sleirsgoevy

On offsets

After the recent release of ps5-kstuff with support for PS4 fpkg files, there is a lot of questions about porting this to other firmwares (4.50 and 4.51 are important in particular, because users of those firmwares can't update to 4.03, but they are still vulnerable to all of the used exploits). The main problem with these ports it the bespoke XOM, which prevents finding the offsets by simply examining the dumps. So in this document I'm going to go over what offsets are important for ps5-kstuff, and how I found them for 4.03.

These are the main categories of offsets:

Kernel data offsets, those can be found from data dumps that are not XOM-protected
Kernel text offsets pointed to by kernel data
doreti_iret offset (that's one offset, but it deserves its own word)
Offsets found from single-stepping of kernel functions

	import html.parser, urllib.parse, urllib.request, pydoc, random

	class Parser(html.parser.HTMLParser):
	def __init__(self):
	html.parser.HTMLParser.__init__(self)
	self.li_stack = [None]
	self.table_stack = [None]
	self.tag_stack = []
	self.repr_stack = ['']
	self.form_stack = [None]

	#include <sys/types.h>
	#include <sys/param.h>
	#include <sys/cpuset.h>
	#include <sys/socket.h>
	#include <sys/mman.h>
	#include <sys/sysctl.h>
	#include <sys/vmmeter.h>
	#include <netinet/in.h>
	#include <string.h>
	#include <unistd.h>

	<script>
	var PAGE_SIZE = 16384;
	var SIZEOF_CSS_FONT_FACE = 0xb8;
	var HASHMAP_BUCKET = 208;
	var STRING_OFFSET = 20;
	var SPRAY_FONTS = 0x1000;
	var GUESS_FONT = 0x200430000;
	var NPAGES = 20;
	var INVALID_POINTER = 0;
	var HAMMER_FONT_NAME = "font8"; //must take bucket 3 of 8 (counting from zero)

	A=/sys/class/android_usb/android0

	set -x
	killall -STOP adbd
	sleep 1
	echo 0 > $A/enable
	echo mass_storage > $A/functions
	echo disk > $A/f_mass_storage/luns
	echo 1 > $A/enable
	sleep 1

	#include <sys/socket.h>
	#include <sys/un.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <dirent.h>
	#include <unistd.h>
	#include <stddef.h>

	void write_request(int fd, const char* c)
	{