SSH握手抱怨缺少主机密钥

Question

我正在尝试连接到远程主机，并检查文件是否存在。在此阶段，我仅尝试连接，但是出现错误：

2017/08/01 18:16:39 unable to connect: ssh: handshake failed: ssh: required host key was nil

我试图找出其他人是否有像我一样的问题，但我却找不到。

我知道我需要在此过程中以某种方式检查knowns_hosts，但我只是想不通如何…

    var hostKey ssh.PublicKey
    // A public key may be used to authenticate against the remote
    // server by using an unencrypted PEM-encoded private key file.
    //
    // If you have an encrypted private key, the crypto/x509 package
    // can be used to decrypt it.
    key, err := ioutil.ReadFile("/home/user/.ssh/id_rsa")
    if err != nil {
        log.Fatalf("unable to read private key: %v", err)
    }

    // Create the Signer for this private key.
    signer, err := ssh.ParsePrivateKey(key)
    if err != nil {
        log.Fatalf("unable to parse private key: %v", err)
    }

    config := &ssh.ClientConfig{
        User: "user",
        Auth: []ssh.AuthMethod{
            // Use the PublicKeys method for remote authentication.
            ssh.PublicKeys(signer),
        },
        HostKeyCallback: ssh.FixedHostKey(hostKey),
    }

    // Connect to the remote server and perform the SSH handshake.
    client, err := ssh.Dial("tcp", "host.com:22", config)
    if err != nil {
        log.Fatalf("unable to connect: %v", err)
    }
    defer client.Close()
}

Answer 1

您在这里寻找的是：

func getHostKey(host string) (ssh.PublicKey, error) {
    file, err := os.Open(filepath.Join(os.Getenv("HOME"), ".ssh", "known_hosts"))
    if err != nil {
        return nil, err
    }
    defer file.Close()

    scanner := bufio.NewScanner(file)
    var hostKey ssh.PublicKey
    for scanner.Scan() {
        fields := strings.Split(scanner.Text(), " ")
        if len(fields) != 3 {
            continue
        }
        if strings.Contains(fields[0], host) {
            var err error
            hostKey, _, _, _, err = ssh.ParseAuthorizedKey(scanner.Bytes())
            if err != nil {
                return nil, errors.New(fmt.Sprintf("error parsing %q: %v", fields[2], err))
            }
            break
        }
    }

    if hostKey == nil {
        return nil, errors.New(fmt.Sprintf("no hostkey for %s", host))
    }
    return hostKey, nil
}

然后将您的hostKey定义行替换为

hostKey, err := getHostKey("host.com")
if err != nil {
    log.Fatal(err)
}

有关此主题的更多信息：

• 我从中获取部分代码的官方样本
• 为什么现在需要hostKey

编辑：还请查看Anton有关golang.org/x/crypto/ssh/knownhosts包装的以下答案。