How to ssh to localhost without password?

问题:

EDIT: Putting exactly what was done

I need to SSH localhost without password, the usual way of doing it (with public keys) do not work.

user@PC:~$ rm -rf .ssh/*
user@PC:~$ ssh-keygen -t rsa > /dev/null 
Enter file in which to save the key (/home/user/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
user@PC:~$ ls .ssh/
id_rsa  id_rsa.pub
user@PC:~$ ssh-copy-id -i localhost 
The authenticity of host 'localhost (::1)' can't be established.
RSA key fingerprint is f7:87:b5:4e:31:a1:72:11:8e:5f:d2:61:bd:b3:40:1a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
user@localhost's password: 
Now try logging into the machine, with "ssh 'localhost'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

user@PC:~$ ssh-agent $SHELL
user@PC:~$ ssh-add -L
The agent has no identities.
user@PC:~$ ssh-add 
Identity added: /home/user/.ssh/id_rsa (/home/user/.ssh/id_rsa)
user@PC:~$ ssh-add -L
ssh-rsa ...MY KEY HERE

user@PC:~$ ssh-copy-id -i localhost 
user@localhost's password: 
Now try logging into the machine, with "ssh 'localhost'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

user@PC:~$ ssh localhost echo 'testing'
user@localhost's password: 

user@PC:~$ 

So as you can see in the last command it is still asking the password! How can I fix that? Ubuntu-10.04, OpenSSH_5.3p1

EDIT2:

Adding some info about the sshd

user@PC:~$ cat /etc/ssh/sshd_config | grep Authentication
# Authentication:
RSAAuthentication yes
PubkeyAuthentication yes
RhostsRSAAuthentication no
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
ChallengeResponseAuthentication no
# PasswordAuthentication yes

EDIT3: Ading result from $ssh -vv localhost

$ssh -vv localhost
...
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /home/user/.ssh/identity
debug1: Offering public key: /home/user/.ssh/id_rsa
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/user/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug1: Next authentication method: password
user@localhost's password: 

回答1:

I did following 3 steps to create the password less login

1. ssh-keygen -t rsa
Press enter for each line 
2. cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
3. chmod og-wx ~/.ssh/authorized_keys 

回答2:

Have discovered the problem.

Running the server with debuging:

$sshd -Dd

I found it was not able to read the auth_key

$chmod 750 $HOME

Fixed it.

回答3:

Another possible answer: the authorized_keys file may exist and be readable. But if it is group- or world-writable, it will still prompt for the password. The answer to THAT problem is

chmod og-wx ~/.ssh/authorized_keys

回答4:

Do the following steps

ssh-keygen -t rsa -C "[e-mail]"
# Creates a new ssh key, using the provided email as a label
# Generating public/private rsa key pair.

Use the default file and empty passphrase (Simply press enter in the next 2 steps)

# start the ssh-agent in the background
eval "$(ssh-agent -s)"
# Agent pid 59566
ssh-add 

Copy the contents of ~/.ssh/id_rsa.pub to ~/.ssh/authorized_keys

Ensure following are the permissions

 ls -l .ssh/
 total 20
-rw-r--r--. 1 swati swati  399 May  5 14:53 authorized_keys
-rw-r--r--. 1 swati swati  761 Jan 12 15:59 config
-rw-------. 1 swati swati 1671 Jan 12 15:44 id_rsa
-rw-r--r--. 1 swati swati  399 Jan 12 15:44 id_rsa.pub
-rw-r--r--. 1 swati swati  410 Jan 12 15:46 known_hosts 

Also, ensure the permissions for .ssh directory are. This is also important

drwx------.   2 swati swati    4096 May  5 14:56 .ssh

回答5:

Two simple steps:

ssh-keygen -t rsa <Press enter for each line>
ssh-copy-id localhost

Enter password and you're done.

回答6:

The correct and safe way of doing it is to copy the keys as has been said here.

In other cases, sshpass can be handy.

sshpass -p raspberry ssh pi@192.168.0.145

Keep in mind that this is not safe at all. Even though it is not a good idea to use it in secure environments, it can be useful for scripting, automated testing...

this can be combined with

ssh -q -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no pi@192.168.0.145

to avoid confirmation questions that prevent scripting from happening.

Again, only use this in development systems where different machines share an IP and security is not important.

https://ownyourbits.com/2017/02/22/easy-passwordless-ssh-with-sshh/

回答7:

as the accepted answer do, if you encount a problem of

    Agent admitted failure to sign using the key.

you need to

    ssh-add

回答8:

I faced the same issue even after following all the recommendations, but found out that the issue was with gnome-keyring interference.

Solution:

1. Go Search , look for “Startup Applications”
2. If you see “SSH Key Agent”, uncheck the box
3. Reboot the machine and connect to localhost.

回答9:

I solved ssh login problem this way.

I generate the key pairs on my server side and then scp back the private key to my windows 10 computer and now I can login without password.

Previously I used key pairs generated by my window 10 laptop and there was no luck at all.

回答10:

On Centos 7

SOLUTION

1 create rsa key
2 vim /etc/ssh/ssh_config
3
#   IdentityFile ~/.ssh/identity
uncoment this line > IdentityFile ~/.ssh/id_rsa
#   IdentityFile ~/.ssh/id_dsa
#   IdentityFile ~/.ssh/id_ecdsa

Note *I did this after copying the key and some of the other answers before this one. But I am pretty sure this is all you have to do but if not I would append the rsa key to authorized_keys and also run the

ssh-copy-id to username@localhost