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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.wifi;
import android.content.pm.UserInfo;
import android.net.IpConfiguration;
import android.net.StaticIpConfiguration;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiEnterpriseConfig;
import android.net.wifi.WifiScanner;
import android.os.UserHandle;
import android.text.TextUtils;
import android.util.Log;
import com.android.internal.annotations.VisibleForTesting;
import com.android.server.wifi.util.NativeUtil;
import java.nio.charset.StandardCharsets;
import java.security.cert.X509Certificate;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Comparator;
import java.util.List;
import java.util.Objects;
/**
* WifiConfiguration utility for any {@link android.net.wifi.WifiConfiguration} related operations.
* Currently contains:
* > Helper method to check if the WifiConfiguration object is visible to the provided users.
* > Helper methods to identify the encryption of a WifiConfiguration object.
*/
public class WifiConfigurationUtil {
private static final String TAG = "WifiConfigurationUtil";
/**
* Constants used for validating external config objects.
*/
private static final int ENCLOSING_QUTOES_LEN = 2;
private static final int SSID_UTF_8_MIN_LEN = 1 + ENCLOSING_QUTOES_LEN;
private static final int SSID_UTF_8_MAX_LEN = 32 + ENCLOSING_QUTOES_LEN;
private static final int SSID_HEX_MIN_LEN = 2;
private static final int SSID_HEX_MAX_LEN = 64;
private static final int PSK_ASCII_MIN_LEN = 8 + ENCLOSING_QUTOES_LEN;
private static final int PSK_ASCII_MAX_LEN = 63 + ENCLOSING_QUTOES_LEN;
private static final int PSK_HEX_LEN = 64;
@VisibleForTesting
public static final String PASSWORD_MASK = "*";
/**
* Check whether a network configuration is visible to a user or any of its managed profiles.
*
* @param config the network configuration whose visibility should be checked
* @param profiles the user IDs of the user itself and all its managed profiles (can be obtained
* via {@link android.os.UserManager#getProfiles})
* @return whether the network configuration is visible to the user or any of its managed
* profiles
*/
public static boolean isVisibleToAnyProfile(WifiConfiguration config, List<UserInfo> profiles) {
return (config.shared || doesUidBelongToAnyProfile(config.creatorUid, profiles));
}
/**
* Check whether a uid belong to a user or any of its managed profiles.
*
* @param uid uid of the app.
* @param profiles the user IDs of the user itself and all its managed profiles (can be obtained
* via {@link android.os.UserManager#getProfiles})
* @return whether the uid belongs to the user or any of its managed profiles.
*/
public static boolean doesUidBelongToAnyProfile(int uid, List<UserInfo> profiles) {
final int userId = UserHandle.getUserId(uid);
for (UserInfo profile : profiles) {
if (profile.id == userId) {
return true;
}
}
return false;
}
/**
* Checks if the provided |wepKeys| array contains any non-null value;
*/
public static boolean hasAnyValidWepKey(String[] wepKeys) {
for (int i = 0; i < wepKeys.length; i++) {
if (wepKeys[i] != null) {
return true;
}
}
return false;
}
/**
* Helper method to check if the provided |config| corresponds to a PSK network or not.
*/
public static boolean isConfigForPskNetwork(WifiConfiguration config) {
return config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.WPA_PSK);
}
/**
* Helper method to check if the provided |config| corresponds to a EAP network or not.
*/
public static boolean isConfigForEapNetwork(WifiConfiguration config) {
return (config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.WPA_EAP)
|| config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.IEEE8021X));
}
/**
* Helper method to check if the provided |config| corresponds to a WEP network or not.
*/
public static boolean isConfigForWepNetwork(WifiConfiguration config) {
return (config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.NONE)
&& hasAnyValidWepKey(config.wepKeys));
}
/**
* Helper method to check if the provided |config| corresponds to an open network or not.
*/
public static boolean isConfigForOpenNetwork(WifiConfiguration config) {
return !(isConfigForWepNetwork(config) || isConfigForPskNetwork(config)
|| isConfigForEapNetwork(config));
}
/**
* Compare existing and new WifiConfiguration objects after a network update and return if
* IP parameters have changed or not.
*
* @param existingConfig Existing WifiConfiguration object corresponding to the network.
* @param newConfig New WifiConfiguration object corresponding to the network.
* @return true if IP parameters have changed, false otherwise.
*/
public static boolean hasIpChanged(WifiConfiguration existingConfig,
WifiConfiguration newConfig) {
if (existingConfig.getIpAssignment() != newConfig.getIpAssignment()) {
return true;
}
if (newConfig.getIpAssignment() == IpConfiguration.IpAssignment.STATIC) {
return !Objects.equals(existingConfig.getStaticIpConfiguration(),
newConfig.getStaticIpConfiguration());
}
return false;
}
/**
* Compare existing and new WifiConfiguration objects after a network update and return if
* proxy parameters have changed or not.
*
* @param existingConfig Existing WifiConfiguration object corresponding to the network.
* @param newConfig New WifiConfiguration object corresponding to the network.
* @return true if proxy parameters have changed, false if no existing config and proxy settings
* are NONE, false otherwise.
*/
public static boolean hasProxyChanged(WifiConfiguration existingConfig,
WifiConfiguration newConfig) {
if (existingConfig == null) {
return newConfig.getProxySettings() != IpConfiguration.ProxySettings.NONE;
}
if (newConfig.getProxySettings() != existingConfig.getProxySettings()) {
return true;
}
return !Objects.equals(existingConfig.getHttpProxy(), newConfig.getHttpProxy());
}
/**
* Compare existing and new WifiEnterpriseConfig objects after a network update and return if
* credential parameters have changed or not.
*
* @param existingEnterpriseConfig Existing WifiConfiguration object corresponding to the
* network.
* @param newEnterpriseConfig New WifiConfiguration object corresponding to the network.
* @return true if credentials have changed, false otherwise.
*/
@VisibleForTesting
public static boolean hasEnterpriseConfigChanged(WifiEnterpriseConfig existingEnterpriseConfig,
WifiEnterpriseConfig newEnterpriseConfig) {
if (existingEnterpriseConfig != null && newEnterpriseConfig != null) {
if (existingEnterpriseConfig.getEapMethod() != newEnterpriseConfig.getEapMethod()) {
return true;
}
if (existingEnterpriseConfig.getPhase2Method()
!= newEnterpriseConfig.getPhase2Method()) {
return true;
}
if (!TextUtils.equals(existingEnterpriseConfig.getIdentity(),
newEnterpriseConfig.getIdentity())
|| !TextUtils.equals(existingEnterpriseConfig.getAnonymousIdentity(),
newEnterpriseConfig.getAnonymousIdentity())) {
return true;
}
if (!TextUtils.equals(existingEnterpriseConfig.getPassword(),
newEnterpriseConfig.getPassword())) {
return true;
}
X509Certificate[] existingCaCerts = existingEnterpriseConfig.getCaCertificates();
X509Certificate[] newCaCerts = newEnterpriseConfig.getCaCertificates();
if (!Arrays.equals(existingCaCerts, newCaCerts)) {
return true;
}
} else {
// One of the configs may have an enterpriseConfig
if (existingEnterpriseConfig != null || newEnterpriseConfig != null) {
return true;
}
}
return false;
}
/**
* Compare existing and new WifiConfiguration objects after a network update and return if
* credential parameters have changed or not.
*
* @param existingConfig Existing WifiConfiguration object corresponding to the network.
* @param newConfig New WifiConfiguration object corresponding to the network.
* @return true if credentials have changed, false otherwise.
*/
public static boolean hasCredentialChanged(WifiConfiguration existingConfig,
WifiConfiguration newConfig) {
if (!Objects.equals(existingConfig.allowedKeyManagement,
newConfig.allowedKeyManagement)) {
return true;
}
if (!Objects.equals(existingConfig.allowedProtocols, newConfig.allowedProtocols)) {
return true;
}
if (!Objects.equals(existingConfig.allowedAuthAlgorithms,
newConfig.allowedAuthAlgorithms)) {
return true;
}
if (!Objects.equals(existingConfig.allowedPairwiseCiphers,
newConfig.allowedPairwiseCiphers)) {
return true;
}
if (!Objects.equals(existingConfig.allowedGroupCiphers,
newConfig.allowedGroupCiphers)) {
return true;
}
if (!Objects.equals(existingConfig.preSharedKey, newConfig.preSharedKey)) {
return true;
}
if (!Arrays.equals(existingConfig.wepKeys, newConfig.wepKeys)) {
return true;
}
if (existingConfig.wepTxKeyIndex != newConfig.wepTxKeyIndex) {
return true;
}
if (existingConfig.hiddenSSID != newConfig.hiddenSSID) {
return true;
}
if (hasEnterpriseConfigChanged(existingConfig.enterpriseConfig,
newConfig.enterpriseConfig)) {
return true;
}
return false;
}
private static boolean validateSsid(String ssid, boolean isAdd) {
if (isAdd) {
if (ssid == null) {
Log.e(TAG, "validateSsid : null string");
return false;
}
} else {
if (ssid == null) {
// This is an update, so the SSID can be null if that is not being changed.
return true;
}
}
if (ssid.isEmpty()) {
Log.e(TAG, "validateSsid failed: empty string");
return false;
}
if (ssid.startsWith("\"")) {
// UTF-8 SSID string
byte[] ssidBytes = ssid.getBytes(StandardCharsets.UTF_8);
if (ssidBytes.length < SSID_UTF_8_MIN_LEN) {
Log.e(TAG, "validateSsid failed: utf-8 ssid string size too small: "
+ ssidBytes.length);
return false;
}
if (ssidBytes.length > SSID_UTF_8_MAX_LEN) {
Log.e(TAG, "validateSsid failed: utf-8 ssid string size too large: "
+ ssidBytes.length);
return false;
}
} else {
// HEX SSID string
if (ssid.length() < SSID_HEX_MIN_LEN) {
Log.e(TAG, "validateSsid failed: hex string size too small: " + ssid.length());
return false;
}
if (ssid.length() > SSID_HEX_MAX_LEN) {
Log.e(TAG, "validateSsid failed: hex string size too large: " + ssid.length());
return false;
}
}
try {
NativeUtil.decodeSsid(ssid);
} catch (IllegalArgumentException e) {
Log.e(TAG, "validateSsid failed: malformed string: " + ssid);
return false;
}
return true;
}
private static boolean validatePsk(String psk, boolean isAdd) {
if (isAdd) {
if (psk == null) {
Log.e(TAG, "validatePsk: null string");
return false;
}
} else {
if (psk == null) {
// This is an update, so the psk can be null if that is not being changed.
return true;
} else if (psk.equals(PASSWORD_MASK)) {
// This is an update, so the app might have returned back the masked password, let
// it thru. WifiConfigManager will handle it.
return true;
}
}
if (psk.isEmpty()) {
Log.e(TAG, "validatePsk failed: empty string");
return false;
}
if (psk.startsWith("\"")) {
// ASCII PSK string
byte[] pskBytes = psk.getBytes(StandardCharsets.US_ASCII);
if (pskBytes.length < PSK_ASCII_MIN_LEN) {
Log.e(TAG, "validatePsk failed: ascii string size too small: " + pskBytes.length);
return false;
}
if (pskBytes.length > PSK_ASCII_MAX_LEN) {
Log.e(TAG, "validatePsk failed: ascii string size too large: " + pskBytes.length);
return false;
}
} else {
// HEX PSK string
if (psk.length() != PSK_HEX_LEN) {
Log.e(TAG, "validatePsk failed: hex string size mismatch: " + psk.length());
return false;
}
}
try {
NativeUtil.hexOrQuotedStringToBytes(psk);
} catch (IllegalArgumentException e) {
Log.e(TAG, "validatePsk failed: malformed string: " + psk);
return false;
}
return true;
}
private static boolean validateBitSet(BitSet bitSet, int validValuesLength) {
if (bitSet == null) return false;
BitSet clonedBitset = (BitSet) bitSet.clone();
clonedBitset.clear(0, validValuesLength);
return clonedBitset.isEmpty();
}
private static boolean validateBitSets(WifiConfiguration config) {
// 1. Check |allowedKeyManagement|.
if (!validateBitSet(config.allowedKeyManagement,
WifiConfiguration.KeyMgmt.strings.length)) {
Log.e(TAG, "validateBitsets failed: invalid allowedKeyManagement bitset "
+ config.allowedKeyManagement);
return false;
}
// 2. Check |allowedProtocols|.
if (!validateBitSet(config.allowedProtocols,
WifiConfiguration.Protocol.strings.length)) {
Log.e(TAG, "validateBitsets failed: invalid allowedProtocols bitset "
+ config.allowedProtocols);
return false;
}
// 3. Check |allowedAuthAlgorithms|.
if (!validateBitSet(config.allowedAuthAlgorithms,
WifiConfiguration.AuthAlgorithm.strings.length)) {
Log.e(TAG, "validateBitsets failed: invalid allowedAuthAlgorithms bitset "
+ config.allowedAuthAlgorithms);
return false;
}
// 4. Check |allowedGroupCiphers|.
if (!validateBitSet(config.allowedGroupCiphers,
WifiConfiguration.GroupCipher.strings.length)) {
Log.e(TAG, "validateBitsets failed: invalid allowedGroupCiphers bitset "
+ config.allowedGroupCiphers);
return false;
}
// 5. Check |allowedPairwiseCiphers|.
if (!validateBitSet(config.allowedPairwiseCiphers,
WifiConfiguration.PairwiseCipher.strings.length)) {
Log.e(TAG, "validateBitsets failed: invalid allowedPairwiseCiphers bitset "
+ config.allowedPairwiseCiphers);
return false;
}
return true;
}
private static boolean validateKeyMgmt(BitSet keyMgmnt) {
if (keyMgmnt.cardinality() > 1) {
if (keyMgmnt.cardinality() != 2) {
Log.e(TAG, "validateKeyMgmt failed: cardinality != 2");
return false;
}
if (!keyMgmnt.get(WifiConfiguration.KeyMgmt.WPA_EAP)) {
Log.e(TAG, "validateKeyMgmt failed: not WPA_EAP");
return false;
}
if (!keyMgmnt.get(WifiConfiguration.KeyMgmt.IEEE8021X)
&& !keyMgmnt.get(WifiConfiguration.KeyMgmt.WPA_PSK)) {
Log.e(TAG, "validateKeyMgmt failed: not PSK or 8021X");
return false;
}
}
return true;
}
private static boolean validateIpConfiguration(IpConfiguration ipConfig) {
if (ipConfig == null) {
Log.e(TAG, "validateIpConfiguration failed: null IpConfiguration");
return false;
}
if (ipConfig.getIpAssignment() == IpConfiguration.IpAssignment.STATIC) {
StaticIpConfiguration staticIpConfig = ipConfig.getStaticIpConfiguration();
if (staticIpConfig == null) {
Log.e(TAG, "validateIpConfiguration failed: null StaticIpConfiguration");
return false;
}
if (staticIpConfig.ipAddress == null) {
Log.e(TAG, "validateIpConfiguration failed: null static ip Address");
return false;
}
}
return true;
}
/**
* Enums to specify if the provided config is being validated for add or update.
*/
public static final boolean VALIDATE_FOR_ADD = true;
public static final boolean VALIDATE_FOR_UPDATE = false;
/**
* Validate the configuration received from an external application.
*
* This method checks for the following parameters:
* 1. {@link WifiConfiguration#SSID}
* 2. {@link WifiConfiguration#preSharedKey}
* 3. {@link WifiConfiguration#allowedKeyManagement}
* 4. {@link WifiConfiguration#allowedProtocols}
* 5. {@link WifiConfiguration#allowedAuthAlgorithms}
* 6. {@link WifiConfiguration#allowedGroupCiphers}
* 7. {@link WifiConfiguration#allowedPairwiseCiphers}
* 8. {@link WifiConfiguration#getIpConfiguration()}
*
* @param config {@link WifiConfiguration} received from an external application.
* @param isAdd {@link #VALIDATE_FOR_ADD} to indicate a network config received for an add,
* {@link #VALIDATE_FOR_UPDATE} for a network config received for an update.
* These 2 cases need to be handled differently because the config received for an
* update could contain only the fields that are being changed.
* @return true if the parameters are valid, false otherwise.
*/
public static boolean validate(WifiConfiguration config, boolean isAdd) {
if (!validateSsid(config.SSID, isAdd)) {
return false;
}
if (!validateBitSets(config)) {
return false;
}
if (!validateKeyMgmt(config.allowedKeyManagement)) {
return false;
}
if (config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.WPA_PSK)
&& !validatePsk(config.preSharedKey, isAdd)) {
return false;
}
if (!validateIpConfiguration(config.getIpConfiguration())) {
return false;
}
// TBD: Validate some enterprise params as well in the future here.
return true;
}
/**
* Check if the provided two networks are the same.
* Note: This does not check if network selection BSSID's are the same.
*
* @param config Configuration corresponding to a network.
* @param config1 Configuration corresponding to another network.
*
* @return true if |config| and |config1| are the same network.
* false otherwise.
*/
public static boolean isSameNetwork(WifiConfiguration config, WifiConfiguration config1) {
if (config == null && config1 == null) {
return true;
}
if (config == null || config1 == null) {
return false;
}
if (config.networkId != config1.networkId) {
return false;
}
if (!Objects.equals(config.SSID, config1.SSID)) {
return false;
}
if (WifiConfigurationUtil.hasCredentialChanged(config, config1)) {
return false;
}
return true;
}
/**
* Create a PnoNetwork object from the provided WifiConfiguration.
*
* @param config Configuration corresponding to the network.
* @return PnoNetwork object corresponding to the network.
*/
public static WifiScanner.PnoSettings.PnoNetwork createPnoNetwork(
WifiConfiguration config) {
WifiScanner.PnoSettings.PnoNetwork pnoNetwork =
new WifiScanner.PnoSettings.PnoNetwork(config.SSID);
if (config.hiddenSSID) {
pnoNetwork.flags |= WifiScanner.PnoSettings.PnoNetwork.FLAG_DIRECTED_SCAN;
}
pnoNetwork.flags |= WifiScanner.PnoSettings.PnoNetwork.FLAG_A_BAND;
pnoNetwork.flags |= WifiScanner.PnoSettings.PnoNetwork.FLAG_G_BAND;
if (config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.WPA_PSK)) {
pnoNetwork.authBitField |= WifiScanner.PnoSettings.PnoNetwork.AUTH_CODE_PSK;
} else if (config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.WPA_EAP)
|| config.allowedKeyManagement.get(WifiConfiguration.KeyMgmt.IEEE8021X)) {
pnoNetwork.authBitField |= WifiScanner.PnoSettings.PnoNetwork.AUTH_CODE_EAPOL;
} else {
pnoNetwork.authBitField |= WifiScanner.PnoSettings.PnoNetwork.AUTH_CODE_OPEN;
}
return pnoNetwork;
}
/**
* General WifiConfiguration list sorting algorithm:
* 1, Place the fully enabled networks first.
* 2. Next place all the temporarily disabled networks.
* 3. Place the permanently disabled networks last (Permanently disabled networks are removed
* before WifiConfigManager uses this comparator today!).
*
* Among the networks with the same status, sort them in the order determined by the return of
* {@link #compareNetworksWithSameStatus(WifiConfiguration, WifiConfiguration)} method
* implementation.
*/
public abstract static class WifiConfigurationComparator implements
Comparator<WifiConfiguration> {
private static final int ENABLED_NETWORK_SCORE = 3;
private static final int TEMPORARY_DISABLED_NETWORK_SCORE = 2;
private static final int PERMANENTLY_DISABLED_NETWORK_SCORE = 1;
@Override
public int compare(WifiConfiguration a, WifiConfiguration b) {
int configAScore = getNetworkStatusScore(a);
int configBScore = getNetworkStatusScore(b);
if (configAScore == configBScore) {
return compareNetworksWithSameStatus(a, b);
} else {
return Integer.compare(configBScore, configAScore);
}
}
// This needs to be implemented by the connected/disconnected PNO list comparator.
abstract int compareNetworksWithSameStatus(WifiConfiguration a, WifiConfiguration b);
/**
* Returns an integer representing a score for each configuration. The scores are assigned
* based on the status of the configuration. The scores are assigned according to the order:
* Fully enabled network > Temporarily disabled network > Permanently disabled network.
*/
private int getNetworkStatusScore(WifiConfiguration config) {
if (config.getNetworkSelectionStatus().isNetworkEnabled()) {
return ENABLED_NETWORK_SCORE;
} else if (config.getNetworkSelectionStatus().isNetworkTemporaryDisabled()) {
return TEMPORARY_DISABLED_NETWORK_SCORE;
} else {
return PERMANENTLY_DISABLED_NETWORK_SCORE;
}
}
}
}