,
server_side=True,
certfile="server.crt",
keyfile="server.key",
ciphers="ALL:aNULL:eNULL")
data = conn_sock.read()
logger.debug("Read %r", data)
conn_sock.close()
logger.debug("Done")
def parse_args(argv):
parser = argparse.ArgumentParser(
formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument("--verbose", "-v", action="store_true",
help="Turn on debug logging")
parser.add_argument("--ciphers", "-c",
default=ssl._DEFAULT_CIPHERS,
help="Cipher list to test. Defaults to this python's "
"default client list")
args = parser.parse_args(argv[1:])
return args
if __name__ == "__main__":
args = parse_args(sys.argv)
log_level = logging.DEBUG if args.verbose else logging.INFO
logging.basicConfig(level=log_level)
logger = logging.getLogger("client")
if not os.path.isfile('server.crt') or not os.path.isfile('server.key'):
print("Must generate server.crt and server.key before running")
print("Try:")
print("openssl req -x509 -newkey rsa:2048 -keyout server.key -out server.crt -nodes -days 365 -subj '/CN=127.0.0.1'")
sys.exit(1)
queue = multiprocessing.Queue()
server_proc = multiprocessing.Process(target=server, args=(log_level, queue))
server_proc.start()
logger.debug("Waiting for server address")
server_addr = queue.get()
chosen_ciphers = []
try:
cipher_list = args.ciphers
while True:
client_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_sock = ssl.wrap_socket(client_sock,
ssl_version=ssl.PROTOCOL_SSLv23,
ciphers=cipher_list)
logger.debug("Connecting to %r", server_addr)
client_sock.connect(server_addr)
logger.debug("Connected")
chosen_cipher = client_sock.cipher()
chosen_ciphers.append(chosen_cipher)
client_sock.write("ping")
client_sock.close()
# Exclude the first choice cipher from the list, to see what we get
# next time.
cipher_list += ':!' + chosen_cipher[0]
except ssl.SSLError as err:
if 'handshake failure' in str(err):
logger.debug("Handshake failed - no more ciphers to try")
else:
logger.exception("Something bad happened")
except Exception:
logger.exception("Something bad happened")
else:
server_proc.join()
finally:
server_proc.terminate()
print("Python: {}".format(sys.version))
print("OpenSSL: {}".format(ssl.OPENSSL_VERSION))
print("Expanding cipher list: {}".format(args.ciphers))
print("{} ciphers found:".format(len(chosen_ciphers)))
print("\n".join(repr(cipher) for cipher in chosen_ciphers))
注意它是如何默认测试python内置的默认密码列表的：
day@laptop ~/test
$ python --version
Python 2.7.8
day@laptop ~/test
$ python ssltest.py -h
usage: ssltest.py [-h] [--verbose] [--ciphers CIPHERS]
optional arguments:
-h, --help show this help message and exit
--verbose, -v Turn on debug logging (default: False)
--ciphers CIPHERS, -c CIPHERS
Cipher list to test. Defaults to this python's default
client list (default:
DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2)
所以我们可以很容易地看到默认客户端密码列表扩展为什么，以及它如何从 python 2.7.8 更改为 2.7.9：
day@laptop ~/test
$ ~/dists/python-2.7.8-with-pywin32-218-x86/python ssltest.py
Python: 2.7.8 (default, Jun 30 2014, 16:03:49) [MSC v.1500 32 bit (Intel)]
OpenSSL: OpenSSL 1.0.1h 5 Jun 2014
Expanding cipher list: DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2
12 ciphers found:
('AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
('AES256-SHA256', 'TLSv1/SSLv3', 256)
('AES256-SHA', 'TLSv1/SSLv3', 256)
('CAMELLIA256-SHA', 'TLSv1/SSLv3', 256)
('DES-CBC3-SHA', 'TLSv1/SSLv3', 168)
('AES128-GCM-SHA256', 'TLSv1/SSLv3', 128)
('AES128-SHA256', 'TLSv1/SSLv3', 128)
('AES128-SHA', 'TLSv1/SSLv3', 128)
('SEED-SHA', 'TLSv1/SSLv3', 128)
('CAMELLIA128-SHA', 'TLSv1/SSLv3', 128)
('RC4-SHA', 'TLSv1/SSLv3', 128)
('RC4-MD5', 'TLSv1/SSLv3', 128)
day@laptop ~/test
$ ~/dists/python-2.7.9-with-pywin32-219-x86/python ssltest.py
Python: 2.7.9 (default, Dec 10 2014, 12:24:55) [MSC v.1500 32 bit (Intel)]
OpenSSL: OpenSSL 1.0.1j 15 Oct 2014
Expanding cipher list: ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+HIGH:DH+HIGH:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+HIGH:RSA+3DES:ECDH+RC4:DH+RC4:RSA+RC4:!aNULL:!eNULL:!MD5
18 ciphers found:
('ECDHE-RSA-AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
('ECDHE-RSA-AES128-GCM-SHA256', 'TLSv1/SSLv3', 128)
('ECDHE-RSA-AES256-SHA384', 'TLSv1/SSLv3', 256)
('ECDHE-RSA-AES256-SHA', 'TLSv1/SSLv3', 256)
('ECDHE-RSA-AES128-SHA256', 'TLSv1/SSLv3', 128)
('ECDHE-RSA-AES128-SHA', 'TLSv1/SSLv3', 128)
('ECDHE-RSA-DES-CBC3-SHA', 'TLSv1/SSLv3', 112)
('AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
('AES128-GCM-SHA256', 'TLSv1/SSLv3', 128)
('AES256-SHA256', 'TLSv1/SSLv3', 256)
('AES256-SHA', 'TLSv1/SSLv3', 256)
('AES128-SHA256', 'TLSv1/SSLv3', 128)
('AES128-SHA', 'TLSv1/SSLv3', 128)
('CAMELLIA256-SHA', 'TLSv1/SSLv3', 256)
('CAMELLIA128-SHA', 'TLSv1/SSLv3', 128)
('DES-CBC3-SHA', 'TLSv1/SSLv3', 112)
('ECDHE-RSA-RC4-SHA', 'TLSv1/SSLv3', 128)
('RC4-SHA', 'TLSv1/SSLv3', 128)
我认为这回答了我的问题。除非有人能看出这种方法有问题吗？