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|
package sshutil
import (
"errors"
"fmt"
"net"
"strconv"
"strings"
"golang.org/x/crypto/ssh"
)
const defaultPort = 22
var errCallbackDone = errors.New("callback failed on purpose")
// addDefaultPort appends a default port if hostport doesn't contain one
func addDefaultPort(hostport string, defaultPort int) string {
_, _, err := net.SplitHostPort(hostport)
if err == nil {
return hostport
}
hostport = net.JoinHostPort(hostport, strconv.Itoa(defaultPort))
return hostport
}
// SSHKeyScan scans a ssh server for the hostkey; server should be in the form hostname, or hostname:port
func SSHKeyScan(server string) (string, error) {
var key string
KeyScanCallback := func(hostport string, remote net.Addr, pubKey ssh.PublicKey) error {
hostname, _, err := net.SplitHostPort(hostport)
if err != nil {
return err
}
key = strings.TrimSpace(fmt.Sprintf("%s %s", hostname, string(ssh.MarshalAuthorizedKey(pubKey))))
return errCallbackDone
}
config := &ssh.ClientConfig{
HostKeyCallback: KeyScanCallback,
}
server = addDefaultPort(server, defaultPort)
conn, err := ssh.Dial("tcp", server, config)
if key != "" {
// as long as we get the key, the function worked
err = nil
}
if conn != nil {
_ = conn.Close()
}
return key, err
}
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