java - 使用 JKS keystore 通过 Ganymed SSH 进行公钥身份验证

Question

我正在尝试从 Java keystore 中提取私钥，然后将其提供给 Ganymed SSH 以建立与公钥身份验证的连接。但是它拒绝连接。

我可以通过 Cygwin (ssh -i) 成功连接以下程序生成的文件，但程序本身无法在同一台机器上通过身份验证。我究竟做错了什么？

我没有得到异常，Connection.authenticateWithPublicKey(String, char[], String)只是返回 false，所以这不应该是格式问题。如果我不加密私钥也没关系，结果是一样的。此外，我还能够通过 putty-gen 和 ssh-keygen 生成的文件连接到与此类似的程序。

您将需要以下内容进行编译(bouncycaSTLe 和 ganymed):

• bcprov
• bcpkix
• ganymed-ssh2

生成 keystore :

keytool -genkeypair -keystore keystore.jks -alias myalias -storepass password -keypass password -keyalg RSA -dname CN=myalias,O=example.com -storetype JKS -validity 365 -v

代码(期望主机和端口作为参数以及工作目录中的上述 keystore ):

import ch.ethz.ssh2.Connection;
import java.io.ByteArrayOutputStream;
import java.io.CharArrayWriter;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.security.GeneralSecurityException;
import java.security.Key;
import java.security.KeyStore;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.cert.Certificate;
import java.security.interfaces.DSAParams;
import java.security.interfaces.DSAPublicKey;
import java.security.interfaces.RSAPublicKey;
import javax.xml.bind.DatatypeConverter;
import org.bouncycastle.openssl.PEMEncryptor;
import org.bouncycastle.openssl.jcajce.JcaPEMWriter;
import org.bouncycastle.openssl.jcajce.JcePEMEncryptorBuilder;

public class KeystoreGanymedSSH {

    public static void main(String[] args)
            throws Exception {
        String keystorePath = "keystore.jks";
        char[] password = "password".toCharArray();
        String alias = "myalias";

        String host = args[0];
        int port = Integer.parseInt(args[1]);

        // keystore init
        KeyStore keystore = KeyStore.getInstance("JKS");
        InputStream in;
        try {
            in = new FileInputStream(keystorePath);
        } catch (FileNotFoundException ex) {
            System.out.println("Generate keystore using this command:");
            System.out.println("keytool -genkeypair -keystore keystore.jks"
                    + " -alias myalias -storepass password -keypass password"
                    + " -keyalg RSA -dname CN=myalias,O=example.com -storetype"
                    + " JKS -validity 365 -v");
            throw ex;
        }
        try {
            keystore.load(in, password);
        } finally {
            in.close();
        }

        // get public key in OpenSSH format
        String authorizedKeysEntry = genAuthorizedKeysEntry(keystore, alias);
        if (authorizedKeysEntry == null) {
            throw new Exception("could not generate authorized_keys entry");
        }
        System.out.println("Public key for pasting into OpenSSH authorized_keys file (always same):");
        System.out.println(authorizedKeysEntry);
        System.out.println();

        Writer writer;

        // write to file
        writer = new OutputStreamWriter(
                new FileOutputStream(new File("authorized_keys")), "UTF-8");
        try {
            writer.write(authorizedKeysEntry);
        } finally {
            writer.close();
        }

        // obtain PEM encrypted char[]
        Key key = keystore.getKey(alias, password);
        writer = new CharArrayWriter();
        JcaPEMWriter pw = new JcaPEMWriter(writer);
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
        PEMEncryptor encryptor = new JcePEMEncryptorBuilder("DES-EDE3-CBC")
                .setSecureRandom(random).build(password);
        pw.writeObject(key, encryptor);
        pw.flush();
        char[] privateKey = ((CharArrayWriter)writer).toCharArray();

        System.out.println("Encrypted private key (changes on each run):");
        System.out.println(new String(privateKey));
        String name = "RSA".equals(key.getAlgorithm()) ? "id_rsa" : "id_dsa";
        writer = new OutputStreamWriter(
                new FileOutputStream(new File(name)), "UTF-8");
        try {
            writer.write(privateKey);
        } finally {
            writer.close();
        }

        // attempt ganymed connection   
        Connection connection = null;
        try {
            System.out.println("Connecting to " + host + ":" + port);
            connection = new Connection(host, port);        
            connection.connect(); // no known_hosts

            if (!connection.isAuthMethodAvailable(alias, "publickey")) {
                System.out.println("Public key auth is not available.");
                return;
            }

            boolean result = connection.authenticateWithPublicKey(
                    alias, privateKey, new String(password));

            System.out.println(result ? "Authentication success." : "Authentication failure.");
        } finally {
            if (connection != null) {
                connection.close();
            }
        }

    }

    private static String genAuthorizedKeysEntry(
            KeyStore keystore, String alias) throws GeneralSecurityException, IOException {
        Certificate[] chain = keystore.getCertificateChain(alias);
        if (chain == null || chain.length <= 0) {
            return null;
        }
        PublicKey publicKey = chain[0].getPublicKey();
        if ("RSA".equals(publicKey.getAlgorithm())) {
            RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            DataOutputStream dos = new DataOutputStream(baos);
            String type = "ssh-rsa";
            dos.writeInt(type.getBytes("UTF-8").length);
            dos.write(type.getBytes("UTF-8"));
            byte[] exponent = rsaPublicKey.getPublicExponent().toByteArray();
            dos.writeInt(exponent.length);
            dos.write(exponent);
            byte[] modulus = rsaPublicKey.getModulus().toByteArray();
            dos.writeInt(modulus.length);
            dos.write(modulus);
            String encoded = DatatypeConverter.printBase64Binary(
                    baos.toByteArray());
            return type + " " + encoded + " " + alias;
        } else if ("DSA".equals(publicKey.getAlgorithm())) {
            DSAPublicKey dsaPublicKey = (DSAPublicKey) publicKey;
            DSAParams params = dsaPublicKey.getParams();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            DataOutputStream dos = new DataOutputStream(baos);
            String type = "ssh-dss";
            dos.writeInt(type.getBytes("UTF-8").length);
            dos.write(type.getBytes("UTF-8"));
            byte[] p = params.getP().toByteArray();
            dos.writeInt(p.length);
            dos.write(p);
            byte[] q = params.getQ().toByteArray();
            dos.writeInt(q.length);
            dos.write(q);
            byte[] g = params.getG().toByteArray();
            dos.writeInt(g.length);
            dos.write(g);
            byte[] y = dsaPublicKey.getY().toByteArray();
            dos.writeInt(y.length);
            dos.write(y);
            String encoded = DatatypeConverter.printBase64Binary(
                    baos.toByteArray());
            return type + " " + encoded + " " + alias;
        } else {
            return null;
        }
    }
}

示例输出:

Public key for pasting into OpenSSH authorized_keys file (always same):
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCJLXgRaVdbZNuCsTgUsw2UPGdEA4La8ggQZWkevgAEMrgF+YYT2uN6BYDgD7hzs3ZTLXz2KUQLkMe7xLvimAsg6YXUi46IGEkTSOBFR0yYj+12O2BNbAxOXLIDIMBK5bsDwnuOsFedbeILFU4DaV+igJKO1zHWNbmbmd4RlfrIgH7Blfce8zSVkEdLkqEmydbg4xmj6r+MlzA5HSNZJILivb1XYNnoLjRH1SwUC8Rj6bjgBdNEXLOH0FNpCatHk9R00GaSZjcDZRKNAKnBSEIpw01TKaJlyQUTGqYGjK7UIbbafwMuYKR1rIzkyh4Usxvd3FvMdmKQSUeCnZU296YF myalias

Encrypted private key (changes on each run):
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,86DF7B50D4E319F6
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-----END RSA PRIVATE KEY-----

Connecting to 10.0.3.138:22
Authentication failure.

Edit01

我已经用 jsch 试过了和 sshj并且所有这些都无法连接。上面提取私钥的代码一定有问题。令我困惑的是我可以使用 ssh -i 进行连接。此外，如果我将上述私钥加载到 putty-gen 中，我将获得与程序输出中相同的 authorized_keys 字符串(已存在于远程计算机的 .ssh/authorized_keys 中)。但是，如果我将它保存为一个 ppk 文件，然后尝试与它建立一个 putty session ，它也不会通过(服务器拒绝了我们的 key )。

Answer 1

我发布的代码没有任何错误。这只是我的一个巨大失败。

我使用 keystore 别名作为用户名，在远程 linux 机器上作为用户帐户不存在。创建帐户后，一切正常。我正在编辑错误的 authorized_keys 文件(在其他帐户上)并期望它能够通过一些只有妖精、 unicorn 和显然是我的大脑才知道的晦涩黑魔法起作用。

至于为什么它在我执行 ssh -i 时有效... 默认值。愚蠢的默认值。我根本没有指定用户名，所以它默认为 Cygwin 当前正在使用的用户名，而且碰巧它与我正在编辑 authorized_keys 文件的远程帐户具有相同的名称。

太棒了。惊人的。刚刚好。我需要去找一座桥，让自己从现在开始跳下去。

我在代码中所做的工作适用于 ganymed、jsch 和 sshj(对其他两个 API 进行了一些小的修改)。