syzkaller-repros/linux/502c872feb9bbb5ad6494c349c7faa87a9f1777b.c

// general protection fault in strlen
// https://syzkaller.appspot.com/bug?id=502c872feb9bbb5ad6494c349c7faa87a9f1777b
// status:fixed
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/if_arp.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}
#include <setjmp.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <string.h>

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

static void fail(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
  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);
  }
  doexit(sig);
}

static void install_segv_handler()
{
  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 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;
}

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)
    fail("tun: snprintf failed");
  if ((size_t)rv >= size)
    fail("tun: string '%s...' doesn't fit into buffer", str);
}

static void snprintf_check(char* str, size_t size, const char* format, ...)
{
  va_list args;

  va_start(args, format);
  vsnprintf_check(str, size, format, args);
  va_end(args);
}

#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);
  rv = system(command);
  if (panic && rv != 0)
    fail("tun: command \"%s\" failed with code %d", &command[0], rv);

  va_end(args);
}

static int tunfd = -1;
static int tun_frags_enabled;

#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define MAX_PIDS 32
#define ADDR_MAX_LEN 32

#define LOCAL_MAC "aa:aa:aa:aa:%02hx:aa"
#define REMOTE_MAC "aa:aa:aa:aa:%02hx:bb"

#define LOCAL_IPV4 "172.20.%d.170"
#define REMOTE_IPV4 "172.20.%d.187"

#define LOCAL_IPV6 "fe80::%02hx:aa"
#define REMOTE_IPV6 "fe80::%02hx:bb"

#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020

static void initialize_tun(int id)
{
  if (id >= MAX_PIDS)
    fail("tun: no more than %d executors", MAX_PIDS);

  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;
  }

  char iface[IFNAMSIZ];
  snprintf_check(iface, sizeof(iface), "syz%d", id);

  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, 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)
      fail("tun: ioctl(TUNSETIFF) failed");
  }
  if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
    fail("tun: ioctl(TUNGETIFF) failed");
  tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;

  char local_mac[ADDR_MAX_LEN];
  snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id);
  char remote_mac[ADDR_MAX_LEN];
  snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id);

  char local_ipv4[ADDR_MAX_LEN];
  snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id);
  char remote_ipv4[ADDR_MAX_LEN];
  snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id);

  char local_ipv6[ADDR_MAX_LEN];
  snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id);
  char remote_ipv6[ADDR_MAX_LEN];
  snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id);

  execute_command(1, "sysctl -w net.ipv6.conf.%s.accept_dad=0", iface);

  execute_command(1, "sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  iface);

  execute_command(1, "ip link set dev %s address %s", iface, local_mac);
  execute_command(1, "ip addr add %s/24 dev %s", local_ipv4, iface);
  execute_command(1, "ip -6 addr add %s/120 dev %s", local_ipv6, iface);
  execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv4, remote_mac, iface);
  execute_command(1, "ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv6, remote_mac, iface);
  execute_command(1, "ip link set dev %s up", iface);
}

#define DEV_IPV4 "172.20.%d.%d"
#define DEV_IPV6 "fe80::%02hx:%02hx"
#define DEV_MAC "aa:aa:aa:aa:%02hx:%02hx"

static void initialize_netdevices(int id)
{
  unsigned i;
  const char* devtypes[] = {"ip6gretap", "bridge", "vcan"};
  const char* devnames[] = {"lo",       "sit0",    "bridge0", "vcan0",
                            "tunl0",    "gre0",    "gretap0", "ip_vti0",
                            "ip6_vti0", "ip6tnl0", "ip6gre0", "ip6gretap0",
                            "erspan0"};

  for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++)
    execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]);
  for (i = 0; i < sizeof(devnames) / (sizeof(devnames[0])); i++) {
    char addr[ADDR_MAX_LEN];
    snprintf_check(addr, sizeof(addr), DEV_IPV4, id, id + 10);
    execute_command(0, "ip -4 addr add %s/24 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_IPV6, id, id + 10);
    execute_command(0, "ip -6 addr add %s/120 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_MAC, id, id + 10);
    execute_command(0, "ip link set dev %s address %s", devnames[i], addr);
    execute_command(0, "ip link set dev %s up", devnames[i]);
  }
}

static void setup_tun(uint64_t pid, bool enable_tun)
{
  if (enable_tun) {
    initialize_tun(pid);
    initialize_netdevices(pid);
  }
}

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;
    fail("tun: read failed with %d", rv);
  }
  return rv;
}

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

static void test();

void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      fail("loop fork failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      flush_tun();
      test();
      doexit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid)
        break;
      usleep(1000);
      if (current_time_ms() - start > 5 * 1000) {
        kill(-pid, SIGKILL);
        kill(pid, SIGKILL);
        while (waitpid(-1, &status, __WALL) != pid) {
        }
        break;
      }
    }
  }
}

struct thread_t {
  int created, running, call;
  pthread_t th;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;
static int collide;

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
    syscall(SYS_futex, &th->running, FUTEX_WAKE);
  }
  return 0;
}

static void execute(int num_calls)
{
  int call, thread;
  running = 0;
  for (call = 0; call < num_calls; call++) {
    for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        pthread_create(&th->th, &attr, thr, th);
      }
      if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
        syscall(SYS_futex, &th->running, FUTEX_WAKE);
        if (collide && call % 2)
          break;
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (running)
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

long r[1];
uint64_t procid;
void execute_call(int call)
{
  switch (call) {
  case 0:
    syscall(__NR_mmap, 0x20000000, 0xf23000, 3, 0x32, -1, 0);
    break;
  case 1:
    r[0] = syscall(__NR_socket, 0x10, 3, 6);
    break;
  case 2:
    NONFAILING(*(uint8_t*)0x2077d000 = 0xac);
    NONFAILING(*(uint8_t*)0x2077d001 = 0x14);
    NONFAILING(*(uint8_t*)0x2077d002 = 0);
    NONFAILING(*(uint8_t*)0x2077d003 = 0xbb);
    NONFAILING(*(uint8_t*)0x2077d010 = 0);
    NONFAILING(*(uint8_t*)0x2077d011 = 0);
    NONFAILING(*(uint8_t*)0x2077d012 = 0);
    NONFAILING(*(uint8_t*)0x2077d013 = 0);
    NONFAILING(*(uint8_t*)0x2077d014 = 0);
    NONFAILING(*(uint8_t*)0x2077d015 = 0);
    NONFAILING(*(uint8_t*)0x2077d016 = 0);
    NONFAILING(*(uint8_t*)0x2077d017 = 0);
    NONFAILING(*(uint8_t*)0x2077d018 = 0);
    NONFAILING(*(uint8_t*)0x2077d019 = 0);
    NONFAILING(*(uint8_t*)0x2077d01a = -1);
    NONFAILING(*(uint8_t*)0x2077d01b = -1);
    NONFAILING(*(uint32_t*)0x2077d01c = htobe32(0x7f000001));
    NONFAILING(*(uint16_t*)0x2077d020 = 0);
    NONFAILING(*(uint16_t*)0x2077d022 = htobe16(0));
    NONFAILING(*(uint16_t*)0x2077d024 = 0);
    NONFAILING(*(uint16_t*)0x2077d026 = htobe16(0));
    NONFAILING(*(uint16_t*)0x2077d028 = 0);
    NONFAILING(*(uint8_t*)0x2077d02a = 0);
    NONFAILING(*(uint8_t*)0x2077d02b = 0);
    NONFAILING(*(uint8_t*)0x2077d02c = 0);
    NONFAILING(*(uint32_t*)0x2077d030 = 0);
    NONFAILING(*(uint32_t*)0x2077d034 = 0);
    NONFAILING(*(uint64_t*)0x2077d038 = 0);
    NONFAILING(*(uint64_t*)0x2077d040 = 0);
    NONFAILING(*(uint64_t*)0x2077d048 = 0);
    NONFAILING(*(uint64_t*)0x2077d050 = 0);
    NONFAILING(*(uint64_t*)0x2077d058 = 0);
    NONFAILING(*(uint64_t*)0x2077d060 = 0);
    NONFAILING(*(uint64_t*)0x2077d068 = 0);
    NONFAILING(*(uint64_t*)0x2077d070 = 0);
    NONFAILING(*(uint64_t*)0x2077d078 = 0);
    NONFAILING(*(uint64_t*)0x2077d080 = 0);
    NONFAILING(*(uint64_t*)0x2077d088 = 0);
    NONFAILING(*(uint64_t*)0x2077d090 = 0);
    NONFAILING(*(uint32_t*)0x2077d098 = 0);
    NONFAILING(*(uint32_t*)0x2077d09c = 0);
    NONFAILING(*(uint8_t*)0x2077d0a0 = 0);
    NONFAILING(*(uint8_t*)0x2077d0a1 = 0);
    NONFAILING(*(uint8_t*)0x2077d0a2 = 0);
    NONFAILING(*(uint8_t*)0x2077d0a3 = 0);
    NONFAILING(*(uint32_t*)0x2077d0a8 = htobe32(0xe0000001));
    NONFAILING(*(uint32_t*)0x2077d0b8 = 0);
    NONFAILING(*(uint8_t*)0x2077d0bc = 0);
    NONFAILING(*(uint16_t*)0x2077d0c0 = 0);
    NONFAILING(*(uint64_t*)0x2077d0c4 = htobe64(0));
    NONFAILING(*(uint64_t*)0x2077d0cc = htobe64(1));
    NONFAILING(*(uint32_t*)0x2077d0d4 = 0);
    NONFAILING(*(uint8_t*)0x2077d0d8 = 0);
    NONFAILING(*(uint8_t*)0x2077d0d9 = 0);
    NONFAILING(*(uint8_t*)0x2077d0da = 0);
    NONFAILING(*(uint32_t*)0x2077d0dc = 0);
    NONFAILING(*(uint32_t*)0x2077d0e0 = 0);
    NONFAILING(*(uint32_t*)0x2077d0e4 = 0);
    syscall(__NR_setsockopt, r[0], 0x10e, 0xb, 0x2077d000, 0xe8);
    break;
  case 3:
    NONFAILING(*(uint64_t*)0x20f1efc8 = 0x20f1e000);
    NONFAILING(*(uint32_t*)0x20f1efd0 = 0xc);
    NONFAILING(*(uint64_t*)0x20f1efd8 = 0x207dfff0);
    NONFAILING(*(uint64_t*)0x20f1efe0 = 1);
    NONFAILING(*(uint64_t*)0x20f1efe8 = 0);
    NONFAILING(*(uint64_t*)0x20f1eff0 = 0);
    NONFAILING(*(uint32_t*)0x20f1eff8 = 0);
    NONFAILING(*(uint16_t*)0x20f1e000 = 0x10);
    NONFAILING(*(uint16_t*)0x20f1e002 = 0);
    NONFAILING(*(uint32_t*)0x20f1e004 = 0);
    NONFAILING(*(uint32_t*)0x20f1e008 = 0);
    NONFAILING(*(uint64_t*)0x207dfff0 = 0x2088cc98);
    NONFAILING(*(uint64_t*)0x207dfff8 = 0xf4);
    NONFAILING(*(uint32_t*)0x2088cc98 = 0xf4);
    NONFAILING(*(uint16_t*)0x2088cc9c = 0x18);
    NONFAILING(*(uint16_t*)0x2088cc9e = 0x3c2c);
    NONFAILING(*(uint32_t*)0x2088cca0 = 0);
    NONFAILING(*(uint32_t*)0x2088cca4 = 0);
    NONFAILING(*(uint32_t*)0x2088cca8 = htobe32(0));
    NONFAILING(*(uint8_t*)0x2088ccb8 = 0xac);
    NONFAILING(*(uint8_t*)0x2088ccb9 = 0x14);
    NONFAILING(*(uint8_t*)0x2088ccba = 0);
    NONFAILING(*(uint8_t*)0x2088ccbb = 0xbb);
    NONFAILING(*(uint16_t*)0x2088ccc8 = 0);
    NONFAILING(*(uint16_t*)0x2088ccca = htobe16(0));
    NONFAILING(*(uint16_t*)0x2088cccc = 0);
    NONFAILING(*(uint16_t*)0x2088ccce = htobe16(0));
    NONFAILING(*(uint16_t*)0x2088ccd0 = 0);
    NONFAILING(*(uint8_t*)0x2088ccd2 = 0);
    NONFAILING(*(uint8_t*)0x2088ccd3 = 0);
    NONFAILING(*(uint8_t*)0x2088ccd4 = 0);
    NONFAILING(*(uint32_t*)0x2088ccd8 = 0);
    NONFAILING(*(uint32_t*)0x2088ccdc = 0);
    NONFAILING(*(uint8_t*)0x2088cce0 = -1);
    NONFAILING(*(uint8_t*)0x2088cce1 = 1);
    NONFAILING(*(uint8_t*)0x2088cce2 = 0);
    NONFAILING(*(uint8_t*)0x2088cce3 = 0);
    NONFAILING(*(uint8_t*)0x2088cce4 = 0);
    NONFAILING(*(uint8_t*)0x2088cce5 = 0);
    NONFAILING(*(uint8_t*)0x2088cce6 = 0);
    NONFAILING(*(uint8_t*)0x2088cce7 = 0);
    NONFAILING(*(uint8_t*)0x2088cce8 = 0);
    NONFAILING(*(uint8_t*)0x2088cce9 = 0);
    NONFAILING(*(uint8_t*)0x2088ccea = 0);
    NONFAILING(*(uint8_t*)0x2088cceb = 0);
    NONFAILING(*(uint8_t*)0x2088ccec = 0);
    NONFAILING(*(uint8_t*)0x2088cced = 0);
    NONFAILING(*(uint8_t*)0x2088ccee = 0);
    NONFAILING(*(uint8_t*)0x2088ccef = 1);
    NONFAILING(*(uint32_t*)0x2088ccf0 = 0);
    NONFAILING(*(uint8_t*)0x2088ccf4 = 0);
    NONFAILING(*(uint32_t*)0x2088ccf8 = htobe32(0));
    NONFAILING(*(uint64_t*)0x2088cd08 = 0);
    NONFAILING(*(uint64_t*)0x2088cd10 = 0);
    NONFAILING(*(uint64_t*)0x2088cd18 = 0);
    NONFAILING(*(uint64_t*)0x2088cd20 = 0);
    NONFAILING(*(uint64_t*)0x2088cd28 = 0);
    NONFAILING(*(uint64_t*)0x2088cd30 = 0);
    NONFAILING(*(uint64_t*)0x2088cd38 = 0);
    NONFAILING(*(uint64_t*)0x2088cd40 = 0);
    NONFAILING(*(uint64_t*)0x2088cd48 = 0);
    NONFAILING(*(uint64_t*)0x2088cd50 = 0);
    NONFAILING(*(uint64_t*)0x2088cd58 = 0);
    NONFAILING(*(uint64_t*)0x2088cd60 = 0);
    NONFAILING(*(uint32_t*)0x2088cd68 = 0);
    NONFAILING(*(uint32_t*)0x2088cd6c = 0);
    NONFAILING(*(uint32_t*)0x2088cd70 = 0);
    NONFAILING(*(uint32_t*)0x2088cd74 = 0);
    NONFAILING(*(uint32_t*)0x2088cd78 = 0);
    NONFAILING(*(uint16_t*)0x2088cd7c = 0);
    NONFAILING(*(uint8_t*)0x2088cd7e = 0);
    NONFAILING(*(uint8_t*)0x2088cd7f = 0);
    NONFAILING(*(uint8_t*)0x2088cd80 = 0);
    NONFAILING(*(uint8_t*)0x2088cd88 = 0);
    syscall(__NR_sendmsg, r[0], 0x20f1efc8, 0);
    break;
  }
}

void test()
{
  memset(r, -1, sizeof(r));
  execute(4);
  collide = 1;
  execute(4);
}

int main()
{
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      install_segv_handler();
      for (;;) {
        setup_tun(procid, true);
        loop();
      }
    }
  }
  sleep(1000000);
  return 0;
}