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update pwntools

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firmianay 2017-10-12 17:08:08 +08:00
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395
doc/2.7_pwntools.md
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@ -40,12 +40,47 @@ $ yaourt -S python2-pwntools
$ yaourt -S python2-pwntools-git
```
但是由于 Arch 没有 PPA 源，如果想要支持更多的体系结构（如 arm, aarch64 等），只能手动编译安装相应的 binutils，使用下面的脚本，注意将变量 `V` 和 `ARCH` 换成你需要的。[binutils](https://ftp.gnu.org/gnu/binutils/)
```bash
#!/usr/bin/env bash
V = 2.29 # binutils version
ARCH = arm # target architecture
cd /tmp
wget -nc https://ftp.gnu.org/gnu/binutils/binutils-$V.tar.xz
wget -nc https://ftp.gnu.org/gnu/binutils/binutils-$V.tar.xz.sig
# gpg --keyserver keys.gnupg.net --recv-keys C3126D3B4AE55E93
# gpg --verify binutils-$V.tar.xz.sig
tar xf binutils-$V.tar.xz
mkdir binutils-build
cd binutils-build
export AR=ar
export AS=as
../binutils-$V/configure \
--prefix=/usr/local \
--target=$ARCH-unknown-linux-gnu \
--disable-static \
--disable-multilib \
--disable-werror \
--disable-nls
make
sudo make install
```
测试安装是否成功：
```python
>>> import pwn
>>> pwn.asm("xor eax,eax")
'1\xc0'
>>> from pwn import *
>>> asm('nop')
'\x90'
>>> asm('nop', arch='arm')
'\x00\xf0 \xe3'
```
@ -68,7 +103,7 @@ Pwntools 分为两个模块，一个是 `pwn`，简单地使用 `from pwn import
- `libcdb`：libc 数据库
- `log`：日志记录
- **`memleak`**：用于内存泄露
- `rop`：ROP 利用模块，包括 rop 和 srop
- **`rop`**：ROP 利用模块，包括 rop 和 srop
- `runner`：运行 shellcode
- **`shellcraft`**：shellcode 生成器
- `term`：终端处理
@ -107,106 +142,310 @@ Pwntools 分为两个模块，一个是 `pwn`，简单地使用 `from pwn import
- `close()`：关闭管道
下面是一个例子，先使用 listen 开启一个本地的监听端口，然后使用 remote 开启一个套接字管道与之交互：
```
In [1]: from pwn import *
In [2]: l = listen()
```text
>>> from pwn import *
>>> l = listen()
[x] Trying to bind to 0.0.0.0 on port 0
[x] Trying to bind to 0.0.0.0 on port 0: Trying 0.0.0.0
[+] Trying to bind to 0.0.0.0 on port 0: Done
[x] Waiting for connections on 0.0.0.0:35117
[x] Waiting for connections on 0.0.0.0:46147
>>> r = remote('localhost', l.lport)
[x] Opening connection to localhost on port 46147
[x] Opening connection to localhost on port 46147: Trying ::1
[x] Opening connection to localhost on port 46147: Trying 127.0.0.1
[+] Opening connection to localhost on port 46147: Done
>>> [+] Waiting for connections on 0.0.0.0:46147: Got connection from 127.0.0.1 on port 38684
In [3]: r = remote('localhost', l.lport)
[x] Opening connection to localhost on port 35117
[x] Opening connection to localhost on port 35117: Trying ::1
[x] Opening connection to localhost on port 35117: Trying 127.0.0.1
[+] Opening connection to localhost on port 35117: Done
[+] Waiting for connections on 0.0.0.0:35117: Got connection from 127.0.0.1 on port 36966
In [4]: c = l.wait_for_connection()
In [5]: r.send('hello\n')
In [6]: c.recv()
Out[6]: 'hello\n'
In [7]: r.send('hello\n')
In [8]: c.recvline()
Out[8]: 'hello\n'
In [9]: r.sendline('hello')
In [10]: c.recv()
Out[10]: 'hello\n'
In [11]: r.sendline('hello')
In [12]: c.recvline()
Out[12]: 'hello\n'
In [13]: r.sendline('hello')
In [14]: c.recvline(keepends=False)
Out[14]: 'hello'
In [15]: r.send('hello world')
In [16]: c.recvuntil('hello')
Out[16]: 'hello'
In [17]: c.recv()
Out[17]: ' world'
In [18]: c.close()
[*] Closed connection to 127.0.0.1 port 36966
In [19]: r.close()
[*] Closed connection to localhost port 35117
>>> c = l.wait_for_connection()
>>> r.send('hello\n')
>>> c.recv()
'hello\n'
>>> r.send('hello\n')
>>> c.recvline()
'hello\n'
>>> r.sendline('hello')
>>> c.recv()
'hello\n'
>>> r.sendline('hello')
>>> c.recvline()
'hello\n'
>>> r.sendline('hello')
>>> c.recvline(keepends=False)
'hello'
>>> r.send('hello world')
>>> c.recvuntil('hello')
'hello'
>>> c.recv()
' world'
>>> c.close()
[*] Closed connection to 127.0.0.1 port 38684
>>> r.close()
[*] Closed connection to localhost port 46147
```
下面是一个与进程交互的例子：
```
In [1]: p = process('/bin/sh')
```text
>>> p = process('/bin/sh')
[x] Starting local process '/bin/sh'
[+] Starting local process '/bin/sh': pid 32165
In [2]: p.sendline('sleep 3; echo hello world;')
In [3]: p.recvline(timeout=1)
Out[3]: 'hello world\n'
In [4]: p.sendline('sleep 3; echo hello world;')
In [5]: p.recvline(timeout=1)
Out[5]: ''
In [6]: p.recvline(timeout=5)
Out[6]: 'hello world\n'
In [7]: p.interactive()
[+] Starting local process '/bin/sh': pid 26481
>>> p.sendline('sleep 3; echo hello world;')
>>> p.recvline(timeout=1)
'hello world\n'
>>> p.sendline('sleep 3; echo hello world;')
>>> p.recvline(timeout=1)
''
>>> p.recvline(timeout=5)
'hello world\n'
>>> p.interactive()
[*] Switching to interactive mode
whoami
firmy
^C[*] Interrupted
>>> p.close()
[*] Stopped process '/bin/sh' (pid 26481)
```
In [8]: p.close()
[*] Stopped process '/bin/sh' (pid 32165)
#### shellcraft
使用 shellcraft 模块可以生成对应架构和 shellcode 代码，直接使用链式调用的方法就可以得到，首先指定体系结构，再指定操作系统：
```
>>> print shellcraft.i386.nop().strip('\n')
nop
>>> print shellcraft.i386.linux.sh()
/* execve(path='/bin///sh', argv=['sh'], envp=0) */
/* push '/bin///sh\x00' */
push 0x68
push 0x732f2f2f
push 0x6e69622f
mov ebx, esp
/* push argument array ['sh\x00'] */
/* push 'sh\x00\x00' */
push 0x1010101
xor dword ptr [esp], 0x1016972
xor ecx, ecx
push ecx /* null terminate */
push 4
pop ecx
add ecx, esp
push ecx /* 'sh\x00' */
mov ecx, esp
xor edx, edx
/* call execve() */
push SYS_execve /* 0xb */
pop eax
int 0x80
```
#### asm
该模块用于汇编和反汇编代码。
#### dynelf
体系结构，端序和字长需要在 `asm()` 和 `disasm()` 中设置，但为了避免重复，运行时变量最好使用 `pwnlib.context` 来设置。
汇编：(`pwnlib.asm.asm`)
```text
>>> asm('nop')
'\x90'
>>> asm(shellcraft.nop())
'\x90'
>>> asm('nop', arch='arm')
'\x00\xf0 \xe3'
>>> context.arch = 'arm'
>>> context.os = 'linux'
>>> context.endian = 'little'
>>> context.word_size = 32
>>> context
ContextType(arch = 'arm', bits = 32, endian = 'little', os = 'linux')
>>> asm('nop')
'\x00\xf0 \xe3'
```
```
>>> asm('mov eax, 1')
'\xb8\x01\x00\x00\x00'
>>> asm('mov eax, 1').encode('hex')
'b801000000'
```
请注意，这里我们生成了 i386 和 arm 两种不同体系结构的 `nop`，当你使用不同与本机平台的汇编时，需要安装该平台的 binutils，方法在上面已经介绍过了。
反汇编：(`pwnlib.asm.disasm`)
```text
>>> print disasm('\xb8\x01\x00\x00\x00')
0: b8 01 00 00 00 mov eax,0x1
>>> print disasm('6a0258cd80ebf9'.decode('hex'))
0: 6a 02 push 0x2
2: 58 pop eax
3: cd 80 int 0x80
5: eb f9 jmp 0x0
```
构建具有指定二进制数据的 ELF 文件：(`pwnlib.asm.make_elf`)
```text
>>> context.clear(arch='amd64')
>>> context
ContextType(arch = 'amd64', bits = 64, endian = 'little')
>>> bin_sh = asm(shellcraft.amd64.linux.sh())
>>> bin_sh
'jhH\xb8/bin///sPH\x89\xe7hri\x01\x01\x814$\x01\x01\x01\x011\xf6Vj\x08^H\x01\xe6VH\x89\xe61\xd2j;X\x0f\x05'
>>> filename = make_elf(bin_sh, extract=False)
>>> filename
'/tmp/pwn-asm-V4GWGN/step3-elf'
>>> p = process(filename)
[x] Starting local process '/tmp/pwn-asm-V4GWGN/step3-elf'
[+] Starting local process '/tmp/pwn-asm-V4GWGN/step3-elf': pid 28323
>>> p.sendline('echo hello')
>>> p.recv()
'hello\n'
```
这里我们生成了 amd64，即 64 位 `/bin/sh` 的 shellcode，配合上 asm 函数，即可通过 `make_elf` 得到 ELF 文件。
另一个函数 `pwnlib.asm.make_elf_from_assembly` 允许你构建具有指定汇编代码的 ELF 文件：
```text
>>> asm_sh = shellcraft.amd64.linux.sh()
>>> print asm_sh
/* execve(path='/bin///sh', argv=['sh'], envp=0) */
/* push '/bin///sh\x00' */
push 0x68
mov rax, 0x732f2f2f6e69622f
push rax
mov rdi, rsp
/* push argument array ['sh\x00'] */
/* push 'sh\x00' */
push 0x1010101 ^ 0x6873
xor dword ptr [rsp], 0x1010101
xor esi, esi /* 0 */
push rsi /* null terminate */
push 8
pop rsi
add rsi, rsp
push rsi /* 'sh\x00' */
mov rsi, rsp
xor edx, edx /* 0 */
/* call execve() */
push SYS_execve /* 0x3b */
pop rax
syscall
>>> filename = make_elf_from_assembly(asm_sh)
>>> filename
'/tmp/pwn-asm-ApZ4_p/step3'
>>> p = process(filename)
[x] Starting local process '/tmp/pwn-asm-ApZ4_p/step3'
[+] Starting local process '/tmp/pwn-asm-ApZ4_p/step3': pid 28429
>>> p.sendline('echo hello')
>>> p.recv()
'hello\n'
```
与上一个函数不同的是，`make_elf_from_assembly` 直接从汇编生成 ELF 文件，并且保留了所有的符号，例如标签和局部变量等。
#### elf
该模块用于 ELF 二进制文件的操作，包括符号查找、虚拟内存、文件偏移，以及修改和保存二进制文件等功能。(`pwnlib.elf.elf.ELF`)
```text
>>> e = ELF('/bin/cat')
[*] '/bin/cat'
Arch: amd64-64-little
RELRO: Full RELRO
Stack: Canary found
NX: NX enabled
PIE: PIE enabled
>>> print hex(e.address)
0x400000
>>> print hex(e.symbols['write'])
0x401680
>>> print hex(e.got['write'])
0x60b070
>>> print hex(e.plt['write'])
0x401680
```
上面的代码分别获得了 ELF 文件装载的基地址、函数地址、GOT 表地址和 PLT 表地址。
我们常常用它打开一个 libc.so，从而得到 system 函数的位置，这在 CTF 中是非常有用的：
```text
>>> e = ELF('/usr/lib/libc.so.6')
[*] '/usr/lib/libc.so.6'
Arch: amd64-64-little
RELRO: Full RELRO
Stack: Canary found
NX: NX enabled
PIE: PIE enabled
>>> print hex(e.symbols['system'])
0x42010
```
我们甚至可以修改 ELF 文件的代码：
```text
>>> e = ELF('/bin/cat')
>>> e.read(e.address+1, 3)
'ELF'
>>> e.asm(e.address, 'ret')
>>> e.save('/tmp/quiet-cat')
>>> disasm(file('/tmp/quiet-cat','rb').read(1))
' 0: c3 ret'
```
下面是一些常用函数：
- `asm(address, assembly)`：汇编指定指令并插入到 ELF 的指定地址处，需要使用 ELF.save() 保存
- `bss(offset)`：返回 `.bss` 段加上 `offset` 后的地址
- `checksec()`：打印出文件使用的安全保护
- `disable_nx()`：关闭 NX
- `disasm(address, n_bytes)`：返回对指定虚拟地址进行反汇编后的字符串
- `offset_to_vaddr(offset)`：将指定偏移转换为虚拟地址
- `vaddr_to_offset(address)`：将指定虚拟地址转换为文件偏移
- `read(address, count)`：从指定虚拟地址读取 `count` 个字节的数据
- `write(address, data)`：在指定虚拟地址处写入 `data`
- `section(name)`：获取 `name` 段的数据
- `debug()`：使用 `gdb.debug()` 进行调试
最后还要注意一下 `pwnlib.elf.corefile`，它用于处理核心转储文件（Core Dump），当我们在写利用代码时，核心转储文件是非常有用的，关于它更详细的内容已经在前面 Linux基础一章中讲过，这里我们还是使用那一章中的示例代码，但使用 pwntools 来操作。
```
>>> core = Corefile('/tmp/core-a.out-30555-1507796886')
[x] Parsing corefile...
[*] '/tmp/core-a.out-30555-1507796886'
Arch: i386-32-little
EIP: 0x565cd57b
ESP: 0x4141413d
Exe: '/home/firmy/a.out' (0x565cd000)
Fault: 0x4141413d
[+] Parsing corefile...: Done
>>> core.registers
{'xds': 43, 'eip': 1448924539, 'xss': 43, 'esp': 1094795581, 'xgs': 99, 'edi': 0, 'orig_eax': 4294967295, 'xcs': 35, 'eax': 1, 'ebp': 1094795585, 'xes': 43, 'eflags': 66182, 'edx': 4151195744, 'ebx': 1094795585, 'xfs': 0, 'esi': 4151189032, 'ecx': 1094795585}
>>> print core.maps
565cd000-565ce000 r-xp 1000 /home/firmy/a.out
565ce000-565cf000 r--p 1000 /home/firmy/a.out
565cf000-565d0000 rw-p 1000 /home/firmy/a.out
57b3c000-57b5e000 rw-p 22000
f7510000-f76df000 r-xp 1cf000 /usr/lib32/libc-2.26.so
f76df000-f76e0000 ---p 1000 /usr/lib32/libc-2.26.so
f76e0000-f76e2000 r--p 2000 /usr/lib32/libc-2.26.so
f76e2000-f76e3000 rw-p 1000 /usr/lib32/libc-2.26.so
f76e3000-f76e6000 rw-p 3000
f7722000-f7724000 rw-p 2000
f7724000-f7726000 r--p 2000 [vvar]
f7726000-f7728000 r-xp 2000 [vdso]
f7728000-f774d000 r-xp 25000 /usr/lib32/ld-2.26.so
f774d000-f774e000 r--p 1000 /usr/lib32/ld-2.26.so
f774e000-f774f000 rw-p 1000 /usr/lib32/ld-2.26.so
ffe37000-ffe58000 rw-p 21000 [stack]
>>> print hex(core.fault_addr)
0x4141413d
>>> print hex(core.pc)
0x565cd57b
>>> print core.libc
f7510000-f76df000 r-xp 1cf000 /usr/lib32/libc-2.26.so
```
#### dynelf
`pwnlib.dynelf.DynELF`
该模块是专门用来应对无 libc 情况下的漏洞利用。它首先找到 glibc 的基地址，然后使用符号表和字符串表对所有符号进行解析，直到找到我们需要的函数的符号。这是一个有趣的话题，我们会专门开一个章节去讲解它。详见 *4.4 使用 DynELF 泄露函数地址*
#### fmtstr
`pwnlib.fmtstr.FmtStr`，`pwnlib.fmtstr.fmtstr_payload`
该模块用于格式化字符串漏洞的利用，格式化字符串漏洞是 CTF 中一种常见的题型，我们会在后面的章节中详细讲述，关于该模块的使用也会留到那儿。详见 *3.3.1 格式化字符串漏洞*
#### gdb
#### memleak
#### shellcraft
#### rop
#### util

30
src/Others/2.7_pwntools.sh Normal file
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@ -0,0 +1,30 @@
#!/usr/bin/env bash
V = 2.29 # binutils version
ARCH = arm # target architecture
cd /tmp
wget -nc https://ftp.gnu.org/gnu/binutils/binutils-$V.tar.xz
wget -nc https://ftp.gnu.org/gnu/binutils/binutils-$V.tar.xz.sig
# gpg --keyserver keys.gnupg.net --recv-keys C3126D3B4AE55E93
# gpg --verify binutils-$V.tar.xz.sig
tar xf binutils-$V.tar.xz
mkdir binutils-build
cd binutils-build
export AR=ar
export AS=as
../binutils-$V/configure \
--prefix=/usr/local \
--target=$ARCH-unknown-linux-gnu \
--disable-static \
--disable-multilib \
--disable-werror \
--disable-nls
make
sudo make install