Bug 1024831

Summary: Error during GSS key exchange
Product: Red Hat Enterprise Linux 7 Reporter: Petr Lautrbach <plautrba>
Component: opensshAssignee: Petr Lautrbach <plautrba>
Status: CLOSED CURRENTRELEASE QA Contact: Miroslav Vadkerti <mvadkert>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.0CC: ksrot, mgrepl, mvadkert, nalin, plautrba, pvrabec, tmraz
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: openssh-6.3p1-4.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 1024004 Environment:
Last Closed: 2014-06-13 11:48:07 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Petr Lautrbach 2013-10-30 13:39:34 UTC 
+++ This bug was initially created as a clone of Bug #1024004 +++

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.
Comment 4 Miroslav Vadkerti 2014-03-25 12:28:19 UTC 
After changing GSSAPIKeyExchange to Yes for both -> server and client I can reproduce the issue with openssh-6.3p1-4.fc20.

I added testing with GSSAPIKeyExchange set to yes on both side to the test ..
Comment 6 Ludek Smid 2014-06-13 11:48:07 UTC 
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.