1 /*
2  * Copyright (C) 2012 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 android.os;
18 
19 import android.util.Slog;
20 
21 import java.io.IOException;
22 import java.io.File;
23 import java.io.FileDescriptor;
24 
25 /**
26  * This class provides access to the centralized jni bindings for
27  * SELinux interaction.
28  * {@hide}
29  */
30 public class SELinux {
31     private static final String TAG = "SELinux";
32 
33     /** Keep in sync with ./external/libselinux/include/selinux/android.h */
34     private static final int SELINUX_ANDROID_RESTORECON_NOCHANGE = 1;
35     private static final int SELINUX_ANDROID_RESTORECON_VERBOSE = 2;
36     private static final int SELINUX_ANDROID_RESTORECON_RECURSE = 4;
37     private static final int SELINUX_ANDROID_RESTORECON_FORCE = 8;
38     private static final int SELINUX_ANDROID_RESTORECON_DATADATA = 16;
39 
40     /**
41      * Determine whether SELinux is disabled or enabled.
42      * @return a boolean indicating whether SELinux is enabled.
43      */
isSELinuxEnabled()44     public static final native boolean isSELinuxEnabled();
45 
46     /**
47      * Determine whether SELinux is permissive or enforcing.
48      * @return a boolean indicating whether SELinux is enforcing.
49      */
isSELinuxEnforced()50     public static final native boolean isSELinuxEnforced();
51 
52     /**
53      * Sets the security context for newly created file objects.
54      * @param context a security context given as a String.
55      * @return a boolean indicating whether the operation succeeded.
56      */
setFSCreateContext(String context)57     public static final native boolean setFSCreateContext(String context);
58 
59     /**
60      * Change the security context of an existing file object.
61      * @param path representing the path of file object to relabel.
62      * @param context new security context given as a String.
63      * @return a boolean indicating whether the operation succeeded.
64      */
setFileContext(String path, String context)65     public static final native boolean setFileContext(String path, String context);
66 
67     /**
68      * Get the security context of a file object.
69      * @param path the pathname of the file object.
70      * @return a security context given as a String.
71      */
getFileContext(String path)72     public static final native String getFileContext(String path);
73 
74     /**
75      * Get the security context of a peer socket.
76      * @param fd FileDescriptor class of the peer socket.
77      * @return a String representing the peer socket security context.
78      */
getPeerContext(FileDescriptor fd)79     public static final native String getPeerContext(FileDescriptor fd);
80 
81     /**
82      * Gets the security context of the current process.
83      * @return a String representing the security context of the current process.
84      */
getContext()85     public static final native String getContext();
86 
87     /**
88      * Gets the security context of a given process id.
89      * @param pid an int representing the process id to check.
90      * @return a String representing the security context of the given pid.
91      */
getPidContext(int pid)92     public static final native String getPidContext(int pid);
93 
94     /**
95      * Check permissions between two security contexts.
96      * @param scon The source or subject security context.
97      * @param tcon The target or object security context.
98      * @param tclass The object security class name.
99      * @param perm The permission name.
100      * @return a boolean indicating whether permission was granted.
101      */
checkSELinuxAccess(String scon, String tcon, String tclass, String perm)102     public static final native boolean checkSELinuxAccess(String scon, String tcon, String tclass, String perm);
103 
104     /**
105      * Restores a file to its default SELinux security context.
106      * If the system is not compiled with SELinux, then {@code true}
107      * is automatically returned.
108      * If SELinux is compiled in, but disabled, then {@code true} is
109      * returned.
110      *
111      * @param pathname The pathname of the file to be relabeled.
112      * @return a boolean indicating whether the relabeling succeeded.
113      * @exception NullPointerException if the pathname is a null object.
114      */
restorecon(String pathname)115     public static boolean restorecon(String pathname) throws NullPointerException {
116         if (pathname == null) { throw new NullPointerException(); }
117         return native_restorecon(pathname, 0);
118     }
119 
120     /**
121      * Restores a file to its default SELinux security context.
122      * If the system is not compiled with SELinux, then {@code true}
123      * is automatically returned.
124      * If SELinux is compiled in, but disabled, then {@code true} is
125      * returned.
126      *
127      * @param pathname The pathname of the file to be relabeled.
128      * @return a boolean indicating whether the relabeling succeeded.
129      */
native_restorecon(String pathname, int flags)130     private static native boolean native_restorecon(String pathname, int flags);
131 
132     /**
133      * Restores a file to its default SELinux security context.
134      * If the system is not compiled with SELinux, then {@code true}
135      * is automatically returned.
136      * If SELinux is compiled in, but disabled, then {@code true} is
137      * returned.
138      *
139      * @param file The File object representing the path to be relabeled.
140      * @return a boolean indicating whether the relabeling succeeded.
141      * @exception NullPointerException if the file is a null object.
142      */
restorecon(File file)143     public static boolean restorecon(File file) throws NullPointerException {
144         try {
145             return native_restorecon(file.getCanonicalPath(), 0);
146         } catch (IOException e) {
147             Slog.e(TAG, "Error getting canonical path. Restorecon failed for " +
148                     file.getPath(), e);
149             return false;
150         }
151     }
152 
153     /**
154      * Recursively restores all files under the given path to their default
155      * SELinux security context. If the system is not compiled with SELinux,
156      * then {@code true} is automatically returned. If SELinux is compiled in,
157      * but disabled, then {@code true} is returned.
158      *
159      * @return a boolean indicating whether the relabeling succeeded.
160      */
restoreconRecursive(File file)161     public static boolean restoreconRecursive(File file) {
162         try {
163             return native_restorecon(file.getCanonicalPath(), SELINUX_ANDROID_RESTORECON_RECURSE);
164         } catch (IOException e) {
165             Slog.e(TAG, "Error getting canonical path. Restorecon failed for " +
166                     file.getPath(), e);
167             return false;
168         }
169     }
170 }
171