Can not ssh with tr_TR.UTF-8 locales (Bad configuration options)

/etc/default/locale is attached.

/etc/environment is attached.

strace of ssh gitlab.com

Status changed to 'Confirmed' because the bug affects multiple users.

Trying to reproduce:
Xenial - all cases working with&without Identity or gsapi configs
Yakkety - login as usual works
Yakkety - Adding LANG=tr_TR.UTF-8 login still works
Yakkety - Adding LANG=tr_TR.UTF-8 and enabling Identity / gssapi configs login still works

I currently have "openssh-client 1:7.3p1-1" on my client (Yakkety).
My server was a 16.04.1 with 1:7.2p2-4ubuntu2.1

Do you have any other parts to your GSSAPI config or such that might be relevant.

If not having anything confidential please share your ~/.ssh/config and /etc/ssh/ssh_config for the error and the "fixed" case by modifying the conf files.

@ChristianEhrhardt, I uploded both of them.

"Do you have any other parts to your GSSAPI config or such that might be relevant."

I don't have anything like that. I event do not touch/modify/edit /etc/ssh/ssh_config file.

Thanks for uploading.
I really see nothing in your files that would cause this.
Still I reproduced your setup on my yakkety machine but run into no issues what so ever when setting tr_TR locales.

I see you also opened a askubuntu thread - linking here as FYI http://askubuntu.com/questions/843891/can-not-clone-a-git-repository-over-ssh-bad-configuration-option.

ATM - I fail to reproduce, but would like to understand what is going on.

@ChristianEhrhardt, you are welcome. I thank you for trying to help me! Yes, I reported this problem in AskUbuntu, then decided to report it as a bug.

Is there a way for me to debug ssh? Or "bisect" it? I am going to try to install a previous version of ssh package.

@ChristianEhrhardt, I installed 1:7.2p2-4ubuntu2.1 version of openssh-client package from Xenial after purging 1:7.3p1-1 version. With this version, I can ssh to any host without using LC_ALL=C variable.

    ssh launchpad.net
    ssh: connect to host launchpad.net port 22: Connection refused

    ssh gitlab.com
    Permission denied (publickey).

LC_ALL=C apt-cache policy openssh-client
openssh-client:
  Installed: 1:7.2p2-4ubuntu2.1
  Candidate: 1:7.3p1-1
  Version table:
     1:7.3p1-1 500
        500 http://archive.ubuntu.com/ubuntu yakkety/main amd64 Packages
 *** 1:7.2p2-4ubuntu2.1 100
        100 /var/lib/dpkg/status

I'm going to leave this as Incomplete, since it isn't clear to me that this is a bug in Ubuntu at all. If you can provide steps that will produce the problem on a different system, then we can look further. Otherwise, please understand that this bug will not make progress, and that you're more likely to find people to help you outside the bug tracking system, for example in your askubuntu.com question.

I have encountered this bug today. You can reproduce it by launching ssh in Turkish locale environment:

LC_ALL=tr_TR.UTF8 ssh <email address hidden>

Ubuntu version is 16.10, and openssh-client version is 1:7.3p1-1. I guess the client converts parameters in config files to lowercase when parsing and gives error because both GSSAPIAuthentication and GSSAPIDelegateCredentials parameters has "I" character.

Turkish have two separate "i" character dotted and dotless. Per the Unicode standard, our lowercase "i" becomes "İ" (U+0130 "Latin Capital Letter I With Dot Above") when it moves to uppercase. Similarly, our uppercase "I" becomes "ı" (U+0131 "Latin Small Letter Dotless I") when it moves to lowercase.

For additional info, you can check out the links below:
http://www.moserware.com/2008/02/does-your-code-pass-turkey-test.html
https://blog.codinghorror.com/whats-wrong-with-turkey/
http://mattryall.net/blog/2009/02/the-infamous-turkish-locale-bug

This is an upstream regression very probably caused by:

  https://anongit.mindrot.org/openssh.git/commit/?id=65c6c6b567ab5ab12945a5ad8e0ab3a8c26119cc

I'd suggest filing it upstream at https://bugzilla.mindrot.org/ - it may
be possible to preserve the intent of the above change by substituting a
deliberately-locale-unaware version of tolower() when parsing
configuration files, or maybe just by calling setlocale() after parsing
configuration files.

 status triaged

Thank you @Colin Watson. I reported this to the upstream. Here is the link to the bug: https://bugzilla.mindrot.org/show_bug.cgi?id=2643

This bug was fixed in the package openssh - 1:7.4p1-5

---------------
openssh (1:7.4p1-5) unstable; urgency=medium

  * Create mux socket for regression tests in a temporary directory.
  * Work around clock_gettime kernel bug on Linux x32 (closes: #849923).

 -- Colin Watson <email address hidden> Tue, 03 Jan 2017 14:43:28 +0000