You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
54 lines
2.0 KiB
54 lines
2.0 KiB
7 years ago
|
Guide for legacy support enablement
|
||
|
|
===================================
|
||
|
|
|
||
|
|
To improve security provided by use of OpenSSL especially in context of
|
||
|
|
TLS connections we regularly review and deprecate algorithms and algorithm
|
||
|
|
settings which are no longer viewed as secure.
|
||
|
|
|
||
|
|
For some of these deprecated algorithms we provide a way for the
|
||
|
|
system administrator to reenable them.
|
||
|
|
|
||
|
|
Deprecated algorithms, protocols and settings in OpenSSL
|
||
|
|
========================================================
|
||
|
|
|
||
|
|
Previous Red Hat Enterprise Linux 7 update releases:
|
||
|
|
|
||
|
|
* SSL2 protocol disabled by default.
|
||
|
|
* Minimum DH group size accepted by SSL/TLS client 768 bits.
|
||
|
|
* Verification of certificates and signatures using MD5 hash
|
||
|
|
disabled.
|
||
|
|
|
||
|
|
Red Hat Enterprise Linux 7.4:
|
||
|
|
|
||
|
|
* SSL2 protocol support completely disabled (cannot be re-enabled).
|
||
|
|
* All SSL/TLS export ciphers disabled.
|
||
|
|
* All SSL/TLS ciphersuites with keys smaller than 128 bits disabled.
|
||
|
|
* Minimum DH group size accepted by SSL/TLS client 1024 bits.
|
||
|
|
* Disabled support for verification of certificates and signatures
|
||
|
|
using MD2, MD4, MD5, and SHA0 hashes.
|
||
|
|
|
||
|
|
Legacy support enablement
|
||
|
|
=========================
|
||
|
|
|
||
|
|
The OpenSSL now supports /etc/pki/tls/legacy-settings configuration file
|
||
|
|
which can be created by the system administrator which contains lines with
|
||
|
|
simple Key Value pairs.
|
||
|
|
|
||
|
|
The library recognizes the following possible configuration settings in
|
||
|
|
that file:
|
||
|
|
|
||
|
|
LegacySigningMDs md2 md5
|
||
|
|
MinimumDHBits 512
|
||
|
|
|
||
|
|
The LegacySigningMDs option allows reenabling support for verification of
|
||
|
|
signatures with the specified hash algorithms. These can be any combination
|
||
|
|
of md2, md4, md5 and sha. (sha represents SHA0 algorithm, not SHA1.) Any
|
||
|
|
unrecognized algorithms are ignored.
|
||
|
|
|
||
|
|
The MinimumDHBits option allows setting of the minimum bit size of DH group
|
||
|
|
accepted by SSL/TLS client. It can be any value between 512 and 10000.
|
||
|
|
|
||
|
|
If the configuration file is not present the built-in defaults (that is the
|
||
|
|
secure defaults) are used. Any unrecognized lines (with other parameter
|
||
|
|
names or comments) are ignored.
|