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net/ipv6: use-after-free in sock_wfree

Started byAndrey Konovalov <andreyknvl@google.com>
First post2017-01-09 18:10 +0100
Last post2017-01-09 20:10 +0100
Articles 6 — 2 participants

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Contents

  net/ipv6: use-after-free in sock_wfree Andrey Konovalov <andreyknvl@google.com> - 2017-01-09 18:10 +0100
    Re: net/ipv6: use-after-free in sock_wfree Andrey Konovalov <andreyknvl@google.com> - 2017-01-09 18:20 +0100
      Re: net/ipv6: use-after-free in sock_wfree Eric Dumazet <edumazet@google.com> - 2017-01-09 18:30 +0100
        Re: net/ipv6: use-after-free in sock_wfree Eric Dumazet <edumazet@google.com> - 2017-01-09 20:10 +0100
          Re: net/ipv6: use-after-free in sock_wfree Andrey Konovalov <andreyknvl@google.com> - 2017-01-10 13:00 +0100
        Re: net/ipv6: use-after-free in sock_wfree Andrey Konovalov <andreyknvl@google.com> - 2017-01-09 20:10 +0100

#1554505 — net/ipv6: use-after-free in sock_wfree

FromAndrey Konovalov <andreyknvl@google.com>
Date2017-01-09 18:10 +0100
Subjectnet/ipv6: use-after-free in sock_wfree
Message-ID<sXLCi-6V3-31@gated-at.bofh.it>

[Multipart message — attachments visible in raw view] — view raw

Hi!

I've got the following error report while running the syzkaller fuzzer.

On commit a121103c922847ba5010819a3f250f1f7fc84ab8 (4.10-rc3).

A reproducer is attached.

==================================================================
BUG: KASAN: use-after-free in sock_wfree+0x118/0x120
Read of size 8 at addr ffff880062da0060 by task a.out/4140

page:ffffea00018b6800 count:1 mapcount:0 mapping:          (null)
index:0x0 compound_mapcount: 0
flags: 0x100000000008100(slab|head)
raw: 0100000000008100 0000000000000000 0000000000000000 0000000180130013
raw: dead000000000100 dead000000000200 ffff88006741f140 0000000000000000
page dumped because: kasan: bad access detected

CPU: 0 PID: 4140 Comm: a.out Not tainted 4.10.0-rc3+ #59
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:15
 dump_stack+0x292/0x398 lib/dump_stack.c:51
 describe_address mm/kasan/report.c:262
 kasan_report_error+0x121/0x560 mm/kasan/report.c:370
 kasan_report mm/kasan/report.c:392
 __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:413
 sock_flag ./arch/x86/include/asm/bitops.h:324
 sock_wfree+0x118/0x120 net/core/sock.c:1631
 skb_release_head_state+0xfc/0x250 net/core/skbuff.c:655
 skb_release_all+0x15/0x60 net/core/skbuff.c:668
 __kfree_skb+0x15/0x20 net/core/skbuff.c:684
 kfree_skb+0x16e/0x4e0 net/core/skbuff.c:705
 inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
 inet_frag_put ./include/net/inet_frag.h:133
 nf_ct_frag6_gather+0x1125/0x38b0 net/ipv6/netfilter/nf_conntrack_reasm.c:617
 ipv6_defrag+0x21b/0x350 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
 nf_hook_entry_hookfn ./include/linux/netfilter.h:102
 nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
 nf_hook ./include/linux/netfilter.h:212
 __ip6_local_out+0x52c/0xaf0 net/ipv6/output_core.c:160
 ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
 rawv6_push_pending_frames net/ipv6/raw.c:613
 rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
 sock_sendmsg_nosec net/socket.c:635
 sock_sendmsg+0xca/0x110 net/socket.c:645
 sock_write_iter+0x326/0x620 net/socket.c:848
 new_sync_write fs/read_write.c:499
 __vfs_write+0x483/0x760 fs/read_write.c:512
 vfs_write+0x187/0x530 fs/read_write.c:560
 SYSC_write fs/read_write.c:607
 SyS_write+0xfb/0x230 fs/read_write.c:599
 entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
RIP: 0033:0x7ff26e6f5b79
RSP: 002b:00007ff268e0ed98 EFLAGS: 00000206 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff268e0f9c0 RCX: 00007ff26e6f5b79
RDX: 0000000000000010 RSI: 0000000020f50fe1 RDI: 0000000000000003
RBP: 00007ff26ebc1220 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ff268e0f9c0 R14: 00007ff26efec040 R15: 0000000000000003

The buggy address belongs to the object at ffff880062da0000
 which belongs to the cache RAWv6 of size 1504
The buggy address ffff880062da0060 is located 96 bytes inside
 of 1504-byte region [ffff880062da0000, ffff880062da05e0)

Freed by task 4113:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:502
 set_track mm/kasan/kasan.c:514
 kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578
 slab_free_hook mm/slub.c:1352
 slab_free_freelist_hook mm/slub.c:1374
 slab_free mm/slub.c:2951
 kmem_cache_free+0xb2/0x2c0 mm/slub.c:2973
 sk_prot_free net/core/sock.c:1377
 __sk_destruct+0x49c/0x6e0 net/core/sock.c:1452
 sk_destruct+0x47/0x80 net/core/sock.c:1460
 __sk_free+0x57/0x230 net/core/sock.c:1468
 sk_free+0x23/0x30 net/core/sock.c:1479
 sock_put ./include/net/sock.h:1638
 sk_common_release+0x31e/0x4e0 net/core/sock.c:2782
 rawv6_close+0x54/0x80 net/ipv6/raw.c:1214
 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:431
 sock_release+0x8d/0x1e0 net/socket.c:599
 sock_close+0x16/0x20 net/socket.c:1063
 __fput+0x332/0x7f0 fs/file_table.c:208
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x19b/0x270 kernel/task_work.c:116
 exit_task_work ./include/linux/task_work.h:21
 do_exit+0x186b/0x2800 kernel/exit.c:839
 do_group_exit+0x149/0x420 kernel/exit.c:943
 SYSC_exit_group kernel/exit.c:954
 SyS_exit_group+0x1d/0x20 kernel/exit.c:952
 entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203

Allocated by task 4115:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:502
 set_track mm/kasan/kasan.c:514
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
 slab_post_alloc_hook mm/slab.h:432
 slab_alloc_node mm/slub.c:2708
 slab_alloc mm/slub.c:2716
 kmem_cache_alloc+0x1af/0x250 mm/slub.c:2721
 sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1334
 sk_alloc+0x105/0x1010 net/core/sock.c:1396
 inet6_create+0x44d/0x1150 net/ipv6/af_inet6.c:183
 __sock_create+0x4f6/0x880 net/socket.c:1199
 sock_create net/socket.c:1239
 SYSC_socket net/socket.c:1269
 SyS_socket+0xf9/0x230 net/socket.c:1249
 entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203

Memory state around the buggy address:
 ffff880062d9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff880062d9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff880062da0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff880062da0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880062da0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

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#1554518

FromAndrey Konovalov <andreyknvl@google.com>
Date2017-01-09 18:20 +0100
Message-ID<sXLLY-6Yo-11@gated-at.bofh.it>
In reply to#1554505
On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
> Hi!
>
> I've got the following error report while running the syzkaller fuzzer.
>
> On commit a121103c922847ba5010819a3f250f1f7fc84ab8 (4.10-rc3).
>
> A reproducer is attached.
>
> ==================================================================
> BUG: KASAN: use-after-free in sock_wfree+0x118/0x120
> Read of size 8 at addr ffff880062da0060 by task a.out/4140
>
> page:ffffea00018b6800 count:1 mapcount:0 mapping:          (null)
> index:0x0 compound_mapcount: 0
> flags: 0x100000000008100(slab|head)
> raw: 0100000000008100 0000000000000000 0000000000000000 0000000180130013
> raw: dead000000000100 dead000000000200 ffff88006741f140 0000000000000000
> page dumped because: kasan: bad access detected
>
> CPU: 0 PID: 4140 Comm: a.out Not tainted 4.10.0-rc3+ #59
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:15
>  dump_stack+0x292/0x398 lib/dump_stack.c:51
>  describe_address mm/kasan/report.c:262
>  kasan_report_error+0x121/0x560 mm/kasan/report.c:370
>  kasan_report mm/kasan/report.c:392
>  __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:413
>  sock_flag ./arch/x86/include/asm/bitops.h:324
>  sock_wfree+0x118/0x120 net/core/sock.c:1631
>  skb_release_head_state+0xfc/0x250 net/core/skbuff.c:655
>  skb_release_all+0x15/0x60 net/core/skbuff.c:668
>  __kfree_skb+0x15/0x20 net/core/skbuff.c:684
>  kfree_skb+0x16e/0x4e0 net/core/skbuff.c:705
>  inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
>  inet_frag_put ./include/net/inet_frag.h:133
>  nf_ct_frag6_gather+0x1125/0x38b0 net/ipv6/netfilter/nf_conntrack_reasm.c:617
>  ipv6_defrag+0x21b/0x350 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
>  nf_hook_entry_hookfn ./include/linux/netfilter.h:102
>  nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
>  nf_hook ./include/linux/netfilter.h:212
>  __ip6_local_out+0x52c/0xaf0 net/ipv6/output_core.c:160
>  ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
>  ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
>  ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
>  rawv6_push_pending_frames net/ipv6/raw.c:613
>  rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927
>  inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
>  sock_sendmsg_nosec net/socket.c:635
>  sock_sendmsg+0xca/0x110 net/socket.c:645
>  sock_write_iter+0x326/0x620 net/socket.c:848
>  new_sync_write fs/read_write.c:499
>  __vfs_write+0x483/0x760 fs/read_write.c:512
>  vfs_write+0x187/0x530 fs/read_write.c:560
>  SYSC_write fs/read_write.c:607
>  SyS_write+0xfb/0x230 fs/read_write.c:599
>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
> RIP: 0033:0x7ff26e6f5b79
> RSP: 002b:00007ff268e0ed98 EFLAGS: 00000206 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 00007ff268e0f9c0 RCX: 00007ff26e6f5b79
> RDX: 0000000000000010 RSI: 0000000020f50fe1 RDI: 0000000000000003
> RBP: 00007ff26ebc1220 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
> R13: 00007ff268e0f9c0 R14: 00007ff26efec040 R15: 0000000000000003
>
> The buggy address belongs to the object at ffff880062da0000
>  which belongs to the cache RAWv6 of size 1504
> The buggy address ffff880062da0060 is located 96 bytes inside
>  of 1504-byte region [ffff880062da0000, ffff880062da05e0)
>
> Freed by task 4113:
>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>  set_track mm/kasan/kasan.c:514
>  kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578
>  slab_free_hook mm/slub.c:1352
>  slab_free_freelist_hook mm/slub.c:1374
>  slab_free mm/slub.c:2951
>  kmem_cache_free+0xb2/0x2c0 mm/slub.c:2973
>  sk_prot_free net/core/sock.c:1377
>  __sk_destruct+0x49c/0x6e0 net/core/sock.c:1452
>  sk_destruct+0x47/0x80 net/core/sock.c:1460
>  __sk_free+0x57/0x230 net/core/sock.c:1468
>  sk_free+0x23/0x30 net/core/sock.c:1479
>  sock_put ./include/net/sock.h:1638
>  sk_common_release+0x31e/0x4e0 net/core/sock.c:2782
>  rawv6_close+0x54/0x80 net/ipv6/raw.c:1214
>  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
>  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:431
>  sock_release+0x8d/0x1e0 net/socket.c:599
>  sock_close+0x16/0x20 net/socket.c:1063
>  __fput+0x332/0x7f0 fs/file_table.c:208
>  ____fput+0x15/0x20 fs/file_table.c:244
>  task_work_run+0x19b/0x270 kernel/task_work.c:116
>  exit_task_work ./include/linux/task_work.h:21
>  do_exit+0x186b/0x2800 kernel/exit.c:839
>  do_group_exit+0x149/0x420 kernel/exit.c:943
>  SYSC_exit_group kernel/exit.c:954
>  SyS_exit_group+0x1d/0x20 kernel/exit.c:952
>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>
> Allocated by task 4115:
>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>  set_track mm/kasan/kasan.c:514
>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605
>  kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
>  slab_post_alloc_hook mm/slab.h:432
>  slab_alloc_node mm/slub.c:2708
>  slab_alloc mm/slub.c:2716
>  kmem_cache_alloc+0x1af/0x250 mm/slub.c:2721
>  sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1334
>  sk_alloc+0x105/0x1010 net/core/sock.c:1396
>  inet6_create+0x44d/0x1150 net/ipv6/af_inet6.c:183
>  __sock_create+0x4f6/0x880 net/socket.c:1199
>  sock_create net/socket.c:1239
>  SYSC_socket net/socket.c:1269
>  SyS_socket+0xf9/0x230 net/socket.c:1249
>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>
> Memory state around the buggy address:
>  ffff880062d9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff880062d9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>ffff880062da0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                        ^
>  ffff880062da0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff880062da0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================

Sometimes this reproducer leads to another report:

INFO: rcu_sched self-detected stall on CPU
1-...: (1 GPs behind) idle=ead/140000000000001/0 softirq=8122/8123 fqs=6497
(t=26000 jiffies g=3021 c=3020 q=345)
Task dump for CPU 1:
syz-executor    R  running task    18904  3943   3941 0x0000000c
Call Trace:
 <IRQ>
 sched_show_task+0x3fa/0x560 kernel/sched/core.c:5217
 dump_cpu_task+0x71/0x90 kernel/sched/core.c:8822
 rcu_dump_cpu_stacks+0x318/0x35e kernel/rcu/tree.c:1290
 print_cpu_stall+0x39f/0x6e0 kernel/rcu/tree.c:1434
 check_cpu_stall.isra.63+0x702/0xe80 kernel/rcu/tree.c:1502
 __rcu_pending kernel/rcu/tree.c:3469
 rcu_pending kernel/rcu/tree.c:3533
 rcu_check_callbacks+0x27f/0xda0 kernel/rcu/tree.c:2867
 update_process_times+0x30/0x60 kernel/time/timer.c:1612
 tick_sched_handle.isra.18+0xb3/0xe0 kernel/time/tick-sched.c:151
 tick_sched_timer+0x72/0x120 kernel/time/tick-sched.c:1158
 __run_hrtimer kernel/time/hrtimer.c:1238
 __hrtimer_run_queues+0x38c/0xf80 kernel/time/hrtimer.c:1302
 hrtimer_interrupt+0x1ab/0x5c0 kernel/time/hrtimer.c:1336
 local_apic_timer_interrupt+0x6f/0xe0 arch/x86/kernel/apic/apic.c:936
 smp_apic_timer_interrupt+0x71/0xa0 arch/x86/kernel/apic/apic.c:960
 apic_timer_interrupt+0x93/0xa0
RIP: 0010:__sanitizer_cov_trace_pc+0x46/0x60 kernel/kcov.c:93
RSP: 0018:ffff88006ad66a98 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff10
RAX: 0000000000004000 RBX: ffff880068f4e500 RCX: ffffc90000e6c000
RDX: 0000000000004000 RSI: ffffffff83d652b7 RDI: ffff880064f09f51
RBP: ffff88006ad66a98 R08: ffffed000d633ca1 R09: ffffed000d633ca1
R10: 0000000000000001 R11: ffffed000d633ca0 R12: ffff880064f00020
R13: ffff88006ad66c28 R14: 0000000000009f38 R15: dffffc0000000000
 </IRQ>
 _decode_session6+0x8a7/0x13f0 net/ipv6/xfrm6_policy.c:147
 __xfrm_decode_session+0x63/0x100 net/xfrm/xfrm_policy.c:2475
 xfrm_decode_session_reverse ./include/net/xfrm.h:1117
 icmpv6_route_lookup+0x410/0x780 net/ipv6/icmp.c:362
 icmp6_send+0x1611/0x29b0 net/ipv6/icmp.c:515
 icmpv6_send+0x12e/0x260 net/ipv6/ip6_icmp.c:42
 ip6_fragment+0x583/0x3920 net/ipv6/ip6_output.c:864
 ip6_finish_output+0x322/0x960 net/ipv6/ip6_output.c:146
 NF_HOOK_COND ./include/linux/netfilter.h:246
 ip6_output+0x1cb/0x8d0 net/ipv6/ip6_output.c:162
 dst_output ./include/net/dst.h:501
 ip6_local_out+0x95/0x170 net/ipv6/output_core.c:172
 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
 rawv6_push_pending_frames net/ipv6/raw.c:613
 rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
 sock_sendmsg_nosec net/socket.c:635
 sock_sendmsg+0xca/0x110 net/socket.c:645
 sock_write_iter+0x326/0x620 net/socket.c:848
 new_sync_write fs/read_write.c:499
 __vfs_write+0x483/0x760 fs/read_write.c:512
 vfs_write+0x187/0x530 fs/read_write.c:560
 SYSC_write fs/read_write.c:607
 SyS_write+0xfb/0x230 fs/read_write.c:599
 entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
RIP: 0033:0x4421d9
RSP: 002b:00007f090e289b58 EFLAGS: 00000296 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00000000004421d9
RDX: 000000000000ffff RSI: 0000000020aa4fda RDI: 0000000000000005
RBP: 00000000006de8c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000700000
R13: ffffffffffffffff R14: 0000000020f4a000 R15: 0000000000000010

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#1554530

FromEric Dumazet <edumazet@google.com>
Date2017-01-09 18:30 +0100
Message-ID<sXLVE-74k-25@gated-at.bofh.it>
In reply to#1554518
On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
>> Hi!
>>
>> I've got the following error report while running the syzkaller fuzzer.
>>
>> On commit a121103c922847ba5010819a3f250f1f7fc84ab8 (4.10-rc3).
>>
>> A reproducer is attached.
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in sock_wfree+0x118/0x120
>> Read of size 8 at addr ffff880062da0060 by task a.out/4140
>>
>> page:ffffea00018b6800 count:1 mapcount:0 mapping:          (null)
>> index:0x0 compound_mapcount: 0
>> flags: 0x100000000008100(slab|head)
>> raw: 0100000000008100 0000000000000000 0000000000000000 0000000180130013
>> raw: dead000000000100 dead000000000200 ffff88006741f140 0000000000000000
>> page dumped because: kasan: bad access detected
>>
>> CPU: 0 PID: 4140 Comm: a.out Not tainted 4.10.0-rc3+ #59
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> Call Trace:
>>  __dump_stack lib/dump_stack.c:15
>>  dump_stack+0x292/0x398 lib/dump_stack.c:51
>>  describe_address mm/kasan/report.c:262
>>  kasan_report_error+0x121/0x560 mm/kasan/report.c:370
>>  kasan_report mm/kasan/report.c:392
>>  __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:413
>>  sock_flag ./arch/x86/include/asm/bitops.h:324
>>  sock_wfree+0x118/0x120 net/core/sock.c:1631
>>  skb_release_head_state+0xfc/0x250 net/core/skbuff.c:655
>>  skb_release_all+0x15/0x60 net/core/skbuff.c:668
>>  __kfree_skb+0x15/0x20 net/core/skbuff.c:684
>>  kfree_skb+0x16e/0x4e0 net/core/skbuff.c:705
>>  inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
>>  inet_frag_put ./include/net/inet_frag.h:133
>>  nf_ct_frag6_gather+0x1125/0x38b0 net/ipv6/netfilter/nf_conntrack_reasm.c:617
>>  ipv6_defrag+0x21b/0x350 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
>>  nf_hook_entry_hookfn ./include/linux/netfilter.h:102
>>  nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
>>  nf_hook ./include/linux/netfilter.h:212
>>  __ip6_local_out+0x52c/0xaf0 net/ipv6/output_core.c:160
>>  ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
>>  ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
>>  ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
>>  rawv6_push_pending_frames net/ipv6/raw.c:613
>>  rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927
>>  inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
>>  sock_sendmsg_nosec net/socket.c:635
>>  sock_sendmsg+0xca/0x110 net/socket.c:645
>>  sock_write_iter+0x326/0x620 net/socket.c:848
>>  new_sync_write fs/read_write.c:499
>>  __vfs_write+0x483/0x760 fs/read_write.c:512
>>  vfs_write+0x187/0x530 fs/read_write.c:560
>>  SYSC_write fs/read_write.c:607
>>  SyS_write+0xfb/0x230 fs/read_write.c:599
>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>> RIP: 0033:0x7ff26e6f5b79
>> RSP: 002b:00007ff268e0ed98 EFLAGS: 00000206 ORIG_RAX: 0000000000000001
>> RAX: ffffffffffffffda RBX: 00007ff268e0f9c0 RCX: 00007ff26e6f5b79
>> RDX: 0000000000000010 RSI: 0000000020f50fe1 RDI: 0000000000000003
>> RBP: 00007ff26ebc1220 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
>> R13: 00007ff268e0f9c0 R14: 00007ff26efec040 R15: 0000000000000003
>>
>> The buggy address belongs to the object at ffff880062da0000
>>  which belongs to the cache RAWv6 of size 1504
>> The buggy address ffff880062da0060 is located 96 bytes inside
>>  of 1504-byte region [ffff880062da0000, ffff880062da05e0)
>>
>> Freed by task 4113:
>>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>>  set_track mm/kasan/kasan.c:514
>>  kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578
>>  slab_free_hook mm/slub.c:1352
>>  slab_free_freelist_hook mm/slub.c:1374
>>  slab_free mm/slub.c:2951
>>  kmem_cache_free+0xb2/0x2c0 mm/slub.c:2973
>>  sk_prot_free net/core/sock.c:1377
>>  __sk_destruct+0x49c/0x6e0 net/core/sock.c:1452
>>  sk_destruct+0x47/0x80 net/core/sock.c:1460
>>  __sk_free+0x57/0x230 net/core/sock.c:1468
>>  sk_free+0x23/0x30 net/core/sock.c:1479
>>  sock_put ./include/net/sock.h:1638
>>  sk_common_release+0x31e/0x4e0 net/core/sock.c:2782
>>  rawv6_close+0x54/0x80 net/ipv6/raw.c:1214
>>  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
>>  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:431
>>  sock_release+0x8d/0x1e0 net/socket.c:599
>>  sock_close+0x16/0x20 net/socket.c:1063
>>  __fput+0x332/0x7f0 fs/file_table.c:208
>>  ____fput+0x15/0x20 fs/file_table.c:244
>>  task_work_run+0x19b/0x270 kernel/task_work.c:116
>>  exit_task_work ./include/linux/task_work.h:21
>>  do_exit+0x186b/0x2800 kernel/exit.c:839
>>  do_group_exit+0x149/0x420 kernel/exit.c:943
>>  SYSC_exit_group kernel/exit.c:954
>>  SyS_exit_group+0x1d/0x20 kernel/exit.c:952
>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>>
>> Allocated by task 4115:
>>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>>  set_track mm/kasan/kasan.c:514
>>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605
>>  kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
>>  slab_post_alloc_hook mm/slab.h:432
>>  slab_alloc_node mm/slub.c:2708
>>  slab_alloc mm/slub.c:2716
>>  kmem_cache_alloc+0x1af/0x250 mm/slub.c:2721
>>  sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1334
>>  sk_alloc+0x105/0x1010 net/core/sock.c:1396
>>  inet6_create+0x44d/0x1150 net/ipv6/af_inet6.c:183
>>  __sock_create+0x4f6/0x880 net/socket.c:1199
>>  sock_create net/socket.c:1239
>>  SYSC_socket net/socket.c:1269
>>  SyS_socket+0xf9/0x230 net/socket.c:1249
>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>>
>> Memory state around the buggy address:
>>  ffff880062d9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>  ffff880062d9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>>ffff880062da0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>                                                        ^
>>  ffff880062da0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>  ffff880062da0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> ==================================================================
>
> Sometimes this reproducer leads to another report:

Looks very similar to issue fixed in 8282f27449bf15548cb82c77b6e04ee0ab827bdc

Could you try :

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c
b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 9948b5ce52dad3a823edede517f17069bd7226dc..986d4ca38832b17703b09e50209ec133885c7276
100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -589,6 +589,7 @@ int nf_ct_frag6_gather(struct net *net, struct
sk_buff *skb, u32 user)
        hdr = ipv6_hdr(skb);
        fhdr = (struct frag_hdr *)skb_transport_header(skb);

+       skb_orphan(skb);
        fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
                     skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
        if (fq == NULL) {
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 6b78bab27755b2758f3c8ecd5b9c6d61615af4b6..fdec2a4cc559ab956c58d26535bdf010c0a8964a
100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -367,7 +367,6 @@ static int handle_fragments(struct net *net,
struct sw_flow_key *key,
        } else if (key->eth.type == htons(ETH_P_IPV6)) {
                enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;

-               skb_orphan(skb);
                memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
                err = nf_ct_frag6_gather(net, skb, user);
                if (err) {

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#1554615

FromEric Dumazet <edumazet@google.com>
Date2017-01-09 20:10 +0100
Message-ID<sXNuq-86p-13@gated-at.bofh.it>
In reply to#1554530
On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
>
> Hi Eric,
>
> This patch fixes the issue.
>
> Thanks!

Thanks Andrey.

Could you please post your .config for next KASAN reports ?

I am asking this because I could not reproduce the issue with my own
builds, so I had to guess but could not test the fix myself.

Thanks !

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#1555199

FromAndrey Konovalov <andreyknvl@google.com>
Date2017-01-10 13:00 +0100
Message-ID<sY3fQ-R8-27@gated-at.bofh.it>
In reply to#1554615
On Mon, Jan 9, 2017 at 8:08 PM, Eric Dumazet <edumazet@google.com> wrote:
> On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
>>
>> Hi Eric,
>>
>> This patch fixes the issue.
>>
>> Thanks!
>
> Thanks Andrey.
>
> Could you please post your .config for next KASAN reports ?

Sure, no problem!

>
> I am asking this because I could not reproduce the issue with my own
> builds, so I had to guess but could not test the fix myself.
>
> Thanks !

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#1554616

FromAndrey Konovalov <andreyknvl@google.com>
Date2017-01-09 20:10 +0100
Message-ID<sXNuq-86p-15@gated-at.bofh.it>
In reply to#1554530
On Mon, Jan 9, 2017 at 6:21 PM, Eric Dumazet <edumazet@google.com> wrote:
> On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
>> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
>>> Hi!
>>>
>>> I've got the following error report while running the syzkaller fuzzer.
>>>
>>> On commit a121103c922847ba5010819a3f250f1f7fc84ab8 (4.10-rc3).
>>>
>>> A reproducer is attached.
>>>
>>> ==================================================================
>>> BUG: KASAN: use-after-free in sock_wfree+0x118/0x120
>>> Read of size 8 at addr ffff880062da0060 by task a.out/4140
>>>
>>> page:ffffea00018b6800 count:1 mapcount:0 mapping:          (null)
>>> index:0x0 compound_mapcount: 0
>>> flags: 0x100000000008100(slab|head)
>>> raw: 0100000000008100 0000000000000000 0000000000000000 0000000180130013
>>> raw: dead000000000100 dead000000000200 ffff88006741f140 0000000000000000
>>> page dumped because: kasan: bad access detected
>>>
>>> CPU: 0 PID: 4140 Comm: a.out Not tainted 4.10.0-rc3+ #59
>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>>> Call Trace:
>>>  __dump_stack lib/dump_stack.c:15
>>>  dump_stack+0x292/0x398 lib/dump_stack.c:51
>>>  describe_address mm/kasan/report.c:262
>>>  kasan_report_error+0x121/0x560 mm/kasan/report.c:370
>>>  kasan_report mm/kasan/report.c:392
>>>  __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:413
>>>  sock_flag ./arch/x86/include/asm/bitops.h:324
>>>  sock_wfree+0x118/0x120 net/core/sock.c:1631
>>>  skb_release_head_state+0xfc/0x250 net/core/skbuff.c:655
>>>  skb_release_all+0x15/0x60 net/core/skbuff.c:668
>>>  __kfree_skb+0x15/0x20 net/core/skbuff.c:684
>>>  kfree_skb+0x16e/0x4e0 net/core/skbuff.c:705
>>>  inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
>>>  inet_frag_put ./include/net/inet_frag.h:133
>>>  nf_ct_frag6_gather+0x1125/0x38b0 net/ipv6/netfilter/nf_conntrack_reasm.c:617
>>>  ipv6_defrag+0x21b/0x350 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
>>>  nf_hook_entry_hookfn ./include/linux/netfilter.h:102
>>>  nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
>>>  nf_hook ./include/linux/netfilter.h:212
>>>  __ip6_local_out+0x52c/0xaf0 net/ipv6/output_core.c:160
>>>  ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
>>>  ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
>>>  ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
>>>  rawv6_push_pending_frames net/ipv6/raw.c:613
>>>  rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927
>>>  inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
>>>  sock_sendmsg_nosec net/socket.c:635
>>>  sock_sendmsg+0xca/0x110 net/socket.c:645
>>>  sock_write_iter+0x326/0x620 net/socket.c:848
>>>  new_sync_write fs/read_write.c:499
>>>  __vfs_write+0x483/0x760 fs/read_write.c:512
>>>  vfs_write+0x187/0x530 fs/read_write.c:560
>>>  SYSC_write fs/read_write.c:607
>>>  SyS_write+0xfb/0x230 fs/read_write.c:599
>>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>>> RIP: 0033:0x7ff26e6f5b79
>>> RSP: 002b:00007ff268e0ed98 EFLAGS: 00000206 ORIG_RAX: 0000000000000001
>>> RAX: ffffffffffffffda RBX: 00007ff268e0f9c0 RCX: 00007ff26e6f5b79
>>> RDX: 0000000000000010 RSI: 0000000020f50fe1 RDI: 0000000000000003
>>> RBP: 00007ff26ebc1220 R08: 0000000000000000 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
>>> R13: 00007ff268e0f9c0 R14: 00007ff26efec040 R15: 0000000000000003
>>>
>>> The buggy address belongs to the object at ffff880062da0000
>>>  which belongs to the cache RAWv6 of size 1504
>>> The buggy address ffff880062da0060 is located 96 bytes inside
>>>  of 1504-byte region [ffff880062da0000, ffff880062da05e0)
>>>
>>> Freed by task 4113:
>>>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>>>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>>>  set_track mm/kasan/kasan.c:514
>>>  kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578
>>>  slab_free_hook mm/slub.c:1352
>>>  slab_free_freelist_hook mm/slub.c:1374
>>>  slab_free mm/slub.c:2951
>>>  kmem_cache_free+0xb2/0x2c0 mm/slub.c:2973
>>>  sk_prot_free net/core/sock.c:1377
>>>  __sk_destruct+0x49c/0x6e0 net/core/sock.c:1452
>>>  sk_destruct+0x47/0x80 net/core/sock.c:1460
>>>  __sk_free+0x57/0x230 net/core/sock.c:1468
>>>  sk_free+0x23/0x30 net/core/sock.c:1479
>>>  sock_put ./include/net/sock.h:1638
>>>  sk_common_release+0x31e/0x4e0 net/core/sock.c:2782
>>>  rawv6_close+0x54/0x80 net/ipv6/raw.c:1214
>>>  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
>>>  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:431
>>>  sock_release+0x8d/0x1e0 net/socket.c:599
>>>  sock_close+0x16/0x20 net/socket.c:1063
>>>  __fput+0x332/0x7f0 fs/file_table.c:208
>>>  ____fput+0x15/0x20 fs/file_table.c:244
>>>  task_work_run+0x19b/0x270 kernel/task_work.c:116
>>>  exit_task_work ./include/linux/task_work.h:21
>>>  do_exit+0x186b/0x2800 kernel/exit.c:839
>>>  do_group_exit+0x149/0x420 kernel/exit.c:943
>>>  SYSC_exit_group kernel/exit.c:954
>>>  SyS_exit_group+0x1d/0x20 kernel/exit.c:952
>>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>>>
>>> Allocated by task 4115:
>>>  save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
>>>  save_stack+0x43/0xd0 mm/kasan/kasan.c:502
>>>  set_track mm/kasan/kasan.c:514
>>>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605
>>>  kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
>>>  slab_post_alloc_hook mm/slab.h:432
>>>  slab_alloc_node mm/slub.c:2708
>>>  slab_alloc mm/slub.c:2716
>>>  kmem_cache_alloc+0x1af/0x250 mm/slub.c:2721
>>>  sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1334
>>>  sk_alloc+0x105/0x1010 net/core/sock.c:1396
>>>  inet6_create+0x44d/0x1150 net/ipv6/af_inet6.c:183
>>>  __sock_create+0x4f6/0x880 net/socket.c:1199
>>>  sock_create net/socket.c:1239
>>>  SYSC_socket net/socket.c:1269
>>>  SyS_socket+0xf9/0x230 net/socket.c:1249
>>>  entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203
>>>
>>> Memory state around the buggy address:
>>>  ffff880062d9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>>  ffff880062d9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>>>ffff880062da0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>                                                        ^
>>>  ffff880062da0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>  ffff880062da0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>> ==================================================================
>>
>> Sometimes this reproducer leads to another report:
>
> Looks very similar to issue fixed in 8282f27449bf15548cb82c77b6e04ee0ab827bdc
>
> Could you try :

Hi Eric,

This patch fixes the issue.

Thanks!

>
> diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c
> b/net/ipv6/netfilter/nf_conntrack_reasm.c
> index 9948b5ce52dad3a823edede517f17069bd7226dc..986d4ca38832b17703b09e50209ec133885c7276
> 100644
> --- a/net/ipv6/netfilter/nf_conntrack_reasm.c
> +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
> @@ -589,6 +589,7 @@ int nf_ct_frag6_gather(struct net *net, struct
> sk_buff *skb, u32 user)
>         hdr = ipv6_hdr(skb);
>         fhdr = (struct frag_hdr *)skb_transport_header(skb);
>
> +       skb_orphan(skb);
>         fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
>                      skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
>         if (fq == NULL) {
> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> index 6b78bab27755b2758f3c8ecd5b9c6d61615af4b6..fdec2a4cc559ab956c58d26535bdf010c0a8964a
> 100644
> --- a/net/openvswitch/conntrack.c
> +++ b/net/openvswitch/conntrack.c
> @@ -367,7 +367,6 @@ static int handle_fragments(struct net *net,
> struct sw_flow_key *key,
>         } else if (key->eth.type == htons(ETH_P_IPV6)) {
>                 enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
>
> -               skb_orphan(skb);
>                 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
>                 err = nf_ct_frag6_gather(net, skb, user);
>                 if (err) {

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