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          | finotti   |  | 
        
					| Post subject: [SOLVED] SSH passwordless login stopped working  Posted: 03.12.2015, 14:38 |  | 
  
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 Joined: 2010-09-12
 Posts: 493
 
 Status: Offline
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          | I've just updated my system and now passworless login with SSH stopped working. 
 
       Code: 
# apt-cache policy openssh-client
 openssh-client:
 Installed: 1:7.1p1-1
 Candidate: 1:7.1p1-1
 Version table:
 *** 1:7.1p1-1 500
 500 http://httpredir.debian.org/debian sid/main amd64 Packages
 100 /var/lib/dpkg/status
 1:6.9p1-3 500
 500 http://http.debian.net/debian testing/main amd64 Packages
 
 
 Version 1:6.9p1-3, running on my home desktop, works.
 
 If anyone knows a fix (other than waiting for a new updated), I'd appreciate it.
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 Last edited by finotti on 03.12.2015, 14:49; edited 1 time in total
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          | finotti   |  | 
        
					| Post subject: RE: SSH passwordless login stopped working  Posted: 03.12.2015, 14:49 |  | 
  
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 Joined: 2010-09-12
 Posts: 493
 
 Status: Offline
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          | OK more info. 
 
       Code: 
$ ssh -v desk
 [...]
 debug1: Skipping ssh-dss key /home/finotti/.ssh/id_dsa for not in PubkeyAcceptedKeyTypes
 [...]
 
 
 So, maybe DSA keys are now considered insecure?
 
 Adding
 
       Code: 
PubkeyAcceptedKeyTypes ssh-dss
 
 
 to .ssh/config fixes it, but maybe it would be better to change the keys...  (Can someone confirm this?)
 
 EDIT: FYI, RSA keys work.
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          | peekaboo   |  | 
        
					| Post subject: RE: SSH passwordless login stopped working  Posted: 05.12.2015, 20:22 |  | 
  
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 Joined: 2015-12-05
 Posts: 1
 Location: Germay
 Status: Offline
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          | Hi, 
 According to bettercrypto.org, DSA should not be used anymore for SSH. See chapter 2.2 Applied Crypto Hardening Paper at » https://bettercrypto.org/ «.
 So it's likely DSA has been removed completely now starting with OpenSSH 7.
 
 Regards!
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          | slh   |  | 
        
					| Post subject: RE: SSH passwordless login stopped working  Posted: 05.12.2015, 21:49 |  | 
  
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 Joined: 2010-08-25
 Posts: 962
 
 Status: Offline
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          | Just to end (part of-) the speculation, have a look at the package changelog (/usr/share/doc/openssh-server/changelog.Debian.gz):       Code: 
openssh (1:7.1p1-1) unstable; urgency=medium
 * New upstream release (http://www.openssh.com/txt/release-7.0, closes:
 #785190):
 - Support for the legacy SSH version 1 protocol is disabled by default
 at compile time.
 - Support for the 1024-bit diffie-hellman-group1-sha1 key exchange is
 disabled by default at run-time.  It may be re-enabled using the
 instructions at http://www.openssh.com/legacy.html
 - Support for ssh-dss, ssh-dss-cert-* host and user keys is disabled by
 default at run-time.  These may be re-enabled using the instructions
 at http://www.openssh.com/legacy.html
 - Support for the legacy v00 cert format has been removed.
 - The default for the sshd_config(5) PermitRootLogin option has changed
 from "yes" to "prohibit-password".
 - PermitRootLogin=without-password/prohibit-password now bans all
 interactive authentication methods, allowing only public-key,
 hostbased and GSSAPI authentication (previously it permitted
 keyboard-interactive and password-less authentication if those were
 enabled).
 - ssh_config(5): Add PubkeyAcceptedKeyTypes option to control which
 public key types are available for user authentication.
 - sshd_config(5): Add HostKeyAlgorithms option to control which public
 key types are offered for host authentications.
 - ssh(1), sshd(8): Extend Ciphers, MACs, KexAlgorithms,
 HostKeyAlgorithms, PubkeyAcceptedKeyTypes and HostbasedKeyTypes
 options to allow appending to the default set of algorithms instead of
 replacing it.  Options may now be prefixed with a '+' to append to the
 default, e.g. "HostKeyAlgorithms=+ssh-dss".
 - sshd_config(5): PermitRootLogin now accepts an argument of
 'prohibit-password' as a less-ambiguous synonym of 'without-
 password'.
 - ssh(1), sshd(8): Add compatability workarounds for Cisco and more
 PuTTY versions.
 - Fix some omissions and errors in the PROTOCOL and PROTOCOL.mux
 documentation relating to Unix domain socket forwarding.
 - ssh(1): Improve the ssh(1) manual page to include a better description
 of Unix domain socket forwarding (closes: #779068).
 - ssh(1), ssh-agent(1): Skip uninitialised PKCS#11 slots, fixing
 failures to load keys when they are present.
 - ssh(1), ssh-agent(1): Do not ignore PKCS#11 hosted keys that wth empty
 CKA_ID.
 - sshd(8): Clarify documentation for UseDNS option.
 - Check realpath(3) behaviour matches what sftp-server requires and use
 a replacement if necessary.
 * New upstream release (http://www.openssh.com/txt/release-7.1):
 - sshd(8): OpenSSH 7.0 contained a logic error in PermitRootLogin=
 prohibit-password/without-password that could, depending on
 compile-time configuration, permit password authentication to root
 while preventing other forms of authentication.  This problem was
 reported by Mantas Mikulenas.
 - ssh(1), sshd(8): Add compatibility workarounds for FuTTY.
 - ssh(1), sshd(8): Refine compatibility workarounds for WinSCP.
 - Fix a number of memory faults (double-free, free of uninitialised
 memory, etc) in ssh(1) and ssh-keygen(1).  Reported by Mateusz
 Kocielski.
 * Change "PermitRootLogin without-password" to the new preferred spelling
 of "PermitRootLogin prohibit-password" in sshd_config, and update
 documentation to reflect the new upstream default.
 * Enable conch interoperability tests under autopkgtest.
 
 -- Colin Watson <xxx>  Wed, 02 Dec 2015 20:18:35 +0000
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          | finotti   |  | 
        
					| Post subject: RE: SSH passwordless login stopped working  Posted: 06.12.2015, 13:43 |  | 
  
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 Joined: 2010-09-12
 Posts: 493
 
 Status: Offline
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          | Thanks for confirming it!  I've changed my keys to RSA. |  
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					| Post subject: RE: SSH passwordless login stopped working  Posted: 06.12.2015, 15:55 |  | 
  
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 Joined: 2010-09-19
 Posts: 205
 
 Status: Offline
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          | How do I check if I have DSA, and how do I convert it RSA? |  
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          | slh   |  | 
        
					| Post subject: RE: SSH passwordless login stopped working  Posted: 06.12.2015, 23:35 |  | 
  
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 Joined: 2010-08-25
 Posts: 962
 
 Status: Offline
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          | Look into the key-files under ~/.ssh/, you'll see "-----BEGIN RSA PRIVATE KEY-----" or "ssh-rsa" for the public key, compared to "-----BEGIN DSA PRIVATE KEY-----" or "ssh-dss" respectively; most of the time, the key naming will also tell you. |  
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					| Post subject: RE: SSH passwordless login stopped working  Posted: 12.12.2015, 11:41 |  | 
  
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 Joined: 2010-09-19
 Posts: 205
 
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