After i installed SSH,
i try to configure Chroot, but then i got following error when i try to login.
Feb 29 11:53:49 tng-ubuntu sshd[15314]: error: /dev/pts/2: No such file or directory
Not very sure about what happen, i try many many options, actually almost spent a whole afternoon, still don't know what is the issue.
Can someone help?
Subsystem sftp internal-sftp -l VERBOSE
Whenever i have following section in my sshd_config, it failed.
I already try to change /home to /home/%u or %h ...
Match Group sftponly
ChrootDirectory /home
AllowTcpForwarding no
X11Forwarding no
ForceCommand internal-sftp -l VERBOSE
Actually my configuration works, but i was verifying using SSH login, and my SSH failed to login. Though i still don't know why my SSH failed to login, but anyway, my SFTP works.
Need to check further why the SSH failed to login.
Related
I'm facing a weird behavior trying to run rsync as sudo through ssh with passwordless login.
This is something I do with dozens of servers, I'm having this frustrating problem connecting to a couple of Ubuntu 18.04.4 servers
PREMISE
the passwordless SSH from CLIENT to SERVER with account USER works
nicely
When I'm logged in SERVER I can sudo everything with
account USER
On SERVER I've added the following to /etc/sudoers
user ALL=NOPASSWD:/usr/bin/rsync
Now, if I launch this simple test from machine CLIENT as user USER, I receive the following sudo error message:
$ ssh utente#192.168.200.135 -p 2310 sudo rsync
sudo: no tty present and no askpass program specified
Moreover, looking in the SERVER's /var/log/auth.log I found this errors:
sudo: pam_unix(sudo:auth): conversation failed
sudo: pam_unix(sudo:auth): auth could not identify password for [user]
am not an PAM expert, but tested the following solution working on Ubuntu 16.04.5 and 20.04.1
NOTE : Configuration set to default on /etc/ssh/sshd_config
$ sudo visudo -f /etc/sudoers.d/my_config_file
add the below lines
my_username ALL=(ALL) NOPASSWD:ALL
and don't forget to restart sshd
$ sudo systemctl restart sshd
I've found a solution thanks to Centos. Infact, because of the more complex configuration of /etc/sudoers in Centos (compared to Ubuntu or Debian), I've been forced to put my additional configurations to an external file in /etc/sudoers.d/ instead than putting it directly into /etc/sudoers
SOLUTION:
Putting additional configurations directly into /etc/sudoers wouldn't work
Putting the needed additional settings in a file within the directory /etc/sudoers.d/ will work
e.g. , these are the config lines put in a file named /etc/sudoers.d/my_config_file:
Host_Alias MYSERVERHOST=192.168.1.135,localhost
# User that will execute Rsync with Sudo from a remote client
rsyncuser MYSERVERHOST=NOPASSWD:/usr/bin/rsync
Why /etc/sudoers didn't work? It's unknown to me even after two days worth of Internet search. I find this very obscure and awful.
What follows is a quote from this useful article: https://askubuntu.com/a/931207
Unlike /etc/sudoers, the contents of /etc/sudoers.d survive system upgrades, so it's preferrable to create a file there than to modify /etc/sudoers.
For the editing of any configuration file to be used by sudo the command visudo is preferable.
i.e.
$ sudo visudo -f /etc/sudoers.d/my_config_file
I had a similar problem on a custom linux server, but the solution was similar to the answers above.
As soon as I removed the line your_user ALL=(ALL) NOPASSWD:ALL from /etc/sudoers, the errors were gone.
I'm using ansible to provision my Centos 7 produciton cluster. Unfortunately, execution of below command results with ansible Tiemout and Linux Pluggable Authentication Modules (pam) error conversation failed.
The same ansible command works well, executed against virtual lab mad out of vagrant boxes.
Ansible Command
$ ansible master_server -m yum -a 'name=vim state=installed' -b -K -u lukas -vvvv
123.123.123.123 | FAILED! => {
"msg": "Timeout (7s) waiting for privilege escalation prompt: \u001b[?1h\u001b=\r\r"
}
SSHd Log
# /var/log/secure
Aug 26 13:36:19 master_server sudo: pam_unix(sudo:auth): conversation failed
Aug 26 13:36:19 master_server sudo: pam_unix(sudo:auth): auth could not identify password for [lukas]
I've found the problem. It turned out to be PAM's auth module problem! Let me describe how I got to the solution.
Context:
I set up my machine for debugging - that is I had four terminal windows opened.
1st terminal (local machine): Here, I was executing ansible prduction_server -m yum -a 'name=vim state=installed' -b -K -u username
2nd terminal (production server): Here, I executed journalctl -f (system wide log).
3rd terminal (production server): Here, I executed tail -f /var/log/secure (log for sshd).
4th terminal (production server): Here, I was editing vi /etc/pam.d/sudo file.
Every time, I executed command from 1st terminal I got this errors:
# ansible error - on local machine
Timeout (7s) waiting for privilege escalation prompt error.
# sshd error - on remote machine
pam_unix(sudo:auth): conversation failed
pam_unix(sudo:auth): [username]
I showed my entire setup to my colleague, and he told me that the error had to do something with "PAM". Frankly, It was the first time that I've heard about PAM. So, I had to read this PAM Tutorial.
I figured out, that error relates to auth interface located in /etc/pam.d/sudo module. Diging over the internet, I stambled upon this pam_permit.so module with sufficient controll flag, that fixed my problem!
Solution
Basically, what I added was auth sufficient pam_permit.so line to /etc/pam.d/sudo file. Look at the example below.
$ cat /etc/pam.d/sudo
#%PAM-1.0
# Fixing ssh "auth could not identify password for [username]"
auth sufficient pam_permit.so
# Below is original config
auth include system-auth
account include system-auth
password include system-auth
session optional pam_keyinit.so revoke
session required pam_limits.so
session include system-auth
Conclusion:
I spent 4 days to arrive to this solution. I stumbled upon over a dozens solutions that did not worked for me, starting from "duplicated sudo password in ansible hosts/config file", "ldap specific configuration" to getting advice from always grumpy system admins!
Note:
Since, I'm not expert in PAM, I'm not aware if this fix affects other aspects of the system, so be cautious over blindly copy pasting this code! However, if you are expert on PAM please share with us alternative solutions or input. Thanks!
Assuming the lukas user is a local account, you should look at how the pam_unix.so module is declared in your system-auth pam file. But more information about the user account and pam configuration is necessary for a specific answer.
While adding auth sufficient pam_permit.so is enough to gain access. Using it in anything but the most insecure test environment would not be recommended. From the pam_permit man page:
pam_permit is a PAM module that always permit access. It does nothing
else.
So adding pam_permit.so as sufficient for authentication in this manner will completely bypass the security for all users.
Found myself in the same situation, tearing my hair out. In my case, hidden toward the end of the sudoers file, there was the line:
%sudo ALL=(ALL:ALL) ALL
This undoes authorizations that come before it. If you're not using the sudo group then this line can safely be deleted.
I had this error since upgrading sudo to version 1.9.4 with pacman. I hadn't noticed that pacman had provided a new sudoers file.
I just needed to merge /etc/sudoers.pacnew.
See here for more details: https://wiki.archlinux.org/index.php/Pacman/Pacnew_and_Pacsave
I know that this doesn't answer the original question (which pertains to a Centos system), but this is the top Google result for the error message, so I thought I'd leave my solution here in case anyone stumbles across this problem coming from an Arch Linux based operating system.
I got the same error when I tried to restart apache2 with sudo service apache2 restart
When logging into root I was able to see the real error lied with the configuration of apache2. Turned out I removed a site's SSL-Certificate files a few months ago but didn't disable the site in apache2. a2dissite did the trick.
Need to run bash-script at sudo-user on remote hosts using Ansible. My working machine is Win10 + Cygwin (sorry, it wasn't my fault).
So, i tested it on non-sudo scripts (it doesn't need root access) - and it works.
No, first time it didn't work at all: Failed to connect to the host via ssh: my_user#server1: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password)
So, i used this: "ssh-keygen -t rsa" -> "ssh-copy-id my_user#server1" || "ssh-copy-id my_user#server2" under my_user: created an ssh-key and shered it to remote hosts. After that i could run scripts under my_user on server1, server2 and so on...
Now, i need run sudo-scripts. But i can't understand, how it'll be.
on Cygwin there're no ROOT-user. And i don't know, how can to generete ssh-key for nonexistent user.
how to run ansible playbook with root? remote_user: root goes with error: Failed to connect to the host via ssh: my_user#server1: Permission denied Look, it's my_user, not root. Does it run as my_user or root-user?
Maybe i do it wrong at all, and are there any "best practice"-vay to run sudo-scripts?
Oh, please, give me a help to solve my problem.
Seems like auth as root disabled on remote server.
In /etc/ssh/sshd_config find PermitRootLogin and set it on Yes, but I'll not recommend you to do that.
Actually, use exactly root user - it's bad practice.
Check permissions for your my_user. Maybe you can grant it sudo rights without password.
To do that edit /etc/sudoers as root, find this line:
# Allow members of group sudo to execute any command
And after it add this:
my_user ALL=(ALL) NOPASSWD: ALL
After it you'll be able to execute any sudo command without password on remote machine.
I did it, but what i did?
So, steps of solution:
set become: true at playbook, abuote here:
hosts:
test_hosts
become: true
vars:
Next, run playbook with "-K" attibute: ansible-playbook ./your_playbook.yml -K
So, it works: ran and even exec scripts under sudo.
But i can't understand, how can i set what user i use as "executable user".
I have a host with Solaris installed:
# uname -a
SunOS <hostname> 5.10 Generic_147147-26 sun4u sparc SUNW,Sun-Fire-V250
When I'm trying to execute any svn command as non-root user to a remote repository I'm getting SSL error:
<username># svn log https://svn.example.com/repository/file
SSL negotiation failed: SSL error: bad packet length
But if I switch to a root user everything seems to work fine:
root# svn log https://svn.example.com/repository/file
Authentication realm: <https://svn.example.com:443>
Password for 'root':
I've tried to remove ssl.svn.server/<hash> file for remote host and this works for root account (I have to accept the certificate again) but I'm getting the same SSL error for non-root user.
Any ideas how to fix this?
Is it possible that the regular user "username" had accepted a previous/different certificate from that host?
You may try to remove or rename the .svn directory into your "username" home and see if it solves the issue: if this is the case probably your "username" have stored some wrong setting in its .svn settings files.
Is it possible that root and "usarname" are using a different svn executable due to $PATH order? (You may check it using which svn command).
Hope it helps.
From workstation (Windows) trying to execute
knife ssh 'name:*' 'sudo chef-client'
But it shows error message of
WARNING: Failed to connect to ******** – Net::SSH::AuthenticationFailed: Authentication failed for user ************
How do I solve this error?
Another question is how to execute 'sudo chef-client' on all nodes from workstation without using any passwords?
If you run knife ssh --help you'll get a list of available options. Try adding -VV for verbose output. That's usually helpful as it should tell you what user knife is trying to connect as.
My guess is you'll have to incorporate one or more of the ssh options (a few listed here):
-x, --ssh-user USERNAME
-i, --identity-file IDENTITY_FILE
-P, --ssh-password [PASSWORD] (will prompt if flag specified but no password is given)
The docs (https://docs.getchef.com/knife_ssh.html) also have some helpful examples
Your SSH authentication isn't working, fix that. Key-based authentication is something I'm sure you can look up on Google, but in general set your public key in .ssh/authorized_keys and setup your agent on your workstation.