4.3.1.3 创建/使用伙伴内容供应器
合作伙伴内容供应器只能由特定应用使用。 该系统由伙伴公司的应用和内部应用组成，用于保护在伙伴应用和内部应用之间处理的信息和功能。
下面显示了用于实现伙伴内容供应器的示例代码。
要点（创建内容供应器）：
-
将导出属性显式设置为
true。 -
验证请求应用的证书是否已在自己的白名单中注册。
-
即使数据来自伙伴应用，也要小心并安全地处理收到的请求数据。
-
可以返回开放给伙伴应用的信息。
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.jssec.android.provider.partnerprovider">
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<!-- *** POINT 1 *** Explicitly set the exported attribute to true. -->
<provider
android:name=".PartnerProvider"
android:authorities="org.jssec.android.provider.partnerprovider"
android:exported="true" />
</application>
</manifest>
PartnerProvider.java
package org.jssec.android.provider.partnerprovider;
import java.util.List;
import org.jssec.android.shared.PkgCertWhitelists;
import org.jssec.android.shared.Utils;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.os.Binder;
import android.os.Build;
public class PartnerProvider extends ContentProvider {
public static final String AUTHORITY = "org.jssec.android.provider.partnerprovider";
public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.org.jssec.contenttype";
public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.org.jssec.contenttype";
// Expose the interface that the Content Provider provides.
public interface Download {
public static final String PATH = "downloads";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + PATH);
}
public interface Address {
public static final String PATH = "addresses";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + PATH);
}
// UriMatcher
private static final int DOWNLOADS_CODE = 1;
private static final int DOWNLOADS_ID_CODE = 2;
private static final int ADDRESSES_CODE = 3;
private static final int ADDRESSES_ID_CODE = 4;
private static UriMatcher sUriMatcher;
static {
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(AUTHORITY, Download.PATH, DOWNLOADS_CODE);
sUriMatcher.addURI(AUTHORITY, Download.PATH + "/#", DOWNLOADS_ID_CODE);
sUriMatcher.addURI(AUTHORITY, Address.PATH, ADDRESSES_CODE);
sUriMatcher.addURI(AUTHORITY, Address.PATH + "/#", ADDRESSES_ID_CODE);
}
// Since this is a sample program,
// query method returns the following fixed result always without using database.
private static MatrixCursor sAddressCursor = new MatrixCursor(new String[] { "_id", "city" });
static {
sAddressCursor.addRow(new String[] { "1", "New York" });
sAddressCursor.addRow(new String[] { "2", "London" });
sAddressCursor.addRow(new String[] { "3", "Paris" });
}
private static MatrixCursor sDownloadCursor = new MatrixCursor(new String[] { "_id", "path" });
static {
sDownloadCursor.addRow(new String[] { "1", "/sdcard/downloads/sample.jpg" });
sDownloadCursor.addRow(new String[] { "2", "/sdcard/downloads/sample.txt" });
}
// *** POINT 2 *** Verify if the certificate of a requesting application has been registered in the
own white list.
private static PkgCertWhitelists sWhitelists = null;
private static void buildWhitelists(Context context) {
boolean isdebug = Utils.isDebuggable(context);
sWhitelists = new PkgCertWhitelists();
// Register certificate hash value of partner application org.jssec.android.provider.partneruser.
sWhitelists.add("org.jssec.android.provider.partneruser", isdebug ?
// Certificate hash value of "androiddebugkey" in the debug.keystore.
"0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255" :
// Certificate hash value of "partner key" in the keystore.
"1F039BB5 7861C27A 3916C778 8E78CE00 690B3974 3EB8259F E2627B8D 4C0EC35A");
// Register following other partner applications in the same way.
}
private static boolean checkPartner(Context context, String pkgname) {
if (sWhitelists == null) buildWhitelists(context);
return sWhitelists.test(context, pkgname);
}
// Get the package name of the calling application.
private String getCallingPackage(Context context) {
String pkgname;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
pkgname = super.getCallingPackage();
} else {
pkgname = null;
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo> procList = am.getRunningAppProcesses();
int callingPid = Binder.getCallingPid();
if (procList != null) {
for (RunningAppProcessInfo proc : procList) {
if (proc.pid == callingPid) {
pkgname = proc.pkgList[proc.pkgList.length - 1];
break;
}
}
}
}
return pkgname;
}
@Override
public boolean onCreate() {
return true;
}
@Override
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
case DOWNLOADS_CODE:
case ADDRESSES_CODE:
return CONTENT_TYPE;
case DOWNLOADS_ID_CODE:
case ADDRESSES_ID_CODE:
return CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Invalid URI:" + uri);
}
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
// *** POINT 2 *** Verify if the certificate of a requesting application has been registered in the own white list.
if (!checkPartner(getContext(), getCallingPackage(getContext()))) {
throw new SecurityException("Calling application is not a partner application.");
}
// *** POINT 3 *** Handle the received request data carefully and securely,
// even though the data comes from a partner application.
// Here, whether uri is within expectations or not, is verified by UriMatcher#match() and switch case.
// Checking for other parameters are omitted here, due to sample.
// Refer to "3.2 Handle Input Data Carefully and Securely."
// *** POINT 4 *** Information that is granted to disclose to partner applications can be returned.
// It depends on application whether the query result can be disclosed or not.
switch (sUriMatcher.match(uri)) {
case DOWNLOADS_CODE:
case DOWNLOADS_ID_CODE:
return sDownloadCursor;
case ADDRESSES_CODE:
case ADDRESSES_ID_CODE:
return sAddressCursor;
default:
throw new IllegalArgumentException("Invalid URI:" + uri);
}
}
@Override
public Uri insert(Uri uri, ContentValues values) {
// *** POINT 2 *** Verify if the certificate of a requesting application has been registered in the own white list.
if (!checkPartner(getContext(), getCallingPackage(getContext()))) {
throw new SecurityException("Calling application is not a partner application.");
}
// *** POINT 3 *** Handle the received request data carefully and securely,
// even though the data comes from a partner application.
// Here, whether uri is within expectations or not, is verified by UriMatcher#match() and switch case.
// Checking for other parameters are omitted here, due to sample.
// Refer to "3.2 Handle Input Data Carefully and Securely."
// *** POINT 4 *** Information that is granted to disclose to partner applications can be returned.
// It depends on application whether the issued ID has sensitive meaning or not.
switch (sUriMatcher.match(uri)) {
case DOWNLOADS_CODE:
return ContentUris.withAppendedId(Download.CONTENT_URI, 3);
case ADDRESSES_CODE:
return ContentUris.withAppendedId(Address.CONTENT_URI, 4);
default:
throw new IllegalArgumentException("Invalid URI:" + uri);
}
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
// *** POINT 2 *** Verify if the certificate of a requesting application has been registered in the own white list.
if (!checkPartner(getContext(), getCallingPackage(getContext()))) {
throw new SecurityException("Calling application is not a partner application.");
}
// *** POINT 3 *** Handle the received request data carefully and securely,
// even though the data comes from a partner application.
// Here, whether uri is within expectations or not, is verified by UriMatcher#match() and switch case.
// Checking for other parameters are omitted here, due to sample.
// Refer to "3.2 Handle Input Data Carefully and Securely."
// *** POINT 4 *** Information that is granted to disclose to partner applications can be returned.
// It depends on application whether the number of updated records has sensitive meaning or not.
switch (sUriMatcher.match(uri)) {
case DOWNLOADS_CODE:
return 5; // Return number of updated records
case DOWNLOADS_ID_CODE:
return 1;
case ADDRESSES_CODE:
return 15;
case ADDRESSES_ID_CODE:
return 1;
default:
throw new IllegalArgumentException("Invalid URI:" + uri);
}
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
// *** POINT 2 *** Verify if the certificate of a requesting application has been registered in the own white list.
if (!checkPartner(getContext(), getCallingPackage(getContext()))) {
throw new SecurityException("Calling application is not a partner application.");
}
// *** POINT 3 *** Handle the received request data carefully and securely,
// even though the data comes from a partner application.
// Here, whether uri is within expectations or not, is verified by UriMatcher#match() and switch case.
// Checking for other parameters are omitted here, due to sample.
// Refer to "3.2 Handle Input Data Carefully and Securely."
// *** POINT 4 *** Information that is granted to disclose to partner applications can be returned.
// It depends on application whether the number of deleted records has sensitive meaning or not.
switch (sUriMatcher.match(uri)) {
case DOWNLOADS_CODE:
return 10; // Return number of deleted records
case DOWNLOADS_ID_CODE:
return 1;
case ADDRESSES_CODE:
return 20;
case ADDRESSES_ID_CODE:
return 1;
default:
throw new IllegalArgumentException("Invalid URI:" + uri);
}
}
}
下面是使用伙伴内容供应器的活动示例：
要点（使用内容供应器）：
-
验证目标应用的证书是否已在自己的白名单中注册。
-
可以发送开放给伙伴应用的信息。
-
即使数据来自伙伴应用，也要小心并安全地处理收到的结果数据。
PartnerActivity.java
package org.jssec.android.provider.partneruser;
import org.jssec.android.shared.PkgCertWhitelists;
import org.jssec.android.shared.Utils;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.pm.ProviderInfo;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class PartnerUserActivity extends Activity {
// Target Content Provider Information
private static final String AUTHORITY = "org.jssec.android.provider.partnerprovider";
private interface Address {
public static final String PATH = "addresses";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + PATH);
}
// *** POINT 4 *** Verify if the certificate of the target application has been registered in the own white list.
private static PkgCertWhitelists sWhitelists = null;
private static void buildWhitelists(Context context) {
boolean isdebug = Utils.isDebuggable(context);
sWhitelists = new PkgCertWhitelists();
// Register certificate hash value of partner application org.jssec.android.provider.partnerprovider.
sWhitelists.add("org.jssec.android.provider.partnerprovider", isdebug ?
// Certificate hash value of "androiddebugkey" in the debug.keystore.
"0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255" :
// Certificate hash value of "partner key" in the keystore.
"D397D343 A5CBC10F 4EDDEB7C A10062DE 5690984F 1FB9E88B D7B3A7C2 42E142CA");
// Register following other partner applications in the same way.
}
private static boolean checkPartner(Context context, String pkgname) {
if (sWhitelists == null) buildWhitelists(context);
return sWhitelists.test(context, pkgname);
}
// Get package name of target content provider.
private String providerPkgname(Uri uri) {
String pkgname = null;
ProviderInfo pi = getPackageManager().resolveContentProvider(uri.getAuthority(), 0);
if (pi != null) pkgname = pi.packageName;
return pkgname;
}
public void onQueryClick(View view) {
logLine("[Query]");
// *** POINT 4 *** Verify if the certificate of the target application has been registered in the own white list.
if (!checkPartner(this, providerPkgname(Address.CONTENT_URI))) {
logLine(" The target content provider is not served by partner applications.");
return;
}
Cursor cursor = null;
try {
// *** POINT 5 *** Information that is granted to disclose to partner applications can be sent.
cursor = getContentResolver().query(Address.CONTENT_URI, null, null, null, null);
// *** POINT 6 *** Handle the received result data carefully and securely,
// even though the data comes from a partner application.
// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
if (cursor == null) {
logLine(" null cursor");
} else {
boolean moved = cursor.moveToFirst();
while (moved) {
logLine(String.format(" %d, %s", cursor.getInt(0), cursor.getString(1)));
moved = cursor.moveToNext();
}
}
}
finally {
if (cursor != null) cursor.close();
}
}
public void onInsertClick(View view) {
logLine("[Insert]");
// *** POINT 4 *** Verify if the certificate of the target application has been registered in the own white list.
if (!checkPartner(this, providerPkgname(Address.CONTENT_URI))) {
logLine(" The target content provider is not served by partner applications.");
return;
}
// *** POINT 5 *** Information that is granted to disclose to partner applications can be sent.
ContentValues values = new ContentValues();
values.put("city", "Tokyo");
Uri uri = getContentResolver().insert(Address.CONTENT_URI, values);
// *** POINT 6 *** Handle the received result data carefully and securely,
// even though the data comes from a partner application.
// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
logLine(" uri:" + uri);
}
public void onUpdateClick(View view) {
logLine("[Update]");
// *** POINT 4 *** Verify if the certificate of the target application has been registered in the own white list.
if (!checkPartner(this, providerPkgname(Address.CONTENT_URI))) {
logLine(" The target content provider is not served by partner applications.");
return;
}
// *** POINT 5 *** Information that is granted to disclose to partner applications can be sent.
ContentValues values = new ContentValues();
values.put("city", "Tokyo");
String where = "_id = ?";
String[] args = { "4" };
int count = getContentResolver().update(Address.CONTENT_URI, values, where, args);
// *** POINT 6 *** Handle the received result data carefully and securely,
// even though the data comes from a partner application.
// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
logLine(String.format(" %s records updated", count));
}
public void onDeleteClick(View view) {
logLine("[Delete]");
// *** POINT 4 *** Verify if the certificate of the target application has been registered in the own white list.
if (!checkPartner(this, providerPkgname(Address.CONTENT_URI))) {
logLine(" The target content provider is not served by partner applications.");
return;
}
// *** POINT 5 *** Information that is granted to disclose to partner applications can be sent.
int count = getContentResolver().delete(Address.CONTENT_URI, null, null);
// *** POINT 6 *** Handle the received result data carefully and securely,
// even though the data comes from a partner application.
// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
logLine(String.format(" %s records deleted", count));
}
private TextView mLogView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mLogView = (TextView)findViewById(R.id.logview);
}
private void logLine(String line) {
mLogView.append(line);
mLogView.append("¥n");
}
}
PkgCertWhitelists.java
package org.jssec.android.shared;
import java.util.HashMap;
import java.util.Map;
import android.content.Context;
public class PkgCertWhitelists {
private Map<String, String> mWhitelists = new HashMap<String, String>();
public boolean add(String pkgname, String sha256) {
if (pkgname == null) return false;
if (sha256 == null) return false;
sha256 = sha256.replaceAll(" ", "");
if (sha256.length() != 64) return false; // SHA-256 -> 32 bytes -> 64 chars
sha256 = sha256.toUpperCase();
if (sha256.replaceAll("[0-9A-F]+", "").length() != 0) return false; // found non hex char
mWhitelists.put(pkgname, sha256);
return true;
}
public boolean test(Context ctx, String pkgname) {
// Get the correct hash value which corresponds to pkgname.
String correctHash = mWhitelists.get(pkgname);
// Compare the actual hash value of pkgname with the correct hash value.
return PkgCert.test(ctx, pkgname, correctHash);
}
}
PkgCert.java
package org.jssec.android.shared;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;
public class PkgCert {
public static boolean test(Context ctx, String pkgname, String correctHash) {
if (correctHash == null) return false;
correctHash = correctHash.replaceAll(" ", "");
return correctHash.equals(hash(ctx, pkgname));
}
public static String hash(Context ctx, String pkgname) {
if (pkgname == null) return null;
try {
PackageManager pm = ctx.getPackageManager();
PackageInfo pkginfo = pm.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);
if (pkginfo.signatures.length != 1) return null; // Will not handle multiple signatures.
Signature sig = pkginfo.signatures[0];
byte[] cert = sig.toByteArray();
byte[] sha256 = computeSha256(cert);
return byte2hex(sha256);
} catch (NameNotFoundException e) {
return null;
}
}
private static byte[] computeSha256(byte[] data) {
try {
return MessageDigest.getInstance("SHA-256").digest(data);
} catch (NoSuchAlgorithmException e) {
return null;
}
}
private static String byte2hex(byte[] data) {
if (data == null) return null;
final StringBuilder hexadecimal = new StringBuilder();
for (final byte b : data) {
hexadecimal.append(String.format("%02X", b));
}
return hexadecimal.toString();
}
}
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