Shima(しーま) syarochan

These results are with glibc malloc on x86_64. The last public PaX and grsecurity patches don't support arm64 which is one of the two architectures (x86_64 kernels including x32/x86_32 and arm64 kernels including armv7 userspace) focused on by linux-hardened. There isn't anything other than x86_64 to compare across all 3 kernels although linux-hardened has the same end result for both x86_64 and arm64 (with slightly different starting points) and there are few mainline differences. The linux-hardened implementation of ASLR is a very minimal modification of the mainline implementation to fix the weaknesses compared to grsecurity. The intention is to upstream all of these changes, although care needs to be taken to properly justify them to avoid getting anything rejected unnecessarily.

Explanation of differences between kernels:

Mainline and linux-hardened base randomization entropy for the mmap base and executable to the vm.mmap_rnd_bits sysctl for 64-bit and

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参考文献

Your First Format String Attacks.

1. What's the `Format String Bugs'?

　Format String Bugs(以降, FSBとする)とは, sprintf()やfprintf()などのprintf関数群やsyslog()などのFormat Strings(以降, 書式指定子とする)を扱える関数において, ユーザが自由に書式指定子を配置できるバグである. これを利用した攻撃手法をFormat String Attacksと呼び, この攻撃によりターゲットとなるプロセスがアクセス可能な任意のメモリの読み書きが行えるようになる. また, それを利用しプログラムの制御を乗っ取ることも可能である.
　実際のプログラムに多く存在するとは到底言えないような脆弱性ではあるが稀に見つかることはある. CVE-2012-0809[1]ではsudoのデバッグ機能にFSBが見つかり, 実際にlocal exploitが公開されたりもした. 前述の通り珍しいものではあるが, 任意のメモリの書き換えができるなど非常に強力なものであることからCTFではよく題材にされる.
　この記事ではFSBの検証に以下の環境を使用した.

sh-4.3$ uname -a
Linux Arch_Laptop 4.0.4-1-ARCH #1 SMP PREEMPT Mon May 18 06:43:19 CEST 2015 x86_64 GNU/Linux

	// Original source link https://twitter.com/hFireF0X/status/887930221466443776
	// If you are here from any other link - do know that they just steal original info without giving any credit to source
	// This bug has been fixed in 16273 public build.
	#include "global.h"

	HINSTANCE g_hInstance;
	HANDLE g_ConOut = NULL;
	BOOL g_ConsoleOutput = FALSE;
	WCHAR g_BE = 0xFEFF;

	# This file has no update anymore. Please see https://github.com/worawit/MS17-010
	import sys
	from struct import pack

	if len(sys.argv) < 4:
	print('Usage: {} sc_x86 sc_x64 sc_out'.format(sys.argv[0]))
	sys.exit()

	sc_x86 = open(sys.argv[1], 'rb').read()
	sc_x64 = open(sys.argv[2], 'rb').read()