Heap on P01NT

Pointers and Memory Management

Thu, 13 Aug 2026 10:00:00 +0300

Bismillah.

In this article we will cover pointers and their types, along with an introduction to memory management and allocation. This is the final article of the basics series, God willing.

Note: we will not expand into memory management as deeply as the topic deserves — we cover the core concepts that help us understand pointers, because the subject warrants its own article.

Pointers are a powerful tool giving direct control over memory, which makes them of paramount importance when analyzing programs and understanding binary instructions.

Virtual Memory: Stack vs Heap

Thu, 13 Aug 2026 10:00:00 +0300

Bismillah.

In this article we discuss the design of stack and heap memory, and clarify the differences between them.

Note: this article does not cover everything exhaustively, but it will bring us to a full understanding of the topics we discuss.

Memory Layout

As mentioned in the pointers article, program memory in modern x86/x64 systems divides into 5 main segments (some say 4 by merging Data with BSS):

Text Segment — the executable instructions (read-only).
Data Segment — initialized globals.
BSS Segment — uninitialized globals.
Heap — dynamic allocation.
Stack — locals and function frames.

+-----------------+ high addresses
| Stack | grows downward
| | |
| v |
+-----------------+
| (gap) |
+-----------------+
| ^ |
| | |
| Heap | grows upward
+-----------------+
| BSS |
| Data |
| Text |
+-----------------+ low addresses

We are dealing only with the user space here — kernel space is another topic.

Dynamic Memory Allocation

Thu, 13 Aug 2026 10:00:00 +0300

Bismillah.

After discussing the heap and the stack and understanding the internal structure of each, today we cover dynamic memory allocation in an expanded way — free-memory management and the most common vulnerabilities in this area.

Dynamic Memory Allocation: understanding it is essential for analyzing software, exploiting vulnerabilities, and understanding how programs work from the inside.

Core Allocation Functions

1. malloc() and free()

malloc allocates a heap block of a given size (in bytes) without initialization — its contents are garbage values: