使用 JSch SFTP 库时如何解析 Java UnknownHostKey? [英] How to resolve Java UnknownHostKey, while using JSch SFTP library?

问题描述

我正在运行一个 Java 程序，我使用 Java SFTP 将文件从一个文件夹传输到另一个文件夹.我遇到的问题是我的 Java SFTP(使用 JSch)中出现以下错误:

<块引用>

C:OracleMiddlewareOracle_Homeoracle_commonjdkinjavaw.exe-server -classpath C:JDevelopermyworkJava_Hello_World.adf;C:JDevelopermyworkJava_Hello_WorldClientclasses;C:UsersADMINDownloadsjsch-0.1.53.jar-Djavax.net.ssl.trustStore=C:UsersIBM_AD~1AppDataLocalTemp rustStore5840796204189742395.jksFileTransfer com.jcraft.jsch.JSchException:UnknownHostKey:127.0.0.1.RSA 密钥指纹为 a2:39:3f:44:88:e9:1f:d7:d1:71:f4:85:98:fb:90:dc在 com.jcraft.jsch.Session.checkHost(Session.java:797) 在com.jcraft.jsch.Session.connect(Session.java:342) 在com.jcraft.jsch.Session.connect(Session.java:183) 在FileTransfer.main(FileTransfer.java:33) 进程以退出代码退出0.

以下是我目前的代码:

FileTransfer fileTransfer = new FileTransfer();JSch jsch = new JSch();尝试 {字符串主机 = "127.0.0.1";内部端口 = 22;字符串用户 = "用户";Session session = jsch.getSession(user, host, port);session = jsch.getSession("用户名", "127.0.0.1", 22);会话连接()；//这里的错误，java.net.ConnectExceptionChannelSftp sftp = null;sftp = (ChannelSftp)session.openChannel("sftp") ;//渠道;//额外的配置代码java.util.Properties config = new java.util.Properties();config.put("StrictHostKeyChecking", "no");session.setConfig(config);//结束额外的配置代码sftp.rename("C:\Users\ADMIN\Desktop\Work\ConnectOne_Bancorp\Java_Work\SFTP_1\house.bmp", "C:\Users\ADMIN\Desktop\Work\ConnectOne_Bancorp\Java_Work\SFTP_2\house.bmp");session.disconnect();} catch (JSchException e) {e.printStackTrace();} catch (SftpException e) {e.printStackTrace();}//收尾

我的 Cygwin 已设置，我检查(使用 netstat -a -b )它正在运行.

解决方案

您试图通过将 StrictHostKeyChecking 设置为 no 来跳过主机密钥检查.

但是你必须在检查之前这样做，即在 session.connect() 之前.

<小时>

无论如何，你永远不应该这样做，除非你不关心安全.主机密钥检查旨在保护您免受中间人攻击.

相反，设置一个预期的主机密钥让 JSch 验证它.

例如:

• 调用JSch.setKnownHosts 提供了一个类似 .ssh/known_hosts 的文件的路径.

  要生成类似 .ssh/known_hosts 的文件，您可以使用来自 OpenSSH 的 ssh-keyscan 命令.如果你从 *nix 服务器连接，你应该有可用的命令，只需运行

  ssh-keyscan example.com >已知主机

  它将具有如下格式:

  <预> <代码> example.com SSH-RSA AAAAB3NzaC1yc2EAAAABIwAAAQEA0hVqZOvZ7yWgie9OHdTORJVI5fJJoH1yEGamAd5G3werH0z7e9ybtq1mGUeRkJtea7bzru0ISR0EZ9HIONoGYrDmI7S + BiwpDBUKjva4mAsvzzvsy6Ogy/apkxm6Kbcml8u4wjxaOw3NKzKqeBvR3pc + nQVA + SJUZq8D2XBRd4EDUFXeLzwqwen9G7gSLGB1hJkSuRtGRfOHbLUuCKNR8RV82i3JvlSnAwb3MwN0m3WGdlJA8J + 5YAg4e6JgSKrsCObZK7W1R6iuyuH1zA + dtAHyDyYVHB4FnYZPL0hgz2PSb9c + iDEiFcT/LT4/dQ的+ kRW6DYn66lS8peS8zCJ9CSQ ==

  并在您的 JSch 代码中引用生成的 known_hosts 文件.

  如果您使用的是 Windows，则可以从 ssh-keyscan 的 Windows 版本"noreferrer">Win32-OpenSSH 项目 或适用于 Windows 的 Git.

• 调用 JSch.getHostKeyRepository().add() 以提供预期的主机密钥(例如，硬编码，作为您的其他凭据).

  请参阅从 .pub 格式的公钥创建 JSch HostKey 实例.

I'm running a java program where I transfer a file from one folder to another, using Java SFTP. The problem I'm having is that I'm getting the following error in my Java SFTP (using JSch) :

C:OracleMiddlewareOracle_Homeoracle_commonjdkinjavaw.exe -server -classpath C:JDevelopermyworkJava_Hello_World.adf;C:JDevelopermyworkJava_Hello_WorldClientclasses;C:UsersADMINDownloadsjsch-0.1.53.jar -Djavax.net.ssl.trustStore=C:UsersIBM_AD~1AppDataLocalTemp rustStore5840796204189742395.jks FileTransfer com.jcraft.jsch.JSchException: UnknownHostKey: 127.0.0.1. RSA key fingerprint is a2:39:3f:44:88:e9:1f:d7:d1:71:f4:85:98:fb:90:dc at com.jcraft.jsch.Session.checkHost(Session.java:797) at com.jcraft.jsch.Session.connect(Session.java:342) at com.jcraft.jsch.Session.connect(Session.java:183) at FileTransfer.main(FileTransfer.java:33) Process exited with exit code 0.

The following is my code so far:

FileTransfer fileTransfer = new FileTransfer();              

JSch jsch = new JSch();

try {

    String host = "127.0.0.1";
    int port = 22;

    String user = "user";
    Session session = jsch.getSession(user, host, port);      
    session = jsch.getSession("username", "127.0.0.1", 22);
    session.connect();  // bug here , java.net.ConnectException

    ChannelSftp sftp = null;
    sftp = (ChannelSftp)session.openChannel("sftp") ; //channel;

    //extra config code
    java.util.Properties config = new java.util.Properties(); 
    config.put("StrictHostKeyChecking", "no");
    session.setConfig(config);
    // end extra config code

    sftp.rename("C:\Users\ADMIN\Desktop\Work\ConnectOne_Bancorp\Java_Work\SFTP_1\house.bmp", "C:\Users\ADMIN\Desktop\Work\ConnectOne_Bancorp\Java_Work\SFTP_2\house.bmp");  
    session.disconnect();

} catch (JSchException e) {
    e.printStackTrace();  
} catch (SftpException e) {
    e.printStackTrace();
} //end-catch

My Cygwin is set up, and I checked (with netstat -a -b ) that it's running.

解决方案

You are trying to skip a host key checking by setting StrictHostKeyChecking to no.

But you have to do that before the checking, i.e. before the session.connect().

---

Anyway, you should never do this, unless you do not care about security. The host key checking is there to protect you from man-in-the-middle attacks.

Instead, set up an expected host key to let JSch verify it.

For example:

• Call JSch.setKnownHosts providing a path to a .ssh/known_hosts-like file.

  To generate the .ssh/known_hosts-like file, you can use an ssh-keyscan command from OpenSSH. If you are connecting from a *nix server, you should have the command available, just run

  ssh-keyscan example.com > known_hosts
  

  It will have a format like:

  example.com ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0hVqZOvZ7yWgie9OHdTORJVI5fJJoH1yEGamAd5G3werH0z7e9ybtq1mGUeRkJtea7bzru0ISR0EZ9HIONoGYrDmI7S+BiwpDBUKjva4mAsvzzvsy6Ogy/apkxm6Kbcml8u4wjxaOw3NKzKqeBvR3pc+nQVA+SJUZq8D2XBRd4EDUFXeLzwqwen9G7gSLGB1hJkSuRtGRfOHbLUuCKNR8RV82i3JvlSnAwb3MwN0m3WGdlJA8J+5YAg4e6JgSKrsCObZK7W1R6iuyuH1zA+dtAHyDyYVHB4FnYZPL0hgz2PSb9c+iDEiFcT/lT4/dQ+kRW6DYn66lS8peS8zCJ9CSQ==
  

  And reference the generated known_hosts file in your JSch code.

  If you are on Windows, you can get a Windows build of ssh-keyscan from Win32-OpenSSH project or Git for Windows.

• Call JSch.getHostKeyRepository().add() to provide the expected host key (e.g. hard-coded, as your other credentials).

  See Creating JSch HostKey instance from a public key in .pub format.

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