From: Andrey Konovalov <andreyknvl@google.com>
To: Vlad Yasevich <vyasevich@gmail.com>,
Neil Horman <nhorman@tuxdriver.com>,
"David S. Miller" <davem@davemloft.net>,
linux-sctp@vger.kernel.org, netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Kostya Serebryany <kcc@google.com>,
Eric Dumazet <edumazet@google.com>,
syzkaller <syzkaller@googlegroups.com>
Subject: net/sctp: null-ptr-deref in sctp_inet_listen
Date: Mon, 7 Nov 2016 22:44:45 +0100 [thread overview]
Message-ID: <CAAeHK+yCE-e2scjs=rUwr+XHmmCcd33P--7MVFmxrTQ_AFZcOA@mail.gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1969 bytes --]
Hi,
I've got the following error report while running the syzkaller fuzzer:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 1 PID: 3851 Comm: a.out Not tainted 4.9.0-rc4+ #354
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff880065f1d800 task.stack: ffff880063840000
RIP: 0010:[<ffffffff8394151b>] [<ffffffff8394151b>]
sctp_inet_listen+0x29b/0x790 net/sctp/socket.c:6870
RSP: 0018:ffff880063847dd0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 1ffff1000c708fbd RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff880063847e70 R08: dffffc0000000000 R09: dffffc0000000000
R10: 0000000000000002 R11: 0000000000000002 R12: ffff88006b350800
R13: 0000000000000000 R14: 1ffff1000d66a1a5 R15: 0000000000000000
FS: 00007fd1f0f3d7c0(0000) GS:ffff88006cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000064af9000 CR4: 00000000000006e0
Stack:
ffff880063847de0 ffff880066165900 ffff88006b350d20 0000000041b58ab3
ffffffff847ff589 ffffffff83941280 dffffc0000000000 0000000000000000
ffff880069b9f740 0000000000000000 ffff880063847e38 ffffffff819f04ef
Call Trace:
[< inline >] SYSC_listen net/socket.c:1396
[<ffffffff82b73cf6>] SyS_listen+0x206/0x250 net/socket.c:1382
[<ffffffff83fc1501>] entry_SYSCALL_64_fastpath+0x1f/0xc2
arch/x86/entry/entry_64.S:209
Code: 00 0f 85 f4 04 00 00 4d 8b ac 24 28 05 00 00 49 b8 00 00 00 00
00 fc ff df 49 8d 7d 02 48 89 fe 49 89 fa 48 c1 ee 03 41 83 e2 07 <46>
0f b6 0c 06 41 83 c2 01 45 38 ca 7c 09 45 84 c9 0f 85 87 04
RIP [<ffffffff8394151b>] sctp_inet_listen+0x29b/0x790 net/sctp/socket.c:6870
RSP <ffff880063847dd0>
---[ end trace f2b501fc22999b37 ]---
A reproducer is attached.
On commit bc33b0ca11e3df467777a4fa7639ba488c9d4911 (Nov 5).
Thanks!
[-- Attachment #2: sctp-listen-null-poc.c --]
[-- Type: application/octet-stream, Size: 5968 bytes --]
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#ifndef __NR_syz_fuseblk_mount
#define __NR_syz_fuseblk_mount 1000005
#endif
#ifndef __NR_syz_open_dev
#define __NR_syz_open_dev 1000002
#endif
#ifndef __NR_syz_test
#define __NR_syz_test 1000001
#endif
#ifndef __NR_socket
#define __NR_socket 41
#endif
#ifndef __NR_shutdown
#define __NR_shutdown 48
#endif
#ifndef __NR_listen
#define __NR_listen 50
#endif
#ifndef __NR_syz_open_pts
#define __NR_syz_open_pts 1000003
#endif
#ifndef __NR_mmap
#define __NR_mmap 9
#endif
#ifndef __NR_setsockopt
#define __NR_setsockopt 54
#endif
#ifndef __NR_syz_fuse_mount
#define __NR_syz_fuse_mount 1000004
#endif
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
__thread int skip_segv;
__thread jmp_buf segv_env;
static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED))
_longjmp(segv_env, 1);
exit(sig);
}
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); \
}
static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
if (a0 == 0xc || a0 == 0xb) {
char buf[128];
sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block",
(uint8_t)a1, (uint8_t)a2);
return open(buf, O_RDWR, 0);
} else {
char buf[1024];
char* hash;
strncpy(buf, (char*)a0, sizeof(buf));
buf[sizeof(buf) - 1] = 0;
while ((hash = strchr(buf, '#'))) {
*hash = '0' + (char)(a1 % 10);
a1 /= 10;
}
return open(buf, a2, 0);
}
}
static uintptr_t syz_open_pts(uintptr_t a0, uintptr_t a1)
{
int ptyno = 0;
if (ioctl(a0, TIOCGPTN, &ptyno))
return -1;
char buf[128];
sprintf(buf, "/dev/pts/%d", ptyno);
return open(buf, a1, 0);
}
static uintptr_t syz_fuse_mount(uintptr_t a0, uintptr_t a1,
uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5)
{
uint64_t target = a0;
uint64_t mode = a1;
uint64_t uid = a2;
uint64_t gid = a3;
uint64_t maxread = a4;
uint64_t flags = a5;
int fd = open("/dev/fuse", O_RDWR);
if (fd == -1)
return fd;
char buf[1024];
sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
(long)uid, (long)gid, (unsigned)mode & ~3u);
if (maxread != 0)
sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
if (mode & 1)
strcat(buf, ",default_permissions");
if (mode & 2)
strcat(buf, ",allow_other");
syscall(SYS_mount, "", target, "fuse", flags, buf);
return fd;
}
static uintptr_t syz_fuseblk_mount(uintptr_t a0, uintptr_t a1,
uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5,
uintptr_t a6, uintptr_t a7)
{
uint64_t target = a0;
uint64_t blkdev = a1;
uint64_t mode = a2;
uint64_t uid = a3;
uint64_t gid = a4;
uint64_t maxread = a5;
uint64_t blksize = a6;
uint64_t flags = a7;
int fd = open("/dev/fuse", O_RDWR);
if (fd == -1)
return fd;
if (syscall(SYS_mknodat, AT_FDCWD, blkdev, S_IFBLK, makedev(7, 199)))
return fd;
char buf[256];
sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
(long)uid, (long)gid, (unsigned)mode & ~3u);
if (maxread != 0)
sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
if (blksize != 0)
sprintf(buf + strlen(buf), ",blksize=%ld", (long)blksize);
if (mode & 1)
strcat(buf, ",default_permissions");
if (mode & 2)
strcat(buf, ",allow_other");
syscall(SYS_mount, blkdev, target, "fuseblk", flags, buf);
return fd;
}
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);
case __NR_syz_test:
return 0;
case __NR_syz_open_dev:
return syz_open_dev(a0, a1, a2);
case __NR_syz_open_pts:
return syz_open_pts(a0, a1);
case __NR_syz_fuse_mount:
return syz_fuse_mount(a0, a1, a2, a3, a4, a5);
case __NR_syz_fuseblk_mount:
return syz_fuseblk_mount(a0, a1, a2, a3, a4, a5, a6, a7);
}
}
long r[6];
int main()
{
install_segv_handler();
memset(r, -1, sizeof(r));
r[0] = execute_syscall(__NR_mmap, 0x20000000ul, 0xa000ul, 0x3ul,
0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
r[1] = execute_syscall(__NR_socket, 0xaul, 0x1ul, 0x84ul, 0, 0, 0, 0,
0, 0);
NONFAILING(*(uint32_t*)0x20000000 = (uint32_t)0x7);
r[3] = execute_syscall(__NR_setsockopt, r[1], 0x1ul, 0x2ul,
0x20000000ul, 0x4ul, 0, 0, 0, 0);
r[4] =
execute_syscall(__NR_shutdown, r[1], 0x1ul, 0, 0, 0, 0, 0, 0, 0);
r[5] = execute_syscall(__NR_listen, r[1], 0x0ul, 0, 0, 0, 0, 0, 0, 0);
return 0;
}
next reply other threads:[~2016-11-07 21:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 21:44 Andrey Konovalov [this message]
2016-11-08 10:06 ` net/sctp: null-ptr-deref in sctp_inet_listen Xin Long
2016-11-08 18:46 ` Andrey Konovalov
2016-11-09 3:32 ` Xin Long
2016-11-09 19:24 ` Andrey Konovalov
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