I want to change the location where the Authorized SSH keys are saved. Therefore, I changed the location of the authorized keys file in /etc/ssh/sshd_config to
AuthorizedKeysFile /etc/ssh/authorized_keys/%u/authorized_keys
The ssh service was restarted with sudo systemctl restart ssh and the owner and group of the /etc/ssh/authorized_keys/user directory is the right user/group.
The server is accessible for the already included ssh keys in /etc/ssh/authorized_keys/user/authorized_keys, but adding a new ssh key from some other device to the server with ssh-copy-id -i ~/.ssh/id_rsa user#server saves the key in the default directory ~/.ssh/authorized_keys.
Grateful for any advice or help!
For anybody coming by this later, ssh-copy-id is on the client, and the sshd_config is on the server. It cannot know where to write to. It assumes the default location.
Furthermore, you don't want every user able to write into /etc/ssh/authorized_keys anyway. If you've specifically set ownership to the user for /etc/ssh/authorized_keys/user then there's no obvious benefit vs having it in the default location. The advantage of doing what you've suggested is for centralized management of keys, an advantage you only have if the users are NOT permitted to write to it.
I have built an MF container image and pushed it. I have copied the file in (Mac) ~/.ssh/id_rsa.pub to mfpf-server/usr/ssh before building the image.
I am trying to connect using the command in Mac terminal:
ssh -i ~/.ssh/id_rsa admin#public_ip
It says:
Permission denied (publickey).
Any idea? What is the user I shall use?
your problem is very probably related to the permissions of the pub key copied on the container or to the configuration of your key.
You could check the permissions of key copied on the container, sshd is really strict on permissions for the authorized_keys files: if authorized_keys is writable for anybody other than the user or can be made writable by anybody other than the user, sshd will refuse to authenticate (unless sshd is configured with StrictModes no)
Moreover such a problem won't be showed using ssh -v, it will showed only on daemon logs (on the container)
From man sshd(8):
~/.ssh/authorized_keys
Lists the public keys (RSA/DSA) that can be used for logging in
as this user. The format of this file is described above. The
content of the file is not highly sensitive, but the recommended
permissions are read/write for the user, and not accessible by
others.
If this file, the ~/.ssh directory, or the user's home directory
are writable by other users, then the file could be modified or
replaced by unauthorized users. In this case, sshd will not
allow it to be used unless the StrictModes option has been set to
“no”.
So I suggest you to check about the files and directories permissions.
Then check that the content of your pub key has been copied correctly on authorized_keys listing
/root/.ssh/authorized_keys
To access the container with the ssh key you need to use the "root" user.
ssh -i ~/.ssh/id_rsa root#<ip address>
The target server is a relatively clean install of Ubuntu 14.04. I generated a new ssh key using ssh-keygen and added it to my server using ssh-copy-id. I also checked that the public key was in the ~/.ssh/authorized_keys file on the server.
Even still, I am prompted for a password every time I try to ssh into the server.
I noticed something weird however. After I log into my first session using my password, the next concurrent sessions don't ask for a password. They seem to be using the ssh key properly. I've noticed this behaviour on two different clients (Mint OSX).
Are you sure your SSH key isn't protected by a password? Try the following:
How do I remove the passphrase for the SSH key without having to create a new key?
If that's not the case, it may just be that ssh is having trouble locating your private key. Try using the -i flag to explicitly point out its location.
ssh -i /path/to/private_key username#yourhost.com
Thank you Samuel Jun for the link to help.ubuntu.com - SSH Public Key Login Troubleshooting !
Just a little caveat:
If you copy your authorized keys file outside your encrypted home directory please make sure your root install is encrypted as well (imho Ubuntu still allows for unencrypted root install coupled with encryption of the home directory).
Otherwise this defeats the whole purpose of using encryption in the first place ;)
If this is happening to you on Windows (I'm on Windows 10)
Try running the program that you're trying to connect via ssh to the server as administrator.
For me I was using powershell with scoop to install a couple of things so that I could ssh straight from it. Anyway... I ran PowerShell as admin and tried connecting again and it didn't ask for my password.
For LinuxSE
Check the SE context with
% ls -dZ ~user/.ssh
Must contain unconfined_u:object_r:ssh_home_t:s0
If not, that was the problem , as root run
# for i in ~user/.ssh ~user/.ssh/*
do
semanage fcontext -a -t ssh_home_t $i
done
# restorecon -v -R ~user/.ssh
It looks like it's related to encryption on your home directory and therefore the authorized_keys file cannot be read.
https://unix.stackexchange.com/a/238570
Make sure your ssh public key was copied to the remote host in the right format. If you open the key file to edit it should read 1 line.
Basically, just do ssh-copy-id username#remote. It will take care of the rest.
I tried to push my blog (Octopress) to github and got this error:
MacBook-Air:octopress bdeely$ git push origin source
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
I generated an SSH key, saved it, and even linked it with my GitHub account in the SSH key settings, but I went ahead and checked the status and got the same error:
MacBook-Air:.ssh bdeely$ ssh -T git#github.com
Permission denied (publickey).
In addition to this, I checked github's help page, did the following and got this error message:
MacBook-Air:~ bdeely$ ssh-add -l
The agent has no identities.
Does anyone know what is wrong and how I can fix this?
On OSX, if you type
ssh-add -l
and you get back "no identities", that means your ssh agent does not have any identities loaded into it. Oftentimes, when the mac reboots, you have no identities.
I add mine back after a re-boot by explicitly running
ssh-add
This loads a default identity from ~/.ssh/id_rsa
You can also use the ssh-add command with a specific identity
ssh-add ~/foo/bar/is_rsa
After you add your identies, you can seem them all listed by typing
ssh-add -l
Make sure you have at least one listed.
Follow the commands:
mkdir ~/.ssh //in case that the folder doesnt exist...
cd ~/.ssh
ssh-keygen -t rsa -C "youremail#somewhere.gr"
#hit enter when asks for file to save the key.
#enter the passphrase
At last copy the id_rsa.pub into your github account.
Try this in your terminal:
eval `ssh-agent -s`
ssh-add ~/.ssh/id_rsa
enter your passphrase if any and it should work. Hope this helps :-)
I hope this helps you:
I was having the identical problem and about to take my own eyes out with insane frustration; nothing online led me to an answer and I was trying to use the git push command without specifying the URL exactly (which could also solve the problem I believe), so I didn't see how the connection was failing.
I had set up my .ssh/config correctly for two users with two different keys, even using IdentitiesOnly yes which is supposed to override ssh-agent that was automatically supplying the WRONG ssh identity.
I finally realized the problem as I examined the local repository configuration - it was the entry
[remote "origin"]
url = git#github.com:{my-username}/{my-repo-name}.git
My configuration in .ssh/config file was using the same HostName github.com entry for both users and I'm completely new to all this so I didn't realize that to correctly override ssh-agent, I had to specify the exact URL or else the specific identities in my .ssh/config file would be ignored and the first key that ssy-agent listed (which was the wrong one my my case) would be used by default.
I fixed this by changing the local repo URL to url = git#github-personal:{my-username}/{my-repo-name}.git, where I had set Host github-personal as the identity in my .ssh/config.
Another way to solve this would be specifying the user in the URL in the git push command itself, or even better, a solution described here in a post AFTER solving this my own crappy way:
https://superuser.com/questions/272465/using-multiple-ssh-public-keys
I can't believe that no official source could offer a solution for or even properly explain this edge-case that seems really common (accessing two different github accounts from one machine with SSL).
I experienced the same problem. The reason was that I moved the key-files to another folder; it worked successfully when I moved them back to where they were originally.
When i ssh to a machine, sometime i get this error warning and it prompts to say "yes" or "no". This cause some trouble when running from scripts that automatically ssh to other machines.
Warning Message:
The authenticity of host '<host>' can't be established.
ECDSA key fingerprint is SHA256:TER0dEslggzS/BROmiE/s70WqcYy6bk52fs+MLTIptM.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'pc' (ECDSA) to the list of known hosts.
Is there a way to automatically say "yes" or ignore this?
Depending on your ssh client, you can set the StrictHostKeyChecking option to no on the command line, and/or send the key to a null known_hosts file. You can also set these options in your config file, either for all hosts or for a given set of IP addresses or host names.
ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no
EDIT
As #IanDunn notes, there are security risks to doing this. If the resource you're connecting to has been spoofed by an attacker, they could potentially replay the destination server's challenge back to you, fooling you into thinking that you're connecting to the remote resource while in fact they are connecting to that resource with your credentials. You should carefully consider whether that's an appropriate risk to take on before altering your connection mechanism to skip HostKeyChecking.
Reference.
Old question that deserves a better answer.
You can prevent interactive prompt without disabling StrictHostKeyChecking (which is insecure).
Incorporate the following logic into your script:
if [ -z "$(ssh-keygen -F $IP)" ]; then
ssh-keyscan -H $IP >> ~/.ssh/known_hosts
fi
It checks if public key of the server is in known_hosts. If not, it requests public key from the server and adds it to known_hosts.
In this way you are exposed to Man-In-The-Middle attack only once, which may be mitigated by:
ensuring that the script connects first time over a secure channel
inspecting logs or known_hosts to check fingerprints manually (to be done only once)
To disable (or control disabling), add the following lines to the beginning of /etc/ssh/ssh_config...
Host 192.168.0.*
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
Options:
The Host subnet can be * to allow unrestricted access to all IPs.
Edit /etc/ssh/ssh_config for global configuration or ~/.ssh/config for user-specific configuration.
See http://linuxcommando.blogspot.com/2008/10/how-to-disable-ssh-host-key-checking.html
Similar question on superuser.com - see https://superuser.com/a/628801/55163
Make sure ~/.ssh/known_hosts is writable. That fixed it for me.
The best way to go about this is to use 'BatchMode' in addition to 'StrictHostKeyChecking'. This way, your script will accept a new hostname and write it to the known_hosts file, but won't require yes/no intervention.
ssh -o BatchMode=yes -o StrictHostKeyChecking=no user#server.example.com "uptime"
This warning is issued due the security features, do not disable this feature.
It's just displayed once.
If it still appears after second connection, the problem is probably in writing to the known_hosts file.
In this case you'll also get the following message:
Failed to add the host to the list of known hosts
You may fix it by changing owner of changing the permissions of the file to be writable by your user.
sudo chown -v $USER ~/.ssh/known_hosts
Edit your config file normally located at '~/.ssh/config', and at the beggining of the file, add the below lines
Host *
User your_login_user
StrictHostKeyChecking no
IdentityFile ~/my_path/id_rsa.pub
User set to your_login_user says that this settings belongs to your_login_user
StrictHostKeyChecking set to no will avoid the prompt
IdentityFile is path to RSA key
This works for me and my scripts, good luck to you.
Ideally, you should create a self-managed certificate authority. Start with generating a key pair:
ssh-keygen -f cert_signer
Then sign each server's public host key:
ssh-keygen -s cert_signer -I cert_signer -h -n www.example.com -V +52w /etc/ssh/ssh_host_rsa_key.pub
This generates a signed public host key:
/etc/ssh/ssh_host_rsa_key-cert.pub
In /etc/ssh/sshd_config, point the HostCertificate to this file:
HostCertificate /etc/ssh/ssh_host_rsa_key-cert.pub
Restart the sshd service:
service sshd restart
Then on the SSH client, add the following to ~/.ssh/known_hosts:
#cert-authority *.example.com ssh-rsa AAAAB3Nz...cYwy+1Y2u/
The above contains:
#cert-authority
The domain *.example.com
The full contents of the public key cert_signer.pub
The cert_signer public key will trust any server whose public host key is signed by the cert_signer private key.
Although this requires a one-time configuration on the client side, you can trust multiple servers, including those that haven't been provisioned yet (as long as you sign each server, that is).
For more details, see this wiki page.
Do this -> chmod +w ~/.ssh/known_hosts. This adds write permission to the file at ~/.ssh/known_hosts. After that the remote host will be added to the known_hosts file when you connect to it the next time.
With reference to Cori's answer, I modified it and used below command, which is working. Without exit, remaining command was actually logging to remote machine, which I didn't want in script
ssh -o StrictHostKeyChecking=no user#ip_of_remote_machine "exit"
Add these to your /etc/ssh/ssh_config
Host *
UserKnownHostsFile=/dev/null
StrictHostKeyChecking=no
Generally this problem occurs when you are modifying the keys very oftenly. Based on the server it might take some time to update the new key that you have generated and pasted in the server. So after generating the key and pasting in the server, wait for 3 to 4 hours and then try. The problem should be solved. It happened with me.
The following steps are used to authenticate yourself to the host
Generate a ssh key. You will be asked to create a password for the key
ssh-keygen -f ~/.ssh/id_ecdsa -t ecdsa -b 521
(above uses the recommended encryption technique)
Copy the key over to the remote host
ssh-copy-id -i ~/.ssh/id_ecdsa user#host
N.B the user # host will be different to you. You will need to type in the password for this server, not the keys password.
You can now login to the server securely and not get an error message.
ssh user#host
All source information is located here:
ssh-keygen
For anyone who finds this and is simply looking to prevent the prompt on first connection, but still wants ssh to strictly check the key on subsequent connections (trust on first use), you can set StrictHostKeyChecking to accept-new in ~/.ssh/config, which will do what you're looking for. You can read more about it in man ssh_config. I strongly discourage disabling key checking altogether.
Run this in host server it's premonition issue
chmod -R 700 ~/.ssh
I had the same error and wanted to draw attention to the fact that - as it just happened to me - you might just have wrong privileges.You've set up your .ssh directory as either regular or root user and thus you need to be the correct user. When this error appeared, I was root but I configured .ssh as regular user. Exiting root fixed it.
This is trying to establish password-less authentication. So, if you try to run that command manually once, it will ask to provide the password there. After entering password, it saves that password permanently, and it will never ask again to type 'yes' or 'no'.
For me the reason is that I have wrong permission on ~/.ssh/known_hosts.
I have no write permission on known_hosts file. So it ask me again and again.
In my case, the host was unkown and instead of typing yes to the question are you sure you want to continue connecting(yes/no/[fingerprint])? I was just hitting enter .
I solve the issue which gives below written error:
Error:
The authenticity of host 'XXX.XXX.XXX' can't be established.
RSA key fingerprint is 09:6c:ef:cd:55:c4:4f:ss:5a:88:46:0a:a9:27:83:89.
Solution:
1. install any openSSH tool.
2. run command ssh
3. it will ask for do u add this host like.
accept YES.
4. This host will add in the known host list.
5. Now you are able to connect with this host.
This solution is working now......