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 import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
20 
21 import android.annotation.SystemApi;
22 import android.compat.annotation.UnsupportedAppUsage;
23 
24 /**
25  * Network security policy for this process/application.
26  *
27  * <p>Network stacks/components are expected to honor this policy. Components which can use the
28  * Android framework API should be accessing this policy via the framework's
29  * {@code android.security.NetworkSecurityPolicy} instead of via this class.
30  *
31  * <p>The policy can be determined by the {@link #isCleartextTrafficPermitted()},
32  * {@link #isCleartextTrafficPermitted(String)} and
33  * {@link #isCertificateTransparencyVerificationRequired(String)} methods.
34  *
35  * @hide
36  */
37 @SystemApi(client = MODULE_LIBRARIES)
38 @libcore.api.IntraCoreApi
39 public abstract class NetworkSecurityPolicy {
40 
41     private static volatile NetworkSecurityPolicy instance = new DefaultNetworkSecurityPolicy();
42 
43     /**
44      * Constructs a default {@code NetworkSecurityPolicy}.
45      *
46      * @see {@link #DefaultNetworkSecurityPolicy}.
47      *
48      * @hide
49      */
50     @SystemApi(client = MODULE_LIBRARIES)
NetworkSecurityPolicy()51     public NetworkSecurityPolicy() {
52     }
53 
54     /**
55      * Gets current singleton {@code NetworkSecurityPolicy} instance.
56      *
57      * @return the current {@code NetworkSecurityPolicy}.
58      *
59      * @hide
60      */
61     @SystemApi(client = MODULE_LIBRARIES)
62     @libcore.api.IntraCoreApi
getInstance()63     public static NetworkSecurityPolicy getInstance() {
64         return instance;
65     }
66 
67     /**
68      * Sets current singleton instance
69      *
70      * @param policy new {@code NetworlSecurityPolicy} instance.
71      *
72      * @hide
73      */
74     @SystemApi(client = MODULE_LIBRARIES)
setInstance(NetworkSecurityPolicy policy)75     public static void setInstance(NetworkSecurityPolicy policy) {
76         if (policy == null) {
77             throw new NullPointerException("policy == null");
78         }
79         instance = policy;
80     }
81 
82     /**
83      * Returns {@code true} if cleartext network traffic (e.g. HTTP, FTP, XMPP, IMAP, SMTP --
84      * without TLS or STARTTLS) is permitted for all network communications of this process.
85      *
86      * <p>{@link #isCleartextTrafficPermitted(String)} should be used to determine if cleartext
87      * traffic is permitted for a specific host.
88      *
89      * <p>When cleartext network traffic is not permitted, the platform's components (e.g. HTTP
90      * stacks, {@code WebView}, {@code MediaPlayer}) will refuse this process's requests to use
91      * cleartext traffic. Third-party libraries are encouraged to do the same.
92      *
93      * <p>This flag is honored on a best effort basis because it's impossible to prevent all
94      * cleartext traffic from an application given the level of access provided to applications on
95      * Android. For example, there's no expectation that {@link java.net.Socket} API will honor this
96      * flag. Luckily, most network traffic from apps is handled by higher-level network stacks which
97      * can be made to honor this flag. Platform-provided network stacks (e.g. HTTP and FTP) honor
98      * this flag from day one, and well-established third-party network stacks will eventually
99      * honor it.
100      *
101      * @return {@code true} if cleartext traffic is permitted and {@code false} otherwise.
102      *
103      * @hide
104      */
105     @UnsupportedAppUsage
106     @SystemApi(client = MODULE_LIBRARIES)
isCleartextTrafficPermitted()107     public abstract boolean isCleartextTrafficPermitted();
108 
109     /**
110      * Returns {@code true} if cleartext network traffic (e.g. HTTP, FTP, XMPP, IMAP, SMTP --
111      * without TLS or STARTTLS) is permitted for communicating with {@code hostname} for this
112      * process.
113      *
114      * <p>See {@link #isCleartextTrafficPermitted} for more details.
115      *
116      * @param hostname hostname to check if cleartext traffic is permitted for
117      * @return {@code true} if cleartext traffic is permitted and {@code false} otherwise
118      *
119      * @hide
120      */
121     @SystemApi(client = MODULE_LIBRARIES)
isCleartextTrafficPermitted(String hostname)122     public abstract boolean isCleartextTrafficPermitted(String hostname);
123 
124     /**
125      * Returns {@code true} if Certificate Transparency information is required to be presented by
126      * the server and verified by the client in TLS connections to {@code hostname}.
127      *
128      * <p>See RFC6962 section 3.3 for more details.
129      *
130      * @param hostname hostname to check whether certificate transparency verification
131      *                 is required
132      * @return {@code true} if certificate transparency verification is required and
133      *         {@code false} otherwise
134      *
135      * @hide
136      */
137     @SystemApi(client = MODULE_LIBRARIES)
138     @libcore.api.IntraCoreApi
isCertificateTransparencyVerificationRequired(String hostname)139     public abstract boolean isCertificateTransparencyVerificationRequired(String hostname);
140 
141     /**
142      * Default network security policy that allows cleartext traffic and does not require
143      * certificate transparency verification.
144      *
145      * @hide
146      */
147     public static final class DefaultNetworkSecurityPolicy extends NetworkSecurityPolicy {
148         @Override
isCleartextTrafficPermitted()149         public boolean isCleartextTrafficPermitted() {
150             return true;
151         }
152 
153         @Override
isCleartextTrafficPermitted(String hostname)154         public boolean isCleartextTrafficPermitted(String hostname) {
155             return isCleartextTrafficPermitted();
156         }
157 
158         @Override
isCertificateTransparencyVerificationRequired(String hostname)159         public boolean isCertificateTransparencyVerificationRequired(String hostname) {
160             return false;
161         }
162     }
163 }
164