As pointed by @JimB and @putu my server doesn't have Password Authentication enabled. To verify that i ran ssh with verbose option and it gave me back all supported authentication methods. In my case it turned out to be following:
debug1: Authentications that can continue: publickey,keyboard-interactive,hostbased
So i had 2 options to go with, either enable password authentication on the server or use other method to authenticate.
To enable password authentication connect to your server and open sshd config file like so:
vi/etc/ssh/sshd_config
Find line saying: PasswordAuthentication no
Change it to yes, save changes and restart sshd service: service ssh restart
After that password authentication method starts to work as expected. Alternatively other methods can be used, i decided to try keyboard-interactive, the one user usually has when connects over the terminal using ssh. Here is the code snippet that does just that, sends password after password question is asked by remote server:
package main
import (
"bytes"
"golang.org/x/crypto/ssh"
"fmt"
)
func connectViaSsh(user, host string, password string) (*ssh.Client, *ssh.Session) {
config := &ssh.ClientConfig{
User: user,
Auth: []ssh.AuthMethod{
ssh.KeyboardInteractive(SshInteractive),
},
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
}
client, err := ssh.Dial("tcp", host, config)
fmt.Println(err)
session, err := client.NewSession()
fmt.Println(err)
return client, session
}
func SshInteractive(user, instruction string, questions []string, echos []bool) (answers []string, err error) {
answers = make([]string, len(questions))
// The second parameter is unused
for n, _ := range questions {
answers[n] = "your_password"
}
return answers, nil
}
func main() {
var b bytes.Buffer
client, session := connectViaSsh("root", "host:22", "password")
session.Stdout = &b
session.Run("ls")
fmt.Println(b.String())
client.Close()
}
In my case server asks only one question which is password, if your server asks more than that you would need to build an entire chain of answers to feed back in.