sign_and_send_pubkey: signing failed: agent refuse

Question

Configuring a new Digital Ocean droplet with SSH keys. When I run ssh-copy-id this is what I get:

ssh-copy-id user@012.345.67.89
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
sign_and_send_pubkey: signing failed: agent refused operation
user@012.345.67.89's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'user@012.345.67.89'"
and check to make sure that only the key(s) you wanted were added.

However, when I then attempt to ssh in, this happens:

ssh user@012.345.67.89
sign_and_send_pubkey: signing failed: agent refused operation
user@012.345.67.89's password: 

Upon entering the password, I am logged in just fine, but this of course defeats the purpose of creating the SSH key in the first place. I decided to take a look at the ssh-agent server-side and here's what I get:

user@012.345.67.89:~# eval `ssh-agent -s`
Agent pid 5715
user@012.345.67.89:~# ssh-add -l
The agent has no identities.

user/.ssh/authorized_keys does contain an ssh-rsa key entry, as well, but find -name "keynamehere" returns nothing.

Answer 1

I was having the same problem in Linux Ubuntu 18. After the update from Ubuntu 17.10, every git command would show that message.

The way to solve it is to make sure that you have the correct permission on the id_rsa and id_rsa.pub.

Check the current chmod number by using stat --format '%a' <file>. It should be 600 for id_rsa and 644 for id_rsa.pub.

To change the permission on the files use

chmod 600 id_rsa
chmod 644 id_rsa.pub

That solved my issue with the update.

Answer 2

To this error:

# git pull
sign_and_send_pubkey: signing failed: agent refused operation
[e-mail]: Permission denied (publickey).    
fatal: Could not read from remote repository.

Please make sure you have the correct access rights and the repository exists.

Verify or add again the public key in Github account > profile > ssh.

I solved like this:

# chmod 400 ~/.ssh/id_rsa

# ls  ~/.ssh/id_rsa -ls  
4 -r--------. 1 reinaldo reinaldo 1679 Jul 26  2017 /home/reinaldo/.ssh/id_rsa

# git pull                                 
remote: Counting objects: 35, done.
remote: Compressing objects: 100% (19/19), done.
remote: Total 35 (delta 9), reused 34 (delta 9), pack-reused 0
Unpacking objects: 100% (35/35), done.

Thank you.

Answer 3

There could be various reason for getting the SSH error:

sign_and_send_pubkey: signing failed: agent refused operation

Some of them could be related to the issues highlighted by the other answers (see this thread answers), some of them could be hidden and thus would require a closer investigation.

In my case I've got the following error message:

sign_and_send_pubkey: signing failed: agent refused operation

[e-mail]: Permission denied (publickey,gssapi-keyex,gssapi-with-mic)

The only way to find the real problem was to invoke the -v verbose option which resulted in printing a lot of debugging info:

debug1: Connecting to website.domain.com [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug1: identity file /home/user/.ssh/id_rsa.website.domain.com type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_rsa.website.domain.com-cert type -1

Please note that the line saying key_load_public: No such file or directory is referring the next line and not the previous line.

So what SSH really says is that it could not find the public key file named id_rsa.website.domain.com-cert and that seemed to be the problem in my case since my public key file did not contain the -cert suffix.

Long story short: the fix in my case was just to make sure that the public key file was named as expected. I could never suspected that without debugging the connection.

The bottom line is USE THE SSH VERBOSE MODE (-v option) to figure out what is wrong, there could be various reasons, none that could be found on this/another thread.

Answer 4

Yes. Run ssh-add on the client machine. Then repeat command ssh-copy-id userserver@012.345.67.89

Answer 5

Run ssh-add on the client machine, that will add the SSH key to the agent.

Confirm with ssh-add -l (again on the client) that it was indeed added.

Answer 6

For me the problem was a wrong copy/paste of the public key into Gitlab. The copy generated an extra return. Make sure what you paste is a one-line key.