Python3 SSL握手失败求助：SSLV3_ALERT_HANDSHAKE_FAILURE

问题重现 #

尝试实现SSL握手并提取服务器证书的SubjectName/CommonName时，触发如下错误：

File "/usr/lib/python3.10/ssl.py", line 1342, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] sslv3 alert handshake failure (_ssl.c:997)

已尝试的解决方案（均无效） #

• 猴子补丁跳过证书验证：

  ssl._create_default_https_context = ssl._create_unverified_context
  

• 禁用SSL上下文的主机名检查与证书验证：

  sslContext.check_hostname = False
  sslContext.verify_mode = ssl.CERT_NONE
  

• 使用自定义加密套件（字符串存在截断错误）：

  cipher = (':ECDHE-RSA-AES128-GCM-SHA256:DES-CBC3-SHA:AES256-SHA:AES128-SHA:AES128-SHA256:AES256-GCM-SHA384:AES256-SHA256:ECDHE-RSA-DES-CBC3:EDH-RSA-DES-CBC3:EECDH+AESGCM:EDH-RSA-DES-CBC3-SHA:EDH-AESGCM:AES256+EECDH:ECHDE-RSA-AES256-GCM-SHA384:ECHDE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECHDE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:AES256+EDH:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-A$:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK')
  sslContext.set_ciphers(cipher)
  

• 配置OpenSSL允许旧版重协商（未通过环境变量生效）：

  [openssl_init]
  ssl_conf = ssl_sect
  
  [ssl_sect]
  system_default = system_default_sect
  
  [system_default_sect]
  Options = UnsafeLegacyRenegotiation
  

测试脚本 #

import socket
import ssl
import time

cipher = (':ECDHE-RSA-AES128-GCM-SHA256:DES-CBC3-SHA:AES256-SHA:AES128-SHA:AES128-SHA256:AES256-GCM-SHA384:AES256-SHA256:ECDHE-RSA-DES-CBC3:EDH-RSA-DES-CBC3:EECDH+AESGCM:EDH-RSA-DES-CBC3-SHA:EDH-AESGCM:AES256+EECDH:ECHDE-RSA-AES256-GCM-SHA384:ECHDE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECHDE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:AES256+EDH:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-A$:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK')
ssl._create_default_https_context = ssl._create_unverified_context

sslContext = ssl.create_default_context()
sslContext.check_hostname = False
sslContext.set_ciphers(cipher)
sslContext.verify_mode = ssl.CERT_NONE

clientSocket = socket.socket()
secureClientSocket = sslContext.wrap_socket(clientSocket, do_handshake_on_connect=False)

t1 = time.time()
retval = secureClientSocket.connect(("example.com", 443))
print("Time taken to establish the connection:%2.3f"%(time.time() - t1))

t3 = time.time()
secureClientSocket.do_handshake()
print("Time taken for SSL handshake:%2.3f"%(time.time() - t3))

serverCertificate = secureClientSocket.getpeercert()
print("Certificate obtained from the server:")
print(serverCertificate)

环境配置 #

openssl version
OpenSSL 3.0.7 1 Nov 2022 (Library: OpenSSL 3.0.7 1 Nov 2022)

python3 --version
Python 3.10.8

解决建议 #

1. 修复加密套件字符串错误
   你的自定义加密套件字符串中存在截断：DHE-RSA-A$，这会导致OpenSSL无法解析合法的套件列表，直接引发握手失败。删除该错误片段，或直接使用默认加密套件测试（注释掉sslContext.set_ciphers(cipher)）。

2. 移除无效的猴子补丁
   ssl._create_default_https_context仅作用于urllib.request等高层库的默认上下文，你手动创建的sslContext不受其影响，删除该行避免干扰。

3. 简化上下文配置
   先使用最简化的配置确认基础握手是否正常：

   sslContext = ssl.create_default_context()
   sslContext.check_hostname = False
   sslContext.verify_mode = ssl.CERT_NONE
   # 不要设置自定义cipher，先使用默认值
   

4. 验证服务器SSL兼容性
   用OpenSSL命令行测试目标服务器的支持协议与套件：

   openssl s_client -connect example.com:443
   

   查看输出中的Cipher Suite和Protocol，确保客户端使用的协议/套件在服务器支持列表内。

5. 正确加载OpenSSL配置（若需）
   若确实需要启用UnsafeLegacyRenegotiation，需将配置保存为文件（如openssl.cnf），然后通过环境变量指定：

   export OPENSSL_CONF=/path/to/openssl.cnf
   

   再运行Python脚本。

内容的提问来源于stack exchange，提问作者MC874