1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package libcore.net;
18 
19 /**
20  * Network security policy for this process/application.
21  *
22  * <p>Network stacks/components are expected to honor this policy. Components which can use the
23  * Android framework API should be accessing this policy via the framework's
24  * {@code android.security.NetworkSecurityPolicy} instead of via this class.
25  *
26  * <p>The policy currently consists of a single flag: whether cleartext network traffic is
27  * permitted. See {@link #isCleartextTrafficPermitted()}.
28  */
29 public abstract class NetworkSecurityPolicy {
30 
31     private static volatile NetworkSecurityPolicy instance = new DefaultNetworkSecurityPolicy();
32 
getInstance()33     public static NetworkSecurityPolicy getInstance() {
34         return instance;
35     }
36 
setInstance(NetworkSecurityPolicy policy)37     public static void setInstance(NetworkSecurityPolicy policy) {
38         if (policy == null) {
39             throw new NullPointerException("policy == null");
40         }
41         instance = policy;
42     }
43 
44     /**
45      * Returns {@code true} if cleartext network traffic (e.g. HTTP, FTP, XMPP, IMAP, SMTP --
46      * without TLS or STARTTLS) is permitted for all network communications of this process.
47      *
48      * <p>{@link #isCleartextTrafficPermitted(String)} should be used to determine if cleartext
49      * traffic is permitted for a specific host.
50      *
51      * <p>When cleartext network traffic is not permitted, the platform's components (e.g. HTTP
52      * stacks, {@code WebView}, {@code MediaPlayer}) will refuse this process's requests to use
53      * cleartext traffic. Third-party libraries are encouraged to do the same.
54      *
55      * <p>This flag is honored on a best effort basis because it's impossible to prevent all
56      * cleartext traffic from an application given the level of access provided to applications on
57      * Android. For example, there's no expectation that {@link java.net.Socket} API will honor this
58      * flag. Luckily, most network traffic from apps is handled by higher-level network stacks which
59      * can be made to honor this flag. Platform-provided network stacks (e.g. HTTP and FTP) honor
60      * this flag from day one, and well-established third-party network stacks will eventually
61      * honor it.
62      */
isCleartextTrafficPermitted()63     public abstract boolean isCleartextTrafficPermitted();
64 
65     /**
66      * Returns {@code true} if cleartext network traffic (e.g. HTTP, FTP, XMPP, IMAP, SMTP --
67      * without TLS or STARTTLS) is permitted for communicating with {@code hostname} for this
68      * process.
69      *
70      * <p>See {@link #isCleartextTrafficPermitted} for more details.
71      */
isCleartextTrafficPermitted(String hostname)72     public abstract boolean isCleartextTrafficPermitted(String hostname);
73 
74     /**
75      * Returns {@code true} if Certificate Transparency information is required to be presented by
76      * the server and verified by the client in TLS connections to {@code hostname}.
77      *
78      * <p>See RFC6962 section 3.3 for more details.
79      */
isCertificateTransparencyVerificationRequired(String hostname)80     public abstract boolean isCertificateTransparencyVerificationRequired(String hostname);
81 
82     public static final class DefaultNetworkSecurityPolicy extends NetworkSecurityPolicy {
83         @Override
isCleartextTrafficPermitted()84         public boolean isCleartextTrafficPermitted() {
85             return true;
86         }
87 
88         @Override
isCleartextTrafficPermitted(String hostname)89         public boolean isCleartextTrafficPermitted(String hostname) {
90             return isCleartextTrafficPermitted();
91         }
92 
93         @Override
isCertificateTransparencyVerificationRequired(String hostname)94         public boolean isCertificateTransparencyVerificationRequired(String hostname) {
95             return false;
96         }
97     }
98 }
99