syzkaller-repros/linux/1bc933ff3f95204574beaa5f98a9c919bf99d556.c

// KMSAN: uninit-value in vprintk_emit
// https://syzkaller.appspot.com/bug?id=1bc933ff3f95204574beaa5f98a9c919bf99d556
// status:invalid
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if_arp.h>
#include <sched.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.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/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
  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);
  }
  exit(sig);
}

static void install_segv_handler(void)
{
  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 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;
}

#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)

#define BITMASK_LEN_OFF(type, bf_off, bf_len)                                  \
  (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))

#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)                      \
  if ((bf_off) == 0 && (bf_len) == 0) {                                        \
    *(type*)(addr) = (type)(val);                                              \
  } else {                                                                     \
    type new_val = *(type*)(addr);                                             \
    new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));                     \
    new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off);          \
    *(type*)(addr) = new_val;                                                  \
  }

struct csum_inet {
  uint32_t acc;
};

static void csum_inet_init(struct csum_inet* csum)
{
  csum->acc = 0;
}

static void csum_inet_update(struct csum_inet* csum, const uint8_t* data,
                             size_t length)
{
  if (length == 0)
    return;
  size_t i;
  for (i = 0; i < length - 1; i += 2)
    csum->acc += *(uint16_t*)&data[i];
  if (length & 1)
    csum->acc += (uint16_t)data[length - 1];
  while (csum->acc > 0xffff)
    csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}

static uint16_t csum_inet_digest(struct csum_inet* csum)
{
  return ~csum->acc;
}

static void vsnprintf_check(char* str, size_t size, const char* format,
                            va_list args)
{
  int rv;
  rv = vsnprintf(str, size, format, args);
  if (rv < 0)
    exit(1);
  if ((size_t)rv >= size)
    exit(1);
}

#define COMMAND_MAX_LEN 128
#define PATH_PREFIX                                                            \
  "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin "
#define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1)

static void execute_command(bool panic, const char* format, ...)
{
  va_list args;
  char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN];
  int rv;
  va_start(args, format);
  memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN);
  vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format, args);
  va_end(args);
  rv = system(command);
  if (rv) {
    if (panic)
      exit(1);
  }
}

static int tunfd = -1;
static int tun_frags_enabled;
#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define TUN_IFACE "syz_tun"

#define LOCAL_MAC "aa:aa:aa:aa:aa:aa"
#define REMOTE_MAC "aa:aa:aa:aa:aa:bb"

#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"

#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020

static void initialize_tun(void)
{
  tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
  if (tunfd == -1) {
    printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
    printf("otherwise fuzzing or reproducing might not work as intended\n");
    return;
  }
  const int kTunFd = 240;
  if (dup2(tunfd, kTunFd) < 0)
    exit(1);
  close(tunfd);
  tunfd = kTunFd;
  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
  ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
      exit(1);
  }
  if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
    exit(1);
  tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;
  execute_command(0, "sysctl -w net.ipv6.conf.%s.accept_dad=0", TUN_IFACE);
  execute_command(0, "sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  TUN_IFACE);
  execute_command(1, "ip link set dev %s address %s", TUN_IFACE, LOCAL_MAC);
  execute_command(1, "ip addr add %s/24 dev %s", LOCAL_IPV4, TUN_IFACE);
  execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV4, REMOTE_MAC, TUN_IFACE);
  execute_command(0, "ip -6 addr add %s/120 dev %s", LOCAL_IPV6, TUN_IFACE);
  execute_command(0, "ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV6, REMOTE_MAC, TUN_IFACE);
  execute_command(1, "ip link set dev %s up", TUN_IFACE);
}

static int read_tun(char* data, int size)
{
  if (tunfd < 0)
    return -1;
  int rv = read(tunfd, data, size);
  if (rv < 0) {
    if (errno == EAGAIN)
      return -1;
    if (errno == EBADFD)
      return -1;
    exit(1);
  }
  return rv;
}

#define MAX_FRAGS 4
struct vnet_fragmentation {
  uint32_t full;
  uint32_t count;
  uint32_t frags[MAX_FRAGS];
};

static long syz_emit_ethernet(long a0, long a1, long a2)
{
  if (tunfd < 0)
    return (uintptr_t)-1;
  uint32_t length = a0;
  char* data = (char*)a1;
  struct vnet_fragmentation* frags = (struct vnet_fragmentation*)a2;
  struct iovec vecs[MAX_FRAGS + 1];
  uint32_t nfrags = 0;
  if (!tun_frags_enabled || frags == NULL) {
    vecs[nfrags].iov_base = data;
    vecs[nfrags].iov_len = length;
    nfrags++;
  } else {
    bool full = true;
    uint32_t i, count = 0;
    NONFAILING(full = frags->full);
    NONFAILING(count = frags->count);
    if (count > MAX_FRAGS)
      count = MAX_FRAGS;
    for (i = 0; i < count && length != 0; i++) {
      uint32_t size = 0;
      NONFAILING(size = frags->frags[i]);
      if (size > length)
        size = length;
      vecs[nfrags].iov_base = data;
      vecs[nfrags].iov_len = size;
      nfrags++;
      data += size;
      length -= size;
    }
    if (length != 0 && (full || nfrags == 0)) {
      vecs[nfrags].iov_base = data;
      vecs[nfrags].iov_len = length;
      nfrags++;
    }
  }
  return writev(tunfd, vecs, nfrags);
}

static void flush_tun()
{
  char data[SYZ_TUN_MAX_PACKET_SIZE];
  while (read_tun(&data[0], sizeof(data)) != -1) {
  }
}

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)) {
  }
}

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

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();
  if (unshare(CLONE_NEWNET)) {
  }
  initialize_tun();
  loop();
  exit(1);
}

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) {
  }
}

#define SYZ_HAVE_SETUP_TEST 1
static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  flush_tun();
}

#define SYZ_HAVE_RESET_TEST 1
static void reset_test()
{
  int fd;
  for (fd = 3; fd < 30; fd++)
    close(fd);
}

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();
      reset_test();
      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;
    }
  }
}

void execute_one(void)
{
  NONFAILING(*(uint8_t*)0x20000700 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000701 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000702 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000703 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000704 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000705 = 0xaa);
  NONFAILING(*(uint8_t*)0x20000706 = -1);
  NONFAILING(*(uint8_t*)0x20000707 = -1);
  NONFAILING(*(uint8_t*)0x20000708 = -1);
  NONFAILING(*(uint8_t*)0x20000709 = -1);
  NONFAILING(*(uint8_t*)0x2000070a = -1);
  NONFAILING(*(uint8_t*)0x2000070b = -1);
  NONFAILING(*(uint16_t*)0x2000070c = htobe16(0x86dd));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000070e, 0, 0, 4));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000070e, 6, 4, 4));
  NONFAILING(memcpy((void*)0x2000070f, "\xc2\x2d\xf7", 3));
  NONFAILING(*(uint16_t*)0x20000712 = htobe16(0x7c00));
  NONFAILING(*(uint8_t*)0x20000714 = 0x2c);
  NONFAILING(*(uint8_t*)0x20000715 = 0);
  NONFAILING(*(uint8_t*)0x20000716 = 0xfe);
  NONFAILING(*(uint8_t*)0x20000717 = 0x80);
  NONFAILING(*(uint8_t*)0x20000718 = 0);
  NONFAILING(*(uint8_t*)0x20000719 = 0);
  NONFAILING(*(uint8_t*)0x2000071a = 0);
  NONFAILING(*(uint8_t*)0x2000071b = 0);
  NONFAILING(*(uint8_t*)0x2000071c = 0);
  NONFAILING(*(uint8_t*)0x2000071d = 0);
  NONFAILING(*(uint8_t*)0x2000071e = 0);
  NONFAILING(*(uint8_t*)0x2000071f = 0);
  NONFAILING(*(uint8_t*)0x20000720 = 0);
  NONFAILING(*(uint8_t*)0x20000721 = 0);
  NONFAILING(*(uint8_t*)0x20000722 = 0x88);
  NONFAILING(*(uint8_t*)0x20000723 = 0);
  NONFAILING(*(uint8_t*)0x20000724 = 0);
  NONFAILING(*(uint8_t*)0x20000725 = 0);
  NONFAILING(*(uint8_t*)0x20000726 = 0xfe);
  NONFAILING(*(uint8_t*)0x20000727 = 0x80);
  NONFAILING(*(uint8_t*)0x20000728 = 0);
  NONFAILING(*(uint8_t*)0x20000729 = 0);
  NONFAILING(*(uint8_t*)0x2000072a = 0);
  NONFAILING(*(uint8_t*)0x2000072b = 0);
  NONFAILING(*(uint8_t*)0x2000072c = 0);
  NONFAILING(*(uint8_t*)0x2000072d = 0);
  NONFAILING(*(uint8_t*)0x2000072e = 0);
  NONFAILING(*(uint8_t*)0x2000072f = 0);
  NONFAILING(*(uint8_t*)0x20000730 = 0);
  NONFAILING(*(uint8_t*)0x20000731 = 0);
  NONFAILING(*(uint8_t*)0x20000732 = 0);
  NONFAILING(*(uint8_t*)0x20000733 = 0);
  NONFAILING(*(uint8_t*)0x20000734 = 0);
  NONFAILING(*(uint8_t*)0x20000735 = 0xaa);
  NONFAILING(*(uint16_t*)0x20000736 = htobe16(0));
  NONFAILING(*(uint16_t*)0x20000738 = htobe16(0));
  NONFAILING(*(uint8_t*)0x2000073a = 4);
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000073b, 1, 0, 4));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000073b, 0, 4, 4));
  NONFAILING(*(uint16_t*)0x2000073c = htobe16(0));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000073e, 0, 0, 1));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000073e, 0, 1, 4));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2000073e, 0, 5, 3));
  NONFAILING(memcpy((void*)0x2000073f, "\x00\x87\xae", 3));
  NONFAILING(*(uint8_t*)0x20000742 = 0);
  NONFAILING(memcpy((void*)0x20000743, "\xca\x83\x45", 3));
  NONFAILING(*(uint32_t*)0x20000000 = 0);
  NONFAILING(*(uint32_t*)0x20000004 = 0);
  NONFAILING(*(uint32_t*)0x20000008 = 0);
  NONFAILING(*(uint32_t*)0x2000000c = 0);
  NONFAILING(*(uint32_t*)0x20000010 = 0);
  NONFAILING(*(uint32_t*)0x20000014 = 0);
  struct csum_inet csum_1;
  csum_inet_init(&csum_1);
  NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x0, 16));
  NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x0, 16));
  uint32_t csum_1_chunk_2 = 0x10000000;
  csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_2, 4);
  uint32_t csum_1_chunk_3 = 0x21000000;
  csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_3, 4);
  NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x0, 16));
  NONFAILING(*(uint16_t*)0x2000073c = csum_inet_digest(&csum_1));
  syz_emit_ethernet(0x1019f, 0x20000700, 0x20000000);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  install_segv_handler();
  do_sandbox_none();
  return 0;
}