services/camera/libcameraservice/utils/AttributionAndPermissionUtils.h

/*
 * Copyright (C) 2024 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.
 */
#ifndef ANDROID_SERVERS_CAMERA_ATTRIBUTION_AND_PERMISSION_UTILS_H
#define ANDROID_SERVERS_CAMERA_ATTRIBUTION_AND_PERMISSION_UTILS_H

#include <android/content/AttributionSourceState.h>
#include <android/permission/PermissionChecker.h>
#include <binder/BinderService.h>
#include <private/android_filesystem_config.h>

namespace android {

class CameraService;

using content::AttributionSourceState;
using permission::PermissionChecker;

/**
 * Utility class consolidating methods/data for verifying permissions and the identity of the
 * caller.
 */
class AttributionAndPermissionUtils {
  public:
    AttributionAndPermissionUtils() { }
    virtual ~AttributionAndPermissionUtils() {}

    void setCameraService(wp<CameraService> cameraService) {
        mCameraService = cameraService;
    }

    // Utilities handling Binder calling identities (previously in CameraThreadState)
    virtual int getCallingUid();
    virtual int getCallingPid();
    virtual int64_t clearCallingIdentity();
    virtual void restoreCallingIdentity(int64_t token);

    /**
     * Pre-grants the permission if the attribution source uid is for an automotive
     * privileged client. Otherwise uses system service permission checker to check
     * for the appropriate permission. If this function is called for accessing a specific
     * camera,then the cameraID must not be empty. CameraId is used only in case of automotive
     * privileged client so that permission is pre-granted only to access system camera device
     * which is located outside of the vehicle body frame because camera located inside the vehicle
     * cabin would need user permission.
     */
    virtual bool checkPermissionForPreflight(const std::string &cameraId,
            const std::string &permission, const AttributionSourceState& attributionSource,
            const std::string& message, int32_t attributedOpCode);

    // Can camera service trust the caller based on the calling UID?
    virtual bool isTrustedCallingUid(uid_t uid);

    virtual bool isAutomotiveDevice();
    virtual bool isHeadlessSystemUserMode();

    /**
     * Returns true if the client has uid AID_AUTOMOTIVE_EVS and the device is an automotive device.
     */
    virtual bool isAutomotivePrivilegedClient(int32_t uid);

    virtual status_t getUidForPackage(const std::string &packageName, int userId,
            /*inout*/uid_t& uid, int err);
    virtual bool isCallerCameraServerNotDelegating();

    // Utils for checking specific permissions
    virtual bool hasPermissionsForCamera(const std::string& cameraId,
            const AttributionSourceState& attributionSource);
    virtual bool hasPermissionsForSystemCamera(const std::string& cameraId,
            const AttributionSourceState& attributionSource, bool checkCameraPermissions = true);
    virtual bool hasPermissionsForCameraHeadlessSystemUser(const std::string& cameraId,
            const AttributionSourceState& attributionSource);
    virtual bool hasPermissionsForCameraPrivacyAllowlist(
            const AttributionSourceState& attributionSource);
    virtual bool hasPermissionsForOpenCloseListener(
            const AttributionSourceState& attributionSource);

    static const std::string sDumpPermission;
    static const std::string sManageCameraPermission;
    static const std::string sCameraPermission;
    static const std::string sSystemCameraPermission;
    static const std::string sCameraHeadlessSystemUserPermission;
    static const std::string sCameraPrivacyAllowlistPermission;
    static const std::string sCameraSendSystemEventsPermission;
    static const std::string sCameraOpenCloseListenerPermission;
    static const std::string sCameraInjectExternalCameraPermission;

  protected:
    wp<CameraService> mCameraService;

    bool checkAutomotivePrivilegedClient(const std::string &cameraId,
            const AttributionSourceState &attributionSource);

  private:
    std::unique_ptr<permission::PermissionChecker> mPermissionChecker =
            std::make_unique<permission::PermissionChecker>();
};

/**
 * Class to be inherited by classes encapsulating AttributionAndPermissionUtils. Provides an
 * additional utility layer above AttributionAndPermissionUtils calls, and avoids verbosity
 * in the encapsulating class's methods.
 */
class AttributionAndPermissionUtilsEncapsulator {
protected:
    std::shared_ptr<AttributionAndPermissionUtils> mAttributionAndPermissionUtils;

public:
    AttributionAndPermissionUtilsEncapsulator(
        std::shared_ptr<AttributionAndPermissionUtils> attributionAndPermissionUtils)
            : mAttributionAndPermissionUtils(attributionAndPermissionUtils) { }

    static AttributionSourceState buildAttributionSource(int callingPid, int callingUid) {
        AttributionSourceState attributionSource{};
        attributionSource.pid = callingPid;
        attributionSource.uid = callingUid;
        return attributionSource;
    }

    static AttributionSourceState buildAttributionSource(int callingPid, int callingUid,
            int32_t deviceId) {
        AttributionSourceState attributionSource = buildAttributionSource(callingPid, callingUid);
        attributionSource.deviceId = deviceId;
        return attributionSource;
    }

    static AttributionSourceState buildAttributionSource(int callingPid, int callingUid,
            const std::string& packageName, int32_t deviceId) {
        AttributionSourceState attributionSource = buildAttributionSource(callingPid, callingUid,
                deviceId);
        attributionSource.packageName = packageName;
        return attributionSource;
    }

    int getCallingUid() const {
        return mAttributionAndPermissionUtils->getCallingUid();
    }

    int getCallingPid() const {
        return mAttributionAndPermissionUtils->getCallingPid();
    }

    int64_t clearCallingIdentity() const {
        return mAttributionAndPermissionUtils->clearCallingIdentity();
    }

    void restoreCallingIdentity(int64_t token) const {
        mAttributionAndPermissionUtils->restoreCallingIdentity(token);
    }

    // The word 'System' here does not refer to callers only on the system
    // partition. They just need to have an android system uid.
    bool callerHasSystemUid() const {
        return (getCallingUid() < AID_APP_START);
    }

    bool hasPermissionsForCamera(int callingPid, int callingUid, int32_t deviceId) const {
        return hasPermissionsForCamera(std::string(), callingPid, callingUid, deviceId);
    }

    bool hasPermissionsForCamera(int callingPid, int callingUid,
            const std::string& packageName, int32_t deviceId) const {
        return hasPermissionsForCamera(std::string(), callingPid, callingUid, packageName,
                deviceId);
    }

    bool hasPermissionsForCamera(const std::string& cameraId, int callingPid,
            int callingUid, int32_t deviceId) const {
        auto attributionSource = buildAttributionSource(callingPid, callingUid,
                deviceId);
        return mAttributionAndPermissionUtils->hasPermissionsForCamera(cameraId, attributionSource);
    }

    bool hasPermissionsForCamera(const std::string& cameraId, int callingPid, int callingUid,
            const std::string& packageName, int32_t deviceId) const {
        auto attributionSource = buildAttributionSource(callingPid, callingUid, packageName,
                deviceId);
        return mAttributionAndPermissionUtils->hasPermissionsForCamera(cameraId, attributionSource);
    }

    bool hasPermissionsForSystemCamera(const std::string& cameraId, int callingPid, int callingUid,
            bool checkCameraPermissions = true) const  {
        auto attributionSource = buildAttributionSource(callingPid, callingUid);
        return mAttributionAndPermissionUtils->hasPermissionsForSystemCamera(
                    cameraId, attributionSource, checkCameraPermissions);
    }

    bool hasPermissionsForCameraHeadlessSystemUser(const std::string& cameraId, int callingPid,
            int callingUid) const {
        auto attributionSource = buildAttributionSource(callingPid, callingUid);
        return mAttributionAndPermissionUtils->hasPermissionsForCameraHeadlessSystemUser(
                    cameraId, attributionSource);
    }

    bool hasPermissionsForCameraPrivacyAllowlist(int callingPid, int callingUid) const {
        auto attributionSource = buildAttributionSource(callingPid, callingUid);
        return mAttributionAndPermissionUtils->hasPermissionsForCameraPrivacyAllowlist(
                attributionSource);
    }

    bool hasPermissionsForOpenCloseListener(int callingPid, int callingUid) const {
        auto attributionSource = buildAttributionSource(callingPid, callingUid);
        return mAttributionAndPermissionUtils->hasPermissionsForOpenCloseListener(
                attributionSource);
    }

    bool isAutomotiveDevice() const {
        return mAttributionAndPermissionUtils->isAutomotiveDevice();
    }

    bool isAutomotivePrivilegedClient(int32_t uid) const {
        return mAttributionAndPermissionUtils->isAutomotivePrivilegedClient(uid);
    }

    bool isTrustedCallingUid(uid_t uid) const {
        return mAttributionAndPermissionUtils->isTrustedCallingUid(uid);
    }

    bool isHeadlessSystemUserMode() const {
        return mAttributionAndPermissionUtils->isHeadlessSystemUserMode();
    }

    status_t getUidForPackage(const std::string &packageName, int userId,
            /*inout*/uid_t& uid, int err) const {
        return mAttributionAndPermissionUtils->getUidForPackage(packageName, userId, uid, err);
    }

    bool isCallerCameraServerNotDelegating() const {
        return mAttributionAndPermissionUtils->isCallerCameraServerNotDelegating();
    }
};

} // namespace android

#endif // ANDROID_SERVERS_CAMERA_ATTRIBUTION_AND_PERMISSION_UTILS_H