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

From: Andrey Konovalov
Date: Mon Jan 09 2017 - 12:11:58 EST

Next message: Guenter Roeck: "Re: [PATCH 2/2] hwmon/tmp401: Fix some checkstyle warnings"
Previous message: Grygorii Strashko: "Re: [PATCH 0/4] net: ethernet: ti: cpsw: correct common res usage"
In reply to: Andrey Konovalov: "net/ipv6: use-after-free in sock_wfree"
Next in thread: Eric Dumazet: "Re: net/ipv6: use-after-free in sock_wfree"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Mon, Jan 9, 2017 at 6:08 PM, Andrey Konovalov <andreyknvl@xxxxxxxxxx> 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

Next message: Guenter Roeck: "Re: [PATCH 2/2] hwmon/tmp401: Fix some checkstyle warnings"
Previous message: Grygorii Strashko: "Re: [PATCH 0/4] net: ethernet: ti: cpsw: correct common res usage"
In reply to: Andrey Konovalov: "net/ipv6: use-after-free in sock_wfree"
Next in thread: Eric Dumazet: "Re: net/ipv6: use-after-free in sock_wfree"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]