Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-04-18 Thread Eric Biggers 
On Tue, Jan 02, 2018 at 03:58:01PM -0800, syzbot wrote:
> Hello,
> 
> syzkaller hit the following crash on
> 61233580f1f33c50e159c50e24d80ffd2ba2e06b
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
> 
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
> 
> TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
> cookies.  Check SNMP counters.
> ==
> BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 [inline]
> BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
> net/ipv6/tcp_ipv6.c:1144
> Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196
> 
> CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:53
>  print_address_description+0x73/0x250 mm/kasan/report.c:252
>  kasan_report_error mm/kasan/report.c:351 [inline]
>  kasan_report+0x25b/0x340 mm/kasan/report.c:409
>  check_memory_region_inline mm/kasan/kasan.c:260 [inline]
>  check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
>  memcpy+0x37/0x50 mm/kasan/kasan.c:303
>  memcpy include/linux/string.h:344 [inline]
>  tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144
>  tcp_get_cookie_sock+0x102/0x540 net/ipv4/syncookies.c:213
>  cookie_v6_check+0x177d/0x2160 net/ipv6/syncookies.c:255
>  tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1008 [inline]
>  tcp_v6_do_rcv+0xe4d/0x11c0 net/ipv6/tcp_ipv6.c:1316
>  tcp_v6_rcv+0x22ee/0x2b40 net/ipv6/tcp_ipv6.c:1510
>  ip6_input_finish+0x36f/0x1700 net/ipv6/ip6_input.c:284
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327
>  dst_input include/net/dst.h:466 [inline]
>  ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ipv6_rcv+0xf1f/0x1f80 net/ipv6/ip6_input.c:208
>  __netif_receive_skb_core+0x1a3e/0x3450 net/core/dev.c:4461
>  __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4526
>  process_backlog+0x203/0x740 net/core/dev.c:5205
>  napi_poll net/core/dev.c:5603 [inline]
>  net_rx_action+0x792/0x1910 net/core/dev.c:5669
>  __do_softirq+0x2d7/0xb85 kernel/softirq.c:285
>  do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1115
>  
>  do_softirq.part.21+0x14d/0x190 kernel/softirq.c:329
>  do_softirq kernel/softirq.c:177 [inline]
>  __local_bh_enable_ip+0x1ee/0x230 kernel/softirq.c:182
>  local_bh_enable include/linux/bottom_half.h:32 [inline]
>  rcu_read_unlock_bh include/linux/rcupdate.h:727 [inline]
>  ip6_finish_output2+0xba6/0x2390 net/ipv6/ip6_output.c:121
>  ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146
>  NF_HOOK_COND include/linux/netfilter.h:239 [inline]
>  ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:163
>  dst_output include/net/dst.h:460 [inline]
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ip6_xmit+0xd75/0x2080 net/ipv6/ip6_output.c:269
>  inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
>  tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176
>  tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367
>  __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543
>  tcp_send_fin+0x1b0/0xd20 net/ipv4/tcp_output.c:3087
>  tcp_close+0xbe0/0xfc0 net/ipv4/tcp.c:2234
>  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426
>  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432
>  sock_release+0x8d/0x1e0 net/socket.c:600
>  sock_close+0x16/0x20 net/socket.c:1129
>  __fput+0x327/0x7e0 fs/file_table.c:210
>  fput+0x15/0x20 fs/file_table.c:244
>  task_work_run+0x199/0x270 kernel/task_work.c:113
>  exit_task_work include/linux/task_work.h:22 [inline]
>  do_exit+0x9bb/0x1ad0 kernel/exit.c:865
>  do_group_exit+0x149/0x400 kernel/exit.c:968
>  get_signal+0x73f/0x16c0 kernel/signal.c:2335
>  do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809
>  exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
>  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
>  syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
>  entry_SYSCALL_64_fastpath+0x94/0x96
> RIP: 0033:0x4456e9
> RSP: 002b:7fb4de631da8 EFLAGS: 0246 ORIG_RAX: 00ca
> RAX: fe00 RBX: 006dac3c RCX: 004456e9
> RDX:  RSI:  RDI: 006dac3c
> RBP:  R08:  R09:

Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-01-17 Thread Wei Wang 
On Wed, Jan 3, 2018 at 3:31 PM, Cong Wang  wrote:
>
> On Wed, Jan 3, 2018 at 12:55 PM, Ozgur  wrote:
> >
> >
> > 03.01.2018, 21:57, "Cong Wang" :
> >> On Tue, Jan 2, 2018 at 3:58 PM, syzbot
> >>  wrote:
> >>>  Hello,
> >>>
> >>>  syzkaller hit the following crash on
> >>>  61233580f1f33c50e159c50e24d80ffd2ba2e06b
> >>>  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
> >>>  compiler: gcc (GCC) 7.1.1 20170620
> >>>  .config is attached
> >>>  Raw console output is attached.
> >>>  C reproducer is attached
> >>>  syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> >>>  for information about syzkaller reproducers
> >>>
> >>>  IMPORTANT: if you fix the bug, please add the following tag to the 
> >>> commit:
> >>>  Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
> >>>  It will help syzbot understand when the bug is fixed. See footer for
> >>>  details.
> >>>  If you forward the report, please keep this part and the footer.
> >>>
> >>>  TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
> >>>  cookies. Check SNMP counters.
> >>>  ==
> >>>  BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 
> >>> [inline]
> >>>  BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
> >>>  net/ipv6/tcp_ipv6.c:1144
> >>>  Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196
> >>>
> >>>  CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
> >>>  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>>  Google 01/01/2011
> >>>  Call Trace:
> >>>   
> >>>   __dump_stack lib/dump_stack.c:17 [inline]
> >>>   dump_stack+0x194/0x257 lib/dump_stack.c:53
> >>>   print_address_description+0x73/0x250 mm/kasan/report.c:252
> >>>   kasan_report_error mm/kasan/report.c:351 [inline]
> >>>   kasan_report+0x25b/0x340 mm/kasan/report.c:409
> >>>   check_memory_region_inline mm/kasan/kasan.c:260 [inline]
> >>>   check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
> >>>   memcpy+0x37/0x50 mm/kasan/kasan.c:303
> >>>   memcpy include/linux/string.h:344 [inline]
> >>>   tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144
> >>
> >> tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads
> >> to this bug. I guess IPv6 is not supported for TLS? If so, need
> >> a check on proto in tls_init()...
> >
> > Hello,
> >
> > I think IPv6 supports with TLS.
> > There was a previously posted commit by Mellanox:
> >
> > https://patchwork.ozlabs.org/patch/801530/
>
> Good to know.
>
> Can you resend the fix? It could probably fix another warning
> reported by syzbot too.

What is the status on resending the patch?
(https://patchwork.ozlabs.org/patch/801530/)
Another slab-out-of-bound report that could be fixed by it:

syzbot has found reproducer for the following crash on
6bd39bc3da0f4a301fae69c4a32db2768f5118be
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master
compiler: gcc (GCC) 7.1.1 20170620

==
BUG: KASAN: slab-out-of-bounds in ip6_dst_idev
include/net/ip6_fib.h:192 [inline]
BUG: KASAN: slab-out-of-bounds in ip6_xmit+0x1ce9/0x2090
net/ipv6/ip6_output.c:264
Read of size 8 at addr 8801d99a1018 by task syzkaller716686/3664

CPU: 0 PID: 3664 Comm: syzkaller716686 Not tainted 4.15.0-rc7+ #187
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 ip6_dst_idev include/net/ip6_fib.h:192 [inline]
 ip6_xmit+0x1ce9/0x2090 net/ipv6/ip6_output.c:264
 inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
 tcp_transmit_skb+0x1b1b/0x38c0 net/ipv4/tcp_output.c:1176
 tcp_send_syn_data net/ipv4/tcp_output.c:3457 [inline]
 tcp_connect+0x1edb/0x4090 net/ipv4/tcp_output.c:3496
 tcp_v4_connect+0x15ef/0x1e70 net/ipv4/tcp_ipv4.c:257
 __inet_stream_connect+0x2d4/0xf00 net/ipv4/af_inet.c:620
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1168 [inline]
 tcp_sendmsg_locked+0x264e/0x3c70 net/ipv4/tcp.c:1214
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1463
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x320/0x8b0 net/socket.c:2020
 __sys_sendmmsg+0x1ee/0x620 net/socket.c:2110
 SYSC_sendmmsg net/socket.c:2141 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2136
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x43fdd9
RSP: 002b:7ffcaf235288 EFLAGS: 0217 ORIG_RAX: 0133
RAX:

Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-01-15 Thread Dmitry Vyukov 
On Thu, Jan 4, 2018 at 12:31 AM, Cong Wang  wrote:
> On Wed, Jan 3, 2018 at 12:55 PM, Ozgur  wrote:
>>
>>
>> 03.01.2018, 21:57, "Cong Wang" :
>>> On Tue, Jan 2, 2018 at 3:58 PM, syzbot
>>>  wrote:
  Hello,

  syzkaller hit the following crash on
  61233580f1f33c50e159c50e24d80ffd2ba2e06b
  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
  compiler: gcc (GCC) 7.1.1 20170620
  .config is attached
  Raw console output is attached.
  C reproducer is attached
  syzkaller reproducer is attached. See https://goo.gl/kgGztJ
  for information about syzkaller reproducers

  IMPORTANT: if you fix the bug, please add the following tag to the commit:
  Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
  It will help syzbot understand when the bug is fixed. See footer for
  details.
  If you forward the report, please keep this part and the footer.

  TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
  cookies. Check SNMP counters.
  ==
  BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 
 [inline]
  BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
  net/ipv6/tcp_ipv6.c:1144
  Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196

  CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
  Google 01/01/2011
  Call Trace:
   
   __dump_stack lib/dump_stack.c:17 [inline]
   dump_stack+0x194/0x257 lib/dump_stack.c:53
   print_address_description+0x73/0x250 mm/kasan/report.c:252
   kasan_report_error mm/kasan/report.c:351 [inline]
   kasan_report+0x25b/0x340 mm/kasan/report.c:409
   check_memory_region_inline mm/kasan/kasan.c:260 [inline]
   check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
   memcpy+0x37/0x50 mm/kasan/kasan.c:303
   memcpy include/linux/string.h:344 [inline]
   tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144
>>>
>>> tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads
>>> to this bug. I guess IPv6 is not supported for TLS? If so, need
>>> a check on proto in tls_init()...
>>
>> Hello,
>>
>> I think IPv6 supports with TLS.
>> There was a previously posted commit by Mellanox:
>>
>> https://patchwork.ozlabs.org/patch/801530/
>
> Good to know.
>
> Can you resend the fix? It could probably fix another warning
> reported by syzbot too.

FTR this has been assigned CVE-2018-5703

Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-01-03 Thread Cong Wang 
On Wed, Jan 3, 2018 at 12:55 PM, Ozgur  wrote:
>
>
> 03.01.2018, 21:57, "Cong Wang" :
>> On Tue, Jan 2, 2018 at 3:58 PM, syzbot
>>  wrote:
>>>  Hello,
>>>
>>>  syzkaller hit the following crash on
>>>  61233580f1f33c50e159c50e24d80ffd2ba2e06b
>>>  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
>>>  compiler: gcc (GCC) 7.1.1 20170620
>>>  .config is attached
>>>  Raw console output is attached.
>>>  C reproducer is attached
>>>  syzkaller reproducer is attached. See https://goo.gl/kgGztJ
>>>  for information about syzkaller reproducers
>>>
>>>  IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>>  Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
>>>  It will help syzbot understand when the bug is fixed. See footer for
>>>  details.
>>>  If you forward the report, please keep this part and the footer.
>>>
>>>  TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
>>>  cookies. Check SNMP counters.
>>>  ==
>>>  BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 
>>> [inline]
>>>  BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
>>>  net/ipv6/tcp_ipv6.c:1144
>>>  Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196
>>>
>>>  CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
>>>  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>>  Google 01/01/2011
>>>  Call Trace:
>>>   
>>>   __dump_stack lib/dump_stack.c:17 [inline]
>>>   dump_stack+0x194/0x257 lib/dump_stack.c:53
>>>   print_address_description+0x73/0x250 mm/kasan/report.c:252
>>>   kasan_report_error mm/kasan/report.c:351 [inline]
>>>   kasan_report+0x25b/0x340 mm/kasan/report.c:409
>>>   check_memory_region_inline mm/kasan/kasan.c:260 [inline]
>>>   check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
>>>   memcpy+0x37/0x50 mm/kasan/kasan.c:303
>>>   memcpy include/linux/string.h:344 [inline]
>>>   tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144
>>
>> tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads
>> to this bug. I guess IPv6 is not supported for TLS? If so, need
>> a check on proto in tls_init()...
>
> Hello,
>
> I think IPv6 supports with TLS.
> There was a previously posted commit by Mellanox:
>
> https://patchwork.ozlabs.org/patch/801530/

Good to know.

Can you resend the fix? It could probably fix another warning
reported by syzbot too.

Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-01-03 Thread Ozgur 


03.01.2018, 21:57, "Cong Wang" :
> On Tue, Jan 2, 2018 at 3:58 PM, syzbot
>  wrote:
>>  Hello,
>>
>>  syzkaller hit the following crash on
>>  61233580f1f33c50e159c50e24d80ffd2ba2e06b
>>  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
>>  compiler: gcc (GCC) 7.1.1 20170620
>>  .config is attached
>>  Raw console output is attached.
>>  C reproducer is attached
>>  syzkaller reproducer is attached. See https://goo.gl/kgGztJ
>>  for information about syzkaller reproducers
>>
>>  IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>  Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
>>  It will help syzbot understand when the bug is fixed. See footer for
>>  details.
>>  If you forward the report, please keep this part and the footer.
>>
>>  TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
>>  cookies. Check SNMP counters.
>>  ==
>>  BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 [inline]
>>  BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
>>  net/ipv6/tcp_ipv6.c:1144
>>  Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196
>>
>>  CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
>>  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>  Google 01/01/2011
>>  Call Trace:
>>   
>>   __dump_stack lib/dump_stack.c:17 [inline]
>>   dump_stack+0x194/0x257 lib/dump_stack.c:53
>>   print_address_description+0x73/0x250 mm/kasan/report.c:252
>>   kasan_report_error mm/kasan/report.c:351 [inline]
>>   kasan_report+0x25b/0x340 mm/kasan/report.c:409
>>   check_memory_region_inline mm/kasan/kasan.c:260 [inline]
>>   check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
>>   memcpy+0x37/0x50 mm/kasan/kasan.c:303
>>   memcpy include/linux/string.h:344 [inline]
>>   tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144
>
> tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads
> to this bug. I guess IPv6 is not supported for TLS? If so, need
> a check on proto in tls_init()...

Hello,

I think IPv6 supports with TLS.
There was a previously posted commit by Mellanox:

https://patchwork.ozlabs.org/patch/801530/

Ozgur

>>   tcp_get_cookie_sock+0x102/0x540 net/ipv4/syncookies.c:213
>>   cookie_v6_check+0x177d/0x2160 net/ipv6/syncookies.c:255
>>   tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1008 [inline]
>>   tcp_v6_do_rcv+0xe4d/0x11c0 net/ipv6/tcp_ipv6.c:1316
>>   tcp_v6_rcv+0x22ee/0x2b40 net/ipv6/tcp_ipv6.c:1510
>>   ip6_input_finish+0x36f/0x1700 net/ipv6/ip6_input.c:284
>>   NF_HOOK include/linux/netfilter.h:250 [inline]
>>   ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327
>>   dst_input include/net/dst.h:466 [inline]
>>   ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71
>>   NF_HOOK include/linux/netfilter.h:250 [inline]
>>   ipv6_rcv+0xf1f/0x1f80 net/ipv6/ip6_input.c:208
>>   __netif_receive_skb_core+0x1a3e/0x3450 net/core/dev.c:4461
>>   __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4526
>>   process_backlog+0x203/0x740 net/core/dev.c:5205
>>   napi_poll net/core/dev.c:5603 [inline]
>>   net_rx_action+0x792/0x1910 net/core/dev.c:5669
>>   __do_softirq+0x2d7/0xb85 kernel/softirq.c:285
>>   do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1115
>>   
>>   do_softirq.part.21+0x14d/0x190 kernel/softirq.c:329
>>   do_softirq kernel/softirq.c:177 [inline]
>>   __local_bh_enable_ip+0x1ee/0x230 kernel/softirq.c:182
>>   local_bh_enable include/linux/bottom_half.h:32 [inline]
>>   rcu_read_unlock_bh include/linux/rcupdate.h:727 [inline]
>>   ip6_finish_output2+0xba6/0x2390 net/ipv6/ip6_output.c:121
>>   ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146
>>   NF_HOOK_COND include/linux/netfilter.h:239 [inline]
>>   ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:163
>>   dst_output include/net/dst.h:460 [inline]
>>   NF_HOOK include/linux/netfilter.h:250 [inline]
>>   ip6_xmit+0xd75/0x2080 net/ipv6/ip6_output.c:269
>>   inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
>>   tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176
>>   tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367
>>   __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543
>>   tcp_send_fin+0x1b0/0xd20 net/ipv4/tcp_output.c:3087
>>   tcp_close+0xbe0/0xfc0 net/ipv4/tcp.c:2234
>>   inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426
>>   inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432
>>   sock_release+0x8d/0x1e0 net/socket.c:600
>>   sock_close+0x16/0x20 net/socket.c:1129
>>   __fput+0x327/0x7e0 fs/file_table.c:210
>>   fput+0x15/0x20 fs/file_table.c:244
>>   task_work_run+0x199/0x270 kernel/task_work.c:113
>>   exit_task_work include/linux/task_work.h:22 [inline]
>>   do_exit+0x9bb/0x1ad0 kernel/exit.c:865
>>   do_group_exit+0x149/0x400 kernel/exit.c:968
>>   get_signal+0x73f/0x16c0

Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock

2018-01-03 Thread Cong Wang 
On Tue, Jan 2, 2018 at 3:58 PM, syzbot
 wrote:
> Hello,
>
> syzkaller hit the following crash on
> 61233580f1f33c50e159c50e24d80ffd2ba2e06b
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
>
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6dc95bddc6976b800...@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
> TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
> cookies.  Check SNMP counters.
> ==
> BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 [inline]
> BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0
> net/ipv6/tcp_ipv6.c:1144
> Write of size 160 at addr 8801cbdd7460 by task syzkaller545407/3196
>
> CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:53
>  print_address_description+0x73/0x250 mm/kasan/report.c:252
>  kasan_report_error mm/kasan/report.c:351 [inline]
>  kasan_report+0x25b/0x340 mm/kasan/report.c:409
>  check_memory_region_inline mm/kasan/kasan.c:260 [inline]
>  check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
>  memcpy+0x37/0x50 mm/kasan/kasan.c:303
>  memcpy include/linux/string.h:344 [inline]
>  tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144


tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads
to this bug. I guess IPv6 is not supported for TLS? If so, need
a check on proto in tls_init()...




>  tcp_get_cookie_sock+0x102/0x540 net/ipv4/syncookies.c:213
>  cookie_v6_check+0x177d/0x2160 net/ipv6/syncookies.c:255
>  tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1008 [inline]
>  tcp_v6_do_rcv+0xe4d/0x11c0 net/ipv6/tcp_ipv6.c:1316
>  tcp_v6_rcv+0x22ee/0x2b40 net/ipv6/tcp_ipv6.c:1510
>  ip6_input_finish+0x36f/0x1700 net/ipv6/ip6_input.c:284
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327
>  dst_input include/net/dst.h:466 [inline]
>  ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ipv6_rcv+0xf1f/0x1f80 net/ipv6/ip6_input.c:208
>  __netif_receive_skb_core+0x1a3e/0x3450 net/core/dev.c:4461
>  __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4526
>  process_backlog+0x203/0x740 net/core/dev.c:5205
>  napi_poll net/core/dev.c:5603 [inline]
>  net_rx_action+0x792/0x1910 net/core/dev.c:5669
>  __do_softirq+0x2d7/0xb85 kernel/softirq.c:285
>  do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1115
>  
>  do_softirq.part.21+0x14d/0x190 kernel/softirq.c:329
>  do_softirq kernel/softirq.c:177 [inline]
>  __local_bh_enable_ip+0x1ee/0x230 kernel/softirq.c:182
>  local_bh_enable include/linux/bottom_half.h:32 [inline]
>  rcu_read_unlock_bh include/linux/rcupdate.h:727 [inline]
>  ip6_finish_output2+0xba6/0x2390 net/ipv6/ip6_output.c:121
>  ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146
>  NF_HOOK_COND include/linux/netfilter.h:239 [inline]
>  ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:163
>  dst_output include/net/dst.h:460 [inline]
>  NF_HOOK include/linux/netfilter.h:250 [inline]
>  ip6_xmit+0xd75/0x2080 net/ipv6/ip6_output.c:269
>  inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
>  tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176
>  tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367
>  __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543
>  tcp_send_fin+0x1b0/0xd20 net/ipv4/tcp_output.c:3087
>  tcp_close+0xbe0/0xfc0 net/ipv4/tcp.c:2234
>  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426
>  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432
>  sock_release+0x8d/0x1e0 net/socket.c:600
>  sock_close+0x16/0x20 net/socket.c:1129
>  __fput+0x327/0x7e0 fs/file_table.c:210
>  fput+0x15/0x20 fs/file_table.c:244
>  task_work_run+0x199/0x270 kernel/task_work.c:113
>  exit_task_work include/linux/task_work.h:22 [inline]
>  do_exit+0x9bb/0x1ad0 kernel/exit.c:865
>  do_group_exit+0x149/0x400 kernel/exit.c:968
>  get_signal+0x73f/0x16c0 kernel/signal.c:2335
>  do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809
>  exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
>  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
>  syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
>  entry_SYSCALL_64_fastpath+0x94/0x96
> RIP: 0033:0x4456e9
> RSP: 002b:7fb4de631da8 EFLAGS: 0246 ORIG_RAX: