Robust ELF header parsing.

courgette/disassembler.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COURGETTE_DISASSEMBLER_H_
 #define COURGETTE_DISASSEMBLER_H_
 
 #include "base/basictypes.h"
 
 #include "courgette/courgette.h"
@@ skipping 36 matching lines @@
   // Returns a pointer into the memory copy of the file format.
   // FileOffsetToPointer(0) returns a pointer to the start of the file format.
   const uint8* OffsetToPointer(size_t offset) const;
 
  protected:
   Disassembler(const void* start, size_t length);
 
   bool Good();
   bool Bad(const char *reason);
 
+  // Returns true if the array lies within our memory region.
+  bool IsArrayInBounds(size_t offset, size_t elements, size_t element_size) {
+    return offset <= length() && elements <= (length() - offset) / element_size;
+  }
+
   // These helper functions avoid the need for casts in the main code.
   uint16 ReadU16(const uint8* address, size_t offset) {
     return *reinterpret_cast<const uint16*>(address + offset);
   }
 
   uint32 ReadU32(const uint8* address, size_t offset) {
     return *reinterpret_cast<const uint32*>(address + offset);
   }
 
   uint64 ReadU64(const uint8* address, size_t offset) {
@@ skipping 26 matching lines @@
   //
   size_t length_;         // In current memory.
   const uint8* start_;    // In current memory, base for 'file offsets'.
   const uint8* end_;      // In current memory.
 
   DISALLOW_COPY_AND_ASSIGN(Disassembler);
 };
 
 }  // namespace courgette
 #endif  // COURGETTE_DISASSEMBLER_H_