php - 从PHP阅读登录前ssh横幅

Question

我正在尝试使用libssh2-php库函数从PHP连接到ssh服务器。太好了，但是我不知道如何在PHP中读取登录前的旗帜。 “登录前”横幅是在SSH提示登录之前显示的文本，据我所知我无法从连接对象获取流。

因此，鉴于此代码，是否有任何方法可以在登录之前进行读取？

<?php
if (!function_exists("ssh2_connect")) die("function ssh2_connect doesn't exist");
      // log in at server1.example.com on port 22 
if(!($con = ssh2_connect("server1.example.com", 22))){
  echo "fail: unable to establish connection\n";
} else {

 //####### Would really like to get a stream right here to read pre-login banner

// try to authenticate with username root, password secretpassword
if(!ssh2_auth_password($con, "root", "secretpassword")) {
    echo "fail: unable to authenticate\n";
} else {
    // allright, we're in!
    echo "okay: logged in...\n";

    // execute a command
    if (!($stream = ssh2_exec($con, "ls -al" ))) {
        echo "fail: unable to execute command\n";
    } else {
        // collect returning data from command
        stream_set_blocking($stream, true);
        $data = "";
        while ($buf = fread($stream,4096)) {
            $data .= $buf;
        }
        fclose($stream);
    }
 }
}
?>

Answer 1

您可以使用phpseclib, a pure PHP SSH implementation做到这一点。标语应通过执行$ssh->getLastError()(返回字符串)或$ssh->getErrors()(返回字符串数组)来获得。

引用其来源:

// see http://tools.ietf.org/html/rfc4252#section-5.4; only called when the encryption has been activated and when we haven't already logged in
if (($this->bitmap & NET_SSH2_MASK_CONSTRUCTOR) && !($this->bitmap & NET_SSH2_MASK_LOGIN) && ord($payload[0]) == NET_SSH2_MSG_USERAUTH_BANNER) {
    $this->_string_shift($payload, 1);
    extract(unpack('Nlength', $this->_string_shift($payload, 4)));
    $this->errors[] = 'SSH_MSG_USERAUTH_BANNER: ' . utf8_decode($this->_string_shift($payload, $length));
    $payload = $this->_get_binary_packet();
}