syzkaller-repros/linux/cdf8792e8c8aff2dfc22bc6103530cc9d7cb4d77.c

// KMSAN: uninit-value in __request_module (3)
// https://syzkaller.appspot.com/bug?id=cdf8792e8c8aff2dfc22bc6103530cc9d7cb4d77
// status:open
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

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

#include <linux/capability.h>

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 setup_common()
{
  if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
  }
}

static void loop();

static void sandbox_common()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  setsid();
  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = (200 << 20);
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 32 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 136 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 0;
  setrlimit(RLIMIT_CORE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
  if (unshare(CLONE_NEWNS)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(0x02000000)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
  typedef struct {
    const char* name;
    const char* value;
  } sysctl_t;
  static const sysctl_t sysctls[] = {
      {"/proc/sys/kernel/shmmax", "16777216"},
      {"/proc/sys/kernel/shmall", "536870912"},
      {"/proc/sys/kernel/shmmni", "1024"},
      {"/proc/sys/kernel/msgmax", "8192"},
      {"/proc/sys/kernel/msgmni", "1024"},
      {"/proc/sys/kernel/msgmnb", "1024"},
      {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
  };
  unsigned i;
  for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
    write_file(sysctls[i].name, sysctls[i].value);
}

int wait_for_loop(int pid)
{
  if (pid < 0)
    exit(1);
  int status = 0;
  while (waitpid(-1, &status, __WALL) != pid) {
  }
  return WEXITSTATUS(status);
}

static void drop_caps(void)
{
  struct __user_cap_header_struct cap_hdr = {};
  struct __user_cap_data_struct cap_data[2] = {};
  cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
  cap_hdr.pid = getpid();
  if (syscall(SYS_capget, &cap_hdr, &cap_data))
    exit(1);
  const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
  cap_data[0].effective &= ~drop;
  cap_data[0].permitted &= ~drop;
  cap_data[0].inheritable &= ~drop;
  if (syscall(SYS_capset, &cap_hdr, &cap_data))
    exit(1);
}

static int do_sandbox_none(void)
{
  if (unshare(CLONE_NEWPID)) {
  }
  int pid = fork();
  if (pid != 0)
    return wait_for_loop(pid);
  setup_common();
  sandbox_common();
  drop_caps();
  if (unshare(CLONE_NEWNET)) {
  }
  loop();
  exit(1);
}

uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0xffffffffffffffff};

void loop(void)
{
  intptr_t res = 0;
  res = syscall(__NR_socket, 0x10ul, 3ul, 0ul);
  if (res != -1)
    r[0] = res;
  res = syscall(__NR_socket, 0x10ul, 3ul, 0ul);
  if (res != -1)
    r[1] = res;
  res = syscall(__NR_socket, 0x10ul, 0x803ul, 0);
  if (res != -1)
    r[2] = res;
  *(uint64_t*)0x200001c0 = 0;
  *(uint32_t*)0x200001c8 = 0;
  *(uint64_t*)0x200001d0 = 0x20000180;
  *(uint64_t*)0x20000180 = 0;
  *(uint64_t*)0x20000188 = 0;
  *(uint64_t*)0x200001d8 = 1;
  *(uint64_t*)0x200001e0 = 0;
  *(uint64_t*)0x200001e8 = 0;
  *(uint32_t*)0x200001f0 = 0;
  syscall(__NR_sendmsg, r[2], 0x200001c0ul, 0ul);
  *(uint32_t*)0x20000200 = 0x14;
  res = syscall(__NR_getsockname, r[2], 0x20000100ul, 0x20000200ul);
  if (res != -1)
    r[3] = *(uint32_t*)0x20000104;
  *(uint64_t*)0x20000240 = 0;
  *(uint32_t*)0x20000248 = 0;
  *(uint64_t*)0x20000250 = 0x20000140;
  *(uint64_t*)0x20000140 = 0x200003c0;
  memcpy((void*)0x200003c0, "\x38\x00\x00\x00\x24\x00\x07\x05\x00\x00\x00\x00"
                            "\x00\xa2\xa3\x00\x05\x00\x00\x00",
         20);
  *(uint32_t*)0x200003d4 = r[3];
  memcpy((void*)0x200003d8, "\x00\x00\x00\x00\xff\xff\xff\xff\x00\x00\x00\x00"
                            "\x09\x00\x01\x00\x68\x66\x73\x63\x00\x00\x00\x00"
                            "\x08\x00\x02\x00\x00\x00\x00\x00",
         32);
  *(uint64_t*)0x20000148 = 0x38;
  *(uint64_t*)0x20000258 = 1;
  *(uint64_t*)0x20000260 = 0;
  *(uint64_t*)0x20000268 = 0;
  *(uint32_t*)0x20000270 = 0;
  syscall(__NR_sendmsg, r[1], 0x20000240ul, 0ul);
  *(uint64_t*)0x200001c0 = 0;
  *(uint32_t*)0x200001c8 = 0;
  *(uint64_t*)0x200001d0 = 0x20000180;
  *(uint64_t*)0x20000180 = 0x20000400;
  memcpy(
      (void*)0x20000400,
      "4\000\000\000,\000\'\r\000\000\000\000\000\000\000\000\000\000\000\000",
      20);
  *(uint32_t*)0x20000414 = r[3];
  memcpy((void*)0x20000418,
         "\x00\x00\x00\x03\x00\x00\x00\x00\x0f\x00\x00\x00\x0a\x00\x01\x00\xcb"
         "\xb4\x17\x9b\x85\x9c\xc7\x04\x73\x16\x66\x9e\x4e\x20\xb3\x54\x72\x6f"
         "\x75\x74\x65\x00\x00\x00\x04\x00\x02\x00\x5d\x29\x33\xd7\xfa\x2b\x59"
         "\x0e\xc2\x39\x37\x1a\x36\x2d\xf1\x3d\x18\x36\x0c\xe7\xfe\x84\xc2\x8f"
         "\x38\xd1\x1d\xc0\xbb\x26\xd7\xf5\xf7\x6a\x7b\x5c\x6a\xab\x67\x97\x78"
         "\x0d\xa7\x2f\xaa\x69\x3e\x23\x6f\x50\x26\xce\x0a\x5e\x4a\xab\x87\xf2"
         "\x99\xb6\xfb\x6c\xed\x6c\x48\xa8\x97\x86\x77\x38\x80\x4b\x8f\xd5\x74"
         "\x34\xee\xfd\x3b\xa3\x03\x58\x0b\x37\x5d\xc6\x8c\xbe\x0b\x03\xc2\x78"
         "\x87\x86\x06\xf2\xa3\x73\x0a\xfd\x89\xbf\x7c\x7b\x64\xb9\x2c\xb7\x9c"
         "\x00\x00\xe7\xc8\x85\xca\x36\xb4\x10\x00",
         163);
  *(uint64_t*)0x20000188 = 0x34;
  *(uint64_t*)0x200001d8 = 1;
  *(uint64_t*)0x200001e0 = 0;
  *(uint64_t*)0x200001e8 = 0;
  *(uint32_t*)0x200001f0 = 0;
  syscall(__NR_sendmsg, r[0], 0x200001c0ul, 0ul);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
  do_sandbox_none();
  return 0;
}