net/dccp: use-after-free in dccp_invalid_packet

[Andrey Konovalov]

Hi!

I've got the following error report while running the syzkaller fuzzer.

On commit d8e435f3ab6fea2ea324dce72b51dd7761747523 (Nov 26).

dh->dccph_doff is being accessed (line 731) right after skb was freed
(line 732) in net/dccp/ipv4.c.

A reproducer is attached.

==================================================================
BUG: KASAN: use-after-free in dccp_invalid_packet+0x788/0x800
Read of size 1 at addr ffff880066f0e7c8 by task a.out/3895

page:ffffea00019bc380 count:1 mapcount:0 mapping:          (null)
index:0x0 compound_mapcount: 0
flags: 0x100000000004080(slab|head)
page dumped because: kasan: bad access detected

CPU: 1 PID: 3895 Comm: a.out Not tainted 4.9.0-rc6+ #457
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 ffff88006cd07758 ffffffff81c73b14 ffff88006cd077e8 ffff880066f0e7c8
 00000000000000fa 00000000000000fb ffff88006cd077d8 ffffffff81637962
 ffff88006cd07810 ffffffff82cc9c90 ffffffff82cabf7c 0000000000000296
Call Trace:
 <IRQ> [   27.672034]  [<ffffffff81c73b14>] dump_stack+0xb3/0x10f
 [<     inline     >] describe_address mm/kasan/report.c:259
 [<ffffffff81637962>] kasan_report_error+0x122/0x560 mm/kasan/report.c:365
 [<     inline     >] kasan_report mm/kasan/report.c:387
 [<ffffffff81637dde>] __asan_report_load1_noabort+0x3e/0x40
mm/kasan/report.c:405
 [<ffffffff839e8158>] dccp_invalid_packet+0x788/0x800 net/dccp/ipv4.c:732
 [<ffffffff839f4fc1>] dccp_v6_rcv+0x21/0x1720 net/dccp/ipv6.c:658
 [<ffffffff83418f13>] ip6_input_finish+0x423/0x15f0 net/ipv6/ip6_input.c:279
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341a1ae>] ip6_input+0xce/0x340 net/ipv6/ip6_input.c:322
 [<     inline     >] dst_input ./include/net/dst.h:507
 [<ffffffff834185ae>] ip6_rcv_finish+0x23e/0x780 net/ipv6/ip6_input.c:69
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341b4bd>] ipv6_rcv+0x109d/0x1dc0 net/ipv6/ip6_input.c:203
 [<ffffffff82d0805b>] __netif_receive_skb_core+0x187b/0x2a10 net/core/dev.c:4208
 [<ffffffff82d0921a>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4246
 [<ffffffff82d0bbed>] process_backlog+0xed/0x6e0 net/core/dev.c:4855
 [<     inline     >] napi_poll net/core/dev.c:5156
 [<ffffffff82d0b4cd>] net_rx_action+0x76d/0xda0 net/core/dev.c:5221
 [<ffffffff840f59ef>] __do_softirq+0x23f/0x8e5 kernel/softirq.c:284
 [<ffffffff840f3c1c>] do_softirq_own_stack+0x1c/0x30
arch/x86/entry/entry_64.S:904
 <EOI> [   27.672034]  [<ffffffff81251370>] do_softirq.part.17+0x60/0xa0
 [<     inline     >] do_softirq kernel/softirq.c:176
 [<ffffffff81251466>] __local_bh_enable_ip+0xb6/0xc0 kernel/softirq.c:181
 [<     inline     >] local_bh_enable ./include/linux/bottom_half.h:31
 [<     inline     >] rcu_read_unlock_bh ./include/linux/rcupdate.h:967
 [<ffffffff8340b6c0>] ip6_finish_output2+0xb70/0x1f30 net/ipv6/ip6_output.c:122
 [<ffffffff834152b9>] ip6_finish_output+0x3c9/0x7e0 net/ipv6/ip6_output.c:139
 [<     inline     >] NF_HOOK_COND ./include/linux/netfilter.h:246
 [<ffffffff8341588d>] ip6_output+0x1bd/0x6b0 net/ipv6/ip6_output.c:153
 [<     inline     >] dst_output ./include/net/dst.h:501
 [<ffffffff8357a116>] ip6_local_out+0x96/0x170 net/ipv6/output_core.c:170
 [<ffffffff83417b63>] ip6_send_skb+0xa3/0x340 net/ipv6/ip6_output.c:1712
 [<ffffffff83417eb5>] ip6_push_pending_frames+0xb5/0xe0
net/ipv6/ip6_output.c:1732
 [<     inline     >] rawv6_push_pending_frames net/ipv6/raw.c:607
 [<ffffffff83489a9e>] rawv6_sendmsg+0x1c4e/0x2c20 net/ipv6/raw.c:920
 [<ffffffff832a1057>] inet_sendmsg+0x317/0x4e0 net/ipv4/af_inet.c:734
 [<     inline     >] sock_sendmsg_nosec net/socket.c:621
 [<ffffffff82c9d76c>] sock_sendmsg+0xcc/0x110 net/socket.c:631
 [<ffffffff82c9f1b7>] ___sys_sendmsg+0x2d7/0x8b0 net/socket.c:1954
 [<ffffffff82ca1888>] __sys_sendmmsg+0x158/0x390 net/socket.c:2044
 [<     inline     >] SYSC_sendmmsg net/socket.c:2075
 [<ffffffff82ca1af5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2070
 [<ffffffff840f2c41>] entry_SYSCALL_64_fastpath+0x1f/0xc2
arch/x86/entry/entry_64.S:209

The buggy address belongs to the object at ffff880066f0e780
 which belongs to the cache kmalloc-512 of size 512
The buggy address ffff880066f0e7c8 is located 72 bytes inside
 of 512-byte region [ffff880066f0e780, ffff880066f0e980)

Freed by task 3895:
 [<ffffffff811aa1b6>] save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 [<ffffffff81636a76>] save_stack+0x46/0xd0 mm/kasan/kasan.c:495
 [<     inline     >] set_track mm/kasan/kasan.c:507
 [<ffffffff816372d3>] kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:571
 [<     inline     >] slab_free_hook mm/slub.c:1352
 [<     inline     >] slab_free_freelist_hook mm/slub.c:1374
 [<     inline     >] slab_free mm/slub.c:2951
 [<ffffffff816337b8>] kfree+0xe8/0x2b0 mm/slub.c:3871
 [<ffffffff82cb6748>] skb_free_head+0x78/0xb0 net/core/skbuff.c:580
 [<ffffffff82cc50fb>] pskb_expand_head+0x28b/0x8f0 net/core/skbuff.c:1244
 [<ffffffff82cc954c>] __pskb_pull_tail+0xcc/0x1190 net/core/skbuff.c:1613
 [<     inline     >] pskb_may_pull ./include/linux/skbuff.h:1966
 [<ffffffff839e80bb>] dccp_invalid_packet+0x6eb/0x800 net/dccp/ipv4.c:731
 [<ffffffff839f4fc1>] dccp_v6_rcv+0x21/0x1720 net/dccp/ipv6.c:658
 [<ffffffff83418f13>] ip6_input_finish+0x423/0x15f0 net/ipv6/ip6_input.c:279
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341a1ae>] ip6_input+0xce/0x340 net/ipv6/ip6_input.c:322
 [<     inline     >] dst_input ./include/net/dst.h:507
 [<ffffffff834185ae>] ip6_rcv_finish+0x23e/0x780 net/ipv6/ip6_input.c:69
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341b4bd>] ipv6_rcv+0x109d/0x1dc0 net/ipv6/ip6_input.c:203
 [<ffffffff82d0805b>] __netif_receive_skb_core+0x187b/0x2a10 net/core/dev.c:4208
 [<ffffffff82d0921a>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4246
 [<ffffffff82d0bbed>] process_backlog+0xed/0x6e0 net/core/dev.c:4855
 [<     inline     >] napi_poll net/core/dev.c:5156
 [<ffffffff82d0b4cd>] net_rx_action+0x76d/0xda0 net/core/dev.c:5221
 [<ffffffff840f59ef>] __do_softirq+0x23f/0x8e5 kernel/softirq.c:284

Allocated by task 3895:
 [<ffffffff811aa1b6>] save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 [<ffffffff81636a76>] save_stack+0x46/0xd0 mm/kasan/kasan.c:495
 [<     inline     >] set_track mm/kasan/kasan.c:507
 [<ffffffff81636ceb>] kasan_kmalloc+0xab/0xe0 mm/kasan/kasan.c:598
 [<ffffffff81637252>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:537
 [<     inline     >] slab_post_alloc_hook mm/slab.h:417
 [<     inline     >] slab_alloc_node mm/slub.c:2708
 [<ffffffff81635fab>] __kmalloc_node_track_caller+0xcb/0x390 mm/slub.c:4270
 [<ffffffff82cb7671>] __kmalloc_reserve.isra.35+0x41/0xe0 net/core/skbuff.c:138
 [<ffffffff82cc4f8c>] pskb_expand_head+0x11c/0x8f0 net/core/skbuff.c:1212
 [<ffffffff82cc954c>] __pskb_pull_tail+0xcc/0x1190 net/core/skbuff.c:1613
 [<     inline     >] pskb_may_pull ./include/linux/skbuff.h:1966
 [<ffffffff839e804b>] dccp_invalid_packet+0x67b/0x800 net/dccp/ipv4.c:708
 [<ffffffff839f4fc1>] dccp_v6_rcv+0x21/0x1720 net/dccp/ipv6.c:658
 [<ffffffff83418f13>] ip6_input_finish+0x423/0x15f0 net/ipv6/ip6_input.c:279
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341a1ae>] ip6_input+0xce/0x340 net/ipv6/ip6_input.c:322
 [<     inline     >] dst_input ./include/net/dst.h:507
 [<ffffffff834185ae>] ip6_rcv_finish+0x23e/0x780 net/ipv6/ip6_input.c:69
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8341b4bd>] ipv6_rcv+0x109d/0x1dc0 net/ipv6/ip6_input.c:203
 [<ffffffff82d0805b>] __netif_receive_skb_core+0x187b/0x2a10 net/core/dev.c:4208
 [<ffffffff82d0921a>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4246
 [<ffffffff82d0bbed>] process_backlog+0xed/0x6e0 net/core/dev.c:4855
 [<     inline     >] napi_poll net/core/dev.c:5156
 [<ffffffff82d0b4cd>] net_rx_action+0x76d/0xda0 net/core/dev.c:5221
 [<ffffffff840f59ef>] __do_softirq+0x23f/0x8e5 kernel/softirq.c:284

Memory state around the buggy address:
 ffff880066f0e680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff880066f0e700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff880066f0e780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff880066f0e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880066f0e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#ifndef __NR_socket
#define __NR_socket 41
#endif
#ifndef __NR_sendmsg
#define __NR_sendmsg 46
#endif
#ifndef __NR_sendmmsg
#define __NR_sendmmsg 307
#endif
#ifndef __NR_syz_emit_ethernet
#define __NR_syz_emit_ethernet 1000006
#endif
#ifndef __NR_syz_fuse_mount
#define __NR_syz_fuse_mount 1000004
#endif
#ifndef __NR_syz_fuseblk_mount
#define __NR_syz_fuseblk_mount 1000005
#endif
#ifndef __NR_syz_open_dev
#define __NR_syz_open_dev 1000002
#endif
#ifndef __NR_syz_open_pts
#define __NR_syz_open_pts 1000003
#endif
#ifndef __NR_mmap
#define __NR_mmap 9
#endif
#ifndef __NR_connect
#define __NR_connect 42
#endif
#ifndef __NR_syz_test
#define __NR_syz_test 1000001
#endif

#define SYZ_SANDBOX_NONE 1

#define _GNU_SOURCE

#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <linux/capability.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <linux/sched.h>
#include <net/if_arp.h>

#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

const int kFailStatus = 67;
const int kErrorStatus = 68;
const int kRetryStatus = 69;

__attribute__((noreturn)) void fail(const char* msg, ...)
{
  int e = errno;
  fflush(stdout);
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  exit(kFailStatus);
}

__attribute__((noreturn)) void exitf(const char* msg, ...)
{
  int e = errno;
  fflush(stdout);
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  exit(kRetryStatus);
}

static int flag_debug;

void debug(const char* msg, ...)
{
  if (!flag_debug)
    return;
  va_list args;
  va_start(args, msg);
  vfprintf(stdout, msg, args);
  va_end(args);
  fflush(stdout);
}

__thread int skip_segv;
__thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
  if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED))
    _longjmp(segv_env, 1);
  exit(sig);
}

static void install_segv_handler()
{
  struct sigaction sa;
  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 uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
  if (a0 == 0xc || a0 == 0xb) {
    char buf[128];
    sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block",
            (uint8_t)a1, (uint8_t)a2);
    return open(buf, O_RDWR, 0);
  } else {
    char buf[1024];
    char* hash;
    strncpy(buf, (char*)a0, sizeof(buf));
    buf[sizeof(buf) - 1] = 0;
    while ((hash = strchr(buf, '#'))) {
      *hash = '0' + (char)(a1 % 10);
      a1 /= 10;
    }
    return open(buf, a2, 0);
  }
}

static uintptr_t syz_open_pts(uintptr_t a0, uintptr_t a1)
{
  int ptyno = 0;
  if (ioctl(a0, TIOCGPTN, &ptyno))
    return -1;
  char buf[128];
  sprintf(buf, "/dev/pts/%d", ptyno);
  return open(buf, a1, 0);
}

static uintptr_t syz_fuse_mount(uintptr_t a0, uintptr_t a1,
                                uintptr_t a2, uintptr_t a3,
                                uintptr_t a4, uintptr_t a5)
{
  uint64_t target = a0;
  uint64_t mode = a1;
  uint64_t uid = a2;
  uint64_t gid = a3;
  uint64_t maxread = a4;
  uint64_t flags = a5;

  int fd = open("/dev/fuse", O_RDWR);
  if (fd == -1)
    return fd;
  char buf[1024];
  sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
          (long)uid, (long)gid, (unsigned)mode & ~3u);
  if (maxread != 0)
    sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
  if (mode & 1)
    strcat(buf, ",default_permissions");
  if (mode & 2)
    strcat(buf, ",allow_other");
  syscall(SYS_mount, "", target, "fuse", flags, buf);
  return fd;
}

static uintptr_t syz_fuseblk_mount(uintptr_t a0, uintptr_t a1,
                                   uintptr_t a2, uintptr_t a3,
                                   uintptr_t a4, uintptr_t a5,
                                   uintptr_t a6, uintptr_t a7)
{
  uint64_t target = a0;
  uint64_t blkdev = a1;
  uint64_t mode = a2;
  uint64_t uid = a3;
  uint64_t gid = a4;
  uint64_t maxread = a5;
  uint64_t blksize = a6;
  uint64_t flags = a7;

  int fd = open("/dev/fuse", O_RDWR);
  if (fd == -1)
    return fd;
  if (syscall(SYS_mknodat, AT_FDCWD, blkdev, S_IFBLK, makedev(7, 199)))
    return fd;
  char buf[256];
  sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
          (long)uid, (long)gid, (unsigned)mode & ~3u);
  if (maxread != 0)
    sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
  if (blksize != 0)
    sprintf(buf + strlen(buf), ",blksize=%ld", (long)blksize);
  if (mode & 1)
    strcat(buf, ",default_permissions");
  if (mode & 2)
    strcat(buf, ",allow_other");
  syscall(SYS_mount, blkdev, target, "fuseblk", flags, buf);
  return fd;
}

static uintptr_t execute_syscall(int nr, uintptr_t a0, uintptr_t a1,
                                 uintptr_t a2, uintptr_t a3,
                                 uintptr_t a4, uintptr_t a5,
                                 uintptr_t a6, uintptr_t a7,
                                 uintptr_t a8)
{
  switch (nr) {
  default:
    return syscall(nr, a0, a1, a2, a3, a4, a5);
  case __NR_syz_test:
    return 0;
  case __NR_syz_open_dev:
    return syz_open_dev(a0, a1, a2);
  case __NR_syz_open_pts:
    return syz_open_pts(a0, a1);
  case __NR_syz_fuse_mount:
    return syz_fuse_mount(a0, a1, a2, a3, a4, a5);
  case __NR_syz_fuseblk_mount:
    return syz_fuseblk_mount(a0, a1, a2, a3, a4, a5, a6, a7);
  }
}

static void setup_main_process()
{
  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);
  install_segv_handler();

  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    fail("failed to mkdtemp");
  if (chmod(tmpdir, 0777))
    fail("failed to chmod");
  if (chdir(tmpdir))
    fail("failed to chdir");
}

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 = 128 << 20;
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 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);

  unshare(CLONE_NEWNS);
  unshare(CLONE_NEWIPC);
  unshare(CLONE_IO);
}

static int do_sandbox_none()
{
  int pid = fork();
  if (pid)
    return pid;
  sandbox_common();
  loop();
  exit(1);
}

static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  int iter = 0;
  int i;
retry:
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exitf("opendir(%s) failed due to NOFILE, exiting");
    }
    exitf("opendir(%s) failed", dir);
  }
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    struct stat st;
    if (lstat(filename, &st))
      exitf("lstat(%s) failed", filename);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    for (i = 0;; i++) {
      debug("unlink(%s)\n", filename);
      if (unlink(filename) == 0)
        break;
      if (errno == EROFS) {
        debug("ignoring EROFS\n");
        break;
      }
      if (errno != EBUSY || i > 100)
        exitf("unlink(%s) failed", filename);
      debug("umount(%s)\n", filename);
      if (umount2(filename, MNT_DETACH))
        exitf("umount(%s) failed", filename);
    }
  }
  closedir(dp);
  for (i = 0;; i++) {
    debug("rmdir(%s)\n", dir);
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EROFS) {
        debug("ignoring EROFS\n");
        break;
      }
      if (errno == EBUSY) {
        debug("umount(%s)\n", dir);
        if (umount2(dir, MNT_DETACH))
          exitf("umount(%s) failed", dir);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exitf("rmdir(%s) failed", dir);
  }
}

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;
}

long r[39];
void loop()
{
  memset(r, -1, sizeof(r));
  r[0] = execute_syscall(__NR_mmap, 0x20000000ul, 0xe8b000ul, 0x3ul,
                         0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
  r[1] = execute_syscall(__NR_socket, 0xaul, 0x80003ul, 0x21ul, 0, 0, 0,
                         0, 0, 0);
  NONFAILING(memcpy((void*)0x20e7dfe4, "\x0a\x00\x42\x42\xa0\xae\x78"
                                       "\x03\x00\x00\x00\x00\x00\x00"
                                       "\x00\x00\x00\x00\x00\x00\x00"
                                       "\x00\x00\x01\xc1\x97\xc4\x9e",
                    28));
  r[3] = execute_syscall(__NR_connect, r[1], 0x20e7dfe4ul, 0x1cul, 0, 0,
                         0, 0, 0, 0);
  NONFAILING(*(uint64_t*)0x20e83000 = (uint64_t)0x20e80000);
  NONFAILING(*(uint32_t*)0x20e83008 = (uint32_t)0x0);
  NONFAILING(*(uint64_t*)0x20e83010 = (uint64_t)0x2061bfd0);
  NONFAILING(*(uint64_t*)0x20e83018 = (uint64_t)0x2);
  NONFAILING(*(uint64_t*)0x20e83020 = (uint64_t)0x20027000);
  NONFAILING(*(uint64_t*)0x20e83028 = (uint64_t)0x1);
  NONFAILING(*(uint32_t*)0x20e83030 = (uint32_t)0x4);
  NONFAILING(*(uint64_t*)0x2061bfd0 = (uint64_t)0x20e80f0d);
  NONFAILING(*(uint64_t*)0x2061bfd8 = (uint64_t)0x0);
  NONFAILING(*(uint64_t*)0x2061bfe0 = (uint64_t)0x20e83000);
  NONFAILING(*(uint64_t*)0x2061bfe8 = (uint64_t)0x0);
  NONFAILING(*(uint64_t*)0x20027000 = (uint64_t)0x10);
  NONFAILING(*(uint32_t*)0x20027008 = (uint32_t)0x3);
  NONFAILING(*(uint32_t*)0x2002700c = (uint32_t)0x80);
  r[18] = execute_syscall(__NR_sendmsg, r[1], 0x20e83000ul, 0x8000ul, 0,
                          0, 0, 0, 0, 0);
  NONFAILING(*(uint64_t*)0x20e73000 = (uint64_t)0x0);
  NONFAILING(*(uint32_t*)0x20e73008 = (uint32_t)0x0);
  NONFAILING(*(uint64_t*)0x20e73010 = (uint64_t)0x20e80000);
  NONFAILING(*(uint64_t*)0x20e73018 = (uint64_t)0x5);
  NONFAILING(*(uint64_t*)0x20e73020 = (uint64_t)0x20e77000);
  NONFAILING(*(uint64_t*)0x20e73028 = (uint64_t)0x0);
  NONFAILING(*(uint32_t*)0x20e73030 = (uint32_t)0x0);
  NONFAILING(*(uint64_t*)0x20e80000 = (uint64_t)0x20e85f97);
  NONFAILING(*(uint64_t*)0x20e80008 = (uint64_t)0x69);
  NONFAILING(*(uint64_t*)0x20e80010 = (uint64_t)0x20e86f39);
  NONFAILING(*(uint64_t*)0x20e80018 = (uint64_t)0x0);
  NONFAILING(*(uint64_t*)0x20e80020 = (uint64_t)0x20e87000);
  NONFAILING(*(uint64_t*)0x20e80028 = (uint64_t)0x0);
  NONFAILING(*(uint64_t*)0x20e80030 = (uint64_t)0x20e88f01);
  NONFAILING(*(uint64_t*)0x20e80038 = (uint64_t)0xff);
  NONFAILING(*(uint64_t*)0x20e80040 = (uint64_t)0x20e89f9f);
  NONFAILING(*(uint64_t*)0x20e80048 = (uint64_t)0x0);
  NONFAILING(memcpy(
      (void*)0x20e85f97,
      "\x39\xa4\x8d\x53\x4e\x54\x32\xc4\x2a\x71\xb9\xf1\xff\x1d\xd9\x47"
      "\x78\x37\xb6\x72\xba\x74\xc9\xc3\xf1\x5f\x46\x3e\x14\xbb\xb9\x59"
      "\xa3\x88\x40\x9c\x25\x1d\x5c\xf1\xa3\xca\x7e\xa6\x55\x44\x01\x01"
      "\x9d\xab\x07\x96\x46\xa8\xe9\xa5\x2e\x74\x45\x8a\x00\xee\x71\xe6"
      "\xab\x97\x46\xd2\x04\x32\xae\xb2\x68\x66\xcc\x0b\xf3\x0e\x7f\x8c"
      "\x8e\x5e\xd0\xd8\x98\x7e\x54\x15\xa8\x03\x15\x1a\xb9\x9a\xf2\xdf"
      "\x8e\x3b\xe2\xb8\xe7\xee\x46\xa5\x67",
      105));
  NONFAILING(memcpy(
      (void*)0x20e88f01,
      "\xfb\xba\xc0\xcf\x43\x0e\x9b\x34\x87\x5d\xa7\x7c\x88\x45\xe2\xd0"
      "\x52\xbd\xaa\x84\xc2\xcd\x2b\xf2\x89\x73\xcc\x7f\x08\x06\xd6\xe9"
      "\x88\xb7\x2d\xdb\x8a\xc4\x65\xb7\x08\x6b\x96\x9f\x7e\x13\xfe\x1c"
      "\x73\x42\x07\x7c\xac\xc7\x89\x8a\xd3\xad\x57\x5b\x22\x9c\x48\x65"
      "\x37\x86\x1f\xf0\xce\x2b\x22\xf1\x5c\x48\xaf\x63\x66\x34\x14\x19"
      "\xba\xab\xf0\x83\x71\x6f\x19\xea\xd9\x9d\x25\x2f\xe5\x3d\xb1\x5f"
      "\x98\xb5\x50\xc4\x6c\xd1\xe7\xe8\x77\x68\xdc\x4c\xbc\x94\x34\x53"
      "\x73\xbe\x9c\x48\x5d\x87\x20\x79\x0d\x95\x62\xc1\x60\xea\xe3\x92"
      "\x06\xed\x92\xd9\xb2\x76\xcb\xe6\x14\xd1\x72\xd1\x4e\x20\xed\x43"
      "\x81\x67\x82\xf9\x87\xd4\x82\xd7\x98\xcf\x7f\xe0\x7a\x97\x0c\xd1"
      "\xf7\x04\x11\x06\xef\x18\x44\xd0\xd3\x69\x04\x00\x42\x33\xc7\x40"
      "\xdd\xca\x8e\xa3\x32\x52\x9d\x54\x31\x57\xcd\x01\x66\x33\xd2\x97"
      "\xc6\xe6\xa6\x6c\x30\xf2\x8c\x80\xca\x75\xf1\x6b\x11\x71\xfd\x9b"
      "\x05\x94\xf1\x56\x87\x40\xee\xb1\x7f\x0a\xb2\x9c\x92\x1a\xb0\xbc"
      "\xb3\x18\x59\xb6\xb3\x84\x71\xdb\xff\x3e\x4c\x11\x4f\x7f\x04\x9f"
      "\xdf\x7f\x09\xb7\xe2\xf0\x6f\xa9\x35\x22\x93\x09\x81\x18\xd7",
      255));
  r[38] = execute_syscall(__NR_sendmmsg, r[1], 0x20e73000ul, 0x1ul,
                          0x4004ul, 0, 0, 0, 0, 0);
}
int main()
{
  setup_main_process();
  int pid = do_sandbox_none();
  int status = 0;
  while (waitpid(pid, &status, __WALL) != pid) {
  }
  return 0;
}