repro.c

#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/mman.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>

static 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;
}

#define SIZEOF_IO_URING_SQE 64
#define SIZEOF_IO_URING_CQE 16
#define SQ_HEAD_OFFSET 0
#define SQ_TAIL_OFFSET 64
#define SQ_RING_MASK_OFFSET 256
#define SQ_RING_ENTRIES_OFFSET 264
#define SQ_FLAGS_OFFSET 276
#define SQ_DROPPED_OFFSET 272
#define CQ_HEAD_OFFSET 128
#define CQ_TAIL_OFFSET 192
#define CQ_RING_MASK_OFFSET 260
#define CQ_RING_ENTRIES_OFFSET 268
#define CQ_RING_OVERFLOW_OFFSET 284
#define CQ_FLAGS_OFFSET 280
#define CQ_CQES_OFFSET 320

struct io_sqring_offsets {
  uint32_t head;
  uint32_t tail;
  uint32_t ring_mask;
  uint32_t ring_entries;
  uint32_t flags;
  uint32_t dropped;
  uint32_t array;
  uint32_t resv1;
  uint64_t resv2;
};

struct io_cqring_offsets {
  uint32_t head;
  uint32_t tail;
  uint32_t ring_mask;
  uint32_t ring_entries;
  uint32_t overflow;
  uint32_t cqes;
  uint64_t resv[2];
};

struct io_uring_params {
  uint32_t sq_entries;
  uint32_t cq_entries;
  uint32_t flags;
  uint32_t sq_thread_cpu;
  uint32_t sq_thread_idle;
  uint32_t features;
  uint32_t resv[4];
  struct io_sqring_offsets sq_off;
  struct io_cqring_offsets cq_off;
};

#define IORING_OFF_SQ_RING 0
#define IORING_OFF_SQES 0x10000000ULL

#define sys_io_uring_setup 425
static long syz_io_uring_setup(volatile long a0, volatile long a1,
                               volatile long a2, volatile long a3,
                               volatile long a4, volatile long a5)
{
  uint32_t entries = (uint32_t)a0;
  struct io_uring_params* setup_params = (struct io_uring_params*)a1;
  void* vma1 = (void*)a2;
  void* vma2 = (void*)a3;
  void** ring_ptr_out = (void**)a4;
  void** sqes_ptr_out = (void**)a5;
  uint32_t fd_io_uring = syscall(sys_io_uring_setup, entries, setup_params);
  uint32_t sq_ring_sz =
      setup_params->sq_off.array + setup_params->sq_entries * sizeof(uint32_t);
  uint32_t cq_ring_sz = setup_params->cq_off.cqes +
                        setup_params->cq_entries * SIZEOF_IO_URING_CQE;
  uint32_t ring_sz = sq_ring_sz > cq_ring_sz ? sq_ring_sz : cq_ring_sz;
  *ring_ptr_out = mmap(vma1, ring_sz, PROT_READ | PROT_WRITE,
                       MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring,
                       IORING_OFF_SQ_RING);
  uint32_t sqes_sz = setup_params->sq_entries * SIZEOF_IO_URING_SQE;
  *sqes_ptr_out =
      mmap(vma2, sqes_sz, PROT_READ | PROT_WRITE,
           MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, IORING_OFF_SQES);
  return fd_io_uring;
}

static long syz_io_uring_submit(volatile long a0, volatile long a1,
                                volatile long a2, volatile long a3)
{
  char* ring_ptr = (char*)a0;
  char* sqes_ptr = (char*)a1;
  char* sqe = (char*)a2;
  uint32_t sqes_index = (uint32_t)a3;
  uint32_t sq_ring_entries = *(uint32_t*)(ring_ptr + SQ_RING_ENTRIES_OFFSET);
  uint32_t cq_ring_entries = *(uint32_t*)(ring_ptr + CQ_RING_ENTRIES_OFFSET);
  uint32_t sq_array_off =
      (CQ_CQES_OFFSET + cq_ring_entries * SIZEOF_IO_URING_CQE + 63) & ~63;
  if (sq_ring_entries)
    sqes_index %= sq_ring_entries;
  char* sqe_dest = sqes_ptr + sqes_index * SIZEOF_IO_URING_SQE;
  memcpy(sqe_dest, sqe, SIZEOF_IO_URING_SQE);
  uint32_t sq_ring_mask = *(uint32_t*)(ring_ptr + SQ_RING_MASK_OFFSET);
  uint32_t* sq_tail_ptr = (uint32_t*)(ring_ptr + SQ_TAIL_OFFSET);
  uint32_t sq_tail = *sq_tail_ptr & sq_ring_mask;
  uint32_t sq_tail_next = *sq_tail_ptr + 1;
  uint32_t* sq_array = (uint32_t*)(ring_ptr + sq_array_off);
  *(sq_array + sq_tail) = sqes_index;
  __atomic_store_n(sq_tail_ptr, sq_tail_next, __ATOMIC_RELEASE);
  return 0;
}

static long syz_memcpy_off(volatile long a0, volatile long a1, volatile long a2,
                           volatile long a3, volatile long a4)
{
  char* dest = (char*)a0;
  uint32_t dest_off = (uint32_t)a1;
  char* src = (char*)a2;
  uint32_t src_off = (uint32_t)a3;
  size_t n = (size_t)a4;
  return (long)memcpy(dest + dest_off, src + src_off, n);
}

static void kill_and_wait(int pid, int* status)
{
  kill(-pid, SIGKILL);
  kill(pid, SIGKILL);
  for (int 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 = 0;
  for (;; 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 < 5000) {
        continue;
      }
      kill_and_wait(pid, &status);
      break;
    }
  }
}

#ifndef __NR_io_uring_enter
#define __NR_io_uring_enter 426
#endif

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

void execute_one(void)
{
  intptr_t res = 0;
  *(uint32_t*)0x20000084 = 0;
  *(uint32_t*)0x20000088 = 0;
  *(uint32_t*)0x2000008c = 0;
  *(uint32_t*)0x20000090 = 0;
  *(uint32_t*)0x20000098 = 0;
  *(uint32_t*)0x2000009c = 0;
  *(uint32_t*)0x200000a0 = 0;
  *(uint32_t*)0x200000a4 = 0;
  res = -1;
  res = syz_io_uring_setup(1, 0x20000080, 0x200a0000, 0x200b0000, 0x20000100,
                           0x20000140);
  if (res != -1) {
    r[0] = res;
    r[1] = *(uint64_t*)0x20000100;
    r[2] = *(uint64_t*)0x20000140;
  }
  *(uint8_t*)0x200001c0 = 0x1c;
  *(uint8_t*)0x200001c1 = 0;
  *(uint16_t*)0x200001c2 = 0;
  *(uint32_t*)0x200001c4 = 0xffffff9c;
  *(uint64_t*)0x200001c8 = 0;
  *(uint64_t*)0x200001d0 = 0;
  *(uint32_t*)0x200001d8 = 0;
  *(uint32_t*)0x200001dc = 0;
  *(uint64_t*)0x200001e0 = 0x12345;
  *(uint16_t*)0x200001e8 = 0;
  *(uint16_t*)0x200001ea = 0;
  *(uint8_t*)0x200001ec = 0;
  *(uint8_t*)0x200001ed = 0;
  *(uint8_t*)0x200001ee = 0;
  *(uint8_t*)0x200001ef = 0;
  *(uint8_t*)0x200001f0 = 0;
  *(uint8_t*)0x200001f1 = 0;
  *(uint8_t*)0x200001f2 = 0;
  *(uint8_t*)0x200001f3 = 0;
  *(uint8_t*)0x200001f4 = 0;
  *(uint8_t*)0x200001f5 = 0;
  *(uint8_t*)0x200001f6 = 0;
  *(uint8_t*)0x200001f7 = 0;
  *(uint8_t*)0x200001f8 = 0;
  *(uint8_t*)0x200001f9 = 0;
  *(uint8_t*)0x200001fa = 0;
  *(uint8_t*)0x200001fb = 0;
  *(uint8_t*)0x200001fc = 0;
  *(uint8_t*)0x200001fd = 0;
  *(uint8_t*)0x200001fe = 0;
  *(uint8_t*)0x200001ff = 0;
  syz_io_uring_submit(r[1], r[2], 0x200001c0, 0);
  *(uint32_t*)0x20000000 = 0;
  syz_memcpy_off(r[1], 0x10c, 0x20000000, 0, 4);
  syscall(__NR_io_uring_enter, r[0], 1, 1, 1ul, 0ul, 0ul);
}
int main(void)
{
  syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      loop();
    }
  }
  sleep(1000000);
  return 0;
}