h3r2tic

// Copyright (c) 2023 Tomasz Stachowiak
//
// This contribution is dual licensed under EITHER OF
// 
//     Apache License, Version 2.0, (http://www.apache.org/licenses/LICENSE-2.0)
//     MIT license (http://opensource.org/licenses/MIT)
// 
// at your option.

#include "/inc/frame_constants.hlsl"

LinusHenze

iOS 16 introduced launch constraints, which can be used to constraint the launch of an application.
There are three types of constraints:
    Self Constraints, which the launched application itself must meet
    Parent Constraints, which the parent process must meet
    Responsible Constraints, which the "responsible process" must meet (I assume that the responsible process is the process that asked launchd to launch a service)

Additionally, the TrustCache format was updated (see below) to support assigning each binary a "Constraint Category", which forces Self and Parent Constraints.
Note that Self, Parent and Responsible Constraints can also be set by the process performing the launch and they can be included in the code signature, in the new blob type 0xFADE8181. In both cases, the constraints are DER encoded (just like the DER entitlements).

Constraint Categories (from TrustCache, new in version 2):

pwn0rz

#include <IOKit/IOKitLib.h>
#include <mach/mach.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <ctype.h>

void hexdump(void *ptr, int buflen) {
  unsigned char *buf = (unsigned char*)ptr;
  int i, j;

dougallj

# IDA (disassembler) and Hex-Rays (decompiler) plugin for Apple AMX
#
# WIP research. (This was edited to add more info after someone posted it to
# Hacker News. Click "Revisions" to see full changes.)
#
# Copyright (c) 2020 dougallj


# Based on Python port of VMX intrinsics plugin:
# Copyright (c) 2019 w4kfu - Synacktiv

FWEugene

Threads

Foundation offers a Thread class, internally based on pthread, that can be used to create new threads and execute closures.

// Detaches a new thread and uses the specified selector as the thread entry point.
Thread.detachNewThreadSelector(selector: Selector>, toTarget: Any, with: Any)

// Subclass
class MyThread: Thread {

DavidBuchanan314

#include <stdio.h>

#define SQ(x) (x)*(x)

#define M0(x,y) SQ(x)+SQ(y)<4?0:0xe0
#define M1(x,y,x0,y0) (SQ(x)+SQ(y)<4)?M0(SQ(x)-SQ(y)+(x0),2*(x)*(y)+(y0)):0xc0
#define M2(x,y,x0,y0) (SQ(x)+SQ(y)<4)?M1(SQ(x)-SQ(y)+(x0),2*(x)*(y)+(y0),x0,y0):0xa0
#define M3(x,y,x0,y0) (SQ(x)+SQ(y)<4)?M2(SQ(x)-SQ(y)+(x0),2*(x)*(y)+(y0),x0,y0):0x80
#define M4(x,y,x0,y0) (SQ(x)+SQ(y)<4)?M3(SQ(x)-SQ(y)+(x0),2*(x)*(y)+(y0),x0,y0):0x60
#define M5(x,y,x0,y0) (SQ(x)+SQ(y)<4)?M4(SQ(x)-SQ(y)+(x0),2*(x)*(y)+(y0),x0,y0):0x40

mnem

Recursive mutexes are a hack

Recursive mutexes are a hack. There's nothing wrong with using them, but they're a crutch. Got a broken leg or library? Fine, use the crutch. But at least be aware that you're using a crutch, and why; and once in a while check out the leg (or library) to be sure you still need the crutch. And if it's not healing up, go see a doctor, because that's just not OK. When you have no choice, there's no shame in using a crutch... but you can't run very well on a crutch, and you'll also be slowing down anyone who depends on you.

tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

Catfish-Man

As of iOS 11/macOS High Sierra, and only including ones in Foundation and CoreFoundation

Strings:

_NSCFString - a CFStringRef or CFMutableStringRef. This is the most common type of string object currently.
    - May have 8 bit (ASCII) or 16 bit (UTF-16) backing store
_NSCFConstantString - a compile time constant CFStringRef, like you'd get with @"foo"
    - May also be generated by dynamic string creation if matches a string in a pre-baked table of common strings called the StringROM
NSBigMutableString - an NSString backed by a CFStorage (https://github.com/opensource-apple/CF/blob/master/CFStorage.h) for faster handling of very large strings
NSCheapMutableString - a very limited NSMutableString that allows for zero-copy initialization. Used in NSFileManager for temporarily wrapping stack buffers.

JohnSundell

import Foundation

struct EquatableValueSequence<T: Equatable> {
    static func ==(lhs: EquatableValueSequence<T>, rhs: T) -> Bool {
        return lhs.values.contains(rhs)
    }

    static func ==(lhs: T, rhs: EquatableValueSequence<T>) -> Bool {
        return rhs == lhs
    }