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Merge "Resolve Android security comments for Android ID migration."

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This commit is contained in:
Mark Rathjen
2017-01-25 20:20:26 +00:00
committed by Android (Google) Code Review
parent a92c180107 7599f1366e
commit 8bd8564a18
3 changed files with 39 additions and 19 deletions
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4
core/java/android/util/ByteStringUtils.java
View File

@@ -33,7 +33,7 @@ public final class ByteStringUtils {
* @param bytes Byte array to encode.
* @return Hex encoded string representation of bytes.
*/
public static String toString(byte[] bytes) {
public static String toHexString(byte[] bytes) {
if (bytes == null || bytes.length == 0 || bytes.length % 2 != 0) {
return null;
}
@@ -55,7 +55,7 @@ public final class ByteStringUtils {
* @param str Hex encoded string to decode.
* @return Decoded byte array representation of str.
*/
public static byte[] toByteArray(String str) {
public static byte[] fromHexToByteArray(String str) {
if (str == null || str.length() == 0 || str.length() % 2 != 0) {
return null;
}

2
core/java/android/util/PackageUtils.java
View File

@@ -80,6 +80,6 @@ public final class PackageUtils {
messageDigest.update(data);
return ByteStringUtils.toString(messageDigest.digest());
return ByteStringUtils.toHexString(messageDigest.digest());
}
}

52
packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
View File

@@ -80,16 +80,20 @@ import java.io.FileDescriptor;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.nio.ByteBuffer;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import static android.os.Process.ROOT_UID;
import static android.os.Process.SHELL_UID;
@@ -996,7 +1000,7 @@ public class SettingsProvider extends ContentProvider {
continue;
}
// As of Android O (API 24), the SSAID is read from an app-specific entry in table
// As of Android O, the SSAID is read from an app-specific entry in table
// SETTINGS_FILE_SSAID, unless accessed by a system process.
final Setting setting;
if (isNewSsaidSetting(name)) {
@@ -1035,7 +1039,7 @@ public class SettingsProvider extends ContentProvider {
// Get the value.
synchronized (mLock) {
// As of Android O (API 24), the SSAID is read from an app-specific entry in table
// As of Android O, the SSAID is read from an app-specific entry in table
// SETTINGS_FILE_SSAID, unless accessed by a system process.
if (isNewSsaidSetting(name)) {
return getSsaidSettingLocked(owningUserId);
@@ -1978,12 +1982,12 @@ public class SettingsProvider extends ContentProvider {
private void generateUserKeyLocked(int userId) {
// Generate a random key for each user used for creating a new ssaid.
final byte[] keyBytes = new byte[16];
final byte[] keyBytes = new byte[32];
final SecureRandom rand = new SecureRandom();
rand.nextBytes(keyBytes);
// Convert to string for storage in settings table.
final String userKey = ByteStringUtils.toString(keyBytes);
final String userKey = ByteStringUtils.toHexString(keyBytes);
// Store the key in the ssaid table.
final SettingsState ssaidSettings = getSettingsLocked(SETTINGS_TYPE_SSAID, userId);
@@ -1995,6 +1999,10 @@ public class SettingsProvider extends ContentProvider {
}
}
private byte[] getLengthPrefix(byte[] data) {
return ByteBuffer.allocate(4).putInt(data.length).array();
}
public Setting generateSsaidLocked(String packageName, int userId) {
final PackageInfo packageInfo;
try {
@@ -2019,25 +2027,37 @@ public class SettingsProvider extends ContentProvider {
final String userKey = userKeySetting.getValue();
// Convert the user's key back to a byte array.
final byte[] keyBytes = ByteStringUtils.toByteArray(userKey);
if (keyBytes == null || keyBytes.length != 16) {
final byte[] keyBytes = ByteStringUtils.fromHexToByteArray(userKey);
// Validate that the key is of expected length.
// Keys are currently 32 bytes, but were once 16 bytes during Android O development.
if (keyBytes == null || (keyBytes.length != 16 && keyBytes.length != 32)) {
throw new IllegalStateException("User key invalid");
}
final MessageDigest md;
final Mac m;
try {
// Hash package name and signature.
md = MessageDigest.getInstance("SHA-256");
m = Mac.getInstance("HmacSHA256");
m.init(new SecretKeySpec(keyBytes, m.getAlgorithm()));
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("HmacSHA256 is not available");
throw new IllegalStateException("HmacSHA256 is not available", e);
} catch (InvalidKeyException e) {
throw new IllegalStateException("Key is corrupted", e);
}
// Mac the package name and each of the signatures.
byte[] packageNameBytes = packageInfo.packageName.getBytes(StandardCharsets.UTF_8);
m.update(getLengthPrefix(packageNameBytes), 0, 4);
m.update(packageNameBytes);
for (int i = 0; i < packageInfo.signatures.length; i++) {
byte[] sig = packageInfo.signatures[i].toByteArray();
m.update(getLengthPrefix(sig), 0, 4);
m.update(sig);
}
md.update(keyBytes);
md.update(packageInfo.packageName.getBytes(StandardCharsets.UTF_8));
md.update(packageInfo.signatures[0].toByteArray());
// Convert result to a string for storage in settings table. Only want first 64 bits.
final String ssaid = ByteStringUtils.toString(md.digest()).substring(0, 16)
.toLowerCase();
final String ssaid = ByteStringUtils.toHexString(m.doFinal()).substring(0, 16)
.toLowerCase(Locale.US);
// Save the ssaid in the ssaid table.
final String uid = Integer.toString(packageInfo.applicationInfo.uid);