mirror of
https://github.com/nganhkhoa/CTF-All-In-One.git
synced 2024-12-24 19:21:15 +07:00
add 5.8; update 4.5
This commit is contained in:
firmianay
parent
6c28c70474
commit
1874b59e20
@ -65,6 +65,7 @@
|
||||
- [5.5 符号执行](doc/5.5_symbolic.md)
|
||||
- [5.6 LLVM](doc/5.6_llvm.md)
|
||||
- [5.7 Capstone/Keystone](doc/5.7_cap-keystone.md)
|
||||
- [5.8 SAT/SMT](doc/5.8_sat-smt.md)
|
||||
|
||||
- [六、题解篇](doc/6_writeup.md)
|
||||
- pwn
|
||||
|
||||
@ -62,6 +62,7 @@
|
||||
* [5.5 符号执行](doc/5.5_symbolic.md)
|
||||
* [5.6 LLVM](doc/5.6_llvm.md)
|
||||
* [5.7 Capstone/Keystone](doc/5.7_cap-keystone.md)
|
||||
* [5.8 SAT/SMT](doc/5.8_sat-smt.md)
|
||||
* [六、题解篇](doc/6_writeup.md)
|
||||
* pwn
|
||||
* [6.1.1 pwn HCTF2016 brop](doc/6.1.1_pwn_hctf2016_brop.md)
|
||||
|
||||
179
doc/4.5_z3.md
179
doc/4.5_z3.md
@ -1 +1,180 @@
|
||||
# Z3 约束求解器
|
||||
|
||||
- [安装](#安装)
|
||||
- [Z3 理论基础](#z3-理论基础)
|
||||
- [使用 Z3](#使用-z3)
|
||||
- [Z3 在 CTF 中的运用](#z3-在-ctf-中的运用)
|
||||
- [参考资料](#参考资料)
|
||||
|
||||
|
||||
[Z3](https://github.com/Z3Prover/z3) 是一个由微软开发的 Satisfiability Modulo Theories（SMT）求解器。可以用来检查满足一个或多个理论的公式的可满足性，也就是说,它可以自动化地通过内置理论对一阶逻辑多种排列进行可满足性校验。目前其支持的理论有：
|
||||
- equality over free 函数和谓词符号
|
||||
- 实数和整形运算(有限支持非线性运算)
|
||||
- 位向量
|
||||
- 阵列
|
||||
- 元组/记录/枚举类型和代数（递归）数据类型
|
||||
- ...
|
||||
|
||||
因其强大的功能，Z3 已经被用于许多领域中，在安全领域，主要见于符号执行、Fuzzing、二进制逆向、密码学等。另外 Z3 提供了多种语言的接口，这里我们使用 Python。
|
||||
|
||||
|
||||
## 安装
|
||||
在 Linux 环境下，执行下面的命令：
|
||||
```
|
||||
$ git clone https://github.com/Z3Prover/z3.git
|
||||
$ cd z3
|
||||
|
||||
$ python scripts/mk_make.py --python
|
||||
$ cd build
|
||||
$ make
|
||||
$ sudo make install
|
||||
```
|
||||
|
||||
另外还可以使用 pip 来安装 Python 接口，这是二进制分析框架 angr 里内置的修改版：
|
||||
```
|
||||
$ sudo pip install z3-solver
|
||||
```
|
||||
|
||||
|
||||
## Z3 理论基础
|
||||
| Op | Mnmonics | Description |
|
||||
| --- | --- | --- |
|
||||
| 0 | true | 恒真 |
|
||||
| 1 | flase | 恒假 |
|
||||
| 2 | = | 相等 |
|
||||
| 3 | distinct | 不同 |
|
||||
| 4 | ite | if-then-else |
|
||||
| 5 | and | n元 合取 |
|
||||
| 6 | or | n元 析取 |
|
||||
| 7 | iff | implication |
|
||||
| 8 | xor | 异或 |
|
||||
| 9 | not | 否定 |
|
||||
| 10 | implies | Bi-implications |
|
||||
|
||||
|
||||
## 使用 Z3
|
||||
先来看一个简单的例子：
|
||||
```python
|
||||
>>> from z3 import *
|
||||
>>> x = Int('x')
|
||||
>>> y = Int('y')
|
||||
>>> solve(x > 2, y < 10, x + 2*y == 7)
|
||||
[y = 0, x = 7]
|
||||
```
|
||||
首先定义了两个变量 x 和 y，类型是 Z3 内置的整数类型 `Int`，`solve()` 函数会创造一个 solver，然后对括号中的约束条件进行求解，注意在 Z3 默认情况下只会找到满足条件的一组解。
|
||||
|
||||
```python
|
||||
>>> simplify(x + y + 2*x + 3)
|
||||
3 + 3*x + y
|
||||
>>> simplify(x < y + x + 2)
|
||||
Not(y <= -2)
|
||||
>>> simplify(And(x + 1 >= 3, x**2 + x**2 + y**2 + 2 >= 5))
|
||||
And(x >= 2, 2*x**2 + y**2 >= 3)
|
||||
>>>
|
||||
>>> simplify((x + 1)*(y + 1))
|
||||
(1 + x)*(1 + y)
|
||||
>>> simplify((x + 1)*(y + 1), som=True)
|
||||
1 + x + y + x*y
|
||||
```
|
||||
`simplify()` 函数用于对表达式进行化简，同时可以设置一些选项来满足不同的要求。更多选项使用 `help_simplify()` 获得。
|
||||
|
||||
同时，Z3 提供了一些函数可以解析表达式：
|
||||
```python
|
||||
>>> n = x + y >= 3
|
||||
>>> "num args: ", n.num_args()
|
||||
('num args: ', 2)
|
||||
>>> "children: ", n.children()
|
||||
('children: ', [x + y, 3])
|
||||
>>> "1st child:", n.arg(0)
|
||||
('1st child:', x + y)
|
||||
>>> "2nd child:", n.arg(1)
|
||||
('2nd child:', 3)
|
||||
>>> "operator: ", n.decl()
|
||||
('operator: ', >=)
|
||||
>>> "op name: ", n.decl().name()
|
||||
('op name: ', '>=')
|
||||
```
|
||||
|
||||
`set_param()` 函数用于对 Z3 的全局变量进行配置，如运算精度，输出格式等等：
|
||||
```python
|
||||
>>> x = Real('x')
|
||||
>>> y = Real('y')
|
||||
>>> solve(x**2 + y**2 == 3, x**3 == 2)
|
||||
[x = 1.2599210498?, y = -1.1885280594?]
|
||||
>>>
|
||||
>>> set_param(precision=30)
|
||||
>>> solve(x**2 + y**2 == 3, x**3 == 2)
|
||||
[x = 1.259921049894873164767210607278?,
|
||||
y = -1.188528059421316533710369365015?]
|
||||
```
|
||||
|
||||
逻辑运算有 `And`、`Or`、`Not`、`Implies`、`If`，另外 `==` 表示 Bi-implications。
|
||||
```python
|
||||
>>> p = Bool('p')
|
||||
>>> q = Bool('q')
|
||||
>>> r = Bool('r')
|
||||
>>> solve(Implies(p, q), r == Not(q), Or(Not(p), r))
|
||||
[q = False, p = False, r = True]
|
||||
>>>
|
||||
>>> x = Real('x')
|
||||
>>> solve(Or(x < 5, x > 10), Or(p, x**2 == 2), Not(p))
|
||||
[x = -1.4142135623?, p = False]
|
||||
```
|
||||
|
||||
Z3 提供了多种 Solver，即 `Solver` 类，其中实现了很多 SMT 2.0 的命令，如 `push`, `pop`, `check` 等等。
|
||||
```python
|
||||
>>> x = Int('x')
|
||||
>>> y = Int('y')
|
||||
>>> s = Solver() # 创造一个通用 solver
|
||||
>>> type(s) # Solver 类
|
||||
<class 'z3.z3.Solver'>
|
||||
>>> s
|
||||
[]
|
||||
>>> s.add(x > 10, y == x + 2) # 添加约束到 solver 中
|
||||
>>> s
|
||||
[x > 10, y == x + 2]
|
||||
>>> s.check() # 检查 solver 中的约束是否满足
|
||||
sat # satisfiable/满足
|
||||
>>> s.push() # 创建一个回溯点，即将当前栈的大小保存下来
|
||||
>>> s.add(y < 11)
|
||||
>>> s
|
||||
[x > 10, y == x + 2, y < 11]
|
||||
>>> s.check()
|
||||
unsat # unsatisfiable/不满足
|
||||
>>> s.pop(num=1) # 回溯 num 个点
|
||||
>>> s
|
||||
[x > 10, y == x + 2]
|
||||
>>> s.check()
|
||||
sat
|
||||
>>> for c in s.assertions(): # assertions() 返回一个包含所有约束的AstVector
|
||||
... print(c)
|
||||
...
|
||||
x > 10
|
||||
y == x + 2
|
||||
>>> s.statistics() # statistics() 返回最后一个 check() 的统计信息
|
||||
(:max-memory 6.26
|
||||
:memory 4.37
|
||||
:mk-bool-var 1
|
||||
:num-allocs 331960806
|
||||
:rlimit-count 7016)
|
||||
>>> m = s.model() # model() 返回最后一个 check() 的 model
|
||||
>>> type(m) # ModelRef 类
|
||||
<class 'z3.z3.ModelRef'>
|
||||
>>> m
|
||||
[x = 11, y = 13]
|
||||
>>> for d in m.decls(): # decls() 返回 model 包含了所有符号的列表
|
||||
... print("%s = %s" % (d.name(), m[d]))
|
||||
...
|
||||
x = 11
|
||||
y = 13
|
||||
```
|
||||
|
||||
## Z3 在 CTF 中的运用
|
||||
|
||||
|
||||
## 参考资料
|
||||
- [Z3一把梭：用约束求解搞定一类CTF题](https://zhuanlan.zhihu.com/p/30548907)
|
||||
- [Z3 API in Python](https://ericpony.github.io/z3py-tutorial/guide-examples.htm)
|
||||
- [z3py API](http://z3prover.github.io/api/html/index.html)
|
||||
- [Getting Started with Z3: A Guide](https://rise4fun.com/z3/tutorialcontent/guide)
|
||||
- [Wiki](https://github.com/Z3Prover/z3/wiki)
|
||||
|
||||
6
doc/5.8_sat-smt.md
Normal file
6
doc/5.8_sat-smt.md
Normal file
@ -0,0 +1,6 @@
|
||||
# SAT/SMT
|
||||
|
||||
- [参考资料](#参考资料)
|
||||
|
||||
## 参考资料
|
||||
- [Quick introduction into SAT/SMT solvers and symbolic execution](https://yurichev.com/writings/SAT_SMT_draft-EN.pdf)
|
||||
@ -7,3 +7,4 @@
|
||||
- [5.5 Symbolic Execution 符号执行技术](5.5_symbolic.md)
|
||||
- [5.6 LLVM](5.6_llvm.md)
|
||||
- [5.7 Capstone/Keystone](5.7_cap-keystone.md)
|
||||
- [5.8 SAT/SMT](5.8_sat-smt.md)
|
||||
|
||||
@ -3,7 +3,7 @@
|
||||
- [SROP 原理](#srop-原理)
|
||||
- [Linux 系统调用](#linux-系统调用)
|
||||
- [signal 机制](#signal-机制)
|
||||
- [SROP](#SROP)
|
||||
- [SROP](#srop)
|
||||
- [pwnlib.rop.srop](#pwnlibropsrop)
|
||||
- [BackdoorCTF2017 Fun Signals](#backdoorctf2017-fun-signals)
|
||||
- [参考资料](#参考资料)
|
||||
|
||||
@ -20,8 +20,16 @@ $ ldd /usr/bin/ls
|
||||
|
||||
|
||||
## 题目解析
|
||||
```
|
||||
$ file fuckup
|
||||
fuckup: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, stripped
|
||||
$ checksec -f fuckup
|
||||
RELRO STACK CANARY NX PIE RPATH RUNPATH FORTIFY Fortified Fortifiable FILE
|
||||
No RELRO No canary found NX enabled No PIE No RPATH No RUNPATH No 0 0 fuckup
|
||||
```
|
||||
|
||||
## Exploit
|
||||
完整的 exp 如下，其他文件放在了[github](../src/writeup/6.1.6_pwn_defconctf2015_fuckup)相应文件夹中：
|
||||
|
||||
## 参考资料
|
||||
- `man vdso`
|
||||
|
||||
Loading…
Reference in New Issue
Block a user