/*

 * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.net.www.protocol.http;

import java.security.PrivilegedAction;

import java.util.Arrays;

import java.net.URL;

import java.net.URLConnection;

import java.net.ProtocolException;

import java.net.HttpRetryException;

import java.net.PasswordAuthentication;

import java.net.Authenticator;

import java.net.HttpCookie;

import java.net.InetAddress;

import java.net.UnknownHostException;

import java.net.SocketTimeoutException;

import java.net.SocketPermission;

import java.net.Proxy;

import java.net.ProxySelector;

import java.net.URI;

import java.net.InetSocketAddress;

import java.net.CookieHandler;

import java.net.ResponseCache;

import java.net.CacheResponse;

import java.net.SecureCacheResponse;

import java.net.CacheRequest;

import java.net.URLPermission;

import java.net.Authenticator.RequestorType;

import java.security.AccessController;

import java.security.PrivilegedExceptionAction;

import java.security.PrivilegedActionException;

import java.io.*;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Date;

import java.util.Map;

import java.util.List;

import java.util.Locale;

import java.util.StringTokenizer;

import java.util.Iterator;

import java.util.HashSet;

import java.util.HashMap;

import java.util.Set;

import java.util.StringJoiner;

import jdk.internal.access.JavaNetHttpCookieAccess;

import jdk.internal.access.SharedSecrets;

import sun.net.*;

import sun.net.util.IPAddressUtil;

import sun.net.www.*;

import sun.net.www.http.HttpClient;

import sun.net.www.http.PosterOutputStream;

import sun.net.www.http.ChunkedInputStream;

import sun.net.www.http.ChunkedOutputStream;

import sun.util.logging.PlatformLogger;

import java.text.SimpleDateFormat;

import java.util.TimeZone;

import java.net.MalformedURLException;

import java.nio.ByteBuffer;

import java.util.Objects;

import java.util.Properties;

import static sun.net.www.protocol.http.AuthScheme.BASIC;

import static sun.net.www.protocol.http.AuthScheme.DIGEST;

import static sun.net.www.protocol.http.AuthScheme.NTLM;

import static sun.net.www.protocol.http.AuthScheme.NEGOTIATE;

import static sun.net.www.protocol.http.AuthScheme.KERBEROS;

import static sun.net.www.protocol.http.AuthScheme.UNKNOWN;

import sun.security.action.GetIntegerAction;

import sun.security.action.GetPropertyAction;

/**

 * A class to represent an HTTP connection to a remote object.

 */

public class HttpURLConnection extends java.net.HttpURLConnection {

    static String HTTP_CONNECT = "CONNECT";

    static final String version;

    public static final String userAgent;

    /* max # of allowed re-directs */

    static final int defaultmaxRedirects = 20;

    static final int maxRedirects;

    /* Not all servers support the (Proxy)-Authentication-Info headers.

     * By default, we don't require them to be sent

     */

    static final boolean validateProxy;

    static final boolean validateServer;

    /** A, possibly empty, set of authentication schemes that are disabled

     *  when proxying plain HTTP ( not HTTPS ). */

    static final Set<String> disabledProxyingSchemes;

    /** A, possibly empty, set of authentication schemes that are disabled

     *  when setting up a tunnel for HTTPS ( HTTP CONNECT ). */

    static final Set<String> disabledTunnelingSchemes;

    private StreamingOutputStream strOutputStream;

    private static final String RETRY_MSG1 =

        "cannot retry due to proxy authentication, in streaming mode";

    private static final String RETRY_MSG2 =

        "cannot retry due to server authentication, in streaming mode";

    private static final String RETRY_MSG3 =

        "cannot retry due to redirection, in streaming mode";

    /*

     * System properties related to error stream handling:

     *

     * sun.net.http.errorstream.enableBuffering = <boolean>

     *

     * With the above system property set to true (default is false),

     * when the response code is >=400, the HTTP handler will try to

     * buffer the response body (up to a certain amount and within a

     * time limit). Thus freeing up the underlying socket connection

     * for reuse. The rationale behind this is that usually when the

     * server responds with a >=400 error (client error or server

     * error, such as 404 file not found), the server will send a

     * small response body to explain who to contact and what to do to

     * recover. With this property set to true, even if the

     * application doesn't call getErrorStream(), read the response

     * body, and then call close(), the underlying socket connection

     * can still be kept-alive and reused. The following two system

     * properties provide further control to the error stream

     * buffering behaviour.

     *

     * sun.net.http.errorstream.timeout = <int>

     *     the timeout (in millisec) waiting the error stream

     *     to be buffered; default is 300 ms

     *

     * sun.net.http.errorstream.bufferSize = <int>

     *     the size (in bytes) to use for the buffering the error stream;

     *     default is 4k

     */

    /* Should we enable buffering of error streams? */

    private static boolean enableESBuffer = false;

    /* timeout waiting for read for buffered error stream;

     */

    private static int timeout4ESBuffer = 0;

    /* buffer size for buffered error stream;

    */

    private static int bufSize4ES = 0;

    /*

     * Restrict setting of request headers through the public api

     * consistent with JavaScript XMLHttpRequest2 with a few

     * exceptions. Disallowed headers are silently ignored for

     * backwards compatibility reasons rather than throwing a

     * SecurityException. For example, some applets set the

     * Host header since old JREs did not implement HTTP 1.1.

     * Additionally, any header starting with Sec- is

     * disallowed.

     *

     * The following headers are allowed for historical reasons:

     *

     * Accept-Charset, Accept-Encoding, Cookie, Cookie2, Date,

     * Referer, TE, User-Agent, headers beginning with Proxy-.

     *

     * The following headers are allowed in a limited form:

     *

     * Connection: close

     *

     * See http://www.w3.org/TR/XMLHttpRequest2.

     */

    private static final boolean allowRestrictedHeaders;

    private static final Set<String> restrictedHeaderSet;

    private static final String[] restrictedHeaders = {

        /* Restricted by XMLHttpRequest2 */

        //"Accept-Charset",

        //"Accept-Encoding",

        "Access-Control-Request-Headers",

        "Access-Control-Request-Method",

        "Connection", /* close is allowed */

        "Content-Length",

        //"Cookie",

        //"Cookie2",

        "Content-Transfer-Encoding",

        //"Date",

        //"Expect",

        "Host",

        "Keep-Alive",

        "Origin",

        // "Referer",

        // "TE",

        "Trailer",

        "Transfer-Encoding",

        "Upgrade",

        //"User-Agent",

        "Via"

    };

    private static String getNetProperty(String name) {

        PrivilegedAction<String> pa = () -> NetProperties.get(name);

        return AccessController.doPrivileged(pa);

    }

    private static Set<String> schemesListToSet(String list) {

        if (list == null || list.isEmpty())

            return Collections.emptySet();

        Set<String> s = new HashSet<>();

        String[] parts = list.split("\\s*,\\s*");

        for (String part : parts)

            s.add(part.toLowerCase(Locale.ROOT));

        return s;

    }

    static {

        Properties props = GetPropertyAction.privilegedGetProperties();

        maxRedirects = GetIntegerAction.privilegedGetProperty(

                "http.maxRedirects", defaultmaxRedirects);

        version = props.getProperty("java.version");

        String agent = props.getProperty("http.agent");

        if (agent == null) {

            agent = "Java/"+version;

        } else {

            agent = agent + " Java/"+version;

        }

        userAgent = agent;

        // A set of net properties to control the use of authentication schemes

        // when proxying/tunneling.

        String p = getNetProperty("jdk.http.auth.tunneling.disabledSchemes");

        disabledTunnelingSchemes = schemesListToSet(p);

        p = getNetProperty("jdk.http.auth.proxying.disabledSchemes");

        disabledProxyingSchemes = schemesListToSet(p);

        validateProxy = Boolean.parseBoolean(

                props.getProperty("http.auth.digest.validateProxy"));

        validateServer = Boolean.parseBoolean(

                props.getProperty("http.auth.digest.validateServer"));

        enableESBuffer = Boolean.parseBoolean(

                props.getProperty("sun.net.http.errorstream.enableBuffering"));

        timeout4ESBuffer = GetIntegerAction.privilegedGetProperty(

                "sun.net.http.errorstream.timeout", 300);

        if (timeout4ESBuffer <= 0) {

            timeout4ESBuffer = 300; // use the default

        }

        bufSize4ES = GetIntegerAction.privilegedGetProperty(

                "sun.net.http.errorstream.bufferSize", 4096);

        if (bufSize4ES <= 0) {

            bufSize4ES = 4096; // use the default

        }

        allowRestrictedHeaders = Boolean.parseBoolean(

                props.getProperty("sun.net.http.allowRestrictedHeaders"));

        if (!allowRestrictedHeaders) {

            restrictedHeaderSet = new HashSet<>(restrictedHeaders.length);

            for (int i=0; i < restrictedHeaders.length; i++) {

                restrictedHeaderSet.add(restrictedHeaders[i].toLowerCase());

            }

        } else {

            restrictedHeaderSet = null;

        }

    }

    static final String httpVersion = "HTTP/1.1";

    static final String acceptString =

        "text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2";

    // the following http request headers should NOT have their values

    // returned for security reasons.

    private static final String[] EXCLUDE_HEADERS = {

            "Proxy-Authorization",

            "Authorization"

    };

    // also exclude system cookies when any might be set

    private static final String[] EXCLUDE_HEADERS2= {

            "Proxy-Authorization",

            "Authorization",

            "Cookie",

            "Cookie2"

    };

    protected HttpClient http;

    protected Handler handler;

    protected Proxy instProxy;

    protected volatile Authenticator authenticator;

    protected volatile String authenticatorKey;

    private CookieHandler cookieHandler;

    private final ResponseCache cacheHandler;

    // the cached response, and cached response headers and body

    protected CacheResponse cachedResponse;

    private MessageHeader cachedHeaders;

    private InputStream cachedInputStream;

    /* output stream to server */

    protected PrintStream ps = null;

    /* buffered error stream */

    private InputStream errorStream = null;

    /* User set Cookies */

    private boolean setUserCookies = true;

    private String userCookies = null;

    private String userCookies2 = null;

    /* We only have a single static authenticator for now.

     * REMIND:  backwards compatibility with JDK 1.1.  Should be

     * eliminated for JDK 2.0.

     */

    @Deprecated

    private static HttpAuthenticator defaultAuth;

    /* all the headers we send

     * NOTE: do *NOT* dump out the content of 'requests' in the

     * output or stacktrace since it may contain security-sensitive

     * headers such as those defined in EXCLUDE_HEADERS.

     */

    private MessageHeader requests;

    /* The headers actually set by the user are recorded here also

     */

    private MessageHeader userHeaders;

    /* Headers and request method cannot be changed

     * once this flag is set in :-

     *     - getOutputStream()

     *     - getInputStream())

     *     - connect()

     * Access synchronized on this.

     */

    private boolean connecting = false;

    /* The following two fields are only used with Digest Authentication */

    String domain;      /* The list of authentication domains */

    DigestAuthentication.Parameters digestparams;

    /* Current credentials in use */

    AuthenticationInfo  currentProxyCredentials = null;

    AuthenticationInfo  currentServerCredentials = null;

    boolean             needToCheck = true;

    private boolean doingNTLM2ndStage = false; /* doing the 2nd stage of an NTLM server authentication */

    private boolean doingNTLMp2ndStage = false; /* doing the 2nd stage of an NTLM proxy authentication */

    /* try auth without calling Authenticator. Used for transparent NTLM authentication */

    private boolean tryTransparentNTLMServer = true;

    private boolean tryTransparentNTLMProxy = true;

    private boolean useProxyResponseCode = false;

    /* Used by Windows specific code */

    private Object authObj;

    /* Set if the user is manually setting the Authorization or Proxy-Authorization headers */

    boolean isUserServerAuth;

    boolean isUserProxyAuth;

    String serverAuthKey, proxyAuthKey;

    /* Progress source */

    protected ProgressSource pi;

    /* all the response headers we get back */

    private MessageHeader responses;

    /* the stream _from_ the server */

    private InputStream inputStream = null;

    /* post stream _to_ the server, if any */

    private PosterOutputStream poster = null;

    /* Indicates if the std. request headers have been set in requests. */

    private boolean setRequests=false;

    /* Indicates whether a request has already failed or not */

    private boolean failedOnce=false;

    /* Remembered Exception, we will throw it again if somebody

       calls getInputStream after disconnect */

    private Exception rememberedException = null;

    /* If we decide we want to reuse a client, we put it here */

    private HttpClient reuseClient = null;

    /* Tunnel states */

    public enum TunnelState {

        /* No tunnel */

        NONE,

        /* Setting up a tunnel */

        SETUP,

        /* Tunnel has been successfully setup */

        TUNNELING

    }

    private TunnelState tunnelState = TunnelState.NONE;

    /* Redefine timeouts from java.net.URLConnection as we need -1 to mean

     * not set. This is to ensure backward compatibility.

     */

    private int connectTimeout = NetworkClient.DEFAULT_CONNECT_TIMEOUT;

    private int readTimeout = NetworkClient.DEFAULT_READ_TIMEOUT;

    /* A permission converted from a URLPermission */

    private SocketPermission socketPermission;

    /* Logging support */

    private static final PlatformLogger logger =

            PlatformLogger.getLogger("sun.net.www.protocol.http.HttpURLConnection");

    /*

     * privileged request password authentication

     *

     */

    private static PasswordAuthentication

    privilegedRequestPasswordAuthentication(

                            final Authenticator authenticator,

                            final String host,

                            final InetAddress addr,

                            final int port,

                            final String protocol,

                            final String prompt,

                            final String scheme,

                            final URL url,

                            final RequestorType authType) {

        return java.security.AccessController.doPrivileged(

            new java.security.PrivilegedAction<>() {

                public PasswordAuthentication run() {

                    if (logger.isLoggable(PlatformLogger.Level.FINEST)) {

                        logger.finest("Requesting Authentication: host =" + host + " url = " + url);

                    }

                    PasswordAuthentication pass = Authenticator.requestPasswordAuthentication(

                        authenticator, host, addr, port, protocol,

                        prompt, scheme, url, authType);

                    if (logger.isLoggable(PlatformLogger.Level.FINEST)) {

                        logger.finest("Authentication returned: " + (pass != null ? pass.toString() : "null"));

                    }

                    return pass;

                }

            });

    }

    private boolean isRestrictedHeader(String key, String value) {

        if (allowRestrictedHeaders) {

            return false;

        }

        key = key.toLowerCase();

        if (restrictedHeaderSet.contains(key)) {

            /*

             * Exceptions to restricted headers:

             *

             * Allow "Connection: close".

             */

            if (key.equals("connection") && value.equalsIgnoreCase("close")) {

                return false;

            }

            return true;

        } else if (key.startsWith("sec-")) {

            return true;

        }

        return false;

    }

    /*

     * Checks the validity of http message header and whether the header

     * is restricted and throws IllegalArgumentException if invalid or

     * restricted.

     */

    private boolean isExternalMessageHeaderAllowed(String key, String value) {

        checkMessageHeader(key, value);

        if (!isRestrictedHeader(key, value)) {

            return true;

        }

        return false;

    }

    /* Logging support */

    public static PlatformLogger getHttpLogger() {

        return logger;

    }