Hi,
Got the following report while fuzzing the 4.9.66 with syzkaller.
This bug can be triggered by the attached program on Ubuntu16.04
(4.4.0-101-generic)
================================================================
Syzkaller hit 'general protection fault in inet_csk_listen_stop' bug
on commit 4.9.66..
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 8157 Comm: syzkaller674855 Not tainted 4.9.66 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff880073e2f080 task.stack: ffff880073f78000
RIP: 0010:[<ffffffff829e8aaf>] [<ffffffff829e8aaf>]
inet_csk_listen_stop+0x2bf/0x5b0 net/ipv4/inet_connection_sock.c:874
RSP: 0018:ffff880073f7fb48 EFLAGS: 00010207
RAX: 0000000000000111 RBX: dffffc0000000000 RCX: 00000000000601a8
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 000000000000088f
RBP: ffff880073f7fb98 R08: 0000000000000286 R09: 0000000000000003
R10: 000000005bb54075 R11: 00000000ff0b3bcc R12: ffff8800741bb9b8
R13: ffff8800741bb600 R14: dffffc0000000000 R15: 0000000000000807
FS: 0000000000000000(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffb227a8db8 CR3: 000000000360c000 CR4: 00000000000006f0
Stack:
ffff8800741bb9a0 ffffed000e837734 ffff8800741bb7b8 ffff8800741bb998
ffff8800741bb980 ffff8800741bb600 ffff8800741bb612 ffff8800741bb628
0000000000000000 ffffffff8282b170 ffff880073f7fc10 ffffffff829ff2e1
Call Trace:
[<ffffffff829ff2e1>] tcp_close+0xb1/0xf60 net/ipv4/tcp.c:2079
[<ffffffff82aa551d>] inet_release+0xed/0x1c0 net/ipv4/af_inet.c:415
[<ffffffff82bcd500>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:422
[<ffffffff8282b02d>] sock_release+0x8d/0x1d0 net/socket.c:585
[<ffffffff8282b186>] sock_close+0x16/0x20 net/socket.c:1032
[<ffffffff815433a6>] __fput+0x276/0x6e0 fs/file_table.c:208
[<ffffffff81543895>] ____fput+0x15/0x20 fs/file_table.c:244
[<ffffffff81241653>] task_work_run+0xf3/0x160 kernel/task_work.c:116
[<ffffffff811f936d>] exit_task_work include/linux/task_work.h:21 [inline]
[<ffffffff811f936d>] do_exit+0x6fd/0x2900 kernel/exit.c:828
[<ffffffff811fb6d6>] do_group_exit+0xf6/0x340 kernel/exit.c:932
[<ffffffff811fb93d>] SYSC_exit_group kernel/exit.c:943 [inline]
[<ffffffff811fb93d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:941
[<ffffffff82f79fbb>] entry_SYSCALL_64_fastpath+0x1e/0xad
Code: 75 16 e9 72 01 00 00 e8 d0 95 9d fe 4d 85 e4 4d 89 e7 0f 84 61
01 00 00 e8 bf 95 9d fe 49 8d bf 88 00 00 00 48 89 f8 48 c1 e8 03 <80>
3c 18 00 0f 85 7c 02 00 00 4d 8b a7 88 00 00 00 4d 8d b7 80
RIP [<ffffffff829e8aaf>] inet_csk_listen_stop+0x2bf/0x5b0
net/ipv4/inet_connection_sock.c:874
RSP <ffff880073f7fb48>
---[ end trace 5d4d9621d097214d ]---
Kernel panic - not syncing: Fatal exception
Kernel Offset: disabled
Rebooting in 86400 seconds..
--
Regards,
idaifish
#define _GNU_SOURCE
#include <sys/syscall.h>
#include <unistd.h>
#include <pthread.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <sys/prctl.h>
#include <dirent.h>
#include <sys/mount.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.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 <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/uio.h>
__attribute__((noreturn)) static void doexit(int status)
{
volatile unsigned i;
syscall(__NR_exit_group, status);
for (i = 0;; i++) {
}
}
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <setjmp.h>
#include <signal.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 void exitf(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(kRetryStatus);
}
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);
for (;;) {
}
}
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 use_temporary_dir()
{
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 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(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 (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:aa:%02hx"
#define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx"
#define LOCAL_IPV4 "172.20.%d.170"
#define REMOTE_IPV4 "172.20.%d.187"
#define LOCAL_IPV6 "fe80::%02hxaa"
#define REMOTE_IPV6 "fe80::%02hxbb"
#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020
static void initialize_tun(uint64_t pid)
{
if (pid >= MAX_PIDS)
fail("tun: no more than %d executors", MAX_PIDS);
int id = pid;
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("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface);
execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0", iface);
execute_command("ip link set dev %s address %s", iface, local_mac);
execute_command("ip addr add %s/24 dev %s", local_ipv4, iface);
execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface);
execute_command("ip neigh add %s lladdr %s dev %s nud permanent", remote_ipv4, remote_mac, iface);
execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent", remote_ipv6, remote_mac, iface);
execute_command("ip link set dev %s up", iface);
}
static void setup_tun(uint64_t pid, bool enable_tun)
{
if (enable_tun)
initialize_tun(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 remove_dir(const char* dir)
{
DIR* dp;
struct dirent* ep;
int iter = 0;
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;
}
int i;
for (i = 0;; i++) {
if (unlink(filename) == 0)
break;
if (errno == EROFS) {
break;
}
if (errno != EBUSY || i > 100)
exitf("unlink(%s) failed", filename);
if (umount2(filename, MNT_DETACH))
exitf("umount(%s) failed", filename);
}
}
closedir(dp);
int i;
for (i = 0;; i++) {
if (rmdir(dir) == 0)
break;
if (i < 100) {
if (errno == EROFS) {
break;
}
if (errno == EBUSY) {
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 void test();
void loop()
{
int iter;
for (iter = 0;; iter++) {
char cwdbuf[256];
sprintf(cwdbuf, "./%d", iter);
if (mkdir(cwdbuf, 0777))
fail("failed to mkdir");
int pid = fork();
if (pid < 0)
fail("clone failed");
if (pid == 0) {
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setpgrp();
if (chdir(cwdbuf))
fail("failed to chdir");
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;
}
}
remove_dir(cwdbuf);
}
}
long r[5];
void *thr(void *arg)
{
switch ((long)arg) {
case 0:
r[0] = syscall(__NR_mmap, 0x20000000ul, 0xb4c000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul);
break;
case 1:
r[1] = syscall(__NR_socket, 0xaul, 0x1ul, 0x0ul);
break;
case 2:
NONFAILING(*(uint32_t*)0x204feffc = (uint32_t)0x100000807);
r[3] = syscall(__NR_setsockopt, r[1], 0x29ul, 0xd1ul, 0x204feffcul, 0x4ul);
break;
case 3:
r[4] = syscall(__NR_listen, r[1], 0x3ul);
break;
}
return 0;
}
void test()
{
long i;
pthread_t th[8];
memset(r, -1, sizeof(r));
for (i = 0; i < 4; i++) {
pthread_create(&th[i], 0, thr, (void*)i);
usleep(rand()%10000);
}
usleep(rand()%100000);
}
int main()
{
int i; for (i = 0; i < 8; i++) {
if (fork() == 0) {
install_segv_handler();
use_temporary_dir();
setup_tun(i, true);
loop();
return 0;
}
}
sleep(1000000);
return 0;
}
