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KASAN: use-after-free Read in nr_insert_socket

Status: fixed on 2019/08/27 17:15
Subsystems: hams
[Documentation on labels]
Reported-by: syzbot+9399c158fcc09b21d0d2@syzkaller.appspotmail.com
Fix commit: 4638faac0327 netrom: hold sock when setting skb->destructor
First crash: 1738d, last: 1720d
Cause bisection: introduced by (bisect log) :
commit c8c8218ec5af5d2598381883acbefbf604e56b5e
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu Jun 27 21:30:58 2019 +0000

  netrom: fix a memory leak in nr_rx_frame()

Crash: WARNING: refcount bug in nr_insert_socket (log)
Repro: syz .config
  
▶ ▼ Discussions (9)
Title Replies (including bot) Last reply
[PATCH 4.9 000/223] 4.9.187-stable review 231 (231) 2019/08/28 03:02
[PATCH 4.4 000/158] 4.4.187-stable review 166 (166) 2019/08/03 15:57
[PATCH 4.14 000/293] 4.14.135-stable review 302 (302) 2019/07/31 09:35
[PATCH 5.2 00/66] 5.2.4-stable review 78 (78) 2019/07/29 15:12
[PATCH 5.1 00/62] 5.1.21-stable review 68 (68) 2019/07/29 09:02
[PATCH 4.19 00/50] 4.19.62-stable review 56 (56) 2019/07/29 09:02
[Patch net] netrom: hold sock when setting skb->destructor 2 (2) 2019/07/24 22:49
Reminder: 13 open syzbot bugs in "net/netrom" subsystem 2 (2) 2019/07/24 17:02
KASAN: use-after-free Read in nr_insert_socket 1 (2) 2019/07/18 16:48
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2019/07/22 19:32 18m xiyou.wangcong@gmail.com https://github.com/congwang/linux.git netrom OK
2019/07/18 17:28 18m xiyou.wangcong@gmail.com https://github.com/congwang/linux.git netrom OK

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
Read of size 4 at addr ffff8880903977c0 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc2+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x17 mm/kasan/common.c:612
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
 refcount_inc_checked+0x17/0x70 lib/refcount.c:156
 sock_hold include/net/sock.h:649 [inline]
 sk_add_node include/net/sock.h:701 [inline]
 nr_insert_socket+0x2d/0xe0 net/netrom/af_netrom.c:137
 nr_rx_frame+0x1605/0x1e73 net/netrom/af_netrom.c:1023
 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
 </IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 98 1c 6f fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d a4 8d 4a 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 94 8d 4a 00 fb f4 <c3> 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 6e d4 22 fa e8 49
RSP: 0018:ffffffff88c07ce8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e45 RBX: ffffffff88c7a1c0 RCX: 1ffffffff134b3e6
RDX: dffffc0000000000 RSI: ffffffff81781bae RDI: ffffffff873d8f2c
RBP: ffffffff88c07d18 R08: ffffffff88c7a1c0 R09: fffffbfff118f439
R10: fffffbfff118f438 R11: ffffffff88c7a1c7 R12: dffffc0000000000
R13: ffffffff89a56d38 R14: 0000000000000000 R15: 0000000000000000
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x413/0x760 kernel/sched/idle.c:263
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
 rest_init+0x245/0x37b init/main.c:451
 arch_call_rest_init+0xe/0x1b
 start_kernel+0x912/0x951 init/main.c:785
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:453
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

Allocated by task 0:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:487 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3664
 kmalloc include/linux/slab.h:557 [inline]
 sk_prot_alloc+0x23a/0x310 net/core/sock.c:1603
 sk_alloc+0x39/0xf70 net/core/sock.c:1657
 nr_make_new net/netrom/af_netrom.c:476 [inline]
 nr_rx_frame+0x733/0x1e73 net/netrom/af_netrom.c:959
 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698
 __do_softirq+0x262/0x98c kernel/softirq.c:292

Freed by task 12201:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 sk_prot_free net/core/sock.c:1640 [inline]
 __sk_destruct+0x4f7/0x6e0 net/core/sock.c:1726
 sk_destruct+0x86/0xa0 net/core/sock.c:1734
 __sk_free+0xfb/0x360 net/core/sock.c:1745
 sk_free+0x42/0x50 net/core/sock.c:1756
 sock_put include/net/sock.h:1725 [inline]
 sock_efree+0x61/0x80 net/core/sock.c:2042
 skb_release_head_state+0xeb/0x250 net/core/skbuff.c:652
 skb_release_all+0x16/0x60 net/core/skbuff.c:663
 __kfree_skb net/core/skbuff.c:679 [inline]
 kfree_skb net/core/skbuff.c:697 [inline]
 kfree_skb+0x101/0x3c0 net/core/skbuff.c:691
 nr_accept+0x56e/0x700 net/netrom/af_netrom.c:819
 __sys_accept4+0x34e/0x6a0 net/socket.c:1754
 __do_sys_accept net/socket.c:1795 [inline]
 __se_sys_accept net/socket.c:1792 [inline]
 __x64_sys_accept+0x75/0xb0 net/socket.c:1792
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888090397740
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
 2048-byte region [ffff888090397740, ffff888090397f40)
The buggy address belongs to the page:
page:ffffea000240e580 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00021f8588 ffff8880aa401948 ffff8880aa400e00
raw: 0000000000000000 ffff888090396640 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888090397680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888090397700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff888090397780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888090397800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888090397880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
ODEBUG: activate not available (active state 0) object type: timer_list hint: nr_heartbeat_expiry+0x0/0x410 net/netrom/nr_timer.c:52
WARNING: CPU: 0 PID: 0 at lib/debugobjects.c:481 debug_print_object+0x168/0x250 lib/debugobjects.c:481
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G    B             5.3.0-rc2+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:481
Code: dd a0 31 c6 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48 8b 14 dd a0 31 c6 87 48 c7 c7 a0 26 c6 87 e8 40 c2 05 fe <0f> 0b 83 05 53 55 67 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3
RSP: 0018:ffff8880ae8099d0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff815c5216 RDI: ffffed1015d0132c
RBP: ffff8880ae809a10 R08: ffffffff88c7a1c0 R09: fffffbfff134ada8
R10: fffffbfff134ada7 R11: ffffffff89a56d3f R12: 0000000000000001
R13: ffffffff88db6560 R14: ffffffff8161f080 R15: 1ffff11015d01348
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000002 CR3: 000000008a54e000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 debug_object_activate+0x2e5/0x470 lib/debugobjects.c:680
 debug_timer_activate kernel/time/timer.c:710 [inline]
 __mod_timer kernel/time/timer.c:1035 [inline]
 mod_timer+0x452/0xc10 kernel/time/timer.c:1096
 sk_reset_timer+0x24/0x60 net/core/sock.c:2821
 nr_start_heartbeat+0x47/0x60 net/netrom/nr_timer.c:79
 nr_rx_frame+0x160d/0x1e73 net/netrom/af_netrom.c:1025
 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
 </IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 98 1c 6f fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d a4 8d 4a 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 94 8d 4a 00 fb f4 <c3> 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 6e d4 22 fa e8 49
RSP: 0018:ffffffff88c07ce8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e45 RBX: ffffffff88c7a1c0 RCX: 1ffffffff134b3e6
RDX: dffffc0000000000 RSI: ffffffff81781bae RDI: ffffffff873d8f2c
RBP: ffffffff88c07d18 R08: ffffffff88c7a1c0 R09: fffffbfff118f439
R10: fffffbfff118f438 R11: ffffffff88c7a1c7 R12: dffffc0000000000
R13: ffffffff89a56d38 R14: 0000000000000000 R15: 0000000000000000
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x413/0x760 kernel/sched/idle.c:263
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
 rest_init+0x245/0x37b init/main.c:451
 arch_call_rest_init+0xe/0x1b
 start_kernel+0x912/0x951 init/main.c:785
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:453
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
irq event stamp: 94930
hardirqs last  enabled at (94929): [<ffffffff81669681>] tick_nohz_idle_exit+0x181/0x2e0 kernel/time/tick-sched.c:1180
hardirqs last disabled at (94930): [<ffffffff873c738d>] __schedule+0x1dd/0x1580 kernel/sched/core.c:3821
softirqs last  enabled at (93544): [<ffffffff876006cd>] __do_softirq+0x6cd/0x98c kernel/softirq.c:319
softirqs last disabled at (93365): [<ffffffff8145c02b>] invoke_softirq kernel/softirq.c:373 [inline]
softirqs last disabled at (93365): [<ffffffff8145c02b>] irq_exit+0x19b/0x1e0 kernel/softirq.c:413
---[ end trace 8a169c3594237260 ]---

Crashes (22):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/07/31 09:09 upstream 629f8205a6cc 7c7ded69 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2019/07/25 07:42 net-old 107e47cc80ec 32329ceb .config console log report syz C ci-upstream-net-this-kasan-gce
2019/07/23 08:01 net-old 107e47cc80ec 55e0c077 .config console log report syz C ci-upstream-net-this-kasan-gce
2019/07/17 16:23 net-old a5b647007e9d f613a7c4 .config console log report syz C ci-upstream-net-this-kasan-gce
2019/07/17 07:37 net-old a5b647007e9d 0d10349c .config console log report syz ci-upstream-net-this-kasan-gce
2019/07/20 19:00 net-next-old 31cc088a4f5d 1656845f .config console log report syz ci-upstream-net-kasan-gce
2019/08/03 18:22 upstream dcb8cfbd8fe9 6affd8e8 .config console log report ci-upstream-kasan-gce-root
2019/08/02 08:56 upstream 1e78030e5e5b 835dffe7 .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/31 02:51 upstream 629f8205a6cc 7c7ded69 .config console log report ci-upstream-kasan-gce-root
2019/07/31 02:04 upstream 629f8205a6cc 7c7ded69 .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/30 01:44 upstream 2a11c76e5301 f67095ee .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/26 05:36 upstream 6789f873ed37 732bc5a0 .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/25 22:57 upstream 6789f873ed37 732bc5a0 .config console log report ci-upstream-kasan-gce-root
2019/07/25 03:14 upstream bed38c3e2dca 32329ceb .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/23 01:51 upstream c6dd78fcb8ee 55e0c077 .config console log report ci-upstream-kasan-gce-root
2019/07/20 06:45 upstream abdfd52a295f 1656845f .config console log report ci-upstream-kasan-gce-root
2019/07/19 09:56 upstream 3bfe1fc46794 7bb222f7 .config console log report ci-upstream-kasan-gce-selinux-root
2019/07/30 20:05 net-old 107e47cc80ec f28bf2a5 .config console log report ci-upstream-net-this-kasan-gce
2019/07/27 10:05 net-next-old 31cc088a4f5d c85e1c5b .config console log report ci-upstream-net-kasan-gce
2019/07/23 13:07 net-next-old 31cc088a4f5d de453f34 .config console log report ci-upstream-net-kasan-gce
2019/07/18 16:07 net-next-old 192f0f8e9db7 7bb222f7 .config console log report ci-upstream-net-kasan-gce
2019/07/25 01:20 linux-next 9e6dfe8045f8 32329ceb .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.