syzkaller-repros/linux/f38fb3fa1f2f32a667805c1a0302254e19d79fb1.c

// BUG: unable to handle kernel NULL pointer dereference
// https://syzkaller.appspot.com/bug?id=f38fb3fa1f2f32a667805c1a0302254e19d79fb1
// status:dup
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}

#include <setjmp.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <string.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void fail(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) &&
      (addr < prog_start || addr > prog_end)) {
    _longjmp(segv_env, 1);
  }
  doexit(sig);
  for (;;) {
  }
}

static void install_segv_handler()
{
  struct sigaction sa;

  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
  syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);

  memset(&sa, 0, sizeof(sa));
  sa.sa_sigaction = segv_handler;
  sa.sa_flags = SA_NODEFER | SA_SIGINFO;
  sigaction(SIGSEGV, &sa, NULL);
  sigaction(SIGBUS, &sa, NULL);
}

#define NONFAILING(...)                                                \
  {                                                                    \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);               \
    if (_setjmp(segv_env) == 0) {                                      \
      __VA_ARGS__;                                                     \
    }                                                                  \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);               \
  }

static uint64_t current_time_ms()
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    fail("clock_gettime failed");
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void test();

void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      fail("clone failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      test();
      doexit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid)
        break;
      usleep(1000);
      if (current_time_ms() - start > 5 * 1000) {
        kill(-pid, SIGKILL);
        kill(pid, SIGKILL);
        while (waitpid(-1, &status, __WALL) != pid) {
        }
        break;
      }
    }
  }
}

long r[39];
void* thr(void* arg)
{
  switch ((long)arg) {
  case 0:
    r[0] = syscall(__NR_mmap, 0x20000000ul, 0xf41000ul, 0x3ul, 0x32ul,
                   0xfffffffffffffffful, 0x0ul);
    break;
  case 1:
    r[1] = syscall(__NR_socket, 0x26ul, 0x5ul, 0x0ul);
    break;
  case 2:
    NONFAILING(*(uint16_t*)0x20408000 = (uint16_t)0x26);
    NONFAILING(memcpy(
        (void*)0x20408002,
        "\x61\x65\x61\x64\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
        14));
    NONFAILING(*(uint32_t*)0x20408010 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x20408014 = (uint32_t)0x0);
    NONFAILING(memcpy((void*)0x20408018,
                      "\x67\x63\x6d\x28\x74\x77\x6f\x66\x69\x73\x68\x29"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00",
                      64));
    r[7] = syscall(__NR_bind, r[1], 0x20408000ul, 0x58ul);
    break;
  case 3:
    NONFAILING(memcpy((void*)0x20830ff0, "\x64\x9c\x47\x00\x00\x00\x00"
                                         "\x00\x00\xc0\xb5\xfa\x40\x9d"
                                         "\x4d\x54",
                      16));
    r[9] = syscall(__NR_setsockopt, r[1], 0x117ul, 0x1ul, 0x20830ff0ul,
                   0x10ul);
    break;
  case 4:
    r[10] = syscall(__NR_accept, r[1], 0x0ul, 0x0ul);
    break;
  case 5:
    r[11] = syscall(__NR_accept, r[1], 0x0ul, 0x0ul);
    break;
  case 6:
    NONFAILING(*(uint64_t*)0x205d8000 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x205d8008 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x205d8010 = (uint64_t)0x20b5d000);
    NONFAILING(*(uint64_t*)0x205d8018 = (uint64_t)0x1);
    NONFAILING(*(uint64_t*)0x205d8020 = (uint64_t)0x20f3a000);
    NONFAILING(*(uint64_t*)0x205d8028 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x205d8030 = (uint32_t)0x4080);
    NONFAILING(*(uint64_t*)0x20b5d000 = (uint64_t)0x20a94fc3);
    NONFAILING(*(uint64_t*)0x20b5d008 = (uint64_t)0x24);
    NONFAILING(memcpy((void*)0x20a94fc3,
                      "\x0c\xda\x5e\x1b\x78\xab\x4c\xd5\x04\x0d\x36\x92"
                      "\x41\xd5\x5b\x3b\x0c\x15\xc2\xd7\x69\x48\x69\x35"
                      "\x74\x1f\xc7\x01\xa6\xb9\xd0\xbe\x38\x57\x6a"
                      "\x64",
                      36));
    NONFAILING(*(uint64_t*)0x20f3a000 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x20f3a008 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x20f3a00c = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x20f3a010 = (uint32_t)0x1);
    r[26] = syscall(__NR_sendmsg, r[10], 0x205d8000ul, 0x4ul);
    break;
  case 7:
    NONFAILING(*(uint64_t*)0x207e0000 = (uint64_t)0x20f38ff7);
    NONFAILING(*(uint32_t*)0x207e0008 = (uint32_t)0x9);
    NONFAILING(*(uint64_t*)0x207e0010 = (uint64_t)0x20f38fe0);
    NONFAILING(*(uint64_t*)0x207e0018 = (uint64_t)0x2);
    NONFAILING(*(uint64_t*)0x207e0020 = (uint64_t)0x204d3f31);
    NONFAILING(*(uint64_t*)0x207e0028 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x207e0030 = (uint32_t)0x3);
    NONFAILING(*(uint64_t*)0x20f38fe0 = (uint64_t)0x20f38fed);
    NONFAILING(*(uint64_t*)0x20f38fe8 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x20f38ff0 = (uint64_t)0x207c0000);
    NONFAILING(*(uint64_t*)0x20f38ff8 = (uint64_t)0x26);
    r[38] = syscall(__NR_recvmsg, r[10], 0x207e0000ul, 0x40ul);
    break;
  }
  return 0;
}

void test()
{
  long i;
  pthread_t th[16];

  memset(r, -1, sizeof(r));
  for (i = 0; i < 8; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(rand() % 10000);
  }
  usleep(rand() % 100000);
}

int main()
{
  int i;
  for (i = 0; i < 8; i++) {
    if (fork() == 0) {
      install_segv_handler();
      loop();
      return 0;
    }
  }
  sleep(1000000);
  return 0;
}