upgraded to F23 and ssh keys become useless

[ankit360]

i upgrade my fedora installed on laptop from 22 to 23 through dnf .

but i m not able to connect to remote server with ssh key .

when i use ssh key to access server it ask key passphrase after that to ask me for password of user .

if i user same key on my colleagues laptop, having ububtu. i can able to login through ssh key . same key was working on fedora 22 .

any idea what is issue ?

[nonamedotc]

Have you already checked the permissions of the folder and the key files themselves?

[jvinla]

To fix my ssh problem I had to change the key. The old key was generated by

ssh-keygen -t dsa

ssh no longer uses dsa so another type of key must be used, for example

ssh-keygen -t ecdsa

When the old key was removed and the new key uploaded, ssh started working again. I found this solution google-searching for "fedora 23 ssh key dsa".

[ankit360]

making new key and adding it to remote server is not good solution as i have lots of server without password

[ankit360]

here is the log

[ankit@a360-lan ~]$ ssh -vvv -i key/id_dsa root@xyz
OpenSSH_7.1p1, OpenSSL 1.0.2d-fips 9 Jul 2015
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 56: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to xyz [x.x.x.x] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file key/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file key/id_dsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to xyz:22 as 'root'
debug3: hostkeys_foreach: reading file "/home/ankit/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/ankit/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from xyz
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,ssh-rsa
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-rsa...01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: kex_parse_kexinit: chacha20-poly1305@openssh.com,aes128...lysator.liu.se
debug2: kex_parse_kexinit: chacha20-poly1305@openssh.com,aes128...lysator.liu.se
debug2: kex_parse_kexinit: umac-64-etm@openssh.com,umac-128-etm...60@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: umac-64-etm@openssh.com,umac-128-etm...60@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug1: kex: server->client aes128-ctr umac-64@openssh.com none
debug1: kex: client->server aes128-ctr umac-64@openssh.com none
debug1: kex: diffie-hellman-group-exchange-sha256 need=16 dh_need=16
debug1: kex: diffie-hellman-group-exchange-sha256 need=16 dh_need=16
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<3072<8192) sent
debug1: got SSH2_MSG_KEX_DH_GEX_GROUP
debug2: bits set: 1554/3072
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: got SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: ssh-rsa SHA256:tUTGsWoEsR2aZ0jgEX0Wpt7ug5mMv3j+E/ytcHvM1DE
debug3: hostkeys_foreach: reading file "/home/ankit/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/ankit/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from xyz
debug3: hostkeys_foreach: reading file "/home/ankit/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/ankit/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from 203.153.40.51
debug1: Host 'xyz'' is known and matches the RSA host key.
debug1: Found key in /home/ankit/.ssh/known_hosts:4
debug2: bits set: 1482/3072
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: ankit@a360-lan (0x55fce31ed500),
debug2: key: key/id_dsa ((nil)), explicit
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-keyex
debug3: remaining preferred: gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-keyex
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug2: we did not send a packet, disable method
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Unspecified GSS failure. Minor code may provide more information


debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug2: we did not send a packet, disable method
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: ankit@a360-lan
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Trying private key: key/id_dsa
Enter passphrase for key 'key/id_dsa':
debug1: Skipping ssh-dss key key/id_dsa for not in PubkeyAcceptedKeyTypes
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
root@xyz's password:

[ankit360]

found solution openssh 7 stop dsa key authentication

you can enable it through by adding following parameters in ~/.ssh/config file

PubkeyAcceptedKeyTypes=+ssh-dss

[FeRDNYC]

To fix my ssh problem I had to change the key. The old key was generated by

ssh-keygen -t dsa

ssh no longer uses dsa so another type of key must be used, for example

ssh-keygen -t ecdsa

When the old key was removed and the new key uploaded, ssh started working again. I found this solution google-searching for "fedora 23 ssh key dsa".

I just wanted to note that ECDSA appears to be an unideal choice for replacement key format, since gnome-keyring-daemon unfortunately doesn't pick up $HOME/.ssh/id_ecdsa files. That means that any keys using that format won't be automatically unlocked and added to its ssh-agent at login, the same way that DSA or RSA keys would be.

The proper replacement format for any lingering DSA keys would seem to be RSA (the default for ssh-keygen). However, I have one machine which is failing to successfully authenticate using its RSA keys, since it was upgraded to F23. I still haven't figured out exactly why, at this point, but it seems I'm not alone.