From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Apolinarski To: development@lists.ipfire.org Subject: AW: [PATCH] change Apache TLS cipher list to "Mozilla Modern" Date: Thu, 09 Nov 2017 22:35:39 +0100 Message-ID: <007d01d359a2$b0cec030$126c4090$@ipfire.org> In-Reply-To: <20171108224427.1e7ddf24.peter.mueller@link38.eu> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============3719819051225659835==" List-Id: --===============3719819051225659835== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Peter, >=20 > Hello Wolfgang, >=20 > sorry for replying that late - at the moment I am quite busy. :-| I can fully understand that - my reaction time is usually also a lot longer t= han what I want it to be... > > > > > > Actually I proposed that in the discussion to another patch, but > > > Wolfgang said that we would exclude too many systems. > > > > I still think that there might be too many clients, which do not have sup= port for TLS 1.2. > > I would suggest postponing this step to next year. > To keep it short: I fear this is correct and there are networks - mostly th= ey belong to companies, ironically - with very ancient client > systems. >=20 > However, I would differ between several cases: > (a) Public web sites such as https://www.ipfire.org - for these, I consider= the 'Modern' policy OK since nobody wants to transmit > sensitive data with 3DES or SHA1. If a user cannot connect, it is his/her/i= ts fault. Further, the more SSL errors they get from big web > sites, the more it hurts. >=20 > (b) Internal web sites - which is the case for IPFire's WebUI - may be cons= idered as less critical by some people since they are located > in the always trustworthy and super-safe internal network. Needless to say,= I consider this being bullshit, but that explains why we still > have WinXP & Co. systems running. >=20 > However, in my opinion, we also should apply the 'Modern' policy there sinc= e weak algorithms are weak, no matter in what network > they are used. > And in case this breaks internal systems, it is not our fault either: All y= ou need is a system with FF >=3D 28 or something similar. TLS 1.2 is > far from being brand new and as far as I am concerned, we _can_ expect that= people move to this. Period. They only thing I fear is that the apache configuration for the internal WebU= I is also used for addons like owncloud which might be accessed with mobile c= lients - clients which cannot be updated that easily (this is why I cited the= Android OS version usage statistics). >=20 > Service such as the Captive Portal or the Update Accelerator repo are using= HTTP, so they should not make trouble. TLS 1.2 is "only" > used for the administration web interface, which usually does not have to b= e accessible from all clients. >=20 > This is why I submitted this patch. After the discussion with Michael, it was also on my personal todo list to su= bmit an additional patch with the modern configuration, such that we can choo= se which we like best. So I am glad you did that. >=20 > (c) And there are mail servers, which must be treated differently since the= y fall back to plain text in case no common SSL/TLS ciphers > were found. TLS on MX is meant as a protection layer against passive attack= ers in first place. This is why I'd never use the 'Modern' > policy on MXs. And there are still mail server that do not accept encrypted connections at a= ll and/or do not check certificates for validity. I assume that the mail serv= er world has improved, I still remember when it was not possible to connect s= ecurely to GMX' mail servers. > > > > Also, for the modern configuration, we should edit the SSLProtocol value: > > SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1 This allows anyone to > > understand that only TLSv1.2+ is supported. > Yes, you are right. I forgot that. > > > > Regarding the re-ordering of the cipher suites: > > ECDHE-ECDSA is not always faster than ECDHE-RSA. > > It depends on the size of the EC and the RSA key. > > Although I'm assuming that a 4096-bit key is quite slow... > Surprise! ;-) > > I somewhere read that 2048-bit RSA is faster than 256-bit curve. > Really? I was unaware of this. I think it was some slow Atom machine - I was just a little bit concerned, be= cause the router machines are also constraint when it comes to CPU/RAM resour= ces. > > We are using a 4096-bit RSA together with a 384-bit curve. Did anyone per= form some measurements? > No, not yet. The only numbers I have are from Ivan Ristic, who says: >=20 > algorithm strength CPU time (client) CPU time (server) > ECDHE-ECDSA 256/256 bits 1.09s 0.74s > ECDHE-RSA 256/2048 bits 0.81s 2.06s Ah, interesting. I executed the following command on my Ipfire machine (Intel= NUC): "openssl speed aes rsa ecdsa ecdh" the results are: Method ; Sign ; Verify ; Sign/s ; Verify/s 384 bit ecdsa (nistp384) ; 0.0007s ; 0.0030s ; 1356.3 ; 335.3 rsa 2048 bits; 0.004814s 0.000141s ; 207.7 ; 7075.8 rsa 4096 bits; 0.034930s 0.000531s ; 28.6 ; 1882.1 Method ; op ; op/s 384 bit ecdh (nistp384) ; 0.0025s ; 400.8 RSA is really fast in verification, but I assume that the server (WebUI) sign= s and the client then verifies. So ECDSA is more resource intensive for clien= ts, but RSA is a lot slower on servers. Also, I now recognized that secp384r1 is an NIST curve. Well, maybe this is m= ore a political issue and not that relevant for a WebUI-Frontend... >=20 > Thereof I assume ECDSA keys perform usually better than RSA ones, especiall= y when it comes to server CPU time. Depends on the usage as can be seen above, but in general this is true for se= rvers, especially with increasing key sizes. > > > > > > > > Did you see that conversation? > > > > And I really thought that maybe my mail did not make it through after rea= ding the patch... > I am sorry, but I really did not notice it. Did you say which systems you e= xpect to cause problems with TLS 1.2 only? Yes, according to Mozilla: Oldest compatible clients: Firefox 27, Chrome 30, IE 11 on Windows 7, Edge, O= pera 17, Safari 9, Android 5.0, and Java 8 Android < 5.0 has still a market share of > 25%. https://en.wikipedia.org/wiki/Android_version_history#/media/File:Android_his= torical_version_distribution_-_vector.svg Actually all my clients would be compatible. ;-) Nevertheless, the following additional changes would be a good idea: SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1 SSLCompression off SSLSessionTickets off (the last parameter improves PFS). The apache docs: "TLS session tickets are enabled by default. Using them without restarting th= e web server with an appropriate frequency (e.g. daily) compromises perfect f= orward secrecy." Best regards, Wolfgang > > > > > > > > On Tue, 2017-11-07 at 20:51 +0100, Peter M=C3=BCller wrote: > > > > Change the TLS cipher list of Apache to "Mozilla Modern". > > > > > > > > ECDSA is preferred over RSA to save CPU time on both server and > > > > client. Clients without support for TLS 1.2 and AES will > > > > experience connection failures. > > > > > > > > Signed-off-by: Peter M=C3=BCller > > > > --- > > > > config/httpd/vhosts.d/ipfire-interface-ssl.conf | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/config/httpd/vhosts.d/ipfire-interface-ssl.conf > > > > b/config/httpd/vhosts.d/ipfire-interface-ssl.conf > > > > index c9ccd5be5..d08d3d2bb 100644 > > > > --- a/config/httpd/vhosts.d/ipfire-interface-ssl.conf > > > > +++ b/config/httpd/vhosts.d/ipfire-interface-ssl.conf > > > > @@ -9,7 +9,7 @@ > > > > TransferLog /var/log/httpd/access_log > > > > SSLEngine on > > > > SSLProtocol all -SSLv2 -SSLv3 > > > > - SSLCipherSuite ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-= SHA256:ECDHE-ECDSA > > > > -AES128-SHA:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-SHA38 > > > > 4:EC > > > > DHE-ECDSA-AES256-SHA:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128- > > > > SHA2 > > > > 56:ECDHE-RSA-AES128-SHA:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES2 > > > > 56-S > > > > HA384:ECDHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES128-SHA256:AES128-SHA: > > > > CAMELLIA128-SHA:AES256-GCM-SHA384:AES256-SHA256:AES256-SHA:CAMELLI > > > > A256 > > > > -SHA > > > > + SSLCipherSuite > > > > + ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDH > > > > + E-EC > > > > + DSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES1 > > > > + 28-S > > > > + HA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-CHACHA20-POLY1305:EC > > > > + DHE- > > > > + RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-S > > > > + HA25 > > > > + 6 > > > > SSLHonorCipherOrder on > > > > SSLCertificateFile /etc/httpd/server.crt > > > > SSLCertificateKeyFile /etc/httpd/server.key > > --===============3719819051225659835==--