--- xnu/xnu-3248.50.21/iokit/Kernel/IOBufferMemoryDescriptor.cpp
+++ xnu/xnu-3789.51.2/iokit/Kernel/IOBufferMemoryDescriptor.cpp
@@ -626,6 +626,9 @@
 IOBufferMemoryDescriptor::getBytesNoCopy(vm_size_t start, vm_size_t withLength)
 {
     IOVirtualAddress address;
+
+    if ((start + withLength) < start) return 0;
+
     if (kIOMemoryTypePhysical64 == (_flags & kIOMemoryTypeMask))
 	address = (IOVirtualAddress) _buffer;
     else