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Issues #27850 and #27766: Remove 3DES from ssl default cipher list and add ChaCha20 Poly1305.

This commit is contained in:
Christian Heimes 2016-09-06 20:07:58 +02:00
parent d953f8e10b 03d13c0cbf
commit ac041c0aa7
3 changed files with 33 additions and 15 deletions
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6
Doc/library/ssl.rst
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@ -285,6 +285,12 @@ purposes.
RC4 was dropped from the default cipher string.
.. versionchanged:: 3.6
ChaCha20/Poly1305 was added to the default cipher string.
3DES was dropped from the default cipher string.
Random generation
^^^^^^^^^^^^^^^^^

36
Lib/ssl.py
View File

@ -157,36 +157,42 @@ if _ssl.HAS_TLS_UNIQUE:
else:
CHANNEL_BINDING_TYPES = []
# Disable weak or insecure ciphers by default
# (OpenSSL's default setting is 'DEFAULT:!aNULL:!eNULL')
# 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
# * Prefer AEAD over CBC for better performance and security
# * Prefer AES-GCM over ChaCha20 because most platforms have AES-NI
# (ChaCha20 needs OpenSSL 1.1.0 or patched 1.0.2)
# * Prefer any AES-GCM and ChaCha20 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, and MD5 MACs for security
# reasons
# * Disable NULL authentication, NULL encryption, 3DES 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:!aNULL:'
'!eNULL:!MD5'
)
'ECDH+AESGCM:ECDH+CHACHA20:DH+AESGCM:DH+CHACHA20:ECDH+AES256:DH+AES256:'
'ECDH+AES128:DH+AES:ECDH+HIGH:DH+HIGH:RSA+AESGCM:RSA+AES:RSA+HIGH:'
'!aNULL:!eNULL:!MD5:!3DES'
)
# Restricted and more secure ciphers for the server side
# 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
# * Prefer AEAD over CBC for better performance and security
# * Prefer AES-GCM over ChaCha20 because most platforms have AES-NI
# * Prefer any AES-GCM and ChaCha20 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
# * Disable NULL authentication, NULL encryption, MD5 MACs, DSS, RC4, and
# 3DES for security reasons
_RESTRICTED_SERVER_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'
'ECDH+AESGCM:ECDH+CHACHA20:DH+AESGCM:DH+CHACHA20:ECDH+AES256:DH+AES256:'
'ECDH+AES128:DH+AES:ECDH+HIGH:DH+HIGH:RSA+AESGCM:RSA+AES:RSA+HIGH:'
'!aNULL:!eNULL:!MD5:!DSS:!RC4:!3DES'
)

6
Misc/NEWS
View File

@ -85,6 +85,12 @@ Core and Builtins
Library
-------
- Issue #27850: Remove 3DES from ssl module's default cipher list to counter
measure sweet32 attack (CVE-2016-2183).
- Issue #27766: Add ChaCha20 Poly1305 to ssl module's default ciper list.
(Required OpenSSL 1.1.0 or LibreSSL).
- Issue #25387: Check return value of winsound.MessageBeep.
- Issue #27866: Add SSLContext.get_ciphers() method to get a list of all