net/llc: BUG in llc_sap_state_process/skb_set_owner_r

From: Andrey Konovalov
Date: Sun Feb 12 2017 - 11:44:32 EST

Next message: Andrey Konovalov: "Re: net/llc: bug in llc_pdu_init_as_xid_cmd/skb_over_panic"
Previous message: Nicholas Mc Guire: "[PATCH RFC] spi-nor: provide a range for poll_timout"
Next in thread: Eric Dumazet: "Re: net/llc: BUG in llc_sap_state_process/skb_set_owner_r"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi,

I've got the following error report while fuzzing the kernel with syzkaller.

On commit 926af6273fc683cd98cd0ce7bf0d04a02eed6742.

A reproducer and .config are attached

kernel BUG at ./include/linux/skbuff.h:2389!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 9315 Comm: syz-executor2 Not tainted 4.10.0-rc7+ #126
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88006861c480 task.stack: ffff88006a988000
RIP: 0010:skb_set_owner_r include/linux/skbuff.h:2389 [inline]
RIP: 0010:__sock_queue_rcv_skb+0x8c0/0xda0 net/core/sock.c:425
RSP: 0018:ffff88003ec06b58 EFLAGS: 00010206
RAX: ffff88006861c480 RBX: ffff8800371c2568 RCX: 0000000000000000
RDX: 0000000000000100 RSI: 1ffff10006ba08ab RDI: ffff880035d04560
RBP: ffff88003ec06dc0 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: dffffc0000000000 R12: ffff880035d04540
R13: ffff88003ec06d98 R14: ffff8800371c2590 R15: ffff880035d045a0
FS: 00007fa8005ac700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004a6f68 CR3: 0000000038e25000 CR4: 00000000000006f0
Call Trace:
<IRQ>
sock_queue_rcv_skb+0x3a/0x50 net/core/sock.c:451
llc_sap_state_process+0x3e3/0x4e0 net/llc/llc_sap.c:220
llc_sap_rcv net/llc/llc_sap.c:294 [inline]
llc_sap_handler+0x695/0x1320 net/llc/llc_sap.c:434
llc_rcv+0x6da/0xed0 net/llc/llc_input.c:208
__netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190
__netif_receive_skb+0x2a/0x170 net/core/dev.c:4228
process_backlog+0xe5/0x6c0 net/core/dev.c:4839
napi_poll net/core/dev.c:5202 [inline]
net_rx_action+0xe70/0x1900 net/core/dev.c:5267
__do_softirq+0x2fb/0xb7d kernel/softirq.c:284
do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:902
</IRQ>
do_softirq.part.17+0x1e8/0x230 kernel/softirq.c:328
do_softirq kernel/softirq.c:176 [inline]
__local_bh_enable_ip+0x1f2/0x200 kernel/softirq.c:181
local_bh_enable include/linux/bottom_half.h:31 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:971 [inline]
__dev_queue_xmit+0xd87/0x2860 net/core/dev.c:3399
dev_queue_xmit+0x17/0x20 net/core/dev.c:3405
llc_build_and_send_ui_pkt+0x240/0x330 net/llc/llc_output.c:74
llc_ui_sendmsg+0x98d/0x1430 net/llc/af_llc.c:928
sock_sendmsg_nosec net/socket.c:635 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:645
___sys_sendmsg+0x9d2/0xae0 net/socket.c:1985
__sys_sendmsg+0x138/0x320 net/socket.c:2019
SYSC_sendmsg net/socket.c:2030 [inline]
SyS_sendmsg+0x2d/0x50 net/socket.c:2026
entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x4458b9
RSP: 002b:00007fa8005abb58 EFLAGS: 00000286 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000004458b9
RDX: 0000000000040880 RSI: 0000000020003000 RDI: 0000000000000006
RBP: 00000000006e1b00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000708000
R13: 0000000000000082 R14: 0000000020000000 R15: 0000000000000000
Code: 4b 50 fe e9 b1 f8 ff ff e8 3e 4a 50 fe e9 78 f8 ff ff e8 34 4a
50 fe e9 6d f9 ff ff e8 2a 4a 50 fe e9 93 f9 ff ff e8 20 0a 26 fe <0f>
0b e8 19 0a 26 fe be 3c 01 00 00 48 c7 c7 e0 e9 22 85 e8 b8
RIP: skb_set_owner_r include/linux/skbuff.h:2389 [inline] RSP: ffff88003ec06b58
RIP: __sock_queue_rcv_skb+0x8c0/0xda0 net/core/sock.c:425 RSP: ffff88003ec06b58
---[ end trace 58af2d02ad7f84f0 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#ifndef __NR_sendmsg
#define __NR_sendmsg 46
#endif
#ifndef __NR_mmap
#define __NR_mmap 9
#endif
#ifndef __NR_socket
#define __NR_socket 41
#endif
#ifndef __NR_connect
#define __NR_connect 42
#endif

#define _GNU_SOURCE

#include <sys/ioctl.h>
#include <sys/mman.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/kvm.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 <stdbool.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 doexit(int status)
{
volatile unsigned i;
syscall(__NR_exit_group, status);
for (i = 0;; i++) {
}
}

__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);
doexit(e == ENOMEM ? kRetryStatus : 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);
doexit(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)
{
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)) {
debug("SIGSEGV on %p, skipping\n", addr);
_longjmp(segv_env, 1);
}
debug("SIGSEGV on %p, exiting\n", addr);
doexit(sig);
for (;;) {
}
}

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); \
}

#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; \
}

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);
}
}

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 executor_pid, bool enable_tun)
{
int pid = fork();
if (pid)
return pid;

sandbox_common();

loop();
doexit(1);
}

long r[30];
void* thr(void* arg)
{
switch ((long)arg) {
case 0:
r[0] =
execute_syscall(__NR_mmap, 0x20000000ul, 0x1f2000ul, 0x3ul,
0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
break;
case 1:
r[1] = execute_syscall(__NR_socket, 0x1aul, 0x2ul, 0x1ul, 0, 0, 0,
0, 0, 0);
break;
case 2:
NONFAILING(*(uint16_t*)0x20000000 = (uint16_t)0x1f);
NONFAILING(*(uint8_t*)0x20000002 = (uint8_t)0x8002000004);
NONFAILING(*(uint8_t*)0x20000003 = (uint8_t)0x3);
NONFAILING(*(uint8_t*)0x20000004 = (uint8_t)0x3);
NONFAILING(*(uint8_t*)0x20000005 = (uint8_t)0xfff);
NONFAILING(*(uint8_t*)0x20000006 = (uint8_t)0x401);
NONFAILING(*(uint8_t*)0x20000007 = (uint8_t)0xef);
NONFAILING(*(uint8_t*)0x20000008 = (uint8_t)0x9);
r[10] = execute_syscall(__NR_connect, r[1], 0x20000000ul, 0xaul, 0,
0, 0, 0, 0, 0);
break;
case 3:
NONFAILING(*(uint64_t*)0x20003000 = (uint64_t)0x20000000);
NONFAILING(*(uint32_t*)0x20003008 = (uint32_t)0x60);
NONFAILING(*(uint64_t*)0x20003010 = (uint64_t)0x20008000);
NONFAILING(*(uint64_t*)0x20003018 = (uint64_t)0x0);
NONFAILING(*(uint64_t*)0x20003020 = (uint64_t)0x20007000);
NONFAILING(*(uint64_t*)0x20003028 = (uint64_t)0x10);
NONFAILING(*(uint32_t*)0x20003030 = (uint32_t)0x5);
NONFAILING(*(uint16_t*)0x20000000 = (uint16_t)0x27);
NONFAILING(*(uint32_t*)0x20000004 = (uint32_t)0x0);
NONFAILING(*(uint32_t*)0x20000008 = (uint32_t)0x0);
NONFAILING(*(uint32_t*)0x2000000c = (uint32_t)0x0);
NONFAILING(*(uint8_t*)0x20000010 = (uint8_t)0x0);
NONFAILING(*(uint8_t*)0x20000011 = (uint8_t)0x0);
NONFAILING(memcpy((void*)0x20000012,
"\x4e\xa6\xf0\xe3\x26\x38\x41\x0f\x61\xc3\x84\x5a"
"\xd3\xe8\x12\x96\xe2\x97\x1a\x49\xc7\x07\x55\xb5"
"\x82\x0c\x91\x5b\xe8\xe3\xa2\x1e\x49\x17\x62\x02"
"\x27\x36\xcd\x99\x61\x46\xb6\xa2\x93\x9e\xee\x01"
"\xc9\xcb\xf2\xeb\x94\x9c\x90\xc2\x85\x56\x30\xea"
"\x2a\x71\xf9",
63));
NONFAILING(*(uint64_t*)0x20000058 = (uint64_t)0x0);
NONFAILING(*(uint64_t*)0x20007000 = (uint64_t)0x10);
NONFAILING(*(uint32_t*)0x20007008 = (uint32_t)0x0);
NONFAILING(*(uint32_t*)0x2000700c = (uint32_t)0x0);
r[29] = execute_syscall(__NR_sendmsg, r[1], 0x20003000ul, 0x40880ul,
0, 0, 0, 0, 0, 0);
break;
}
return 0;
}

void loop()
{
long i;
pthread_t th[8];

memset(r, -1, sizeof(r));
srand(getpid());
for (i = 0; i < 4; i++) {
pthread_create(&th[i], 0, thr, (void*)i);
usleep(10000);
}
for (i = 0; i < 4; i++) {
pthread_create(&th[4 + i], 0, thr, (void*)i);
if (rand() % 2)
usleep(rand() % 10000);
}
usleep(100000);
}

int main()
{
setup_main_process();
int pid = do_sandbox_none(0, false);
int status = 0;
while (waitpid(pid, &status, __WALL) != pid) {
}
return 0;
}

Attachment: .config
Description: Binary data

Next message: Andrey Konovalov: "Re: net/llc: bug in llc_pdu_init_as_xid_cmd/skb_over_panic"
Previous message: Nicholas Mc Guire: "[PATCH RFC] spi-nor: provide a range for poll_timout"
Next in thread: Eric Dumazet: "Re: net/llc: BUG in llc_sap_state_process/skb_set_owner_r"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]