cameraserver: Add support for system only cameras

Bug: 133508924
Bug: 138135733

android.permission.CAMERA and android.permission.SYSTEM_CAMERA are both
required by a client process to access system only cameras.

Test: Advertise the back camera as system only;
        1) don't give Camera2 SYSTEM_CAMERA permissions,
           Camera2 can't connect to the back camera
        2) give Camera2 SYSTEM_CAMERA permissions, Camera2 successfully
           connects.
        3) 3P app can't connect to any camera if all cameras are
           advertised as SYSTEM_ONLY_CAMERAs.

Test: CTS CameraDeviceTest, CameraManagerTest

Change-Id: I0309462f962d9c8c92564ef6781b2aae1485a933
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>

camera/ndk/include/camera/NdkCameraMetadataTags.h

@@ -7758,6 +7758,13 @@ typedef enum acamera_metadata_enum_acamera_request_available_capabilities {
      */
     ACAMERA_REQUEST_AVAILABLE_CAPABILITIES_SECURE_IMAGE_DATA         = 13,
 
+    /**
+     * <p>The camera device is only accessible by Android's system components and privileged
+     * applications. Processes need to have the android.permission.SYSTEM_CAMERA in
+     * addition to android.permission.CAMERA in order to connect to this camera device.</p>
+     */
+    ACAMERA_REQUEST_AVAILABLE_CAPABILITIES_SYSTEM_CAMERA             = 14,
+
 } acamera_metadata_enum_android_request_available_capabilities_t;
 
 

services/camera/libcameraservice/CameraService.cpp

@@ -117,7 +117,12 @@ static void setLogLevel(int level) {
 
 // ----------------------------------------------------------------------------
 
+static const String16 sDumpPermission("android.permission.DUMP");
 static const String16 sManageCameraPermission("android.permission.MANAGE_CAMERA");
+static const String16 sCameraPermission("android.permission.CAMERA");
+static const String16 sSystemCameraPermission("android.permission.SYSTEM_CAMERA");
+static const String16
+        sCameraSendSystemEventsPermission("android.permission.CAMERA_SEND_SYSTEM_EVENTS");
 
 // Matches with PERCEPTIBLE_APP_ADJ in ProcessList.java
 static constexpr int32_t kVendorClientScore = 200;
@@ -239,7 +244,7 @@ void CameraService::broadcastTorchModeStatus(const String8& cameraId, TorchModeS
     Mutex::Autolock lock(mStatusListenerLock);
 
     for (auto& i : mListenerList) {
-        i.second->getListener()->onTorchStatusChanged(mapToInterface(status), String16{cameraId});
+        i->getListener()->onTorchStatusChanged(mapToInterface(status), String16{cameraId});
     }
 }
 
@@ -514,6 +519,11 @@ Status CameraService::getCameraCharacteristics(const String16& cameraId,
                 "Camera subsystem is not available");;
     }
 
+    if (shouldRejectSystemCameraConnection(String8(cameraId))) {
+        return STATUS_ERROR_FMT(ERROR_INVALID_OPERATION, "Unable to retrieve camera"
+                "characteristics for system only device %s: ", String8(cameraId).string());
+    }
+
     Status ret{};
 
     status_t res = mCameraProviderManager->getCameraCharacteristics(
@@ -527,9 +537,12 @@ Status CameraService::getCameraCharacteristics(const String16& cameraId,
     int callingPid = CameraThreadState::getCallingPid();
     int callingUid = CameraThreadState::getCallingUid();
     std::vector<int32_t> tagsRemoved;
-    // If it's not calling from cameraserver, check the permission.
+    // If it's not calling from cameraserver, check the permission only if
+    // android.permission.CAMERA is required. If android.permission.SYSTEM_CAMERA was needed,
+    // it would've already been checked in shouldRejectSystemCameraConnection.
     if ((callingPid != getpid()) &&
-            !checkPermission(String16("android.permission.CAMERA"), callingPid, callingUid)) {
+            (getSystemCameraKind(String8(cameraId)) != SystemCameraKind::SYSTEM_ONLY_CAMERA) &&
+            !checkPermission(sCameraPermission, callingPid, callingUid)) {
         res = cameraInfo->removePermissionEntries(
                 mCameraProviderManager->getProviderTagIdLocked(String8(cameraId).string()),
                 &tagsRemoved);
@@ -969,9 +982,18 @@ Status CameraService::validateClientPermissionsLocked(const String8& cameraId,
                 clientName8.string(), clientUid, clientPid);
     }
 
-    // If it's not calling from cameraserver, check the permission.
+    if (shouldRejectSystemCameraConnection(cameraId)) {
+        ALOGW("Attempting to connect to system-only camera id %s, connection rejected",
+                cameraId.c_str());
+        return STATUS_ERROR_FMT(ERROR_DISCONNECTED, "No camera device with ID \"%s\" is"
+                                "available", cameraId.string());
+    }
+    // If it's not calling from cameraserver, check the permission if the
+    // device isn't a system only camera (shouldRejectSystemCameraConnection already checks for
+    // android.permission.SYSTEM_CAMERA for system only camera devices).
     if (callingPid != getpid() &&
-            !checkPermission(String16("android.permission.CAMERA"), clientPid, clientUid)) {
+                (getSystemCameraKind(cameraId) != SystemCameraKind::SYSTEM_ONLY_CAMERA) &&
+                !checkPermission(sCameraPermission, clientPid, clientUid)) {
         ALOGE("Permission Denial: can't use the camera pid=%d, uid=%d", clientPid, clientUid);
         return STATUS_ERROR_FMT(ERROR_PERMISSION_DENIED,
                 "Caller \"%s\" (PID %d, UID %d) cannot open camera \"%s\" without camera permission",
@@ -1324,15 +1346,63 @@ Status CameraService::connectLegacy(
     return ret;
 }
 
-bool CameraService::shouldRejectHiddenCameraConnection(const String8 & cameraId) {
-    // If the thread serving this call is not a hwbinder thread and the caller
-    // isn't the cameraserver itself, and the camera id being requested is to be
-    // publically hidden, we should reject the connection.
+static bool hasPermissionsForSystemCamera(int callingPid, int callingUid) {
+    return checkPermission(sSystemCameraPermission, callingPid, callingUid) &&
+            checkPermission(sCameraPermission, callingPid, callingUid);
+}
+
+bool CameraService::shouldSkipStatusUpdates(const String8& cameraId, bool isVendorListener,
+        int clientPid, int clientUid) const {
+    SystemCameraKind systemCameraKind = getSystemCameraKind(cameraId);
+    // If the client is not a vendor client, don't add listener if
+    //   a) the camera is a publicly hidden secure camera OR
+    //   b) the camera is a system only camera and the client doesn't
+    //      have android.permission.SYSTEM_CAMERA permissions.
+    if (!isVendorListener && (systemCameraKind == SystemCameraKind::HIDDEN_SECURE_CAMERA ||
+            (systemCameraKind == SystemCameraKind::SYSTEM_ONLY_CAMERA &&
+            !hasPermissionsForSystemCamera(clientPid, clientUid)))) {
+        return true;
+    }
+    return false;
+}
+
+bool CameraService::shouldRejectSystemCameraConnection(const String8& cameraId) const {
+    // Rules for rejection:
+    // 1) If cameraserver tries to access this camera device, accept the
+    //    connection.
+    // 2) The camera device is a publicly hidden secure camera device AND some
+    //    component is trying to access it on a non-hwbinder thread (generally a non HAL client),
+    //    reject it.
+    // 3) if the camera device is advertised by the camera HAL as SYSTEM_ONLY
+    //    and the serving thread is a non hwbinder thread, the client must have
+    //    android.permission.SYSTEM_CAMERA permissions to connect.
+
+    int cPid = CameraThreadState::getCallingPid();
+    int cUid = CameraThreadState::getCallingUid();
+    SystemCameraKind systemCameraKind = getSystemCameraKind(cameraId);
+
+    // (1) Cameraserver trying to connect, accept.
+    if (CameraThreadState::getCallingPid() == getpid()) {
+        return false;
+    }
+    // (2)
+    if (!hardware::IPCThreadState::self()->isServingCall() &&
+            systemCameraKind == SystemCameraKind::HIDDEN_SECURE_CAMERA) {
+        ALOGW("Rejecting access to secure hidden camera %s", cameraId.c_str());
+        return true;
+    }
+    // (3) Here we only check for permissions if it is a system only camera device. This is since
+    //     getCameraCharacteristics() allows for calls to succeed (albeit after hiding some
+    //     characteristics) even if clients don't have android.permission.CAMERA. We do not want the
+    //     same behavior for system camera devices.
     if (!hardware::IPCThreadState::self()->isServingCall() &&
-            CameraThreadState::getCallingPid() != getpid() &&
-            mCameraProviderManager->isPublicallyHiddenSecureCamera(cameraId.c_str())) {
+            systemCameraKind == SystemCameraKind::SYSTEM_ONLY_CAMERA &&
+            !hasPermissionsForSystemCamera(cPid, cUid)) {
+        ALOGW("Rejecting access to system only camera %s, inadequete permissions",
+                cameraId.c_str());
         return true;
     }
+
     return false;
 }
 
@@ -1385,14 +1455,6 @@ Status CameraService::connectHelper(const sp<CALLBACK>& cameraCb, const String8&
             (halVersion == -1) ? "default" : std::to_string(halVersion).c_str(),
             static_cast<int>(effectiveApiLevel));
 
-    if (shouldRejectHiddenCameraConnection(cameraId)) {
-        ALOGW("Attempting to connect to system-only camera id %s, connection rejected",
-              cameraId.c_str());
-        return STATUS_ERROR_FMT(ERROR_DISCONNECTED,
-                                "No camera device with ID \"%s\" currently available",
-                                cameraId.string());
-
-    }
     sp<CLIENT> client = nullptr;
     {
         // Acquire mServiceLock and prevent other clients from connecting
@@ -1668,8 +1730,7 @@ Status CameraService::notifySystemEvent(int32_t eventId,
     if (pid != selfPid) {
         // Ensure we're being called by system_server, or similar process with
         // permissions to notify the camera service about system events
-        if (!checkCallingPermission(
-                String16("android.permission.CAMERA_SEND_SYSTEM_EVENTS"))) {
+        if (!checkCallingPermission(sCameraSendSystemEventsPermission)) {
             const int uid = CameraThreadState::getCallingUid();
             ALOGE("Permission Denial: cannot send updates to camera service about system"
                     " events from pid=%d, uid=%d", pid, uid);
@@ -1704,7 +1765,7 @@ void CameraService::notifyMonitoredUids() {
     Mutex::Autolock lock(mStatusListenerLock);
 
     for (const auto& it : mListenerList) {
-        auto ret = it.second->getListener()->onCameraAccessPrioritiesChanged();
+        auto ret = it->getListener()->onCameraAccessPrioritiesChanged();
         if (!ret.isOk()) {
             ALOGE("%s: Failed to trigger permission callback: %d", __FUNCTION__,
                     ret.exceptionCode());
@@ -1720,8 +1781,7 @@ Status CameraService::notifyDeviceStateChange(int64_t newState) {
     if (pid != selfPid) {
         // Ensure we're being called by system_server, or similar process with
         // permissions to notify the camera service about system events
-        if (!checkCallingPermission(
-                String16("android.permission.CAMERA_SEND_SYSTEM_EVENTS"))) {
+        if (!checkCallingPermission(sCameraSendSystemEventsPermission)) {
             const int uid = CameraThreadState::getCallingUid();
             ALOGE("Permission Denial: cannot send updates to camera service about device"
                     " state changes from pid=%d, uid=%d", pid, uid);
@@ -1775,20 +1835,23 @@ Status CameraService::addListenerHelper(const sp<ICameraServiceListener>& listen
         return STATUS_ERROR(ERROR_ILLEGAL_ARGUMENT, "Null listener given to addListener");
     }
 
+    auto clientUid = CameraThreadState::getCallingUid();
+    auto clientPid = CameraThreadState::getCallingPid();
+
     Mutex::Autolock lock(mServiceLock);
 
     {
         Mutex::Autolock lock(mStatusListenerLock);
         for (const auto &it : mListenerList) {
-            if (IInterface::asBinder(it.second->getListener()) == IInterface::asBinder(listener)) {
+            if (IInterface::asBinder(it->getListener()) == IInterface::asBinder(listener)) {
                 ALOGW("%s: Tried to add listener %p which was already subscribed",
                       __FUNCTION__, listener.get());
                 return STATUS_ERROR(ERROR_ALREADY_EXISTS, "Listener already registered");
             }
         }
 
-        auto clientUid = CameraThreadState::getCallingUid();
-        sp<ServiceListener> serviceListener = new ServiceListener(this, listener, clientUid);
+        sp<ServiceListener> serviceListener =
+                new ServiceListener(this, listener, clientUid, clientPid, isVendorListener);
         auto ret = serviceListener->initialize();
         if (ret != NO_ERROR) {
             String8 msg = String8::format("Failed to initialize service listener: %s (%d)",
@@ -1796,7 +1859,10 @@ Status CameraService::addListenerHelper(const sp<ICameraServiceListener>& listen
             ALOGE("%s: %s", __FUNCTION__, msg.string());
             return STATUS_ERROR(ERROR_ILLEGAL_ARGUMENT, msg.string());
         }
-        mListenerList.emplace_back(isVendorListener, serviceListener);
+        // The listener still needs to be added to the list of listeners, regardless of what
+        // permissions the listener process has / whether it is a vendor listener. Since it might be
+        // eligible to listen to other camera ids.
+        mListenerList.emplace_back(serviceListener);
         mUidPolicy->registerMonitorUid(clientUid);
     }
 
@@ -1804,8 +1870,7 @@ Status CameraService::addListenerHelper(const sp<ICameraServiceListener>& listen
     {
         Mutex::Autolock lock(mCameraStatesLock);
         for (auto& i : mCameraStates) {
-            if (!isVendorListener &&
-                mCameraProviderManager->isPublicallyHiddenSecureCamera(i.first.c_str())) {
+            if (shouldSkipStatusUpdates(i.first, isVendorListener, clientPid, clientUid)) {
                 ALOGV("Cannot add public listener for hidden system-only %s for pid %d",
                       i.first.c_str(), CameraThreadState::getCallingPid());
                 continue;
@@ -1844,9 +1909,9 @@ Status CameraService::removeListener(const sp<ICameraServiceListener>& listener)
     {
         Mutex::Autolock lock(mStatusListenerLock);
         for (auto it = mListenerList.begin(); it != mListenerList.end(); it++) {
-            if (IInterface::asBinder(it->second->getListener()) == IInterface::asBinder(listener)) {
-                mUidPolicy->unregisterMonitorUid(it->second->getListenerUid());
-                IInterface::asBinder(listener)->unlinkToDeath(it->second);
+            if (IInterface::asBinder((*it)->getListener()) == IInterface::asBinder(listener)) {
+                mUidPolicy->unregisterMonitorUid((*it)->getListenerUid());
+                IInterface::asBinder(listener)->unlinkToDeath(*it);
                 mListenerList.erase(it);
                 return Status::ok();
             }
@@ -3029,7 +3094,7 @@ static bool tryLock(Mutex& mutex)
 status_t CameraService::dump(int fd, const Vector<String16>& args) {
     ATRACE_CALL();
 
-    if (checkCallingPermission(String16("android.permission.DUMP")) == false) {
+    if (checkCallingPermission(sDumpPermission) == false) {
         dprintf(fd, "Permission Denial: can't dump CameraService from pid=%d, uid=%d\n",
                 CameraThreadState::getCallingPid(),
                 CameraThreadState::getCallingUid());
@@ -3261,13 +3326,13 @@ void CameraService::updateStatus(StatusInternal status, const String8& cameraId,
             Mutex::Autolock lock(mStatusListenerLock);
 
             for (auto& listener : mListenerList) {
-                if (!listener.first &&
-                    mCameraProviderManager->isPublicallyHiddenSecureCamera(cameraId.c_str())) {
+                if (shouldSkipStatusUpdates(cameraId, listener->isVendorListener(),
+                        listener->getListenerPid(), listener->getListenerUid())) {
                     ALOGV("Skipping camera discovery callback for system-only camera %s",
-                          cameraId.c_str());
+                            cameraId.c_str());
                     continue;
                 }
-                listener.second->getListener()->onStatusChanged(mapToInterface(status),
+                listener->getListener()->onStatusChanged(mapToInterface(status),
                         String16(cameraId));
             }
         });

services/camera/libcameraservice/CameraService.h

@@ -633,9 +633,20 @@ private:
         sp<BasicClient>* client,
         std::shared_ptr<resource_policy::ClientDescriptor<String8, sp<BasicClient>>>* partial);
 
-    // Should an operation attempt on a cameraId be rejected, if the camera id is
-    // advertised as a publically hidden secure camera, by the camera HAL ?
-    bool shouldRejectHiddenCameraConnection(const String8 & cameraId);
+    // Should an operation attempt on a cameraId be rejected ? (this can happen
+    // under various conditions. For example if a camera device is advertised as
+    // system only or hidden secure camera, amongst possible others.
+    bool shouldRejectSystemCameraConnection(const String8 & cameraId) const;
+
+    // Should a device status update be skipped for a particular camera device ? (this can happen
+    // under various conditions. For example if a camera device is advertised as
+    // system only or hidden secure camera, amongst possible others.
+    bool shouldSkipStatusUpdates(const String8& cameraId, bool isVendorListener, int clientPid,
+            int clientUid) const;
+
+    inline SystemCameraKind getSystemCameraKind(const String8& cameraId) const {
+        return mCameraProviderManager->getSystemCameraKind(cameraId.c_str());
+    }
 
     // Single implementation shared between the various connect calls
     template<class CALLBACK, class CLIENT>
@@ -810,7 +821,9 @@ private:
     class ServiceListener : public virtual IBinder::DeathRecipient {
         public:
             ServiceListener(sp<CameraService> parent, sp<hardware::ICameraServiceListener> listener,
-                    int uid) : mParent(parent), mListener(listener), mListenerUid(uid) {}
+                    int uid, int pid, bool isVendorClient)
+                    : mParent(parent), mListener(listener), mListenerUid(uid), mListenerPid(pid),
+                      mIsVendorListener(isVendorClient) { }
 
             status_t initialize() {
                 return IInterface::asBinder(mListener)->linkToDeath(this);
@@ -824,16 +837,20 @@ private:
             }
 
             int getListenerUid() { return mListenerUid; }
+            int getListenerPid() { return mListenerPid; }
             sp<hardware::ICameraServiceListener> getListener() { return mListener; }
+            bool isVendorListener() { return mIsVendorListener; }
 
         private:
             wp<CameraService> mParent;
             sp<hardware::ICameraServiceListener> mListener;
-            int mListenerUid;
+            int mListenerUid = -1;
+            int mListenerPid = -1;
+            bool mIsVendorListener = false;
     };
 
     // Guarded by mStatusListenerMutex
-    std::vector<std::pair<bool, sp<ServiceListener>>> mListenerList;
+    std::vector<sp<ServiceListener>> mListenerList;
 
     Mutex       mStatusListenerLock;
 

services/camera/libcameraservice/common/CameraProviderManager.cpp

@@ -534,15 +534,23 @@ void CameraProviderManager::ProviderInfo::DeviceInfo3::queryPhysicalCameraIds()
     }
 }
 
-bool CameraProviderManager::ProviderInfo::DeviceInfo3::isPublicallyHiddenSecureCamera() {
+SystemCameraKind CameraProviderManager::ProviderInfo::DeviceInfo3::getSystemCameraKind() {
     camera_metadata_entry_t entryCap;
     entryCap = mCameraCharacteristics.find(ANDROID_REQUEST_AVAILABLE_CAPABILITIES);
-    if (entryCap.count != 1) {
-        // Do NOT hide this camera device if the capabilities specify anything more
-        // than ANDROID_REQUEST_AVAILABLE_CAPABILITIES_SECURE_IMAGE_DATA.
-        return false;
+    if (entryCap.count == 1 &&
+            entryCap.data.u8[0] == ANDROID_REQUEST_AVAILABLE_CAPABILITIES_SECURE_IMAGE_DATA) {
+        return SystemCameraKind::HIDDEN_SECURE_CAMERA;
     }
-    return entryCap.data.u8[0] == ANDROID_REQUEST_AVAILABLE_CAPABILITIES_SECURE_IMAGE_DATA;
+
+    // Go through the capabilities and check if it has
+    // ANDROID_REQUEST_AVAILABLE_CAPABILITIES_SYSTEM_CAMERA
+    for (size_t i = 0; i < entryCap.count; ++i) {
+        uint8_t capability = entryCap.data.u8[i];
+        if (capability == ANDROID_REQUEST_AVAILABLE_CAPABILITIES_SYSTEM_CAMERA) {
+            return SystemCameraKind::SYSTEM_ONLY_CAMERA;
+        }
+    }
+    return SystemCameraKind::PUBLIC;
 }
 
 void CameraProviderManager::ProviderInfo::DeviceInfo3::getSupportedSizes(
@@ -1046,14 +1054,14 @@ bool CameraProviderManager::isLogicalCamera(const std::string& id,
     return deviceInfo->mIsLogicalCamera;
 }
 
-bool CameraProviderManager::isPublicallyHiddenSecureCamera(const std::string& id) {
+SystemCameraKind CameraProviderManager::getSystemCameraKind(const std::string& id) {
     std::lock_guard<std::mutex> lock(mInterfaceMutex);
 
     auto deviceInfo = findDeviceInfoLocked(id);
     if (deviceInfo == nullptr) {
-        return false;
+        return SystemCameraKind::PUBLIC;
     }
-    return deviceInfo->mIsPublicallyHiddenSecureCamera;
+    return deviceInfo->mSystemCameraKind;
 }
 
 bool CameraProviderManager::isHiddenPhysicalCamera(const std::string& cameraId) {
@@ -1937,7 +1945,7 @@ CameraProviderManager::ProviderInfo::DeviceInfo3::DeviceInfo3(const std::string&
         return;
     }
 
-    mIsPublicallyHiddenSecureCamera = isPublicallyHiddenSecureCamera();
+    mSystemCameraKind = getSystemCameraKind();
 
     status_t res = fixupMonochromeTags();
     if (OK != res) {

services/camera/libcameraservice/common/CameraProviderManager.h

@@ -54,6 +54,26 @@ public:
             sp<VendorTagDescriptor>& descriptor);
 };
 
+enum SystemCameraKind {
+   /**
+    * These camera devices are visible to all apps and system components alike
+    */
+   PUBLIC = 0,
+
+   /**
+    * These camera devices are visible only to processes having the
+    * android.permission.SYSTEM_CAMERA permission. They are not exposed to 3P
+    * apps.
+    */
+   SYSTEM_ONLY_CAMERA,
+
+   /**
+    * These camera devices are visible only to HAL clients (that try to connect
+    * on a hwbinder thread).
+    */
+   HIDDEN_SECURE_CAMERA
+};
+
 /**
  * A manager for all camera providers available on an Android device.
  *
@@ -272,7 +292,7 @@ public:
      */
     bool isLogicalCamera(const std::string& id, std::vector<std::string>* physicalCameraIds);
 
-    bool isPublicallyHiddenSecureCamera(const std::string& id);
+    SystemCameraKind getSystemCameraKind(const std::string& id);
     bool isHiddenPhysicalCamera(const std::string& cameraId);
 
     static const float kDepthARTolerance;
@@ -379,7 +399,7 @@ private:
             std::vector<std::string> mPhysicalIds;
             hardware::CameraInfo mInfo;
             sp<IBase> mSavedInterface;
-            bool mIsPublicallyHiddenSecureCamera = false;
+            SystemCameraKind mSystemCameraKind = SystemCameraKind::PUBLIC;
 
             const hardware::camera::common::V1_0::CameraResourceCost mResourceCost;
 
@@ -497,7 +517,7 @@ private:
             CameraMetadata mCameraCharacteristics;
             std::unordered_map<std::string, CameraMetadata> mPhysicalCameraCharacteristics;
             void queryPhysicalCameraIds();
-            bool isPublicallyHiddenSecureCamera();
+            SystemCameraKind getSystemCameraKind();
             status_t fixupMonochromeTags();
             status_t addDynamicDepthTags();
             static void getSupportedSizes(const CameraMetadata& ch, uint32_t tag,