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Date:   Mon, 19 Apr 2021 22:10:23 -0700
Message-ID: <000000000000a48ad805c06076f0@google.com>
Subject: [syzbot] KASAN: use-after-free Read in sctp_do_8_2_transport_strike
From:   syzbot <syzbot+bbe538efd1046586f587@syzkaller.appspotmail.com>
To:     davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org,
        linux-sctp@vger.kernel.org, marcelo.leitner@gmail.com,
        netdev@vger.kernel.org, nhorman@tuxdriver.com,
        syzkaller-bugs@googlegroups.com, vyasevich@gmail.com
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Precedence: bulk

Hello,

syzbot found the following issue on:

HEAD commit:    bf05bf16 Linux 5.12-rc8
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16a00dfed00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9404cfa686df2c05
dashboard link: https://syzkaller.appspot.com/bug?extid=bbe538efd1046586f587

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bbe538efd1046586f587@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in sctp_do_8_2_transport_strike.constprop.0+0xa27/0xab0 net/sctp/sm_sideeffect.c:531
Read of size 4 at addr ffff888024d65154 by task swapper/1/0

CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 sctp_do_8_2_transport_strike.constprop.0+0xa27/0xab0 net/sctp/sm_sideeffect.c:531
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1636 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline]
 sctp_do_sm+0x114f/0x5120 net/sctp/sm_sideeffect.c:1156
 sctp_generate_timeout_event+0x1bb/0x3d0 net/sctp/sm_sideeffect.c:295
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1431
 expire_timers kernel/time/timer.c:1476 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu kernel/softirq.c:422 [inline]
 irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:137 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
RIP: 0010:acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:517
Code: ed 56 6e f8 84 db 75 ac e8 34 50 6e f8 e8 3f 3f 74 f8 e9 0c 00 00 00 e8 25 50 6e f8 0f 00 2d be a5 c7 00 e8 19 50 6e f8 fb f4 <9c> 5b 81 e3 00 02 00 00 fa 31 ff 48 89 de e8 24 58 6e f8 48 85 db
RSP: 0018:ffffc90000d57d18 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8880111c54c0 RSI: ffffffff8905a167 RDI: 0000000000000000
RBP: ffff888141433864 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8179e0c8 R11: 0000000000000000 R12: 0000000000000001
R13: ffff888141433800 R14: ffff888141433864 R15: ffff888017879004
 acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:652
 cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x3e1/0x590 kernel/sched/idle.c:300
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:397
 start_secondary+0x274/0x350 arch/x86/kernel/smpboot.c:272
 secondary_startup_64_no_verify+0xb0/0xbb

Allocated by task 14433:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:427 [inline]
 ____kasan_kmalloc mm/kasan/common.c:506 [inline]
 ____kasan_kmalloc mm/kasan/common.c:465 [inline]
 __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:684 [inline]
 sctp_transport_new+0x8c/0x690 net/sctp/transport.c:96
 sctp_assoc_add_peer+0x28f/0x1160 net/sctp/associola.c:618
 sctp_process_init+0x12a/0x2940 net/sctp/sm_make_chunk.c:2345
 sctp_sf_do_dupcook_a net/sctp/sm_statefuns.c:1800 [inline]
 sctp_sf_do_5_2_4_dupcook+0x1401/0x2d50 net/sctp/sm_statefuns.c:2200
 sctp_do_sm+0x179/0x5120 net/sctp/sm_sideeffect.c:1153
 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1048
 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80
 sctp_rcv+0xf64/0x2f10 net/sctp/input.c:256
 sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1077
 ip6_protocol_deliver_rcu+0x2e9/0x17f0 net/ipv6/ip6_input.c:422
 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:463
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
 dst_input include/net/dst.h:458 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:297
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5384
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5498
 process_backlog+0x232/0x6c0 net/core/dev.c:6366
 __napi_poll+0xaf/0x440 net/core/dev.c:6913
 napi_poll net/core/dev.c:6980 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7067
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345

Freed by task 0:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
 ____kasan_slab_free mm/kasan/common.c:360 [inline]
 ____kasan_slab_free mm/kasan/common.c:325 [inline]
 __kasan_slab_free+0xf5/0x130 mm/kasan/common.c:367
 kasan_slab_free include/linux/kasan.h:199 [inline]
 slab_free_hook mm/slub.c:1562 [inline]
 slab_free_freelist_hook+0x92/0x210 mm/slub.c:1600
 slab_free mm/slub.c:3161 [inline]
 kfree+0xe5/0x7f0 mm/slub.c:4213
 rcu_do_batch kernel/rcu/tree.c:2559 [inline]
 rcu_core+0x74a/0x12f0 kernel/rcu/tree.c:2794
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345
 __call_rcu kernel/rcu/tree.c:3039 [inline]
 call_rcu+0xb1/0x740 kernel/rcu/tree.c:3114
 sctp_transport_destroy net/sctp/transport.c:167 [inline]
 sctp_transport_put+0x11d/0x180 net/sctp/transport.c:326
 sctp_association_free+0x4d4/0x7d0 net/sctp/associola.c:381
 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:930 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1318 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline]
 sctp_do_sm+0x38b8/0x5120 net/sctp/sm_sideeffect.c:1156
 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1048
 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80
 sctp_rcv+0xf64/0x2f10 net/sctp/input.c:256
 sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1077
 ip6_protocol_deliver_rcu+0x2e9/0x17f0 net/ipv6/ip6_input.c:422
 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:463
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
 dst_input include/net/dst.h:458 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:297
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5384
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5498
 process_backlog+0x232/0x6c0 net/core/dev.c:6366
 __napi_poll+0xaf/0x440 net/core/dev.c:6913
 napi_poll net/core/dev.c:6980 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7067
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345

Second to last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345
 kvfree_call_rcu+0x10e/0x7d0 kernel/rcu/tree.c:3577
 neigh_destroy+0x3ff/0x5f0 net/core/neighbour.c:858
 neigh_release include/net/neighbour.h:425 [inline]
 neigh_cleanup_and_release+0x1fd/0x340 net/core/neighbour.c:103
 neigh_del net/core/neighbour.c:193 [inline]
 neigh_remove_one+0x3cf/0x450 net/core/neighbour.c:214
 neigh_forced_gc net/core/neighbour.c:243 [inline]
 neigh_alloc net/core/neighbour.c:390 [inline]
 ___neigh_create+0x1698/0x25c0 net/core/neighbour.c:578
 ip6_finish_output2+0xf1f/0x1700 net/ipv6/ip6_output.c:114
 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline]
 __ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161
 ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ndisc_send_skb+0xa99/0x1750 net/ipv6/ndisc.c:508
 ndisc_send_ns+0x3a9/0x840 net/ipv6/ndisc.c:650
 addrconf_dad_work+0xc3f/0x12b0 net/ipv6/addrconf.c:4119
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff888024d65000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 340 bytes inside of
 1024-byte region [ffff888024d65000, ffff888024d65400)
The buggy address belongs to the page:
page:ffffea0000935800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24d60
head:ffffea0000935800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000f00000001 ffff888010441dc0
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888024d65000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888024d65080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888024d65100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888024d65180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888024d65200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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