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Update storage permission policy to use AppCompat APIs.

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This CL introduces ENABLE_SCOPED_STORAGE and REQUIRE_SCOPED_STORAGE as
AppCompat changes that are enabled for apps with targetSDK > P and apps
with targetSDK > Q respectively.

This change removes the getMinimumTargetSDK method, as it
is no longer needed.

Change-Id: I6b05252d42d3b2f1030928ffd03c02523c5a01d2
Fix: 147034231
Bug: 144914977
Bug: 131432978
Test: atest RestrictedPermissionsTest
Test: atest RestrictedStoragePermissionSharedUidTest
This commit is contained in:
Bram Bonné
2020-02-06 09:16:13 +01:00
parent 6a1e0b72e3
commit d377354696
1 changed files with 105 additions and 49 deletions
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154
services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java
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@@ -27,16 +27,22 @@ import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_SYST
import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_UPGRADE_EXEMPT;
import static android.content.pm.PackageManager.PERMISSION_GRANTED;
import static java.lang.Integer.min;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.AppOpsManager;
import android.compat.annotation.ChangeId;
import android.compat.annotation.EnabledAfter;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Binder;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.UserHandle;
import android.util.Log;
import com.android.internal.compat.IPlatformCompat;
/**
* The behavior of soft restricted permissions is different for each permission. This class collects
@@ -46,6 +52,27 @@ import android.os.UserHandle;
* {@link com.android.packageinstaller.permission.utils.SoftRestrictedPermissionPolicy}
*/
public abstract class SoftRestrictedPermissionPolicy {
/**
* Enables scoped storage, with exceptions for apps that explicitly request legacy access, or
* apps that hold the {@code android.Manifest.permission#WRITE_MEDIA_STORAGE} permission.
* See https://developer.android.com/training/data-storage#scoped-storage for more information.
*/
@ChangeId
// This change is enabled for apps with targetSDK > {@link android.os.Build.VERSION_CODES.P}
@EnabledAfter(targetSdkVersion = android.os.Build.VERSION_CODES.P)
static final long ENABLE_SCOPED_STORAGE = 144914977L;
/**
* Enforces scoped storage for all apps, preventing individual apps from opting out. This change
* has precedence over {@code ENABLE_SCOPED_STORAGE}.
*/
@ChangeId
// This change is enabled for apps with targetSDK > {@link android.os.Build.VERSION_CODES.Q}.
@EnabledAfter(targetSdkVersion = android.os.Build.VERSION_CODES.Q)
static final long REQUIRE_SCOPED_STORAGE = 131432978L;
private static final String LOG_TAG = SoftRestrictedPermissionPolicy.class.getSimpleName();
private static final int FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT =
FLAG_PERMISSION_RESTRICTION_SYSTEM_EXEMPT
| FLAG_PERMISSION_RESTRICTION_UPGRADE_EXEMPT
@@ -59,41 +86,6 @@ public abstract class SoftRestrictedPermissionPolicy {
}
};
/**
* TargetSDK is per package. To make sure two apps int the same shared UID do not fight over
* what to set, always compute the combined targetSDK.
*
* @param context A context
* @param appInfo The app that is changed
* @param user The user the app belongs to
*
* @return The minimum targetSDK of all apps sharing the uid of the app
*/
private static int getMinimumTargetSDK(@NonNull Context context,
@NonNull ApplicationInfo appInfo, @NonNull UserHandle user) {
PackageManager pm = context.getPackageManager();
int minimumTargetSDK = appInfo.targetSdkVersion;
String[] uidPkgs = pm.getPackagesForUid(appInfo.uid);
if (uidPkgs != null) {
for (String uidPkg : uidPkgs) {
if (!uidPkg.equals(appInfo.packageName)) {
ApplicationInfo uidPkgInfo;
try {
uidPkgInfo = pm.getApplicationInfoAsUser(uidPkg, 0, user);
} catch (PackageManager.NameNotFoundException e) {
continue;
}
minimumTargetSDK = min(minimumTargetSDK, uidPkgInfo.targetSdkVersion);
}
}
}
return minimumTargetSDK;
}
/**
* Get the policy for a soft restricted permission.
*
@@ -114,27 +106,31 @@ public abstract class SoftRestrictedPermissionPolicy {
case READ_EXTERNAL_STORAGE: {
final boolean isWhiteListed;
boolean shouldApplyRestriction;
final int targetSDK;
final boolean hasRequestedLegacyExternalStorage;
final boolean hasWriteMediaStorageGrantedForUid;
final boolean isScopedStorageEnabled;
if (appInfo != null) {
PackageManager pm = context.getPackageManager();
int flags = pm.getPermissionFlags(permission, appInfo.packageName, user);
isWhiteListed = (flags & FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT) != 0;
targetSDK = getMinimumTargetSDK(context, appInfo, user);
shouldApplyRestriction = (flags & FLAG_PERMISSION_APPLY_RESTRICTION) != 0
|| targetSDK > Build.VERSION_CODES.Q;
hasRequestedLegacyExternalStorage = hasUidRequestedLegacyExternalStorage(
appInfo.uid, context);
hasWriteMediaStorageGrantedForUid = hasWriteMediaStorageGrantedForUid(
appInfo.uid, context);
final boolean isScopedStorageRequired =
isChangeEnabledForUid(context, appInfo, user, REQUIRE_SCOPED_STORAGE);
isScopedStorageEnabled =
isChangeEnabledForUid(context, appInfo, user, ENABLE_SCOPED_STORAGE)
|| isScopedStorageRequired;
shouldApplyRestriction = (flags & FLAG_PERMISSION_APPLY_RESTRICTION) != 0
|| isScopedStorageRequired;
} else {
isWhiteListed = false;
shouldApplyRestriction = false;
targetSDK = 0;
hasRequestedLegacyExternalStorage = false;
hasWriteMediaStorageGrantedForUid = false;
isScopedStorageEnabled = false;
}
// We have a check in PermissionPolicyService.PermissionToOpSynchroniser.setUidMode
@@ -144,7 +140,7 @@ public abstract class SoftRestrictedPermissionPolicy {
return new SoftRestrictedPermissionPolicy() {
@Override
public boolean mayGrantPermission() {
return isWhiteListed || targetSDK >= Build.VERSION_CODES.Q;
return isWhiteListed || isScopedStorageEnabled;
}
@Override
public int getExtraAppOpCode() {
@@ -152,7 +148,7 @@ public abstract class SoftRestrictedPermissionPolicy {
}
@Override
public boolean mayAllowExtraAppOp() {
return !shouldApplyRestriction && targetSDK <= Build.VERSION_CODES.Q
return !shouldApplyRestriction
&& (hasRequestedLegacyExternalStorage
|| hasWriteMediaStorageGrantedForUid);
}
@@ -164,22 +160,26 @@ public abstract class SoftRestrictedPermissionPolicy {
}
case WRITE_EXTERNAL_STORAGE: {
final boolean isWhiteListed;
final int targetSDK;
final boolean isScopedStorageEnabled;
if (appInfo != null) {
final int flags = context.getPackageManager().getPermissionFlags(permission,
appInfo.packageName, user);
isWhiteListed = (flags & FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT) != 0;
targetSDK = getMinimumTargetSDK(context, appInfo, user);
final boolean isScopedStorageRequired =
isChangeEnabledForUid(context, appInfo, user, REQUIRE_SCOPED_STORAGE);
isScopedStorageEnabled =
isChangeEnabledForUid(context, appInfo, user, ENABLE_SCOPED_STORAGE)
|| isScopedStorageRequired;
} else {
isWhiteListed = false;
targetSDK = 0;
isScopedStorageEnabled = false;
}
return new SoftRestrictedPermissionPolicy() {
@Override
public boolean mayGrantPermission() {
return isWhiteListed || targetSDK >= Build.VERSION_CODES.Q;
return isWhiteListed || isScopedStorageEnabled;
}
};
}
@@ -188,6 +188,62 @@ public abstract class SoftRestrictedPermissionPolicy {
}
}
/**
* Checks whether an AppCompat change is enabled for all packages sharing a UID with the
* provided application.
*
* @param context A context to use.
* @param appInfo The application for which to check whether the compat change is enabled.
* @param user The user the app belongs to.
* @param changeId A {@link android.compat.annotation.ChangeId} corresponding to the change.
*
* @return true if this change is enabled for all apps sharing the UID of the provided app,
* false otherwise.
*/
private static boolean isChangeEnabledForUid(@NonNull Context context,
@NonNull ApplicationInfo appInfo, @NonNull UserHandle user, long changeId) {
PackageManager pm = context.getPackageManager();
String[] uidPackages = pm.getPackagesForUid(appInfo.uid);
if (uidPackages != null) {
for (String uidPackage : uidPackages) {
ApplicationInfo uidPackageInfo;
try {
uidPackageInfo = pm.getApplicationInfoAsUser(uidPackage, 0, user);
} catch (PackageManager.NameNotFoundException e) {
continue;
}
if (!isChangeEnabled(uidPackageInfo, changeId)) {
// At least one package sharing this UID does not have this change enabled.
return false;
}
}
// All packages sharing this UID returned true for {@link #isChangeEnabled()}.
return true;
} else {
Log.w(LOG_TAG, "Check for change " + changeId + " for uid " + appInfo.uid
+ " produced no packages. Defaulting to using the information for "
+ appInfo.packageName + " only.");
return isChangeEnabled(appInfo, changeId);
}
}
private static boolean isChangeEnabled(@NonNull ApplicationInfo appInfo, long changeId) {
IBinder binder = ServiceManager.getService(Context.PLATFORM_COMPAT_SERVICE);
IPlatformCompat platformCompat = IPlatformCompat.Stub.asInterface(binder);
final long callingId = Binder.clearCallingIdentity();
try {
return platformCompat.isChangeEnabled(changeId, appInfo);
} catch (RemoteException e) {
Log.e(LOG_TAG, "Check for change " + changeId + " failed. Defaulting to enabled.", e);
return true;
} finally {
Binder.restoreCallingIdentity(callingId);
}
}
private static boolean hasUidRequestedLegacyExternalStorage(int uid, @NonNull Context context) {
PackageManager packageManager = context.getPackageManager();
String[] packageNames = packageManager.getPackagesForUid(uid);