Fix PickleIterator::GetReadPointerAndAdvance() not to produce wild addresses

base/pickle.cc

Index: base/pickle.cc
===================================================================
--- base/pickle.cc	(revision 126350)
+++ base/pickle.cc	(working copy)
@@ -45,13 +45,9 @@
 }
 
 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
-  const char* current_read_ptr = read_ptr_;
-  const char* end_data_ptr = read_ptr_ + num_bytes;
-  if (num_bytes < 0)
+  if (num_bytes < 0 || read_end_ptr_ - read_ptr_ < num_bytes)

[jbates, 2012/03/13 16:52:44]

Much cleaner!

     return NULL;
-  // Check for enough space and for wrapping.
-  if (end_data_ptr > read_end_ptr_ || end_data_ptr < current_read_ptr)
-    return NULL;
+  const char* current_read_ptr = read_ptr_;
   read_ptr_ += AlignInt(num_bytes, sizeof(uint32));
   return current_read_ptr;
 }