Description of problem: Since updating to openssh-6.3p1-4.fc20, I've been getting this error when attempting to log in to another system while using GSSAPI key exchange and authentication: nalin@pillbox:~> ssh -vvv blade OpenSSH_6.3, OpenSSL 1.0.1e-fips 11 Feb 2013 debug1: Reading configuration data /home/nalin/.ssh/config debug1: /home/nalin/.ssh/config line 70: Applying options for blade debug1: /home/nalin/.ssh/config line 142: Applying options for * debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 51: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to blade.bos.redhat.com [10.18.57.10] port 22. debug1: Connection established. debug3: Incorrect RSA1 identifier debug3: Could not load "/home/nalin/.ssh/id_rsa" as a RSA1 public key debug1: identity file /home/nalin/.ssh/id_rsa type 1 debug1: identity file /home/nalin/.ssh/id_rsa-cert type -1 debug3: Incorrect RSA1 identifier debug3: Could not load "/home/nalin/.ssh/id_dsa" as a RSA1 public key debug1: identity file /home/nalin/.ssh/id_dsa type 2 debug1: identity file /home/nalin/.ssh/id_dsa-cert type -1 debug1: identity file /home/nalin/.ssh/id_ecdsa type -1 debug1: identity file /home/nalin/.ssh/id_ecdsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.3 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.2 debug1: match: OpenSSH_6.2 pat OpenSSH* debug2: fd 3 setting O_NONBLOCK debug1: Offering GSSAPI proposal: gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group14-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-gex-sha1-A/vxljAEU54gt9a48EiANQ==,gss-group1-sha1-A/vxljAEU54gt9a48EiANQ==,gss-group14-sha1-A/vxljAEU54gt9a48EiANQ==,gss-gex-sha1-bontcUwnM6aGfWCP21alxQ==,gss-group1-sha1-bontcUwnM6aGfWCP21alxQ==,gss-group14-sha1-bontcUwnM6aGfWCP21alxQ==,gss-gex-sha1-eipGX3TCiQSrx573bT1o1Q==,gss-group1-sha1-eipGX3TCiQSrx573bT1o1Q==,gss-group14-sha1-eipGX3TCiQSrx573bT1o1Q== debug3: load_hostkeys: loading entries for host "blade.bos.redhat.com" from file "/home/nalin/.ssh/known_hosts" debug3: load_hostkeys: found key type RSA in file /home/nalin/.ssh/known_hosts:259 debug3: load_hostkeys: loaded 1 keys debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01,ssh-rsa-cert-v00,ssh-rsa debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group14-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-gex-sha1-A/vxljAEU54gt9a48EiANQ==,gss-group1-sha1-A/vxljAEU54gt9a48EiANQ==,gss-group14-sha1-A/vxljAEU54gt9a48EiANQ==,gss-gex-sha1-bontcUwnM6aGfWCP21alxQ==,gss-group1-sha1-bontcUwnM6aGfWCP21alxQ==,gss-group14-sha1-bontcUwnM6aGfWCP21alxQ==,gss-gex-sha1-eipGX3TCiQSrx573bT1o1Q==,gss-group1-sha1-eipGX3TCiQSrx573bT1o1Q==,gss-group14-sha1-eipGX3TCiQSrx573bT1o1Q==,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa-cert-v01,ssh-rsa-cert-v00,ssh-rsa,ecdsa-sha2-nistp256-cert-v01,ecdsa-sha2-nistp384-cert-v01,ecdsa-sha2-nistp521-cert-v01,ssh-dss-cert-v01,ssh-dss-cert-v00,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss,null debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm,aes256-gcm,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm,aes256-gcm,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc.se debug2: kex_parse_kexinit: hmac-md5-etm,hmac-sha1-etm,umac-64-etm,umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-ripemd160-etm,hmac-sha1-96-etm,hmac-md5-96-etm,hmac-md5,hmac-sha1,umac-64,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5-etm,hmac-sha1-etm,umac-64-etm,umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-ripemd160-etm,hmac-sha1-96-etm,hmac-md5-96-etm,hmac-md5,hmac-sha1,umac-64,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib,zlib debug2: kex_parse_kexinit: none,zlib,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: gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==,gss-group14-sha1-toWM5Slw5Ew8Mqkay+al2g==,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-gcm,aes256-gcm,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm,aes256-gcm,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc.se debug2: kex_parse_kexinit: hmac-md5-etm,hmac-sha1-etm,umac-64-etm,umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-ripemd160-etm,hmac-sha1-96-etm,hmac-md5-96-etm,hmac-md5,hmac-sha1,umac-64,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5-etm,hmac-sha1-etm,umac-64-etm,umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-ripemd160-etm,hmac-sha1-96-etm,hmac-md5-96-etm,hmac-md5,hmac-sha1,umac-64,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5-etm debug1: kex: server->client aes128-ctr hmac-md5-etm none debug2: mac_setup: found hmac-md5-etm debug1: kex: client->server aes128-ctr hmac-md5-etm none unsupported kex alg gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g== Version-Release number of selected component (if applicable): Client is openssh-6.3p1-4.fc20.x86_64, server is openssh-server-6.2p2-8.fc20.x86_64. How reproducible: Always Steps to Reproduce: 1. Set up a server on F20 with a keytab using the previous build of openssh. 2. Set up an F20 client with the current version of openssh. 3. Use kinit to get some creds. 4. Try to ssh to the server. Actual results: Error during key exchange. Expected results: Successful login, as before. Additional info: Downgrading back to openssh-6.2p2-8.fc20.x86_64 or turning off the gssapikeyexchange option allows login to succeed.
The code for querying KEX algorithms was slightly refactored in openssh-6.3p1 so openssh-6.3p1-gsskex.patch needs some adjustment. Thanks for the report, I'll push an update soon. In the meantime, there's a test scratch build available for Rawhide - http://koji.fedoraproject.org/koji/taskinfo?taskID=6118958
I can confirm that the above scratch build correctly works against openssh-server-6.2p2-8.fc20.x86_64, where openssh-6.3p1-4.fc20.x86_64 does not. Thanks!
openssh-6.3p1-5.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/openssh-6.3p1-5.fc20
Package openssh-6.3p1-5.fc20: * should fix your issue, * was pushed to the Fedora 20 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing openssh-6.3p1-5.fc20' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2013-20464/openssh-6.3p1-5.fc20 then log in and leave karma (feedback).
openssh-6.3p1-5.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.