From: Cong Wang <xiyou.wangcong@gmail.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Patrick McHardy <kaber@trash.net>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>,
Eric Dumazet <edumazet@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>
Subject: Re: net/ipv6: use-after-free in ipv6_sock_ac_close
Date: Mon, 10 Apr 2017 16:11:34 -0700 [thread overview]
Message-ID: <CAM_iQpVV8srXTTSAR=YoKTmWkJc9Ai-ggZLPOfdpSFKJWEysNA@mail.gmail.com> (raw)
In-Reply-To: <CAAeHK+y_7fyLyJnmUKOruWrw3_8a1V1S4htBTa_Psza=VvQdTg@mail.gmail.com>
On Mon, Apr 10, 2017 at 7:28 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
> Hi,
>
> I've got the following error report while fuzzing the kernel with syzkaller.
>
> On commit 39da7c509acff13fc8cb12ec1bb20337c988ed36 (4.11-rc6).
>
> Unfortunately it's not reproducible.
>
> ==================================================================
> BUG: KASAN: use-after-free in ipv6_sock_ac_close+0x3d6/0x3f0
> net/ipv6/anycast.c:190 at addr ffff88005d6ce020
> Read of size 8 by task syz-executor6/18308
> CPU: 0 PID: 18308 Comm: syz-executor6 Not tainted 4.11.0-rc6+ #206
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:16 [inline]
> dump_stack+0x292/0x398 lib/dump_stack.c:52
> kasan_object_err+0x1c/0x70 mm/kasan/report.c:164
> print_address_description mm/kasan/report.c:202 [inline]
> kasan_report_error mm/kasan/report.c:291 [inline]
> kasan_report+0x252/0x510 mm/kasan/report.c:347
> __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:368
> ipv6_sock_ac_close+0x3d6/0x3f0 net/ipv6/anycast.c:190
> inet6_release+0x48/0x70 net/ipv6/af_inet6.c:430
> sock_release+0x8d/0x1e0 net/socket.c:597
> sock_close+0x16/0x20 net/socket.c:1072
> __fput+0x332/0x7f0 fs/file_table.c:209
> ____fput+0x15/0x20 fs/file_table.c:245
> task_work_run+0x19b/0x270 kernel/task_work.c:116
> exit_task_work include/linux/task_work.h:21 [inline]
> do_exit+0x18b6/0x2830 kernel/exit.c:878
> do_group_exit+0x149/0x420 kernel/exit.c:982
> get_signal+0x76d/0x17e0 kernel/signal.c:2318
> do_signal+0xd2/0x2190 arch/x86/kernel/signal.c:808
> exit_to_usermode_loop+0x170/0x200 arch/x86/entry/common.c:157
> prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
> syscall_return_slowpath+0x3d3/0x420 arch/x86/entry/common.c:260
> entry_SYSCALL_64_fastpath+0xc0/0xc2
I don't see how this is possible except when we have a loop in the
singly linked list np->ipv6_ac_list, it is protected by RTNL lock anyway.
The insertion and removal code looks correct too. But I may miss
something too obvious...
Thanks!
> RIP: 0033:0x4458d9
> RSP: 002b:00007f59304e1cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
> RAX: 0000000000000000 RBX: 0000000000708218 RCX: 00000000004458d9
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000708218
> RBP: 00000000007081f8 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f59304e29c0 R15: 00007f59304e2700
> Object at ffff88005d6ce008, in cache kmalloc-32 size: 32
> Allocated:
> PID = 18270
> save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
> save_stack+0x43/0xd0 mm/kasan/kasan.c:513
> set_track mm/kasan/kasan.c:525 [inline]
> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616
> __kmalloc+0xa0/0x2d0 mm/slub.c:3745
> kmalloc include/linux/slab.h:495 [inline]
> sock_kmalloc+0x11e/0x1b0 net/core/sock.c:1804
> ipv6_sock_ac_join+0x21f/0x7b0 net/ipv6/anycast.c:72
> do_ipv6_setsockopt.isra.7+0x2a77/0x3bc0 net/ipv6/ipv6_sockglue.c:655
> ipv6_setsockopt+0x9b/0x140 net/ipv6/ipv6_sockglue.c:919
> sctp_setsockopt+0x2b4/0x5f10 net/sctp/socket.c:3909
> sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2750
> SYSC_setsockopt net/socket.c:1798 [inline]
> SyS_setsockopt+0x270/0x3a0 net/socket.c:1777
> entry_SYSCALL_64_fastpath+0x1f/0xc2
> Freed:
> PID = 18308
> save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
> save_stack+0x43/0xd0 mm/kasan/kasan.c:513
> set_track mm/kasan/kasan.c:525 [inline]
> kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:589
> slab_free_hook mm/slub.c:1357 [inline]
> slab_free_freelist_hook mm/slub.c:1379 [inline]
> slab_free mm/slub.c:2961 [inline]
> kfree+0xe8/0x2b0 mm/slub.c:3882
> __sock_kfree_s net/core/sock.c:1825 [inline]
> sock_kfree_s+0x29/0x70 net/core/sock.c:1831
> ipv6_sock_ac_close+0x2d0/0x3f0 net/ipv6/anycast.c:198
> inet6_release+0x48/0x70 net/ipv6/af_inet6.c:430
> sock_release+0x8d/0x1e0 net/socket.c:597
> sock_close+0x16/0x20 net/socket.c:1072
> __fput+0x332/0x7f0 fs/file_table.c:209
> ____fput+0x15/0x20 fs/file_table.c:245
> task_work_run+0x19b/0x270 kernel/task_work.c:116
> exit_task_work include/linux/task_work.h:21 [inline]
> do_exit+0x18b6/0x2830 kernel/exit.c:878
> do_group_exit+0x149/0x420 kernel/exit.c:982
> get_signal+0x76d/0x17e0 kernel/signal.c:2318
> do_signal+0xd2/0x2190 arch/x86/kernel/signal.c:808
> exit_to_usermode_loop+0x170/0x200 arch/x86/entry/common.c:157
> prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
> syscall_return_slowpath+0x3d3/0x420 arch/x86/entry/common.c:260
> entry_SYSCALL_64_fastpath+0xc0/0xc2
> Memory state around the buggy address:
> ffff88005d6cdf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88005d6cdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>ffff88005d6ce000: fc fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
> ^
> ffff88005d6ce080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88005d6ce100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
> Disabling lock debugging due to kernel taint
prev parent reply other threads:[~2017-04-10 23:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-10 14:28 net/ipv6: use-after-free in ipv6_sock_ac_close Andrey Konovalov
2017-04-10 23:11 ` Cong Wang [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAM_iQpVV8srXTTSAR=YoKTmWkJc9Ai-ggZLPOfdpSFKJWEysNA@mail.gmail.com' \
--to=xiyou.wangcong@gmail.com \
--cc=andreyknvl@google.com \
--cc=davem@davemloft.net \
--cc=dvyukov@google.com \
--cc=edumazet@google.com \
--cc=jmorris@namei.org \
--cc=kaber@trash.net \
--cc=kcc@google.com \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=syzkaller@googlegroups.com \
--cc=yoshfuji@linux-ipv6.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).