syzkaller-repros/linux/0b5da7af1edc95677e6a4eb483c0eefcd4db4c55.c

// KMSAN: use-after-free in copyout
// https://syzkaller.appspot.com/bug?id=0b5da7af1edc95677e6a4eb483c0eefcd4db4c55
// status:fixed
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

unsigned long long procid;

static void sleep_ms(uint64_t ms)
{
  usleep(ms * 1000);
}

static uint64_t current_time_ms(void)
{
  struct timespec ts;
  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    exit(1);
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static bool write_file(const char* file, const char* what, ...)
{
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);
  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1)
    return false;
  if (write(fd, buf, len) != len) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

static void kill_and_wait(int pid, int* status)
{
  kill(-pid, SIGKILL);
  kill(pid, SIGKILL);
  int i;
  for (i = 0; i < 100; i++) {
    if (waitpid(-1, status, WNOHANG | __WALL) == pid)
      return;
    usleep(1000);
  }
  DIR* dir = opendir("/sys/fs/fuse/connections");
  if (dir) {
    for (;;) {
      struct dirent* ent = readdir(dir);
      if (!ent)
        break;
      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
        continue;
      char abort[300];
      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
               ent->d_name);
      int fd = open(abort, O_WRONLY);
      if (fd == -1) {
        continue;
      }
      if (write(fd, abort, 1) < 0) {
      }
      close(fd);
    }
    closedir(dir);
  } else {
  }
  while (waitpid(-1, status, __WALL) != pid) {
  }
}

static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  write_file("/proc/self/oom_score_adj", "1000");
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      setup_test();
      execute_one();
      exit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
        break;
      sleep_ms(1);
      if (current_time_ms() - start < 5 * 1000)
        continue;
      kill_and_wait(pid, &status);
      break;
    }
  }
}

uint64_t r[3] = {0xffffffffffffffff, 0x0, 0x0};

void execute_one(void)
{
  intptr_t res = 0;
  memcpy((void*)0x200000c0, "/dev/ptmx\000", 10);
  res = syscall(__NR_openat, 0xffffffffffffff9c, 0x200000c0, 0, 0);
  if (res != -1)
    r[0] = res;
  *(uint32_t*)0x20000040 = 0xf;
  syscall(__NR_ioctl, r[0], 0x5423, 0x20000040);
  syscall(__NR_ioctl, r[0], 0x400455c8, 1);
  memcpy((void*)0x20000040, "user\000", 5);
  memcpy((void*)0x20000000, "syz", 3);
  *(uint8_t*)0x20000003 = 0;
  *(uint8_t*)0x20000004 = 0;
  memcpy((void*)0x200002c0,
         "\x58\x5c\xcb\xe4\xed\x83\xb8\x36\xc1\xa6\x47\x49\x14\xdc\x55\xe7\x22"
         "\x06\x29\x7b\x68\x95\xb6\x61\x47\xb3\xc7\x21\x8a\x91\x69\xa8\x5e\xa0"
         "\xbd\xc9\xe1\x58\x7a\x05\x00\x00\x00\x00\x00\x00\x00\x42\xe3\x30\x89"
         "\x75\x4c\x81\x07\xc3\xcd\x39\x23\xdd\x4a\x71\xc2\xff\x06\x00\x7b\x6b"
         "\x48\x16\x12\x2d\x25\x50\x82\x9e\xaa\x94\x35\xc9\x99\x26\x02\x2b\x87"
         "\x53\xa1\x88\x74\x8c\x56\x9f\x43\x5f\xb3\xba\xe9\x6e\xfb\x74\xb5\x0e"
         "\xc9\x3c\x15\x2f\x5e\x8e\x19\x8a\x29\xe5\xc0\xd0\xc6\x00\x00\xce\x06"
         "\x37\xce\x00\x00\xb4\xec\x24\xc5\x3d\x3d\x66\x1f\xf5\xff\x70\xe4\x88"
         "\x84\xca\x00\x00\x18\xce\xa7\x1f\xcf\xac\xf4\x0d\x32\xe4\xb5\x8a\x8d"
         "\x27\x25\x56\x1f\x61\x10\xfd\x7b\x06\xf9\x0b\x52\x74\xcc\x5c\x1e\x29"
         "\x8a\x16\x32\x4f\xe2\x7d\xa2\xa9\xd5\xba\x9f\xf3\xc0\x09\xd3\x08\xbd"
         "\x73\xf4\x77\x25\x39",
         192);
  res = syscall(__NR_add_key, 0x20000040, 0x20000000, 0x200002c0, 0xc0,
                0xfffffffe);
  if (res != -1)
    r[1] = res;
  memcpy((void*)0x20000200, "user\000", 5);
  memcpy((void*)0x200005c0, "syz", 3);
  *(uint8_t*)0x200005c3 = 0;
  *(uint8_t*)0x200005c4 = 0;
  res = syscall(__NR_add_key, 0x20000200, 0x200005c0, 0x200000c0, 0x9a,
                0xfffffffd);
  if (res != -1)
    r[2] = res;
  *(uint32_t*)0x200000c0 = r[2];
  *(uint32_t*)0x200000c4 = r[1];
  *(uint32_t*)0x200000c8 = r[2];
  syscall(__NR_keyctl, 0x17, 0x200000c0, 0x9999999999999999, 0xf9ffffff, 0);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (procid = 0; procid < 6; procid++) {
    if (fork() == 0) {
      loop();
    }
  }
  sleep(1000000);
  return 0;
}