99b49840d3
This is intended to absorb the cost of the IPC to the permission controller. Cached permission checks cost about 3us, while full blown ones are two orders of magnitude slower. CAVEAT: PermissionCache can only handle system permissions safely for now, because the cache is not purged upon global permission changes. Change-Id: I8b8a5e71e191e3c01e8f792f253c379190eee62e
114 lines
3.4 KiB
C++
114 lines
3.4 KiB
C++
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "PermissionCache"
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#include <stdint.h>
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#include <utils/Log.h>
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#include <binder/IPCThreadState.h>
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#include <binder/IServiceManager.h>
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#include <binder/PermissionCache.h>
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#include <utils/String8.h>
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namespace android {
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// ----------------------------------------------------------------------------
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ANDROID_SINGLETON_STATIC_INSTANCE(PermissionCache) ;
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// ----------------------------------------------------------------------------
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PermissionCache::PermissionCache() {
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}
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status_t PermissionCache::check(bool* granted,
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const String16& permission, uid_t uid) const {
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Mutex::Autolock _l(mLock);
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Entry e;
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e.name = permission;
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e.uid = uid;
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ssize_t index = mCache.indexOf(e);
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if (index >= 0) {
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*granted = mCache.itemAt(index).granted;
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return NO_ERROR;
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}
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return NAME_NOT_FOUND;
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}
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void PermissionCache::cache(const String16& permission,
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uid_t uid, bool granted) {
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Mutex::Autolock _l(mLock);
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Entry e;
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ssize_t index = mPermissionNamesPool.indexOf(permission);
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if (index > 0) {
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e.name = mPermissionNamesPool.itemAt(index);
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} else {
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mPermissionNamesPool.add(permission);
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e.name = permission;
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}
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// note, we don't need to store the pid, which is not actually used in
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// permission checks
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e.uid = uid;
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e.granted = granted;
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index = mCache.indexOf(e);
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if (index < 0) {
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mCache.add(e);
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}
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}
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void PermissionCache::purge() {
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Mutex::Autolock _l(mLock);
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mCache.clear();
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}
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bool PermissionCache::checkCallingPermission(const String16& permission) {
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return PermissionCache::checkCallingPermission(permission, NULL, NULL);
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}
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bool PermissionCache::checkCallingPermission(
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const String16& permission, int32_t* outPid, int32_t* outUid) {
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IPCThreadState* ipcState = IPCThreadState::self();
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pid_t pid = ipcState->getCallingPid();
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uid_t uid = ipcState->getCallingUid();
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if (outPid) *outPid = pid;
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if (outUid) *outUid = uid;
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return PermissionCache::checkPermission(permission, pid, uid);
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}
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bool PermissionCache::checkPermission(
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const String16& permission, pid_t pid, uid_t uid) {
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if ((uid == 0) || (pid == getpid())) {
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// root and ourselves is always okay
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return true;
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}
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PermissionCache& pc(PermissionCache::getInstance());
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bool granted = false;
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if (pc.check(&granted, permission, uid) != NO_ERROR) {
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nsecs_t t = -systemTime();
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granted = android::checkPermission(permission, pid, uid);
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t += systemTime();
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LOGD("checking %s for uid=%d => %s (%d us)",
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String8(permission).string(), uid,
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granted?"granted":"denied", (int)ns2us(t));
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pc.cache(permission, uid, granted);
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}
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return granted;
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}
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// ---------------------------------------------------------------------------
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}; // namespace android
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