mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
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241 lines
8.6 KiB
Diff
241 lines
8.6 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Khoa Hong <khoahong@google.com>
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Date: Wed, 19 Oct 2022 16:29:18 +0800
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Subject: [PATCH] Add protections agains use-after-free issues if cancel() or
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queue() is called after a device connection has been closed.
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This is a backport of ag/7528082 and ag/20033068.
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Bug: 132319116
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Bug: 130571162
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Bug: 204584366
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Test: CTS Verifier: USB Accessory Test & USB Device Test
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Change-Id: I952ab566e26a808997e362dc85ebd1d8eb4574b9
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(cherry picked from commit 7a8d56b2fe3496f7717ad1afe45d2ef523b7e252)
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Merged-In: I952ab566e26a808997e362dc85ebd1d8eb4574b9
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---
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.../hardware/usb/UsbDeviceConnection.java | 71 ++++++++++++++--
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.../java/android/hardware/usb/UsbRequest.java | 82 +++++++++++++++++--
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2 files changed, 141 insertions(+), 12 deletions(-)
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diff --git a/core/java/android/hardware/usb/UsbDeviceConnection.java b/core/java/android/hardware/usb/UsbDeviceConnection.java
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index 5b15c0d2fd9c..43a1b39d6be4 100644
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--- a/core/java/android/hardware/usb/UsbDeviceConnection.java
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+++ b/core/java/android/hardware/usb/UsbDeviceConnection.java
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@@ -50,6 +50,8 @@ public class UsbDeviceConnection {
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private final CloseGuard mCloseGuard = CloseGuard.get();
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+ private final Object mLock = new Object();
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+
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/**
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* UsbDevice should only be instantiated by UsbService implementation
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* @hide
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@@ -60,13 +62,23 @@ public class UsbDeviceConnection {
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/* package */ boolean open(String name, ParcelFileDescriptor pfd, @NonNull Context context) {
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mContext = context.getApplicationContext();
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- boolean wasOpened = native_open(name, pfd.getFileDescriptor());
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- if (wasOpened) {
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- mCloseGuard.open("close");
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+ synchronized (mLock) {
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+ boolean wasOpened = native_open(name, pfd.getFileDescriptor());
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+
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+ if (wasOpened) {
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+ mCloseGuard.open("close");
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+ }
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+
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+ return wasOpened;
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}
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+ }
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- return wasOpened;
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+ /***
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+ * @return If this connection is currently open and usable.
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+ */
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+ boolean isOpen() {
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+ return mNativeContext != 0;
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}
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/**
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@@ -78,6 +90,49 @@ public class UsbDeviceConnection {
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return mContext;
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}
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+ /**
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+ * Cancel a request which relates to this connection.
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+ *
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+ * @return true if the request was successfully cancelled.
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+ */
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+ /* package */ boolean cancelRequest(UsbRequest request) {
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+ synchronized (mLock) {
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+ if (!isOpen()) {
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+ return false;
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+ }
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+
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+ return request.cancelIfOpen();
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+ }
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+ }
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+
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+ /**
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+ * This is meant to be called by UsbRequest's queue() in order to synchronize on
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+ * UsbDeviceConnection's mLock to prevent the connection being closed while queueing.
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+ */
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+ /* package */ boolean queueRequest(UsbRequest request, ByteBuffer buffer, int length) {
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+ synchronized (mLock) {
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+ if (!isOpen()) {
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+ return false;
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+ }
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+
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+ return request.queueIfConnectionOpen(buffer, length);
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+ }
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+ }
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+
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+ /**
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+ * This is meant to be called by UsbRequest's queue() in order to synchronize on
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+ * UsbDeviceConnection's mLock to prevent the connection being closed while queueing.
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+ */
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+ /* package */ boolean queueRequest(UsbRequest request, @Nullable ByteBuffer buffer) {
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+ synchronized (mLock) {
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+ if (!isOpen()) {
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+ return false;
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+ }
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+
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+ return request.queueIfConnectionOpen(buffer);
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+ }
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+ }
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+
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/**
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* Releases all system resources related to the device.
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* Once the object is closed it cannot be used again.
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@@ -85,9 +140,11 @@ public class UsbDeviceConnection {
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* to retrieve a new instance to reestablish communication with the device.
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*/
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public void close() {
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- if (mNativeContext != 0) {
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- native_close();
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- mCloseGuard.close();
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+ synchronized (mLock) {
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+ if (isOpen()) {
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+ native_close();
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+ mCloseGuard.close();
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+ }
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}
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}
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diff --git a/core/java/android/hardware/usb/UsbRequest.java b/core/java/android/hardware/usb/UsbRequest.java
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index 2e8f8e12b508..2c77647a26be 100644
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--- a/core/java/android/hardware/usb/UsbRequest.java
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+++ b/core/java/android/hardware/usb/UsbRequest.java
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@@ -107,11 +107,13 @@ public class UsbRequest {
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* Releases all resources related to this request.
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*/
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public void close() {
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- if (mNativeContext != 0) {
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- mEndpoint = null;
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- mConnection = null;
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- native_close();
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- mCloseGuard.close();
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+ synchronized (mLock) {
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+ if (mNativeContext != 0) {
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+ mEndpoint = null;
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+ mConnection = null;
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+ native_close();
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+ mCloseGuard.close();
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+ }
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}
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}
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@@ -183,6 +185,28 @@ public class UsbRequest {
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*/
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@Deprecated
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public boolean queue(ByteBuffer buffer, int length) {
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+ UsbDeviceConnection connection = mConnection;
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+ if (connection == null) {
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+ // The expected exception by CTS Verifier - USB Device test
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+ throw new NullPointerException("invalid connection");
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+ }
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+
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+ // Calling into the underlying UsbDeviceConnection to synchronize on its lock, to prevent
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+ // the connection being closed while queueing.
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+ return connection.queueRequest(this, buffer, length);
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+ }
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+
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+ /**
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+ * This is meant to be called from UsbDeviceConnection after synchronizing using the lock over
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+ * there, to prevent the connection being closed while queueing.
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+ */
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+ /* package */ boolean queueIfConnectionOpen(ByteBuffer buffer, int length) {
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+ UsbDeviceConnection connection = mConnection;
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+ if (connection == null || !connection.isOpen()) {
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+ // The expected exception by CTS Verifier - USB Device test
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+ throw new NullPointerException("invalid connection");
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+ }
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+
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boolean out = (mEndpoint.getDirection() == UsbConstants.USB_DIR_OUT);
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boolean result;
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@@ -227,6 +251,28 @@ public class UsbRequest {
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* @return true if the queueing operation succeeded
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*/
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public boolean queue(@Nullable ByteBuffer buffer) {
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+ UsbDeviceConnection connection = mConnection;
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+ if (connection == null) {
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+ // The expected exception by CTS Verifier - USB Device test
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+ throw new IllegalStateException("invalid connection");
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+ }
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+
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+ // Calling into the underlying UsbDeviceConnection to synchronize on its lock, to prevent
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+ // the connection being closed while queueing.
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+ return connection.queueRequest(this, buffer);
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+ }
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+
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+ /**
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+ * This is meant to be called from UsbDeviceConnection after synchronizing using the lock over
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+ * there, to prevent the connection being closed while queueing.
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+ */
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+ /* package */ boolean queueIfConnectionOpen(@Nullable ByteBuffer buffer) {
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+ UsbDeviceConnection connection = mConnection;
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+ if (connection == null || !connection.isOpen()) {
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+ // The expected exception by CTS Verifier - USB Device test
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+ throw new IllegalStateException("invalid connection");
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+ }
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+
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// Request need to be initialized
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Preconditions.checkState(mNativeContext != 0, "request is not initialized");
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@@ -344,6 +390,32 @@ public class UsbRequest {
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* @return true if cancelling succeeded
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*/
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public boolean cancel() {
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+ UsbDeviceConnection connection = mConnection;
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+ if (connection == null) {
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+ return false;
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+ }
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+
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+ return connection.cancelRequest(this);
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+ }
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+
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+ /**
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+ * Cancels a pending queue operation (for use when the UsbDeviceConnection associated
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+ * with this request is synchronized). This ensures we don't have a race where the
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+ * device is closed and then the request is canceled which would lead to a
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+ * use-after-free because the cancel operation uses the device connection
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+ * information freed in the when UsbDeviceConnection is closed.<br/>
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+ *
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+ * This method assumes the connected is not closed while this method is executed.
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+ *
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+ * @return true if cancelling succeeded.
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+ */
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+ /* package */ boolean cancelIfOpen() {
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+ UsbDeviceConnection connection = mConnection;
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+ if (mNativeContext == 0 || (connection != null && !connection.isOpen())) {
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+ Log.w(TAG,
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+ "Detected attempt to cancel a request on a connection which isn't open");
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+ return false;
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+ }
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return native_cancel();
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}
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