Restrict enumeration of USB Audio Interfaces

Bug: 136083296
Test: build, flash, connect USB interface, examine logs
Test: No regressions for normal audio playback w/ Presonus, USB-C
Headset.

Note that since this ONLY modifies the interfaces enumerated in the
UsbHost API, it has no effect on normal, framework access to USB Audio.

Change-Id: Ib7d4c83744dfb0961360749c01b008aa9ab9baa2

4 files changed, 45 insertions, 15 deletions

diff --git a/services/usb/java/com/android/server/usb/descriptors/UsbConfigDescriptor.java b/services/usb/java/com/android/server/usb/descriptors/UsbConfigDescriptor.java
index de2dd101acfd..3f2d8c8ef47c 100644
--- a/services/usb/java/com/android/server/usb/descriptors/UsbConfigDescriptor.java
+++ b/services/usb/java/com/android/server/usb/descriptors/UsbConfigDescriptor.java
@@ -41,6 +41,8 @@ public final class UsbConfigDescriptor extends UsbDescriptor {
                                  //     D4..0 Reserved, set to 0.
     private int mMaxPower;       // 8:1 Maximum Power Consumption in 2mA units
 
+    private boolean mBlockAudio; // leave it off for now. We be replace with a "Developer Option"
+
     private ArrayList<UsbInterfaceDescriptor> mInterfaceDescriptors =
             new ArrayList<UsbInterfaceDescriptor>();
 
@@ -77,21 +79,35 @@ public final class UsbConfigDescriptor extends UsbDescriptor {
         mInterfaceDescriptors.add(interfaceDesc);
     }
 
+    private boolean isAudioInterface(UsbInterfaceDescriptor descriptor) {
+        return descriptor.getUsbClass() == UsbDescriptor.CLASSID_AUDIO
+                && descriptor.getUsbSubclass() == UsbDescriptor.AUDIO_AUDIOSTREAMING;
+    }
+
     UsbConfiguration toAndroid(UsbDescriptorParser parser) {
         if (UsbDescriptorParser.DEBUG) {
             Log.d(TAG, "  toAndroid()");
         }
+
+        // NOTE - This code running in the server process.
+        //TODO (pmclean@) - remove this
+//        int pid = android.os.Process.myPid();
+//        int uid = android.os.Process.myUid();
+//        Log.d(TAG, "  ---- pid:" + pid + " uid:" + uid);
+
         String name = parser.getDescriptorString(mConfigIndex);
         UsbConfiguration config = new
                 UsbConfiguration(mConfigValue, name, mAttribs, mMaxPower);
-        UsbInterface[] interfaces = new UsbInterface[mInterfaceDescriptors.size()];
-        if (UsbDescriptorParser.DEBUG) {
-            Log.d(TAG, "    " + mInterfaceDescriptors.size() + " interfaces.");
-        }
-        for (int index = 0; index < mInterfaceDescriptors.size(); index++) {
-            interfaces[index] = mInterfaceDescriptors.get(index).toAndroid(parser);
+
+        ArrayList<UsbInterface> filteredInterfaces = new ArrayList<UsbInterface>();
+        for (UsbInterfaceDescriptor descriptor : mInterfaceDescriptors) {
+            if (!mBlockAudio || !isAudioInterface(descriptor)) {
+                filteredInterfaces.add(descriptor.toAndroid(parser));
+            }
         }
-        config.setInterfaces(interfaces);
+        UsbInterface[] interfaceArray = new UsbInterface[0];
+        interfaceArray = filteredInterfaces.toArray(interfaceArray);
+        config.setInterfaces(interfaceArray);
         return config;
     }
 
diff --git a/services/usb/java/com/android/server/usb/descriptors/UsbDescriptorParser.java b/services/usb/java/com/android/server/usb/descriptors/UsbDescriptorParser.java
index 4f62d5a5c967..6ffbd43a7b1a 100644
--- a/services/usb/java/com/android/server/usb/descriptors/UsbDescriptorParser.java
+++ b/services/usb/java/com/android/server/usb/descriptors/UsbDescriptorParser.java
@@ -26,7 +26,7 @@ import java.util.ArrayList;
  */
 public final class UsbDescriptorParser {
     private static final String TAG = "UsbDescriptorParser";
-    public static final boolean DEBUG = false;
+    public static final boolean DEBUG = true;
 
     private final String mDeviceAddr;
 
diff --git a/services/usb/java/com/android/server/usb/descriptors/UsbEndpointDescriptor.java b/services/usb/java/com/android/server/usb/descriptors/UsbEndpointDescriptor.java
index 5eb0a2f75ded..4d0cfea98630 100644
--- a/services/usb/java/com/android/server/usb/descriptors/UsbEndpointDescriptor.java
+++ b/services/usb/java/com/android/server/usb/descriptors/UsbEndpointDescriptor.java
@@ -31,7 +31,7 @@ public class UsbEndpointDescriptor extends UsbDescriptor {
     public static final int MASK_ENDPOINT_ADDRESS = 0b000000000001111;
     public static final int MASK_ENDPOINT_DIRECTION = (byte) 0b0000000010000000;
     public static final int DIRECTION_OUTPUT = 0x0000;
-    public static final int DIRECTION_INPUT = (byte) 0x0080;
+    public static final int DIRECTION_INPUT = 0x0080;
 
     public static final int MASK_ATTRIBS_TRANSTYPE = 0b00000011;
     public static final int TRANSTYPE_CONTROL = 0x00;
@@ -85,7 +85,7 @@ public class UsbEndpointDescriptor extends UsbDescriptor {
     }
 
     public int getEndpointAddress() {
-        return mEndpointAddress;
+        return mEndpointAddress & MASK_ENDPOINT_ADDRESS;
     }
 
     public int getAttributes() {
@@ -108,6 +108,10 @@ public class UsbEndpointDescriptor extends UsbDescriptor {
         return mSyncAddress;
     }
 
+    public int getDirection() {
+        return mEndpointAddress & UsbEndpointDescriptor.MASK_ENDPOINT_DIRECTION;
+    }
+
     /* package */ UsbEndpoint toAndroid(UsbDescriptorParser parser) {
         if (UsbDescriptorParser.DEBUG) {
             Log.d(TAG, "toAndroid() type:"
@@ -137,11 +141,9 @@ public class UsbEndpointDescriptor extends UsbDescriptor {
 
         canvas.openList();
 
-        int address = getEndpointAddress();
         canvas.writeListItem("Address: "
-                + ReportCanvas.getHexString(address & UsbEndpointDescriptor.MASK_ENDPOINT_ADDRESS)
-                + ((address & UsbEndpointDescriptor.MASK_ENDPOINT_DIRECTION)
-                == UsbEndpointDescriptor.DIRECTION_OUTPUT ? " [out]" : " [in]"));
+                + ReportCanvas.getHexString(getEndpointAddress())
+                + (getDirection() == UsbEndpointDescriptor.DIRECTION_OUTPUT ? " [out]" : " [in]"));
 
         int attributes = getAttributes();
         canvas.openListItem();
diff --git a/services/usb/java/com/android/server/usb/descriptors/UsbInterfaceDescriptor.java b/services/usb/java/com/android/server/usb/descriptors/UsbInterfaceDescriptor.java
index 1dc6069bbb0a..64dbd971cc67 100644
--- a/services/usb/java/com/android/server/usb/descriptors/UsbInterfaceDescriptor.java
+++ b/services/usb/java/com/android/server/usb/descriptors/UsbInterfaceDescriptor.java
@@ -31,7 +31,6 @@ import java.util.ArrayList;
  */
 public class UsbInterfaceDescriptor extends UsbDescriptor {
     private static final String TAG = "UsbInterfaceDescriptor";
-
     protected int mInterfaceNumber;   // 2:1 Number of Interface
     protected byte mAlternateSetting; // 3:1 Value used to select alternative setting
     protected byte mNumEndpoints;     // 4:1 Number of Endpoints used for this interface
@@ -73,6 +72,19 @@ public class UsbInterfaceDescriptor extends UsbDescriptor {
         return mNumEndpoints;
     }
 
+    /**
+     * @param index Index of desired UsbEndpointDescriptor.
+     * @return the UsbEndpointDescriptor descriptor at the specified index, or
+     *  null if an invalid index.
+     */
+    public UsbEndpointDescriptor getEndpointDescriptor(int index) {
+        if (index < 0 || index >= mEndpointDescriptors.size()) {
+            return null;
+        }
+
+        return mEndpointDescriptors.get(index);
+    }
+
     public int getUsbClass() {
         return mUsbClass;
     }