Bug 1295064 - winswitch uses outdated ssh kex exchange methods
winswitch uses outdated ssh kex exchange methods
Product: Fedora
Classification: Fedora
Component: winswitch (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Jonathan Underwood
Fedora Extras Quality Assurance
Depends On:
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Reported: 2016-01-01 11:33 EST by Pavel Alexeev
Modified: 2016-12-20 12:32 EST (History)
3 users (show)

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2016-12-20 12:32:15 EST
Type: Bug
Regression: ---
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RHEL 7.3 requirements from Atomic Host:
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Description Pavel Alexeev 2016-01-01 11:33:17 EST
Description of problem:
I've try setup new winswitch server on Fedora and connect to them.

But connection from GUI client fails without any details.

On server i see in /var/log/secure:
Jan  1 16:14:26 digitalocean sshd[4315]: fatal: Unable to negotiate with no matching key exchange method found. Their offer: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]

After add (https://bbs.archlinux.org/viewtopic.php?pid=1521264#p1521264) into /etc/ssh/sshd_config:
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1

I got (after some timeout) another error:
Jan  1 16:19:18 digitalocean sshd[4345]: error: Hm, kex protocol error: type 30 seq 1 [preauth]
Jan  1 16:27:48 digitalocean sshd[4350]: Connection closed by [preauth]

I also found that blog post https://blog.nytsoi.net/2015/07/13/putty-kex-error and it seams relative. Possible winswitch tries connect with old pre-RFC4419 group exchange message.

Version-Release number of selected component (if applicable):
$ rpm -q winswitch

On server:
# rpm -q openssh

How reproducible:
Comment 1 Jonathan Underwood 2016-04-06 08:38:32 EDT
This seems to be this:


Comment 2 Fedora End Of Life 2016-11-24 09:38:36 EST
This message is a reminder that Fedora 23 is nearing its end of life.
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Comment 3 Fedora End Of Life 2016-12-20 12:32:15 EST
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

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