1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.hc.client5.http.protocol;
29
30 import org.apache.hc.core5.annotation.Contract;
31 import org.apache.hc.core5.annotation.ThreadingBehavior;
32 import org.apache.hc.core5.http.EntityDetails;
33 import org.apache.hc.core5.http.FormattedHeader;
34 import org.apache.hc.core5.http.Header;
35 import org.apache.hc.core5.http.HttpResponse;
36 import org.apache.hc.core5.http.HttpResponseInterceptor;
37 import org.apache.hc.core5.http.message.ParserCursor;
38 import org.apache.hc.core5.http.protocol.HttpContext;
39 import org.apache.hc.core5.util.Args;
40 import org.apache.hc.core5.util.CharArrayBuffer;
41 import org.apache.hc.core5.util.TextUtils;
42 import org.apache.hc.core5.util.Tokenizer;
43
44 /**
45 * {@code NextNonceInterceptor} is an HTTP response interceptor that extracts the {@code nextnonce}
46 * parameter from the {@code Authentication-Info} header of an HTTP response. This parameter is used
47 * in HTTP Digest Access Authentication to provide an additional nonce value that the client is expected
48 * to use in subsequent authentication requests. By retrieving and storing this {@code nextnonce} value,
49 * the interceptor facilitates one-time nonce implementations and prevents replay attacks by ensuring that
50 * each request/response interaction includes a fresh nonce.
51 * <p>
52 * If present, the extracted {@code nextnonce} value is stored in the {@link HttpContext} under the attribute
53 * {@code auth-nextnonce}, allowing it to be accessed in subsequent requests. If the header does not contain
54 * the {@code nextnonce} parameter, no context attribute is set.
55 * </p>
56 *
57 * <p>This implementation adheres to the HTTP/1.1 specification, particularly focusing on the {@code Digest}
58 * scheme as defined in HTTP Digest Authentication, and parses header tokens using the {@link Tokenizer}
59 * utility class for robust token parsing.</p>
60 *
61 * <p>In the context of HTTP Digest Access Authentication, the {@code nextnonce} parameter is
62 * a critical part of the security mechanism, designed to mitigate replay attacks and enhance mutual
63 * authentication security. It provides the server with the ability to set and enforce single-use or
64 * session-bound nonces, prompting the client to use the provided {@code nextnonce} in its next request.
65 * This setup helps secure communication by forcing new cryptographic material in each transaction.
66 * </p>
67 *
68 * <p>This interceptor is stateless and thread-safe, making it suitable for use across multiple
69 * threads and HTTP requests. It should be registered with the HTTP client to enable support
70 * for advanced authentication mechanisms that require tracking of nonce values.</p>
71 *
72 * @since 5.5
73 */
74
75 @Contract(threading = ThreadingBehavior.STATELESS)
76 public class NextNonceInterceptor implements HttpResponseInterceptor {
77
78 public static final HttpResponseInterceptor INSTANCE = new NextNonceInterceptor();
79
80 private final Tokenizer tokenParser = Tokenizer.INSTANCE;
81
82
83 private static final String AUTHENTICATION_INFO_HEADER = "Authentication-Info";
84
85 private static final Tokenizer.Delimiter TOKEN_DELIMS = Tokenizer.delimiters('=', ',');
86 private static final Tokenizer.Delimiter VALUE_DELIMS = Tokenizer.delimiters(',');
87
88 /**
89 * Processes the HTTP response and extracts the {@code nextnonce} parameter from the
90 * {@code Authentication-Info} header if available, storing it in the provided {@code context}.
91 *
92 * @param response the HTTP response containing the {@code Authentication-Info} header
93 * @param entity the response entity, ignored by this interceptor
94 * @param context the HTTP context in which to store the {@code nextnonce} parameter
95 * @throws NullPointerException if either {@code response} or {@code context} is null
96 */
97 @Override
98 public void process(final HttpResponse response, final EntityDetails entity, final HttpContext context) {
99 Args.notNull(response, "HTTP response");
100 Args.notNull(context, "HTTP context");
101
102 final Header header = response.getFirstHeader(AUTHENTICATION_INFO_HEADER);
103 if (header != null) {
104 final String nextNonce;
105 if (header instanceof FormattedHeader) {
106 final CharSequence buf = ((FormattedHeader) header).getBuffer();
107 final ParserCursor cursor = new ParserCursor(((FormattedHeader) header).getValuePos(), buf.length());
108 nextNonce = parseNextNonce(buf, cursor);
109 } else {
110 final CharSequence headerValue = header.getValue();
111 final ParserCursor cursor = new ParserCursor(0, headerValue.length());
112 nextNonce = parseNextNonce(headerValue, cursor);
113 }
114 if (!TextUtils.isBlank(nextNonce)) {
115 HttpClientContext.castOrCreate(context).setNextNonce(nextNonce);
116 }
117 }
118 }
119
120 /**
121 * Parses the {@code Authentication-Info} header content represented by a {@link CharArrayBuffer}
122 * to extract the {@code nextnonce} parameter.
123 *
124 * @param buffer the {@link CharArrayBuffer} containing the value of the {@code Authentication-Info} header
125 * @param cursor the {@link ParserCursor} used to navigate through the buffer content
126 * @return the extracted {@code nextnonce} parameter value, or {@code null} if the parameter is not found
127 */
128 private String parseNextNonce(final CharSequence buffer, final ParserCursor cursor) {
129 while (!cursor.atEnd()) {
130 final String name = tokenParser.parseToken(buffer, cursor, TOKEN_DELIMS);
131 if ("nextnonce".equals(name)) {
132 cursor.updatePos(cursor.getPos() + 1);
133 return tokenParser.parseValue(buffer, cursor, VALUE_DELIMS);
134 }
135 if (!cursor.atEnd()) {
136 cursor.updatePos(cursor.getPos() + 1);
137 }
138 }
139 return null;
140 }
141
142 }