如何以编程方式将证书添加到信任库并将其用于验证服务器身份验证

Question

在我的应用程序中，我想使用 https 连接到用户指定的服务器，该服务器使用自签名证书。我现在收集到的是，

• 自签名证书被拒绝（如预期），
• android密钥库/信任库不用于应用程序，因此应用程序必须构建和使用自己的信任库，
• JDK中有一个“keytool”来构建一个可以作为资源提供给应用程序的信任库，但这不是解决方案，因为我事先不知道服务器（及其证书），

因为 https 服务器是用户指定的，所以我事先不知道服务器的证书，因此想要以编程方式将服务器证书添加到应用程序的信任库（通过向用户显示证书并让他接受它）。添加到信任库后，应用程序应使用该信任库对服务器进行身份验证。

我不想简单地接受每个自签名证书，而不需要用户检查指纹，正如网络上的一些示例所建议的那样。

现在的问题是我对 Java 和 Android 完全陌生，并且正在努力理解 AndroidHttpClient 或 DefaultHttpClient 的内部工作原理。我的应用程序中有基本的 HTTP 工作，但没有找到任何关于如何根据用户的需求将证书实际添加到应用程序内的信任库的示例。

有人知道如何实现这一目标，或者知道我可以看的工作示例吗？

任何提示表示赞赏。谢谢。

编辑：在 K9 Mail 的 TrustManagerFactory.java 类。如果您有同样的问题，我建议您看一下。

Answer 1

解决方案是不久前找到的，但还没有人创建答案来帮助指导其他人，所以今天早上我将成为点皮条客（ette）并发布作为解决方案添加的 URL，并从公共源复制代码。希望这有助于指导其他人找到解决方案。 :)

---

这是 URL 下面的代码。

package com.fsck.k9.mail.store;

import android.app.Application;
import android.content.Context;
import android.util.Log;
import com.fsck.k9.K9;
import com.fsck.k9.helper.DomainNameChecker;
import org.apache.commons.io.IOUtils;

import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.HashMap;
import java.util.Map;

public final class TrustManagerFactory {
    private static final String LOG_TAG = "TrustManagerFactory";

    private static X509TrustManager defaultTrustManager;
    private static X509TrustManager unsecureTrustManager;
    private static X509TrustManager localTrustManager;

    private static X509Certificate[] lastCertChain = null;

    private static File keyStoreFile;
    private static KeyStore keyStore;


    private static class SimpleX509TrustManager implements X509TrustManager {
        public void checkClientTrusted(X509Certificate[] chain, String authType)
        throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType)
        throws CertificateException {
        }

        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }

    private static class SecureX509TrustManager implements X509TrustManager {
        private static final Map<String, SecureX509TrustManager> mTrustManager =
            new HashMap<String, SecureX509TrustManager>();

        private final String mHost;

        private SecureX509TrustManager(String host) {
            mHost = host;
        }

        public synchronized static X509TrustManager getInstance(String host) {
            SecureX509TrustManager trustManager;
            if (mTrustManager.containsKey(host)) {
                trustManager = mTrustManager.get(host);
            } else {
                trustManager = new SecureX509TrustManager(host);
                mTrustManager.put(host, trustManager);
            }

            return trustManager;
        }

        public void checkClientTrusted(X509Certificate[] chain, String authType)
        throws CertificateException {
            defaultTrustManager.checkClientTrusted(chain, authType);
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType)
        throws CertificateException {
            // FIXME: Using a static field to store the certificate chain is a bad idea. Instead
            // create a CertificateException subclass and store the chain there.
            TrustManagerFactory.setLastCertChain(chain);
            try {
                defaultTrustManager.checkServerTrusted(chain, authType);
            } catch (CertificateException e) {
                localTrustManager.checkServerTrusted(new X509Certificate[] {chain[0]}, authType);
            }
            if (!DomainNameChecker.match(chain[0], mHost)) {
                try {
                    String dn = chain[0].getSubjectDN().toString();
                    if ((dn != null) && (dn.equalsIgnoreCase(keyStore.getCertificateAlias(chain[0])))) {
                        return;
                    }
                } catch (KeyStoreException e) {
                    throw new CertificateException("Certificate cannot be verified; KeyStore Exception: " + e);
                }
                throw new CertificateException("Certificate domain name does not match "
                                               + mHost);
            }
        }

        public X509Certificate[] getAcceptedIssuers() {
            return defaultTrustManager.getAcceptedIssuers();
        }

    }

    static {
        java.io.InputStream fis = null;
        try {
            javax.net.ssl.TrustManagerFactory tmf = javax.net.ssl.TrustManagerFactory.getInstance("X509");
            Application app = K9.app;
            keyStoreFile = new File(app.getDir("KeyStore", Context.MODE_PRIVATE) + File.separator + "KeyStore.bks");
            keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            try {
                fis = new java.io.FileInputStream(keyStoreFile);
            } catch (FileNotFoundException e1) {
                fis = null;
            }
            try {
                keyStore.load(fis, "".toCharArray());
            } catch (IOException e) {
                Log.e(LOG_TAG, "KeyStore IOException while initializing TrustManagerFactory ", e);
                keyStore = null;
            } catch (CertificateException e) {
                Log.e(LOG_TAG, "KeyStore CertificateException while initializing TrustManagerFactory ", e);
                keyStore = null;
            }
            tmf.init(keyStore);
            TrustManager[] tms = tmf.getTrustManagers();
            if (tms != null) {
                for (TrustManager tm : tms) {
                    if (tm instanceof X509TrustManager) {
                        localTrustManager = (X509TrustManager)tm;
                        break;
                    }
                }
            }
            tmf = javax.net.ssl.TrustManagerFactory.getInstance("X509");
            tmf.init((KeyStore)null);
            tms = tmf.getTrustManagers();
            if (tms != null) {
                for (TrustManager tm : tms) {
                    if (tm instanceof X509TrustManager) {
                        defaultTrustManager = (X509TrustManager) tm;
                        break;
                    }
                }
            }

        } catch (NoSuchAlgorithmException e) {
            Log.e(LOG_TAG, "Unable to get X509 Trust Manager ", e);
        } catch (KeyStoreException e) {
            Log.e(LOG_TAG, "Key Store exception while initializing TrustManagerFactory ", e);
        } finally {
            IOUtils.closeQuietly(fis);
        }
        unsecureTrustManager = new SimpleX509TrustManager();
    }

    private TrustManagerFactory() {
    }

    public static X509TrustManager get(String host, boolean secure) {
        return secure ? SecureX509TrustManager.getInstance(host) :
               unsecureTrustManager;
    }

    public static KeyStore getKeyStore() {
        return keyStore;
    }

    public static void setLastCertChain(X509Certificate[] chain) {
        lastCertChain = chain;
    }
    public static X509Certificate[] getLastCertChain() {
        return lastCertChain;
    }

    public static void addCertificateChain(String alias, X509Certificate[] chain) throws CertificateException {
        try {
            javax.net.ssl.TrustManagerFactory tmf = javax.net.ssl.TrustManagerFactory.getInstance("X509");
            for (X509Certificate element : chain) {
                keyStore.setCertificateEntry
                (element.getSubjectDN().toString(), element);
            }

            tmf.init(keyStore);
            TrustManager[] tms = tmf.getTrustManagers();
            if (tms != null) {
                for (TrustManager tm : tms) {
                    if (tm instanceof X509TrustManager) {
                        localTrustManager = (X509TrustManager) tm;
                        break;
                    }
                }
            }
            java.io.OutputStream keyStoreStream = null;
            try {
                keyStoreStream = new java.io.FileOutputStream(keyStoreFile);
                keyStore.store(keyStoreStream, "".toCharArray());
            } catch (FileNotFoundException e) {
                throw new CertificateException("Unable to write KeyStore: " + e.getMessage());
            } catch (CertificateException e) {
                throw new CertificateException("Unable to write KeyStore: " + e.getMessage());
            } catch (IOException e) {
                throw new CertificateException("Unable to write KeyStore: " + e.getMessage());
            } finally {
                IOUtils.closeQuietly(keyStoreStream);
            }

        } catch (NoSuchAlgorithmException e) {
            Log.e(LOG_TAG, "Unable to get X509 Trust Manager ", e);
        } catch (KeyStoreException e) {
            Log.e(LOG_TAG, "Key Store exception while initializing TrustManagerFactory ", e);
        }
    }
}

Answer 2

您可以使用自签名证书。要使用自签名证书，您可以将其转换为 Android 支持的充气城堡格式密钥库，然后将其作为原始资源存储在 Android 应用程序项目中。如何转换和使用它，所有详细信息可以在Bob的博客上找到。这是相同的链接 - http://blog.crazybob .org/2010/02/android-trusting-ssl-certificates.html。这非常有效。希望这有帮助