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Bug 499962

Summary: =net-misc/openssh-6.5_p1 version bump
Product: Gentoo Linux Reporter: Lars Wendler (Polynomial-C) (RETIRED) <polynomial-c>
Component: Current packagesAssignee: Gentoo's Team for Core System packages <base-system>
Status: RESOLVED FIXED    
Severity: enhancement CC: bugs+gentoo, cloos, h.v.bruinehsen, hanno, tdalman
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
URL: http://www.openssh.org/txt/release-6.5
Whiteboard:
Package list:
Runtime testing required: ---

Description Lars Wendler (Polynomial-C) (RETIRED) gentoo-dev 2014-02-01 11:13:42 UTC 
This release introduced Daniel Bernstein's Curve25519 ECDH algorithm which is supposed to be NSA-backdoor-free ;)

Furthermore chacha20-poly1305@openssh.com transport cipher was introduced as well as a bunch of other new features (see URL).

Of course like with most new openssh releases this one breaks latest known hpn patch again so I took the opportunity to forward-port the patch [1]. Please test that patch thoroughly. I only made sure the patch compiles and doesn't break ssh(d) and scp. Oh and my patch is based on the 6.3p1-hpnssh14v2 version from our gentoo mirrors (not the original hpn patch).

[1] http://dev.gentoo.org/~polynomial-c/openssh-6.5p1-hpnssh14v2.diff.bz2
Comment 1 Tim Harder gentoo-dev 2014-02-01 18:12:22 UTC 
(In reply to Lars Wendler (Polynomial-C) from comment #0)
> Of course like with most new openssh releases this one breaks latest known
> hpn patch again so I took the opportunity to forward-port the patch [1].
> Please test that patch thoroughly. I only made sure the patch compiles and
> doesn't break ssh(d) and scp. Oh and my patch is based on the
> 6.3p1-hpnssh14v2 version from our gentoo mirrors (not the original hpn
> patch).
> 
> [1] http://dev.gentoo.org/~polynomial-c/openssh-6.5p1-hpnssh14v2.diff.bz2

We should probably address the alignment issues with the multithreaded aes-ctr cipher (bugs #498632 and #499552) with this bump if we can.
Comment 2 Jana Saout 2014-02-03 06:35:31 UTC 
When dropping the -ldap use flag, openssh 6.5 compiles fine (with the patch above).

On a side-note:

Note that I played a bit around, and by default, the new DJB EC curve 25519 only seems to be used by default for the key exchange. For host keys, ECDSA is still preferred and for actual encryption, AES 128. Guess they didn't want to break everyone or suddenly sacrifice performance.

One can play around with the defaults in the ssh_config:

Ciphers aes256-gcm@openssh.com,aes256-ctr,chacha20-poly1305@openssh.com,aes192-ctr,aes128-gcm@openssh.com,aes128-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc
MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-256,hmac-sha2-512-etm@openssh.com,hmac-sha2-512,hmac-sha1,hmac-md5,umac-64@openssh.com,hmac-ripemd160
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
HostKeyAlgorithms ssh-ed25519-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp256,ssh-rsa-cert-v00@openssh.com,ssh-rsa,ssh-dss-cert-v00@openssh.com,ssh-dss

(I still preferred aes over the new ChaCha thing, because AES is still commonly believed to be fine).  This switches over the defaults to much stronger algorithms, like SHA-256 for authentication, AES-256 for encryption, GCM for the cipher stream and ED25519 for the host key.

The latter will make ssh connections complain about changed host keys if you connect to a server which is already known! (because the now preferred ED25519 key differs from the cached ECDSA key)

(so... just FYI :)