--- xnu/xnu-1228/libkern/c++/OSData.cpp
+++ xnu/xnu-2782.20.48/libkern/c++/OSData.cpp
@@ -38,7 +38,7 @@
 #define super OSObject
 
 OSDefineMetaClassAndStructors(OSData, OSObject)
-OSMetaClassDefineReservedUnused(OSData, 0);
+OSMetaClassDefineReservedUsed(OSData, 0);    // setDeallocFunction
 OSMetaClassDefineReservedUnused(OSData, 1);
 OSMetaClassDefineReservedUnused(OSData, 2);
 OSMetaClassDefineReservedUnused(OSData, 3);
@@ -190,7 +190,13 @@
     if (capacity != EXTERNAL && data && capacity) {
         kfree(data, capacity);
         ACCUMSIZE( -capacity );
-    }
+    } else if (capacity == EXTERNAL) {
+	DeallocFunction freemem = reserved ? reserved->deallocFunction : NULL;
+	if (freemem && data && length) {
+		freemem(data, length);
+	}
+    }
+    if (reserved) kfree(reserved, sizeof(ExpansionData));
     super::free();
 }
 
@@ -207,27 +213,34 @@
     return capacityIncrement = increment; 
 }
 
+// xx-review: does not check for capacity == EXTERNAL
+
 unsigned int OSData::ensureCapacity(unsigned int newCapacity)
 {
     unsigned char * newData;
+    unsigned int finalCapacity;
 
     if (newCapacity <= capacity)
         return capacity;
 
-    newCapacity = (((newCapacity - 1) / capacityIncrement) + 1)
+    finalCapacity = (((newCapacity - 1) / capacityIncrement) + 1)
                 * capacityIncrement;
 
-    newData = (unsigned char *) kalloc(newCapacity);
-    
+    // integer overflow check
+    if (finalCapacity < newCapacity)
+        return capacity;
+
+    newData = (unsigned char *) kalloc(finalCapacity);
+
     if ( newData ) {
-        bzero(newData + capacity, newCapacity - capacity);
+        bzero(newData + capacity, finalCapacity - capacity);
         if (data) {
             bcopy(data, newData, capacity);
             kfree(data, capacity);
         }
-        ACCUMSIZE( newCapacity - capacity );
+        ACCUMSIZE( finalCapacity - capacity );
         data = (void *) newData;
-        capacity = newCapacity;
+        capacity = finalCapacity;
     }
 
     return capacity;
@@ -321,11 +334,11 @@
 
 bool OSData::isEqualTo(const OSMetaClassBase *obj) const
 {
-    OSData *	data;
+    OSData *	otherData;
     OSString *  str;
 
-    if ((data = OSDynamicCast(OSData, obj)))
-        return isEqualTo(data);
+    if ((otherData = OSDynamicCast(OSData, obj)))
+        return isEqualTo(otherData);
     else if ((str = OSDynamicCast (OSString, obj)))
         return isEqualTo(str);
     else
@@ -381,12 +394,16 @@
     unsigned int i;
     const unsigned char *p;
     unsigned char c;
+    unsigned int serializeLength;
 
     if (s->previouslySerialized(this)) return true;
 
     if (!s->addXMLStartTag(this, "data")) return false;
 
-    for (i = 0, p = (unsigned char *)data; i < length; i++, p++) {
+    serializeLength = length;
+    if (reserved && reserved->disableSerialization) serializeLength = 0;
+
+    for (i = 0, p = (unsigned char *)data; i < serializeLength; i++, p++) {
         /* 3 bytes are encoded as 4 */
         switch (i % 3) {
 	case 0:
@@ -423,3 +440,25 @@
 
     return s->addXMLEndTag("data");
 }
+
+void OSData::setDeallocFunction(DeallocFunction func)
+{
+    if (!reserved)
+    {
+    	reserved = (typeof(reserved)) kalloc(sizeof(ExpansionData));
+        if (!reserved) return;
+        bzero(reserved, sizeof(ExpansionData));
+    }
+    reserved->deallocFunction = func;
+}
+
+void OSData::setSerializable(bool serializable)
+{
+    if (!reserved)
+    {
+    	reserved = (typeof(reserved)) kalloc(sizeof(ExpansionData));
+	if (!reserved) return;
+	bzero(reserved, sizeof(ExpansionData));
+    }
+    reserved->disableSerialization = (!serializable);
+}