TLSv1 on CentOS-8

[Tomas Mraz]

On Fri, 2020-04-17 at 13:03 -0400, Viktor Dukhovni wrote:
> On Fri, Apr 17, 2020 at 05:17:47PM +0200, Tomas Mraz wrote:
> 
> > Or you could modify the /etc/pki/tls/openssl.cnf:
> > Find the .include /etc/crypto-policies/back-ends/opensslcnf.config
> > line in it and insert something like:
> > 
> > CipherString =
> > @SECLEVEL=1:kEECDH:kRSA:kEDH:kPSK:kDHEPSK:kECDHEPSK:!DES:!RC2:!RC4:
> > !IDEA:-SEED:!eNULL:!aNULL:!MD5:-SHA384:-CAMELLIA:-ARIA:-AESCCM8
> 
> How did this particular contraption become a recommended cipherlist?

To explain - this is basically autogenerated value from the crypto
policy definiton of the LEGACY crypto policy with just added the !RC4. 


> What's wrong with "DEFAULT"?  In OpenSSL 1.1.1 it already excludes
> RC4 (if RC4 is at all enabled at compile time):

Nothing wrong with DEFAULT. For manual configuration. This is however
something that is autogenerated.

>     $ openssl ciphers -v 'COMPLEMENTOFDEFAULT+RC4'
>     ECDHE-ECDSA-RC4-SHA     TLSv1 Kx=ECDH     Au=ECDSA Enc=RC4(128)
> Mac=SHA1
>     ECDHE-RSA-RC4-SHA       TLSv1
> Kx=ECDH     Au=RSA  Enc=RC4(128)  Mac=SHA1
>     RC4-SHA                 SSLv3
> Kx=RSA      Au=RSA  Enc=RC4(128)  Mac=SHA1
> 
> I find too many people cargo-culting poorly thought cipher lists from
> some random HOWTO.  Over optimising your cipherlist is subject to
> rapid bitrot, resist the temptation...

Yeah, I should have probably suggested just: CipherString = DEFAULT

There is not much point in being as close to the autogenerated policy
as possible for this particular user's use-case.

-- 
Tomáš Mráz
No matter how far down the wrong road you've gone, turn back.
                                              Turkish proverb
[You'll know whether the road is wrong if you carefully listen to your
conscience.]