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/*
* Copyright (C) 2020 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.
*/
@file:JvmName("AutoRevokePermissions")
package com.android.permissioncontroller.permission.service
import android.Manifest
import android.content.Context
import android.content.pm.PackageManager.FLAG_PERMISSION_AUTO_REVOKED
import android.content.pm.PackageManager.FLAG_PERMISSION_USER_SET
import android.os.UserHandle
import android.os.UserManager
import android.permission.PermissionManager
import androidx.annotation.MainThread
import com.android.permissioncontroller.Constants.INVALID_SESSION_ID
import com.android.permissioncontroller.DumpableLog
import com.android.permissioncontroller.PermissionControllerStatsLog
import com.android.permissioncontroller.PermissionControllerStatsLog.PERMISSION_GRANT_REQUEST_RESULT_REPORTED
import com.android.permissioncontroller.PermissionControllerStatsLog.PERMISSION_GRANT_REQUEST_RESULT_REPORTED__RESULT__AUTO_UNUSED_APP_PERMISSION_REVOKED
import com.android.permissioncontroller.hibernation.getUnusedThresholdMs
import com.android.permissioncontroller.permission.utils.PermissionMapping
import com.android.permissioncontroller.permission.data.LightAppPermGroupLiveData
import com.android.permissioncontroller.permission.data.PackagePermissionsLiveData
import com.android.permissioncontroller.permission.data.get
import com.android.permissioncontroller.permission.model.livedatatypes.LightAppPermGroup
import com.android.permissioncontroller.permission.model.livedatatypes.LightPackageInfo
import com.android.permissioncontroller.permission.utils.KotlinUtils
import com.android.permissioncontroller.permission.utils.application
import com.android.permissioncontroller.permission.utils.forEachInParallel
import com.android.permissioncontroller.permission.utils.updatePermissionFlags
import kotlinx.coroutines.Dispatchers.Main
import java.util.concurrent.atomic.AtomicBoolean
private const val LOG_TAG = "AutoRevokePermissions"
const val DEBUG_AUTO_REVOKE = true
private val EXEMPT_PERMISSIONS = listOf(
Manifest.permission.ACTIVITY_RECOGNITION,
Manifest.permission.POST_NOTIFICATIONS)
private val SERVER_LOG_ID =
PERMISSION_GRANT_REQUEST_RESULT_REPORTED__RESULT__AUTO_UNUSED_APP_PERMISSION_REVOKED
/**
* Revoke granted app permissions for apps that should be auto-revoked
*
* @return list of packages that successfully had their permissions revoked
*/
@MainThread
suspend fun revokeAppPermissions(
apps: Map<UserHandle, List<LightPackageInfo>>,
context: Context,
sessionId: Long = INVALID_SESSION_ID
): Set<Pair<String, UserHandle>> {
val revokedApps = mutableSetOf<Pair<String, UserHandle>>()
val userManager = context.getSystemService(UserManager::class.java)
val permissionManager = context.getSystemService(PermissionManager::class.java)!!
val splitPermissionIndex = SplitPermissionIndex(permissionManager.splitPermissions)
for ((user, userApps) in apps) {
if (userManager == null || !userManager.isUserUnlocked(user)) {
DumpableLog.w(LOG_TAG, "Skipping $user - locked direct boot state")
continue
}
val pkgPermChanges = PermissionChangeStorageImpl.getInstance().loadEvents()
.associateBy { it.packageName }
// For each autorevoke-eligible app...
userApps.forEachInParallel(Main) forEachInParallelOuter@ { pkg: LightPackageInfo ->
if (pkg.grantedPermissions.isEmpty()) {
return@forEachInParallelOuter
}
val packageName = pkg.packageName
val pkgPermChange = pkgPermChanges[packageName]
val now = System.currentTimeMillis()
if (pkgPermChange != null && now - pkgPermChange.eventTime < getUnusedThresholdMs()) {
if (DEBUG_AUTO_REVOKE) {
DumpableLog.i(LOG_TAG, "Not revoking because permissions were changed " +
"recently for package $packageName")
}
return@forEachInParallelOuter
}
val targetSdk = pkg.targetSdkVersion
val pkgPermGroups: Map<String, List<String>> =
PackagePermissionsLiveData[packageName, user]
.getInitializedValue() ?: return@forEachInParallelOuter
// Determine which permGroups are revocable
val revocableGroups = mutableSetOf<String>()
for (groupName in pkgPermGroups.keys) {
if (groupName == PackagePermissionsLiveData.NON_RUNTIME_NORMAL_PERMS) {
continue
}
if (groupName !in PermissionMapping.getPlatformPermissionGroups()) {
continue
}
val group: LightAppPermGroup =
LightAppPermGroupLiveData[packageName, groupName, user]
.getInitializedValue() ?: continue
val fixed = group.isBackgroundFixed || group.isForegroundFixed
val granted = group.permissions.any { (_, perm) ->
perm.isGrantedIncludingAppOp && perm.name !in EXEMPT_PERMISSIONS
}
if (!fixed && granted &&
!group.isGrantedByDefault &&
!group.isGrantedByRole &&
!group.isRevokeWhenRequested &&
group.isUserSensitive) {
revocableGroups.add(groupName)
}
}
// Mark any groups that split from an install-time permission as unrevocable
for (fromPerm in
pkgPermGroups[PackagePermissionsLiveData.NON_RUNTIME_NORMAL_PERMS] ?: emptyList()) {
for (toGroup in
splitPermissionIndex.getPermToGroupSplitsFrom(fromPerm, targetSdk)) {
revocableGroups.remove(toGroup)
}
}
// For each unrevocable group, mark all groups that it splits from and to as unrevocable
for (groupName in pkgPermGroups.keys) {
if (!revocableGroups.contains(groupName)) {
for (fromGroup in
splitPermissionIndex.getGroupToGroupSplitsTo(groupName, targetSdk)) {
revocableGroups.remove(fromGroup)
}
for (toGroup in
splitPermissionIndex.getGroupToGroupSplitsFrom(groupName, targetSdk)) {
revocableGroups.remove(toGroup)
}
}
}
// For each revocable group, revoke all of its permissions
val anyPermsRevoked = AtomicBoolean(false)
pkgPermGroups.entries
.filter { revocableGroups.contains(it.key) }
.forEachInParallel(Main) forEachInParallelInner@ { (groupName, _) ->
val group: LightAppPermGroup =
LightAppPermGroupLiveData[packageName, groupName, user]
.getInitializedValue()!!
val revocablePermissions = group.permissions.keys.toList()
if (revocablePermissions.isEmpty()) {
return@forEachInParallelInner
}
if (DEBUG_AUTO_REVOKE) {
DumpableLog.i(LOG_TAG,
"revokeUnused $packageName - $revocablePermissions")
}
val uid = group.packageInfo.uid
for (permName in revocablePermissions) {
PermissionControllerStatsLog.write(
PERMISSION_GRANT_REQUEST_RESULT_REPORTED,
sessionId, uid, packageName, permName, false, SERVER_LOG_ID,
/* permission_rationale_shown = */ false)
}
if (DEBUG_AUTO_REVOKE) {
DumpableLog.i(LOG_TAG, "revoking $packageName - $revocablePermissions")
DumpableLog.i(LOG_TAG, "State pre revocation: ${group.allPermissions}")
}
anyPermsRevoked.compareAndSet(false, true)
val bgRevokedState = KotlinUtils.revokeBackgroundRuntimePermissions(
context.application, group,
userFixed = false, oneTime = false,
filterPermissions = revocablePermissions)
if (DEBUG_AUTO_REVOKE) {
DumpableLog.i(LOG_TAG,
"Bg state post revocation: ${bgRevokedState.allPermissions}")
}
val fgRevokedState = KotlinUtils.revokeForegroundRuntimePermissions(
context.application, group,
userFixed = false, oneTime = false,
filterPermissions = revocablePermissions)
if (DEBUG_AUTO_REVOKE) {
DumpableLog.i(LOG_TAG,
"Fg state post revocation: ${fgRevokedState.allPermissions}")
}
for (permission in revocablePermissions) {
context.packageManager.updatePermissionFlags(
permission, packageName, user,
FLAG_PERMISSION_AUTO_REVOKED to true,
FLAG_PERMISSION_USER_SET to false)
}
}
if (anyPermsRevoked.get()) {
synchronized(revokedApps) {
revokedApps.add(packageName to user)
}
}
}
if (DEBUG_AUTO_REVOKE) {
synchronized(revokedApps) {
DumpableLog.i(LOG_TAG,
"Done auto-revoke for user ${user.identifier} - revoked $revokedApps")
}
}
}
return revokedApps
}
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