Revert "Revert "Revert "Revert "SF: Updating permissions checking in Surface Flinger.""""
This reverts commit e334440508f8e36729f04e80d963d84eebb5ad59.
Reason for revert: Try #3. Anyone should be able to check whether they can access SF
throught AUTHENTICATE_SURFACE. If they are on the list of producers the call will return
true, otherwise false, but the call itself should not be protected.
Test: SF tests updated. They all pass.
Change-Id: Ie53f34aff6bb25e5976278ed59b03a0d56eb6633
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index bf5c28e..337f89d 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1091,15 +1091,6 @@
status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
NO_THREAD_SAFETY_ANALYSIS {
- IPCThreadState* ipc = IPCThreadState::self();
- const int pid = ipc->getCallingPid();
- const int uid = ipc->getCallingUid();
- if ((uid != AID_SHELL) &&
- !PermissionCache::checkPermission(sDump, pid, uid)) {
- ALOGE("Layer debug info permission denied for pid=%d, uid=%d", pid, uid);
- return PERMISSION_DENIED;
- }
-
// Try to acquire a lock for 1s, fail gracefully
const status_t err = mStateLock.timedLock(s2ns(1));
const bool locked = (err == NO_ERROR);
@@ -3258,9 +3249,8 @@
IPCThreadState* ipc = IPCThreadState::self();
const int pid = ipc->getCallingPid();
const int uid = ipc->getCallingUid();
-
if ((uid != AID_GRAPHICS && uid != AID_SYSTEM) &&
- !PermissionCache::checkPermission(sAccessSurfaceFlinger, pid, uid)) {
+ !PermissionCache::checkPermission(sAccessSurfaceFlinger, pid, uid)) {
return false;
}
return true;
@@ -4446,51 +4436,64 @@
}
status_t SurfaceFlinger::CheckTransactCodeCredentials(uint32_t code) {
- switch (code) {
- case CREATE_CONNECTION:
- case CREATE_DISPLAY:
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wswitch-enum"
+ switch (static_cast<ISurfaceComposerTag>(code)) {
+ // These methods should at minimum make sure that the client requested
+ // access to SF.
case BOOT_FINISHED:
case CLEAR_ANIMATION_FRAME_STATS:
- case GET_ANIMATION_FRAME_STATS:
- case SET_POWER_MODE:
- case GET_HDR_CAPABILITIES:
+ case CREATE_CONNECTION:
+ case CREATE_DISPLAY:
+ case DESTROY_DISPLAY:
case ENABLE_VSYNC_INJECTIONS:
+ case GET_ACTIVE_COLOR_MODE:
+ case GET_ANIMATION_FRAME_STATS:
+ case GET_HDR_CAPABILITIES:
+ case SET_ACTIVE_CONFIG:
+ case SET_ACTIVE_COLOR_MODE:
case INJECT_VSYNC:
- {
- // codes that require permission check
+ case SET_POWER_MODE: {
if (!callingThreadHasUnscopedSurfaceFlingerAccess()) {
IPCThreadState* ipc = IPCThreadState::self();
ALOGE("Permission Denial: can't access SurfaceFlinger pid=%d, uid=%d",
ipc->getCallingPid(), ipc->getCallingUid());
return PERMISSION_DENIED;
}
- break;
- }
- /*
- * Calling setTransactionState is safe, because you need to have been
- * granted a reference to Client* and Handle* to do anything with it.
- *
- * Creating a scoped connection is safe, as per discussion in ISurfaceComposer.h
- */
- case SET_TRANSACTION_STATE:
- case CREATE_SCOPED_CONNECTION:
- {
return OK;
}
- case CAPTURE_SCREEN:
- {
- // codes that require permission check
+ case GET_LAYER_DEBUG_INFO: {
IPCThreadState* ipc = IPCThreadState::self();
const int pid = ipc->getCallingPid();
const int uid = ipc->getCallingUid();
- if ((uid != AID_GRAPHICS) &&
- !PermissionCache::checkPermission(sReadFramebuffer, pid, uid)) {
- ALOGE("Permission Denial: can't read framebuffer pid=%d, uid=%d", pid, uid);
+ if ((uid != AID_SHELL) && !PermissionCache::checkPermission(sDump, pid, uid)) {
+ ALOGE("Layer debug info permission denied for pid=%d, uid=%d", pid, uid);
return PERMISSION_DENIED;
}
- break;
+ return OK;
}
- case CAPTURE_LAYERS: {
+ // Used by apps to hook Choreographer to SurfaceFlinger.
+ case CREATE_DISPLAY_EVENT_CONNECTION:
+ // The following calls are currently used by clients that do not
+ // request necessary permissions. However, they do not expose any secret
+ // information, so it is OK to pass them.
+ case AUTHENTICATE_SURFACE:
+ case GET_ACTIVE_CONFIG:
+ case GET_BUILT_IN_DISPLAY:
+ case GET_DISPLAY_COLOR_MODES:
+ case GET_DISPLAY_CONFIGS:
+ case GET_DISPLAY_STATS:
+ case GET_SUPPORTED_FRAME_TIMESTAMPS:
+ // Calling setTransactionState is safe, because you need to have been
+ // granted a reference to Client* and Handle* to do anything with it.
+ case SET_TRANSACTION_STATE:
+ // Creating a scoped connection is safe, as per discussion in ISurfaceComposer.h
+ case CREATE_SCOPED_CONNECTION: {
+ return OK;
+ }
+ case CAPTURE_LAYERS:
+ case CAPTURE_SCREEN: {
+ // codes that require permission check
IPCThreadState* ipc = IPCThreadState::self();
const int pid = ipc->getCallingPid();
const int uid = ipc->getCallingUid();
@@ -4499,15 +4502,37 @@
ALOGE("Permission Denial: can't read framebuffer pid=%d, uid=%d", pid, uid);
return PERMISSION_DENIED;
}
- break;
+ return OK;
+ }
+ // The following codes are deprecated and should never be allowed to access SF.
+ case CONNECT_DISPLAY_UNUSED:
+ case CREATE_GRAPHIC_BUFFER_ALLOC_UNUSED: {
+ ALOGE("Attempting to access SurfaceFlinger with unused code: %u", code);
+ return PERMISSION_DENIED;
}
}
- return OK;
+
+ // These codes are used for the IBinder protocol to either interrogate the recipient
+ // side of the transaction for its canonical interface descriptor or to dump its state.
+ // We let them pass by default.
+ if (code == IBinder::INTERFACE_TRANSACTION || code == IBinder::DUMP_TRANSACTION ||
+ code == IBinder::PING_TRANSACTION || code == IBinder::SHELL_COMMAND_TRANSACTION ||
+ code == IBinder::SYSPROPS_TRANSACTION) {
+ return OK;
+ }
+ // Numbers from 1000 to 1029 are currently use for backdoors. The code
+ // in onTransact verifies that the user is root, and has access to use SF.
+ if (code >= 1000 && code <= 1029) {
+ ALOGV("Accessing SurfaceFlinger through backdoor code: %u", code);
+ return OK;
+ }
+ ALOGE("Permission Denial: SurfaceFlinger did not recognize request code: %u", code);
+ return PERMISSION_DENIED;
+#pragma clang diagnostic pop
}
-status_t SurfaceFlinger::onTransact(
- uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
-{
+status_t SurfaceFlinger::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
+ uint32_t flags) {
status_t credentialCheck = CheckTransactCodeCredentials(code);
if (credentialCheck != OK) {
return credentialCheck;
diff --git a/services/surfaceflinger/tests/Android.bp b/services/surfaceflinger/tests/Android.bp
index c511c5e..604aa7d 100644
--- a/services/surfaceflinger/tests/Android.bp
+++ b/services/surfaceflinger/tests/Android.bp
@@ -17,6 +17,7 @@
defaults: ["surfaceflinger_defaults"],
test_suites: ["device-tests"],
srcs: [
+ "Credentials_test.cpp",
"Stress_test.cpp",
"SurfaceInterceptor_test.cpp",
"Transaction_test.cpp",
diff --git a/services/surfaceflinger/tests/Credentials_test.cpp b/services/surfaceflinger/tests/Credentials_test.cpp
new file mode 100644
index 0000000..8e23eb8e
--- /dev/null
+++ b/services/surfaceflinger/tests/Credentials_test.cpp
@@ -0,0 +1,331 @@
+#include <algorithm>
+#include <functional>
+#include <limits>
+#include <ostream>
+
+#include <gtest/gtest.h>
+
+#include <gui/ISurfaceComposer.h>
+#include <gui/LayerDebugInfo.h>
+#include <gui/Surface.h>
+#include <gui/SurfaceComposerClient.h>
+
+#include <private/android_filesystem_config.h>
+#include <private/gui/ComposerService.h>
+
+#include <ui/DisplayInfo.h>
+#include <utils/String8.h>
+
+namespace android {
+
+using Transaction = SurfaceComposerClient::Transaction;
+
+namespace {
+const String8 DISPLAY_NAME("Credentials Display Test");
+const String8 SURFACE_NAME("Test Surface Name");
+const int32_t MIN_LAYER_Z = 0;
+const int32_t MAX_LAYER_Z = std::numeric_limits<int32_t>::max();
+const uint32_t ROTATION = 0;
+const float FRAME_SCALE = 1.0f;
+} // namespace
+
+/**
+ * This class tests the CheckCredentials method in SurfaceFlinger.
+ * Methods like EnableVsyncInjections and InjectVsync are not tested since they do not
+ * return anything meaningful.
+ */
+class CredentialsTest : public ::testing::Test {
+protected:
+ void SetUp() override {
+ // Start the tests as root.
+ seteuid(AID_ROOT);
+
+ ASSERT_NO_FATAL_FAILURE(initClient());
+ }
+
+ void TearDown() override {
+ mComposerClient->dispose();
+ mBGSurfaceControl.clear();
+ mComposerClient.clear();
+ // Finish the tests as root.
+ seteuid(AID_ROOT);
+ }
+
+ sp<IBinder> mDisplay;
+ sp<IBinder> mVirtualDisplay;
+ sp<SurfaceComposerClient> mComposerClient;
+ sp<SurfaceControl> mBGSurfaceControl;
+ sp<SurfaceControl> mVirtualSurfaceControl;
+
+ void initClient() {
+ mComposerClient = new SurfaceComposerClient;
+ ASSERT_EQ(NO_ERROR, mComposerClient->initCheck());
+ }
+
+ void setupBackgroundSurface() {
+ mDisplay = SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain);
+ DisplayInfo info;
+ SurfaceComposerClient::getDisplayInfo(mDisplay, &info);
+ const ssize_t displayWidth = info.w;
+ const ssize_t displayHeight = info.h;
+
+ // Background surface
+ mBGSurfaceControl =
+ mComposerClient->createSurface(SURFACE_NAME, displayWidth, displayHeight,
+ PIXEL_FORMAT_RGBA_8888, 0);
+ ASSERT_TRUE(mBGSurfaceControl != nullptr);
+ ASSERT_TRUE(mBGSurfaceControl->isValid());
+
+ Transaction t;
+ t.setDisplayLayerStack(mDisplay, 0);
+ ASSERT_EQ(NO_ERROR,
+ t.setLayer(mBGSurfaceControl, INT_MAX - 3).show(mBGSurfaceControl).apply());
+ }
+
+ void setupVirtualDisplay() {
+ mVirtualDisplay = SurfaceComposerClient::createDisplay(DISPLAY_NAME, true);
+ const ssize_t displayWidth = 100;
+ const ssize_t displayHeight = 100;
+
+ // Background surface
+ mVirtualSurfaceControl =
+ mComposerClient->createSurface(SURFACE_NAME, displayWidth, displayHeight,
+ PIXEL_FORMAT_RGBA_8888, 0);
+ ASSERT_TRUE(mVirtualSurfaceControl != nullptr);
+ ASSERT_TRUE(mVirtualSurfaceControl->isValid());
+
+ Transaction t;
+ t.setDisplayLayerStack(mVirtualDisplay, 0);
+ ASSERT_EQ(NO_ERROR,
+ t.setLayer(mVirtualSurfaceControl, INT_MAX - 3)
+ .show(mVirtualSurfaceControl)
+ .apply());
+ }
+
+ /**
+ * Sets UID to imitate Graphic's process.
+ */
+ void setGraphicsUID() {
+ seteuid(AID_ROOT);
+ seteuid(AID_GRAPHICS);
+ }
+
+ /**
+ * Sets UID to imitate System's process.
+ */
+ void setSystemUID() {
+ seteuid(AID_ROOT);
+ seteuid(AID_SYSTEM);
+ }
+
+ /**
+ * Sets UID to imitate a process that doesn't have any special privileges in
+ * our code.
+ */
+ void setBinUID() {
+ seteuid(AID_ROOT);
+ seteuid(AID_BIN);
+ }
+
+ /**
+ * Template function the check a condition for different types of users: root
+ * graphics, system, and non-supported user. Root, graphics, and system should
+ * always equal privilegedValue, and non-supported user should equal unprivilegedValue.
+ */
+ template <typename T>
+ void checkWithPrivileges(std::function<T()> condition, T privilegedValue, T unprivilegedValue) {
+ // Check with root.
+ seteuid(AID_ROOT);
+ ASSERT_EQ(privilegedValue, condition());
+
+ // Check as a Graphics user.
+ setGraphicsUID();
+ ASSERT_EQ(privilegedValue, condition());
+
+ // Check as a system user.
+ setSystemUID();
+ ASSERT_EQ(privilegedValue, condition());
+
+ // Check as a non-supported user.
+ setBinUID();
+ ASSERT_EQ(unprivilegedValue, condition());
+ }
+};
+
+TEST_F(CredentialsTest, ClientInitTest) {
+ // Root can init can init the client.
+ ASSERT_NO_FATAL_FAILURE(initClient());
+
+ // Graphics can init the client.
+ setGraphicsUID();
+ ASSERT_NO_FATAL_FAILURE(initClient());
+
+ // System can init the client.
+ setSystemUID();
+ ASSERT_NO_FATAL_FAILURE(initClient());
+
+ // No one else can init the client.
+ setBinUID();
+ mComposerClient = new SurfaceComposerClient;
+ ASSERT_EQ(NO_INIT, mComposerClient->initCheck());
+}
+
+TEST_F(CredentialsTest, GetBuiltInDisplayAccessTest) {
+ std::function<bool()> condition = [=]() {
+ sp<IBinder> display(
+ SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ return (display != nullptr);
+ };
+ // Anyone can access display information.
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges(condition, true, true));
+}
+
+TEST_F(CredentialsTest, AllowedGetterMethodsTest) {
+ // The following methods are tested with a UID that is not root, graphics,
+ // or system, to show that anyone can access them.
+ setBinUID();
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ ASSERT_TRUE(display != nullptr);
+
+ DisplayInfo info;
+ ASSERT_EQ(NO_ERROR, SurfaceComposerClient::getDisplayInfo(display, &info));
+
+ Vector<DisplayInfo> configs;
+ ASSERT_EQ(NO_ERROR, SurfaceComposerClient::getDisplayConfigs(display, &configs));
+
+ ASSERT_EQ(NO_ERROR, SurfaceComposerClient::getActiveConfig(display));
+
+ ASSERT_NE(static_cast<ui::ColorMode>(BAD_VALUE),
+ SurfaceComposerClient::getActiveColorMode(display));
+}
+
+TEST_F(CredentialsTest, GetDisplayColorModesTest) {
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ std::function<status_t()> condition = [=]() {
+ Vector<ui::ColorMode> outColorModes;
+ return SurfaceComposerClient::getDisplayColorModes(display, &outColorModes);
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges<status_t>(condition, NO_ERROR, NO_ERROR));
+}
+
+TEST_F(CredentialsTest, SetActiveConfigTest) {
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ std::function<status_t()> condition = [=]() {
+ return SurfaceComposerClient::setActiveConfig(display, 0);
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges<status_t>(condition, NO_ERROR, PERMISSION_DENIED));
+}
+
+TEST_F(CredentialsTest, SetActiveColorModeTest) {
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ std::function<status_t()> condition = [=]() {
+ return SurfaceComposerClient::setActiveColorMode(display, ui::ColorMode::NATIVE);
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges<status_t>(condition, NO_ERROR, PERMISSION_DENIED));
+}
+
+TEST_F(CredentialsTest, CreateSurfaceTest) {
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ DisplayInfo info;
+ SurfaceComposerClient::getDisplayInfo(display, &info);
+ const ssize_t displayWidth = info.w;
+ const ssize_t displayHeight = info.h;
+
+ std::function<bool()> condition = [=]() {
+ mBGSurfaceControl =
+ mComposerClient->createSurface(SURFACE_NAME, displayWidth, displayHeight,
+ PIXEL_FORMAT_RGBA_8888, 0);
+ return mBGSurfaceControl != nullptr && mBGSurfaceControl->isValid();
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges(condition, true, false));
+}
+
+TEST_F(CredentialsTest, CreateDisplayTest) {
+ std::function<bool()> condition = [=]() {
+ sp<IBinder> testDisplay = SurfaceComposerClient::createDisplay(DISPLAY_NAME, true);
+ return testDisplay.get() != nullptr;
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges(condition, true, false));
+
+ condition = [=]() {
+ sp<IBinder> testDisplay = SurfaceComposerClient::createDisplay(DISPLAY_NAME, false);
+ return testDisplay.get() != nullptr;
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges(condition, true, false));
+}
+
+TEST_F(CredentialsTest, DISABLED_DestroyDisplayTest) {
+ setupVirtualDisplay();
+
+ DisplayInfo info;
+ ASSERT_EQ(NO_ERROR, SurfaceComposerClient::getDisplayInfo(mVirtualDisplay, &info));
+ SurfaceComposerClient::destroyDisplay(mVirtualDisplay);
+ // This test currently fails. TODO(b/112002626): Find a way to properly create
+ // a display in the test environment, so that destroy display can remove it.
+ ASSERT_EQ(NAME_NOT_FOUND, SurfaceComposerClient::getDisplayInfo(mVirtualDisplay, &info));
+}
+
+TEST_F(CredentialsTest, CaptureTest) {
+ sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain));
+ std::function<status_t()> condition = [=]() {
+ sp<GraphicBuffer> outBuffer;
+ return ScreenshotClient::capture(display, Rect(), 0 /*reqWidth*/, 0 /*reqHeight*/,
+ MIN_LAYER_Z, MAX_LAYER_Z, false, ROTATION, &outBuffer);
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges<status_t>(condition, NO_ERROR, PERMISSION_DENIED));
+}
+
+TEST_F(CredentialsTest, CaptureLayersTest) {
+ setupBackgroundSurface();
+ sp<GraphicBuffer> outBuffer;
+ std::function<status_t()> condition = [=]() {
+ sp<GraphicBuffer> outBuffer;
+ return ScreenshotClient::captureLayers(mBGSurfaceControl->getHandle(), Rect(), FRAME_SCALE,
+ &outBuffer);
+ };
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges<status_t>(condition, NO_ERROR, PERMISSION_DENIED));
+}
+
+/**
+ * The following tests are for methods accessible directly through SurfaceFlinger.
+ */
+
+/**
+ * An app can pass a buffer queue to the media server and ask the media server to decode a DRM video
+ * to that buffer queue. The media server is the buffer producer in this case. Because the app may create
+ * its own buffer queue and act as the buffer consumer, the media server wants to be careful to avoid
+ * sending decoded video frames to the app. This is where authenticateSurfaceTexture call comes in, to check
+ * the consumer of a buffer queue is SurfaceFlinger.
+ */
+TEST_F(CredentialsTest, AuthenticateSurfaceTextureTest) {
+ setupBackgroundSurface();
+ sp<IGraphicBufferProducer> producer =
+ mBGSurfaceControl->getSurface()->getIGraphicBufferProducer();
+ sp<ISurfaceComposer> sf(ComposerService::getComposerService());
+
+ std::function<bool()> condition = [=]() { return sf->authenticateSurfaceTexture(producer); };
+ // Anyone should be able to check if the consumer of the buffer queue is SF.
+ ASSERT_NO_FATAL_FAILURE(checkWithPrivileges(condition, true, true));
+}
+
+TEST_F(CredentialsTest, GetLayerDebugInfo) {
+ setupBackgroundSurface();
+ sp<ISurfaceComposer> sf(ComposerService::getComposerService());
+
+ // Historically, only root and shell can access the getLayerDebugInfo which
+ // is called when we call dumpsys. I don't see a reason why we should change this.
+ std::vector<LayerDebugInfo> outLayers;
+ // Check with root.
+ seteuid(AID_ROOT);
+ ASSERT_EQ(NO_ERROR, sf->getLayerDebugInfo(&outLayers));
+
+ // Check as a shell.
+ seteuid(AID_SHELL);
+ ASSERT_EQ(NO_ERROR, sf->getLayerDebugInfo(&outLayers));
+
+ // Check as anyone else.
+ seteuid(AID_ROOT);
+ seteuid(AID_BIN);
+ ASSERT_EQ(PERMISSION_DENIED, sf->getLayerDebugInfo(&outLayers));
+}
+} // namespace android
diff --git a/services/surfaceflinger/tests/SurfaceFlinger_test.filter b/services/surfaceflinger/tests/SurfaceFlinger_test.filter
index 731e628..1319e12 100644
--- a/services/surfaceflinger/tests/SurfaceFlinger_test.filter
+++ b/services/surfaceflinger/tests/SurfaceFlinger_test.filter
@@ -1,5 +1,5 @@
{
"presubmit": {
- "filter": "LayerTransactionTest.*:LayerUpdateTest.*:ChildLayerTest.*:SurfaceFlingerStress.*:CropLatchingTest.*:GeometryLatchingTest.*:ScreenCaptureTest.*:DereferenceSurfaceControlTest.*:SurfaceInterceptorTest.*:-CropLatchingTest.FinalCropLatchingBufferOldSize"
+ "filter": "CredentialsTest.*:LayerTransactionTest.*:LayerUpdateTest.*:ChildLayerTest.*:SurfaceFlingerStress.*:CropLatchingTest.*:GeometryLatchingTest.*:ScreenCaptureTest.*:DereferenceSurfaceControlTest.*:SurfaceInterceptorTest.*:-CropLatchingTest.FinalCropLatchingBufferOldSize"
}
}