syzkaller-repros/linux/64cfa65b118e950fc6ca7ab778adfef407185402.c

// memory leak in process_preds
// https://syzkaller.appspot.com/bug?id=64cfa65b118e950fc6ca7ab778adfef407185402
// status:fixed
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <sched.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/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_tun.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/tcp.h>
#include <linux/veth.h>

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(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off))
#define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len)               \
  *(type*)(addr) =                                                             \
      htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) |           \
            (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len))))

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 struct {
  char* pos;
  int nesting;
  struct nlattr* nested[8];
  char buf[1024];
} nlmsg;

static void netlink_init(int typ, int flags, const void* data, int size)
{
  memset(&nlmsg, 0, sizeof(nlmsg));
  struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg.buf;
  hdr->nlmsg_type = typ;
  hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
  memcpy(hdr + 1, data, size);
  nlmsg.pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}

static void netlink_attr(int typ, const void* data, int size)
{
  struct nlattr* attr = (struct nlattr*)nlmsg.pos;
  attr->nla_len = sizeof(*attr) + size;
  attr->nla_type = typ;
  memcpy(attr + 1, data, size);
  nlmsg.pos += NLMSG_ALIGN(attr->nla_len);
}

static int netlink_send(int sock)
{
  if (nlmsg.pos > nlmsg.buf + sizeof(nlmsg.buf) || nlmsg.nesting)
    exit(1);
  struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg.buf;
  hdr->nlmsg_len = nlmsg.pos - nlmsg.buf;
  struct sockaddr_nl addr;
  memset(&addr, 0, sizeof(addr));
  addr.nl_family = AF_NETLINK;
  unsigned n = sendto(sock, nlmsg.buf, hdr->nlmsg_len, 0,
                      (struct sockaddr*)&addr, sizeof(addr));
  if (n != hdr->nlmsg_len)
    exit(1);
  n = recv(sock, nlmsg.buf, sizeof(nlmsg.buf), 0);
  if (n < sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))
    exit(1);
  if (hdr->nlmsg_type != NLMSG_ERROR)
    exit(1);
  return -((struct nlmsgerr*)(hdr + 1))->error;
}

static void netlink_device_change(int sock, const char* name, bool up,
                                  const char* master, const void* mac,
                                  int macsize)
{
  struct ifinfomsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  if (up)
    hdr.ifi_flags = hdr.ifi_change = IFF_UP;
  netlink_init(RTM_NEWLINK, 0, &hdr, sizeof(hdr));
  netlink_attr(IFLA_IFNAME, name, strlen(name));
  if (master) {
    int ifindex = if_nametoindex(master);
    netlink_attr(IFLA_MASTER, &ifindex, sizeof(ifindex));
  }
  if (macsize)
    netlink_attr(IFLA_ADDRESS, mac, macsize);
  int err = netlink_send(sock);
  (void)err;
}

static int netlink_add_addr(int sock, const char* dev, const void* addr,
                            int addrsize)
{
  struct ifaddrmsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
  hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
  hdr.ifa_scope = RT_SCOPE_UNIVERSE;
  hdr.ifa_index = if_nametoindex(dev);
  netlink_init(RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr, sizeof(hdr));
  netlink_attr(IFA_LOCAL, addr, addrsize);
  netlink_attr(IFA_ADDRESS, addr, addrsize);
  return netlink_send(sock);
}

static void netlink_add_addr4(int sock, const char* dev, const char* addr)
{
  struct in_addr in_addr;
  inet_pton(AF_INET, addr, &in_addr);
  int err = netlink_add_addr(sock, dev, &in_addr, sizeof(in_addr));
  (void)err;
}

static void netlink_add_addr6(int sock, const char* dev, const char* addr)
{
  struct in6_addr in6_addr;
  inet_pton(AF_INET6, addr, &in6_addr);
  int err = netlink_add_addr(sock, dev, &in6_addr, sizeof(in6_addr));
  (void)err;
}

static void netlink_add_neigh(int sock, const char* name, const void* addr,
                              int addrsize, const void* mac, int macsize)
{
  struct ndmsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
  hdr.ndm_ifindex = if_nametoindex(name);
  hdr.ndm_state = NUD_PERMANENT;
  netlink_init(RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr, sizeof(hdr));
  netlink_attr(NDA_DST, addr, addrsize);
  netlink_attr(NDA_LLADDR, mac, macsize);
  int err = netlink_send(sock);
  (void)err;
}

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

#define TUN_IFACE "syz_tun"

#define LOCAL_MAC 0xaaaaaaaaaaaa
#define REMOTE_MAC 0xaaaaaaaaaabb

#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;
  char sysctl[64];
  sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
  write_file(sysctl, "0");
  sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
  write_file(sysctl, "0");
  int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  if (sock == -1)
    exit(1);
  netlink_add_addr4(sock, TUN_IFACE, LOCAL_IPV4);
  netlink_add_addr6(sock, TUN_IFACE, LOCAL_IPV6);
  uint64_t macaddr = REMOTE_MAC;
  struct in_addr in_addr;
  inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
  netlink_add_neigh(sock, TUN_IFACE, &in_addr, sizeof(in_addr), &macaddr,
                    ETH_ALEN);
  struct in6_addr in6_addr;
  inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
  netlink_add_neigh(sock, TUN_IFACE, &in6_addr, sizeof(in6_addr), &macaddr,
                    ETH_ALEN);
  macaddr = LOCAL_MAC;
  netlink_device_change(sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN);
  close(sock);
}

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 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 close_fds()
{
  int fd;
  for (fd = 3; fd < 30; fd++)
    close(fd);
}

#define KMEMLEAK_FILE "/sys/kernel/debug/kmemleak"

static void setup_leak()
{
  if (!write_file(KMEMLEAK_FILE, "scan"))
    exit(1);
  sleep(5);
  if (!write_file(KMEMLEAK_FILE, "scan"))
    exit(1);
  if (!write_file(KMEMLEAK_FILE, "clear"))
    exit(1);
}

static void check_leaks(void)
{
  int fd = open(KMEMLEAK_FILE, O_RDWR);
  if (fd == -1)
    exit(1);
  uint64_t start = current_time_ms();
  if (write(fd, "scan", 4) != 4)
    exit(1);
  sleep(1);
  while (current_time_ms() - start < 4 * 1000)
    sleep(1);
  if (write(fd, "scan", 4) != 4)
    exit(1);
  static char buf[128 << 10];
  ssize_t n = read(fd, buf, sizeof(buf) - 1);
  if (n < 0)
    exit(1);
  int nleaks = 0;
  if (n != 0) {
    sleep(1);
    if (write(fd, "scan", 4) != 4)
      exit(1);
    if (lseek(fd, 0, SEEK_SET) < 0)
      exit(1);
    n = read(fd, buf, sizeof(buf) - 1);
    if (n < 0)
      exit(1);
    buf[n] = 0;
    char* pos = buf;
    char* end = buf + n;
    while (pos < end) {
      char* next = strstr(pos + 1, "unreferenced object");
      if (!next)
        next = end;
      char prev = *next;
      *next = 0;
      fprintf(stderr, "BUG: memory leak\n%s\n", pos);
      *next = prev;
      pos = next;
      nleaks++;
    }
  }
  if (write(fd, "clear", 5) != 5)
    exit(1);
  close(fd);
  if (nleaks)
    exit(1);
}

uint64_t r[1] = {0xffffffffffffffff};

void loop(void)
{
  intptr_t res = 0;
  *(uint32_t*)0x204e7000 = 2;
  *(uint32_t*)0x204e7004 = 0x70;
  *(uint8_t*)0x204e7008 = 0xdf;
  *(uint8_t*)0x204e7009 = 0;
  *(uint8_t*)0x204e700a = 0;
  *(uint8_t*)0x204e700b = 0;
  *(uint32_t*)0x204e700c = 0;
  *(uint64_t*)0x204e7010 = 0;
  *(uint64_t*)0x204e7018 = 0;
  *(uint64_t*)0x204e7020 = 0;
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 0, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 1, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 2, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 3, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 4, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 5, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 6, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 7, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 8, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 9, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 10, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 11, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 12, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 13, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 14, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 15, 2);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 17, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 18, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 19, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 20, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 21, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 22, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 23, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 24, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 25, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 26, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 2, 27, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 28, 1);
  STORE_BY_BITMASK(uint64_t, , 0x204e7028, 0, 29, 35);
  *(uint32_t*)0x204e7030 = 0;
  *(uint32_t*)0x204e7034 = 0;
  *(uint64_t*)0x204e7038 = 0;
  *(uint64_t*)0x204e7040 = 3;
  *(uint64_t*)0x204e7048 = 0;
  *(uint64_t*)0x204e7050 = 0;
  *(uint32_t*)0x204e7058 = 0;
  *(uint32_t*)0x204e705c = 0;
  *(uint64_t*)0x204e7060 = 0;
  *(uint32_t*)0x204e7068 = 0;
  *(uint16_t*)0x204e706c = 0;
  *(uint16_t*)0x204e706e = 0;
  res = syscall(__NR_perf_event_open, 0x204e7000, 0, 0, -1, 0);
  if (res != -1)
    r[0] = res;
  memcpy((void*)0x20000400,
         "cpu&00&_\n\000\001\b\000\001\234\323\0165\240\035=\004\n\034`"
         "fo\215\314m\\v\375.\236\tbk1\336\352\033\r;\201\204\207-X\266,"
         "\305\264\"7\"\265yt\202\373\035\203\370.- "
         "\000\000\000(\351`D\001i\\\215l\206lh\250\374\200\336,Kt\364#\305]Y;"
         "\3016v\371\211\t\006\276*\252&"
         "\275\026xQ\216\363\326\032\375\320\004\'y\233|"
         "\344\267\bE\355\227\200s\031W\267[\360%>MM\365\230\276^=q!"
         "\246\017p\0012\000\273\276\235X5\257ep\020R\v&\257\250$"
         "\1777V\355LJ4\317\a\001\325T\n\312\302\206_"
         "\301\316\215\355bS\215\351t\202\3641zwr\346o\210\345\343\347Gcx\300"
         "\221I\001\000\000\000\001\000\000\000K\236\345["
         "\240\n\017\004\246\260sE)\212\320R\303\301,b "
         "\034#IRz6\376J~\332\327_\376\037\345\206\261xu&"
         "\373\362\277\350\177\221\223\253\005\0004\205\206l\215\000\000\000"
         "\000\000\000\000\000\000\000\000\000\000\000\000",
         289);
  syscall(__NR_ioctl, r[0], 0x40082406, 0x20000400);
  close_fds();
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  setup_leak();
  do_sandbox_none();
  check_leaks();
  return 0;
}