diff options
| -rw-r--r-- | Doc/library/ssl.rst | 15 | ||||
| -rw-r--r-- | Lib/ssl.py | 39 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 38 insertions, 19 deletions
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst index 0ed5fb2..3aa1e36 100644 --- a/Doc/library/ssl.rst +++ b/Doc/library/ssl.rst @@ -1665,17 +1665,10 @@ If you have advanced security requirements, fine-tuning of the ciphers enabled when negotiating a SSL session is possible through the :meth:`SSLContext.set_ciphers` method. Starting from Python 3.2.3, the ssl module disables certain weak ciphers by default, but you may want -to further restrict the cipher choice. For example:: - - context = ssl.SSLContext(ssl.PROTOCOL_TLSv1) - context.set_ciphers('HIGH:!aNULL:!eNULL') - -The ``!aNULL:!eNULL`` part of the cipher spec is necessary to disable ciphers -which don't provide both encryption and authentication. Be sure to read -OpenSSL's documentation about the `cipher list -format <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>`_. -If you want to check which ciphers are enabled by a given cipher list, -use the ``openssl ciphers`` command on your system. +to further restrict the cipher choice. Be sure to read OpenSSL's documentation +about the `cipher list format <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>`_. +If you want to check which ciphers are enabled by a given cipher list, use the +``openssl ciphers`` command on your system. Multi-processing ^^^^^^^^^^^^^^^^ @@ -162,14 +162,37 @@ else: # Disable weak or insecure ciphers by default # (OpenSSL's default setting is 'DEFAULT:!aNULL:!eNULL') -_DEFAULT_CIPHERS = 'DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2' - -# restricted and more secure ciphers -# HIGH: high encryption cipher suites with key length >= 128 bits (no MD5) -# !aNULL: only authenticated cipher suites (no anonymous DH) -# !RC4: no RC4 streaming cipher, RC4 is broken -# !DSS: RSA is preferred over DSA -_RESTRICTED_CIPHERS = 'HIGH:!aNULL:!RC4:!DSS' +# Enable a better set of ciphers by default +# This list has been explicitly chosen to: +# * Prefer cipher suites that offer perfect forward secrecy (DHE/ECDHE) +# * Prefer ECDHE over DHE for better performance +# * Prefer any AES-GCM over any AES-CBC for better performance and security +# * Then Use HIGH cipher suites as a fallback +# * Then Use 3DES as fallback which is secure but slow +# * Finally use RC4 as a fallback which is problematic but needed for +# compatibility some times. +# * Disable NULL authentication, NULL encryption, and MD5 MACs for security +# reasons +_DEFAULT_CIPHERS = ( + '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' +) + +# Restricted and more secure ciphers +# This list has been explicitly chosen to: +# * Prefer cipher suites that offer perfect forward secrecy (DHE/ECDHE) +# * Prefer ECDHE over DHE for better performance +# * Prefer any AES-GCM over any AES-CBC for better performance and security +# * Then Use HIGH cipher suites as a fallback +# * Then Use 3DES as fallback which is secure but slow +# * Disable NULL authentication, NULL encryption, MD5 MACs, DSS, and RC4 for +# security reasons +_RESTRICTED_CIPHERS = ( + '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:!aNULL:' + '!eNULL:!MD5:!DSS:!RC4' +) class CertificateError(ValueError): @@ -21,6 +21,9 @@ Core and Builtins Library ------- +- Issue #20995: Enhance default ciphers used by the ssl module to enable + better security an prioritize perfect forward secrecy. + - Issue #20884: Don't assume that __file__ is defined on importlib.__init__. - Issue #20879: Delay the initialization of encoding and decoding tables for |