Adding typed Parcel read APIs 2

Added typed read APIs of `readArray`, `readArrayList`,
`readParcelableArray` and `readSparseArray`.

To avoid unexpected types of objects being unparcelled,
ideally clients would use the readTypedXXX() methods that
take the parcelable creator. However, this won’t be an option
for use cases involving deserializing children objects
inherited from non-final parcelable or serializable objects.
Currently out of ~4k parcelable classes, only ~1.5k
are marked as “final” in the platform. Hence it would be
necessary to introduce new replacements that take
an extra Class<T> parameter and before deserializing
we check that the class written on the wire is the
same or a descendant from the one provided as argument.

Doing so could enhance the security of Parcel deserialization,
More details can be found at go/safer-parcel.

Test: atest -d android.os.cts.ParcelTest
Bug: 195622897
Change-Id: Iaba24c35a0c0acc77ae2d22ac77c5a90efd93329

1 files changed, 142 insertions, 41 deletions

diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index 6be86da9a925..153cbb027c0d 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -20,6 +20,7 @@ import static java.util.Objects.requireNonNull;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SuppressLint;
 import android.annotation.TestApi;
 import android.app.AppOpsManager;
 import android.compat.annotation.UnsupportedAppUsage;
@@ -3094,14 +3095,24 @@ public final class Parcel {
      * Parcelables.
      */
     @Nullable
-    public final ArrayList readArrayList(@Nullable ClassLoader loader) {
-        int N = readInt();
-        if (N < 0) {
-            return null;
-        }
-        ArrayList l = new ArrayList(N);
-        readListInternal(l, N, loader, /* clazz */ null);
-        return l;
+    public ArrayList readArrayList(@Nullable ClassLoader loader) {
+        return readArrayListInternal(loader, /* clazz */ null);
+    }
+
+    /**
+     * Same as {@link #readArrayList(ClassLoader)} but accepts {@code clazz} parameter as
+     * the type required for each item.
+     *
+     * @throws BadParcelableException Throws BadParcelableException if the item to be deserialized
+     * is not an instance of that class or any of its children classes or there was an error
+     * trying to instantiate an element.
+     */
+    @SuppressLint({"ConcreteCollection", "NullableCollection"})
+    @Nullable
+    public <T> ArrayList<T> readArrayList(@Nullable ClassLoader loader,
+            @NonNull Class<? extends T> clazz) {
+        Objects.requireNonNull(clazz);
+        return readArrayListInternal(loader, clazz);
     }
 
     /**
@@ -3111,14 +3122,23 @@ public final class Parcel {
      * Parcelables.
      */
     @Nullable
-    public final Object[] readArray(@Nullable ClassLoader loader) {
-        int N = readInt();
-        if (N < 0) {
-            return null;
-        }
-        Object[] l = new Object[N];
-        readArrayInternal(l, N, loader);
-        return l;
+    public Object[] readArray(@Nullable ClassLoader loader) {
+        return readArrayInternal(loader, /* clazz */ null);
+    }
+
+    /**
+     * Same as {@link #readArray(ClassLoader)} but accepts {@code clazz} parameter as
+     * the type required for each item.
+     *
+     * @throws BadParcelableException Throws BadParcelableException if the item to be deserialized
+     * is not an instance of that class or any of its children classes or there was an error
+     * trying to instantiate an element.
+     */
+    @SuppressLint({"ArrayReturn", "NullableCollection"})
+    @Nullable
+    public <T> T[] readArray(@Nullable ClassLoader loader, @NonNull Class<T> clazz) {
+        Objects.requireNonNull(clazz);
+        return readArrayInternal(loader, clazz);
     }
 
     /**
@@ -3128,14 +3148,23 @@ public final class Parcel {
      * Parcelables.
      */
     @Nullable
-    public final <T> SparseArray<T> readSparseArray(@Nullable ClassLoader loader) {
-        int N = readInt();
-        if (N < 0) {
-            return null;
-        }
-        SparseArray sa = new SparseArray(N);
-        readSparseArrayInternal(sa, N, loader);
-        return sa;
+    public <T> SparseArray<T> readSparseArray(@Nullable ClassLoader loader) {
+        return readSparseArrayInternal(loader, /* clazz */ null);
+    }
+
+    /**
+     * Same as {@link #readSparseArray(ClassLoader)} but accepts {@code clazz} parameter as
+     * the type required for each item.
+     *
+     * @throws BadParcelableException Throws BadParcelableException if the item to be deserialized
+     * is not an instance of that class or any of its children classes or there was an error
+     * trying to instantiate an element.
+     */
+    @Nullable
+    public <T> SparseArray<T> readSparseArray(@Nullable ClassLoader loader,
+            @NonNull Class<? extends T> clazz) {
+        Objects.requireNonNull(clazz);
+        return readSparseArrayInternal(loader, clazz);
     }
 
     /**
@@ -3851,7 +3880,7 @@ public final class Parcel {
                     "Parcel " + this + ": Unmarshalling unknown type code " + type
                             + " at offset " + off);
         }
-        if (clazz != null && !clazz.isInstance(object)) {
+        if (object != null && clazz != null && !clazz.isInstance(object)) {
             throw new BadParcelableException("Unparcelled object " + object
                     + " is not an instance of required class " + clazz.getName()
                     + " provided in the parameter");
@@ -3910,7 +3939,6 @@ public final class Parcel {
     }
 
     /**
-     *
      * @param clazz The type of the parcelable expected or {@code null} for performing no checks.
      */
     @SuppressWarnings("unchecked")
@@ -3969,7 +3997,7 @@ public final class Parcel {
      * as the required type.
      *
      * @throws BadParcelableException Throws BadParcelableException if the item to be deserialized
-     * is not an instance of that class or any of its children class or there there was an error
+     * is not an instance of that class or any of its children classes or there there was an error
      * trying to read the {@link Parcelable.Creator}.
      */
     @Nullable
@@ -4092,17 +4120,25 @@ public final class Parcel {
         return p;
     }
 
-    /** @hide */
+    /**
+     * Same as {@link #readParcelableArray(ClassLoader)}  but accepts {@code clazz} parameter as
+     * the type required for each item.
+     *
+     * @throws BadParcelableException Throws BadParcelableException if the item to be deserialized
+     * is not an instance of that class or any of its children classes or there was an error
+     * trying to instantiate an element.
+     */
+    @SuppressLint({"ArrayReturn", "NullableCollection"})
+    @SuppressWarnings("unchecked")
     @Nullable
-    public final <T extends Parcelable> T[] readParcelableArray(@Nullable ClassLoader loader,
-            @NonNull Class<T> clazz) {
-        int N = readInt();
-        if (N < 0) {
+    public <T> T[] readParcelableArray(@Nullable ClassLoader loader, @NonNull Class<T> clazz) {
+        int n = readInt();
+        if (n < 0) {
             return null;
         }
-        T[] p = (T[]) Array.newInstance(clazz, N);
-        for (int i = 0; i < N; i++) {
-            p[i] = readParcelable(loader);
+        T[] p = (T[]) Array.newInstance(clazz, n);
+        for (int i = 0; i < n; i++) {
+            p[i] = readParcelableInternal(loader, clazz);
         }
         return p;
     }
@@ -4320,9 +4356,12 @@ public final class Parcel {
         return result;
     }
 
-    private void readListInternal(@NonNull List outVal, int n,
-            @Nullable ClassLoader loader) {
-        readListInternal(outVal, n, loader, null);
+    /**
+     * The method is replaced by {@link #readListInternal(List, int, ClassLoader, Class)}, however
+     * we are keeping this unused method here to allow unsupported app usages.
+     */
+    private void readListInternal(@NonNull List outVal, int n, @Nullable ClassLoader loader) {
+        readListInternal(outVal, n, loader,  /* clazz */ null);
     }
 
     /**
@@ -4338,26 +4377,88 @@ public final class Parcel {
         }
     }
 
+    /**
+     * @param clazz The type of the object expected or {@code null} for performing no checks.
+     */
+    @SuppressLint({"ConcreteCollection", "NullableCollection"})
+    @Nullable
+    private <T> ArrayList<T> readArrayListInternal(@Nullable ClassLoader loader,
+            @Nullable Class<? extends T> clazz) {
+        int n = readInt();
+        if (n < 0) {
+            return null;
+        }
+        ArrayList<T> l = new ArrayList<>(n);
+        readListInternal(l, n, loader, clazz);
+        return l;
+    }
+
+    /**
+     * The method is replaced by {@link #readArrayInternal(ClassLoader, Class)}, however
+     * we are keeping this unused method here to allow unsupported app usages.
+     */
     private void readArrayInternal(@NonNull Object[] outVal, int N,
             @Nullable ClassLoader loader) {
         for (int i = 0; i < N; i++) {
-            Object value = readValue(loader);
-            //Log.d(TAG, "Unmarshalling value=" + value);
+            Object value = readValue(loader, /* clazz */ null);
             outVal[i] = value;
         }
     }
 
+    /**
+     * @param clazz The type of the object expected or {@code null} for performing no checks.
+     */
+    @SuppressWarnings("unchecked")
+    @Nullable
+    private <T> T[] readArrayInternal(@Nullable ClassLoader loader, @Nullable Class<T> clazz) {
+        int n = readInt();
+        if (n < 0) {
+            return null;
+        }
+        T[] outVal = (T[]) ((clazz == null) ? new Object[n] : Array.newInstance(clazz, n));
+
+        for (int i = 0; i < n; i++) {
+            T value = readValue(loader, clazz);
+            outVal[i] = value;
+        }
+        return outVal;
+    }
+
+    /**
+     * The method is replaced by {@link #readSparseArray(ClassLoader, Class)}, however
+     * we are keeping this unused method here to allow unsupported app usages.
+     */
     private void readSparseArrayInternal(@NonNull SparseArray outVal, int N,
             @Nullable ClassLoader loader) {
         while (N > 0) {
             int key = readInt();
             Object value = readValue(loader);
-            //Log.i(TAG, "Unmarshalling key=" + key + " value=" + value);
             outVal.append(key, value);
             N--;
         }
     }
 
+    /**
+     * @param clazz The type of the object expected or {@code null} for performing no checks.
+     */
+    @Nullable
+    private <T> SparseArray<T> readSparseArrayInternal(@Nullable ClassLoader loader,
+            @Nullable Class<? extends T> clazz) {
+        int n = readInt();
+        if (n < 0) {
+            return null;
+        }
+        SparseArray<T> outVal = new SparseArray<>(n);
+
+        while (n > 0) {
+            int key = readInt();
+            T value = readValue(loader, clazz);
+            outVal.append(key, value);
+            n--;
+        }
+        return outVal;
+    }
+
 
     private void readSparseBooleanArrayInternal(@NonNull SparseBooleanArray outVal, int N) {
         while (N > 0) {