Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:21 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  
> wrote:
>> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
>> 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 880062da0060 by task a.out/4140
>>>
>>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>>> index:0x0 compound_mapcount: 0
>>> flags: 0x1008100(slab|head)
>>> raw: 01008100   000180130013
>>> raw: dead0100 dead0200 88006741f140 
>>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>>> RBP: 7ff26ebc1220 R08:  R09: 
>>> R10:  R11: 0206 R12: 
>>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>>
>>> The buggy address belongs to the object at 880062da
>>>  which belongs to the cache RAWv6 of size 1504
>>> The buggy address 880062da0060 is located 96 bytes inside
>>>  of 1504-byte region [880062da, 880062da05e0)
>>>
>>> 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
>>>  

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:21 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  
> wrote:
>> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
>> 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 880062da0060 by task a.out/4140
>>>
>>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>>> index:0x0 compound_mapcount: 0
>>> flags: 0x1008100(slab|head)
>>> raw: 01008100   000180130013
>>> raw: dead0100 dead0200 88006741f140 
>>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>>> RBP: 7ff26ebc1220 R08:  R09: 
>>> R10:  R11: 0206 R12: 
>>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>>
>>> The buggy address belongs to the object at 880062da
>>>  which belongs to the cache RAWv6 of size 1504
>>> The buggy address 880062da0060 is located 96 bytes inside
>>>  of 1504-byte region [880062da, 880062da05e0)
>>>
>>> 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
>>>  

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 8:08 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov  
> 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 !

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 8:08 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov  
> 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 !

Re: net/ipv6: use-after-free in sock_wfree

[Eric Dumazet]

On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov  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 !

Re: net/ipv6: use-after-free in sock_wfree

[Eric Dumazet]

On Mon, Jan 9, 2017 at 11:06 AM, Andrey Konovalov  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 !

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:21 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  
> wrote:
>> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
>> 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 880062da0060 by task a.out/4140
>>>
>>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>>> index:0x0 compound_mapcount: 0
>>> flags: 0x1008100(slab|head)
>>> raw: 01008100   000180130013
>>> raw: dead0100 dead0200 88006741f140 
>>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>>> RBP: 7ff26ebc1220 R08:  R09: 
>>> R10:  R11: 0206 R12: 
>>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>>
>>> The buggy address belongs to the object at 880062da
>>>  which belongs to the cache RAWv6 of size 1504
>>> The buggy address 880062da0060 is located 96 bytes inside
>>>  of 1504-byte region [880062da, 880062da05e0)
>>>
>>> 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
>>>  

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:21 PM, Eric Dumazet  wrote:
> On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  
> wrote:
>> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
>> 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 880062da0060 by task a.out/4140
>>>
>>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>>> index:0x0 compound_mapcount: 0
>>> flags: 0x1008100(slab|head)
>>> raw: 01008100   000180130013
>>> raw: dead0100 dead0200 88006741f140 
>>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>>> RBP: 7ff26ebc1220 R08:  R09: 
>>> R10:  R11: 0206 R12: 
>>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>>
>>> The buggy address belongs to the object at 880062da
>>>  which belongs to the cache RAWv6 of size 1504
>>> The buggy address 880062da0060 is located 96 bytes inside
>>>  of 1504-byte region [880062da, 880062da05e0)
>>>
>>> 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
>>>  

Re: net/ipv6: use-after-free in sock_wfree

[Eric Dumazet]

On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  wrote:
> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
> 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 880062da0060 by task a.out/4140
>>
>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>> index:0x0 compound_mapcount: 0
>> flags: 0x1008100(slab|head)
>> raw: 01008100   000180130013
>> raw: dead0100 dead0200 88006741f140 
>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>> RBP: 7ff26ebc1220 R08:  R09: 
>> R10:  R11: 0206 R12: 
>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>
>> The buggy address belongs to the object at 880062da
>>  which belongs to the cache RAWv6 of size 1504
>> The buggy address 880062da0060 is located 96 bytes inside
>>  of 1504-byte region [880062da, 880062da05e0)
>>
>> 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 

Re: net/ipv6: use-after-free in sock_wfree

[Eric Dumazet]

On Mon, Jan 9, 2017 at 9:11 AM, Andrey Konovalov  wrote:
> On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  
> 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 880062da0060 by task a.out/4140
>>
>> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
>> index:0x0 compound_mapcount: 0
>> flags: 0x1008100(slab|head)
>> raw: 01008100   000180130013
>> raw: dead0100 dead0200 88006741f140 
>> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
>> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
>> RDX: 0010 RSI: 20f50fe1 RDI: 0003
>> RBP: 7ff26ebc1220 R08:  R09: 
>> R10:  R11: 0206 R12: 
>> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>>
>> The buggy address belongs to the object at 880062da
>>  which belongs to the cache RAWv6 of size 1504
>> The buggy address 880062da0060 is located 96 bytes inside
>>  of 1504-byte region [880062da, 880062da05e0)
>>
>> 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 

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  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 880062da0060 by task a.out/4140
>
> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
> index:0x0 compound_mapcount: 0
> flags: 0x1008100(slab|head)
> raw: 01008100   000180130013
> raw: dead0100 dead0200 88006741f140 
> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
> RDX: 0010 RSI: 20f50fe1 RDI: 0003
> RBP: 7ff26ebc1220 R08:  R09: 
> R10:  R11: 0206 R12: 
> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>
> The buggy address belongs to the object at 880062da
>  which belongs to the cache RAWv6 of size 1504
> The buggy address 880062da0060 is located 96 bytes inside
>  of 1504-byte region [880062da, 880062da05e0)
>
> 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 

Re: net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov  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 880062da0060 by task a.out/4140
>
> page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
> index:0x0 compound_mapcount: 0
> flags: 0x1008100(slab|head)
> raw: 01008100   000180130013
> raw: dead0100 dead0200 88006741f140 
> 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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
> RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
> RDX: 0010 RSI: 20f50fe1 RDI: 0003
> RBP: 7ff26ebc1220 R08:  R09: 
> R10:  R11: 0206 R12: 
> R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003
>
> The buggy address belongs to the object at 880062da
>  which belongs to the cache RAWv6 of size 1504
> The buggy address 880062da0060 is located 96 bytes inside
>  of 1504-byte region [880062da, 880062da05e0)
>
> 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
>  

net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

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 880062da0060 by task a.out/4140

page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
index:0x0 compound_mapcount: 0
flags: 0x1008100(slab|head)
raw: 01008100   000180130013
raw: dead0100 dead0200 88006741f140 
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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
RDX: 0010 RSI: 20f50fe1 RDI: 0003
RBP: 7ff26ebc1220 R08:  R09: 
R10:  R11: 0206 R12: 
R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003

The buggy address belongs to the object at 880062da
 which belongs to the cache RAWv6 of size 1504
The buggy address 880062da0060 is located 96 bytes inside
 of 1504-byte region [880062da, 880062da05e0)

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
 

net/ipv6: use-after-free in sock_wfree

[Andrey Konovalov]

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 880062da0060 by task a.out/4140

page:ea00018b6800 count:1 mapcount:0 mapping:  (null)
index:0x0 compound_mapcount: 0
flags: 0x1008100(slab|head)
raw: 01008100   000180130013
raw: dead0100 dead0200 88006741f140 
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:7ff268e0ed98 EFLAGS: 0206 ORIG_RAX: 0001
RAX: ffda RBX: 7ff268e0f9c0 RCX: 7ff26e6f5b79
RDX: 0010 RSI: 20f50fe1 RDI: 0003
RBP: 7ff26ebc1220 R08:  R09: 
R10:  R11: 0206 R12: 
R13: 7ff268e0f9c0 R14: 7ff26efec040 R15: 0003

The buggy address belongs to the object at 880062da
 which belongs to the cache RAWv6 of size 1504
The buggy address 880062da0060 is located 96 bytes inside
 of 1504-byte region [880062da, 880062da05e0)

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