From d1772d410235592b482e3b08b1863f6624d9fe6b Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 19 Feb 2023 15:52:21 +0100
Subject: Adding upstream version 2.0.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 deluge/crypto_utils.py | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 deluge/crypto_utils.py

(limited to 'deluge/crypto_utils.py')

diff --git a/deluge/crypto_utils.py b/deluge/crypto_utils.py
new file mode 100644
index 0000000..7672efa
--- /dev/null
+++ b/deluge/crypto_utils.py
@@ -0,0 +1,79 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2007,2008 Andrew Resch <andrewresch@gmail.com>
+#
+# This file is part of Deluge and is licensed under GNU General Public License 3.0, or later, with
+# the additional special exception to link portions of this program with the OpenSSL library.
+# See LICENSE for more details.
+#
+
+from __future__ import division, print_function, unicode_literals
+
+from OpenSSL.crypto import FILETYPE_PEM
+from twisted.internet.ssl import (
+    AcceptableCiphers,
+    Certificate,
+    CertificateOptions,
+    KeyPair,
+    TLSVersion,
+)
+
+# A TLS ciphers list.
+# Sources for more information on TLS ciphers:
+# - https://wiki.mozilla.org/Security/Server_Side_TLS
+# - https://www.ssllabs.com/projects/best-practices/index.html
+# - https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/
+#
+# This list was inspired by the `urllib3` library
+# - https://github.com/urllib3/urllib3/blob/master/urllib3/util/ssl_.py#L79
+#
+# The general intent is:
+# - prefer cipher suites that offer perfect forward secrecy (ECDHE),
+# - prefer AES-GCM over ChaCha20 because hardware-accelerated AES is common,
+# - disable NULL authentication, MD5 MACs and DSS for security reasons.
+TLS_CIPHERS = ':'.join(
+    [
+        'ECDH+AESGCM',
+        'ECDH+CHACHA20',
+        'AES256-GCM-SHA384',
+        'AES128-GCM-SHA256',
+        '!DSS' '!aNULL',
+        '!eNULL',
+        '!MD5',
+    ]
+)
+
+# This value tells OpenSSL to disable all SSL/TLS renegotiation.
+SSL_OP_NO_RENEGOTIATION = 0x40000000
+
+
+def get_context_factory(cert_path, pkey_path):
+    """OpenSSL context factory.
+
+    Generates an OpenSSL context factory using Twisted's CertificateOptions class.
+    This will keep a server cipher order.
+
+    Args:
+        cert_path (string): The path to the certificate file
+        pkey_path (string): The path to the private key file
+
+    Returns:
+        twisted.internet.ssl.CertificateOptions: An OpenSSL context factory
+    """
+
+    with open(cert_path) as cert:
+        certificate = Certificate.loadPEM(cert.read()).original
+    with open(pkey_path) as pkey:
+        private_key = KeyPair.load(pkey.read(), FILETYPE_PEM).original
+    ciphers = AcceptableCiphers.fromOpenSSLCipherString(TLS_CIPHERS)
+    cert_options = CertificateOptions(
+        privateKey=private_key,
+        certificate=certificate,
+        raiseMinimumTo=TLSVersion.TLSv1_2,
+        acceptableCiphers=ciphers,
+    )
+    ctx = cert_options.getContext()
+    ctx.use_certificate_chain_file(cert_path)
+    ctx.set_options(SSL_OP_NO_RENEGOTIATION)
+
+    return cert_options
-- 
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