1 /*
2  * Copyright (C) 2016 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.net.wifi.aware;
18 
19 import android.content.Context;
20 import android.content.pm.PackageManager;
21 import android.hardware.wifi.V1_0.Constants;
22 
23 /**
24  * Provides utilities for the Wifi Aware manager/service.
25  *
26  * @hide
27  */
28 public class WifiAwareUtils {
29     /**
30      * Per spec: The Service Name is a UTF-8 encoded string from 1 to 255 bytes in length. The
31      * only acceptable single-byte UTF-8 symbols for a Service Name are alphanumeric values (A-Z,
32      * a-z, 0-9), the hyphen ('-'), and the period ('.'). All valid multi-byte UTF-8 characters
33      * are acceptable in a Service Name.
34      */
validateServiceName(byte[] serviceNameData)35     public static void validateServiceName(byte[] serviceNameData) throws IllegalArgumentException {
36         if (serviceNameData == null) {
37             throw new IllegalArgumentException("Invalid service name - null");
38         }
39 
40         if (serviceNameData.length < 1 || serviceNameData.length > 255) {
41             throw new IllegalArgumentException("Invalid service name length - must be between "
42                     + "1 and 255 bytes (UTF-8 encoding)");
43         }
44 
45         int index = 0;
46         while (index < serviceNameData.length) {
47             byte b = serviceNameData[index];
48             if ((b & 0x80) == 0x00) {
49                 if (!((b >= '0' && b <= '9') || (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z')
50                         || b == '-' || b == '.')) {
51                     throw new IllegalArgumentException("Invalid service name - illegal characters,"
52                             + " allowed = (0-9, a-z,A-Z, -, .)");
53                 }
54             }
55             ++index;
56         }
57     }
58 
59     /**
60      * Validates that the passphrase is a non-null string of the right size (per the HAL min/max
61      * length parameters).
62      *
63      * @param passphrase Passphrase to test
64      * @return true if passphrase is valid, false if not
65      */
validatePassphrase(String passphrase)66     public static boolean validatePassphrase(String passphrase) {
67         if (passphrase == null
68                 || passphrase.length() < Constants.NanParamSizeLimits.MIN_PASSPHRASE_LENGTH
69                 || passphrase.length() > Constants.NanParamSizeLimits.MAX_PASSPHRASE_LENGTH) {
70             return false;
71         }
72 
73         return true;
74     }
75 
76     /**
77      * Validates that the PMK is a non-null byte array of the right size (32 bytes per spec).
78      *
79      * @param pmk PMK to test
80      * @return true if PMK is valid, false if not
81      */
validatePmk(byte[] pmk)82     public static boolean validatePmk(byte[] pmk) {
83         if (pmk == null || pmk.length != 32) {
84             return false;
85         }
86 
87         return true;
88     }
89 
90     /**
91      * Returns true if the App version is older than minVersion.
92      */
isLegacyVersion(Context context, int minVersion)93     public static boolean isLegacyVersion(Context context, int minVersion) {
94         try {
95             if (context.getPackageManager().getApplicationInfo(context.getOpPackageName(), 0)
96                     .targetSdkVersion < minVersion) {
97                 return true;
98             }
99         } catch (PackageManager.NameNotFoundException e) {
100             // In case of exception, assume known app (more strict checking)
101             // Note: This case will never happen since checkPackage is
102             // called to verify valididity before checking App's version.
103         }
104         return false;
105     }
106 }
107