kconner

macOS Internals

Understand your Mac and iPhone more deeply by tracing the evolution of Mac OS X from prelease to Swift. John Siracusa delivers the details.

Starting Points

How to use this gist

You've got two main options:

travisdowns

The counters that are the easiest to understand and the best for making ratios that are internally consistent (i.e., always fall in the range 0.0 to 1.0) are the mem_load_retired events, e.g., mem_load_retired.l1_hit and mem_load_retired.l1_miss.

These count at the instruction level, i.e., the universe of retired instructions. For example, could make a reasonable hit ratio from mem_load_retired.l1_hit / mem_inst_retired.all_loads and it will be sane (never indicate a hit rate more than 100%, for example).

That one isn't perfect though, in that it may not reflect the true costs of cache misses and the behavior of the program for at least the following reasons:

• It appplies only to loads and can't catch misses imposed by stores (AFAICT there is no event that counts store misses).
• It only counts loads that retire - a lot of the load activity in your process may be due to loads on a speculative path that never retire. Loads on a speculative path may bring in data that is never used, causing misses and d

extremecoders-re

Environment

The steps shown below are done on a Ubuntu VM using Qemu 3.0

$ qemu-system-arm -version
QEMU emulator version 3.0.0
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

To quit Qemu at any time press Ctrl+a x, i.e. Ctrl+a and then x

romanking98

Table of Contents

1. Disclamair
2. House Of Roman
   ------> 2.1 Assumptions
   ------> 2.2 Protections
   ------> 2.3 Quick Walkthrough
   ------> 2.4 Setting the FD to malloc_hook
   ------> 2.5 Fixing the 0x71 freelist
   ------> 2.6 Unsorted Bin attack on malloc_hook

extremecoders-re

Setting up Qemu with a tap interface

There are two parts to networking within QEMU:

• The virtual network device that is provided to the guest (e.g. a PCI network card).
• The network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).

Example: User mode network

vient

AVX2 Encoder

Intro

This is the write-up for the task "AVX2 Encoder" from TCTF (0CTF) Finals 2017.

Description

We are given the following files:

avx2_encoder.exe: PE32+ executable (console) x86-64, for MS Windows