python · miss-islington · Mar 18, 2021 · Jan 15, 2020 · Dec 9, 2020
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst
@@ -634,6 +634,13 @@ Constants

   .. versionadded:: 3.4

+.. data:: VERIFY_ALLOW_PROXY_CERTS
+
+   Possible value for :attr:`SSLContext.verify_flags` to enables proxy
+   certificate verification.
+
+   .. versionadded:: 3.10
+
 .. data:: VERIFY_X509_TRUSTED_FIRST

   Possible value for :attr:`SSLContext.verify_flags`. It instructs OpenSSL to

diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
@@ -1305,6 +1305,8 @@ def test_verify_flags(self):
        self.assertEqual(ctx.verify_flags, ssl.VERIFY_CRL_CHECK_CHAIN)
        ctx.verify_flags = ssl.VERIFY_DEFAULT
        self.assertEqual(ctx.verify_flags, ssl.VERIFY_DEFAULT)
+        ctx.verify_flags = ssl.VERIFY_ALLOW_PROXY_CERTS
+        self.assertEqual(ctx.verify_flags, ssl.VERIFY_ALLOW_PROXY_CERTS)
        # supports any value
        ctx.verify_flags = ssl.VERIFY_CRL_CHECK_LEAF | ssl.VERIFY_X509_STRICT
        self.assertEqual(ctx.verify_flags,

diff --git a/Misc/NEWS.d/next/Library/2020-01-15-11-15-35.bpo-39342.S8PuJO.rst b/Misc/NEWS.d/next/Library/2020-01-15-11-15-35.bpo-39342.S8PuJO.rst
@@ -0,0 +1,4 @@
+Expose ``X509_V_FLAG_ALLOW_PROXY_CERTS`` as
+:data:`~ssl.VERIFY_ALLOW_PROXY_CERTS` to allow proxy certificate validation
+as explained in
+https://www.openssl.org/docs/man1.1.1/man7/proxy-certificates.html.
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
@@ -6181,6 +6181,8 @@ sslmodule_init_constants(PyObject *m)
                            X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
    PyModule_AddIntConstant(m, "VERIFY_X509_STRICT",
                            X509_V_FLAG_X509_STRICT);
+    PyModule_AddIntConstant(m, "VERIFY_ALLOW_PROXY_CERTS",
+                            X509_V_FLAG_ALLOW_PROXY_CERTS);
 #ifdef X509_V_FLAG_TRUSTED_FIRST
    PyModule_AddIntConstant(m, "VERIFY_X509_TRUSTED_FIRST",
                            X509_V_FLAG_TRUSTED_FIRST);