1 files changed, 38 insertions, 0 deletions
diff --git a/core/java/android/util/ArrayMap.java b/core/java/android/util/ArrayMap.java
index df1d4cd..8ea23ba 100644
--- a/core/java/android/util/ArrayMap.java
+++ b/core/java/android/util/ArrayMap.java
@@ -494,6 +494,44 @@ public final class ArrayMap<K, V> implements Map<K, V> {
     }
 
     /**
+     * The use of the {@link #append} function can result in invalid array maps, in particular
+     * an array map where the same key appears multiple times.  This function verifies that
+     * the array map is valid, throwing IllegalArgumentException if a problem is found.  The
+     * main use for this method is validating an array map after unpacking from an IPC, to
+     * protect against malicious callers.
+     * @hide
+     */
+    public void validate() {
+        final int N = mSize;
+        if (N <= 1) {
+            // There can't be dups.
+            return;
+        }
+        int basehash = mHashes[0];
+        int basei = 0;
+        for (int i=1; i<N; i++) {
+            int hash = mHashes[i];
+            if (hash != basehash) {
+                basehash = hash;
+                basei = i;
+                continue;
+            }
+            // We are in a run of entries with the same hash code.  Go backwards through
+            // the array to see if any keys are the same.
+            final Object cur = mArray[i<<1];
+            for (int j=i-1; j>=basei; j--) {
+                final Object prev = mArray[j<<1];
+                if (cur == prev) {
+                    throw new IllegalArgumentException("Duplicate key in ArrayMap: " + cur);
+                }
+                if (cur != null && prev != null && cur.equals(prev)) {
+                    throw new IllegalArgumentException("Duplicate key in ArrayMap: " + cur);
+                }
+            }
+        }
+    }
+
+    /**
      * Perform a {@link #put(Object, Object)} of all key/value pairs in <var>array</var>
      * @param array The array whose contents are to be retrieved.
      */