KASAN: use-after-free Read in nbd_genl_connect (2)

Status: fixed on 2021/11/10 00:50
Subsystems: nbd
[Documentation on labels]
Reported-by: syzbot+2c98885bcd769f56b6d6@syzkaller.appspotmail.com
Fix commit: 7ee656c3ac3d nbd: remove nbd->destroy_complete
First crash: 1809d, last: 1805d
Cause bisection: introduced by (bisect log) [no-op commit]:
commit 86f0a011e548774fd8eb952f67bfeb19f3174dd0
Author: Julian Wiedmann <jwi@linux.ibm.com>
Date: Tue Mar 16 09:45:12 2021 +0000

  s390/dasd: remove dasd_fba_probe() wrapper

Crash: WARNING in kvm_wait (log)
Repro: C syz .config
  
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH 6/6] nbd: remove nbd->destroy_complete 1 (1) 2021/08/25 16:31
Re: [syzbot] KASAN: use-after-free Read in nbd_genl_connect (2) 1 (1) 2021/08/25 09:27
[syzbot] KASAN: use-after-free Read in nbd_genl_connect (2) 0 (1) 2021/08/25 07:12
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in nbd_genl_connect 19 syz, C error 169 1247d 1990d 0/1 upstream: reported C repro on 2021/02/21 14:36
upstream KASAN: use-after-free Read in nbd_genl_connect nbd 19 syz, C inconclusive 16 1974d 1989d 20/29 fixed on 2021/04/09 19:46
linux-4.14 KASAN: use-after-free Read in nbd_genl_connect 19 syz, C 199 1248d 1991d 0/1 upstream: reported C repro on 2021/02/20 12:01

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
BUG: KASAN: use-after-free in nbd_genl_connect+0x235/0x16a0 drivers/block/nbd.c:1869
Read of size 8 at addr ffff8881463eeab0 by task syz-executor010/6561

CPU: 1 PID: 6561 Comm: syz-executor010 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:256
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 nbd_genl_connect+0x235/0x16a0 drivers/block/nbd.c:1869
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x32d/0x590 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x154/0x430 net/netlink/af_netlink.c:2504
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2403
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4406d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffec8655a78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000000103b8 RCX: 00000000004406d9
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffec8655c18
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffec8655a8c
R13: 431bde82d7b634db R14: 00000000004ae018 R15: 00000000004004a0

Allocated by task 1:
 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:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0xa8/0xe0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:594 [inline]
 kzalloc include/linux/slab.h:731 [inline]
 nbd_dev_add+0x54/0xaf0 drivers/block/nbd.c:1696
 nbd_init+0x297/0x2a7 drivers/block/nbd.c:2457
 do_one_initcall+0x103/0x650 init/main.c:1292
 do_initcall_level init/main.c:1367 [inline]
 do_initcalls init/main.c:1383 [inline]
 do_basic_setup init/main.c:1402 [inline]
 kernel_init_freeable+0x6b4/0x73d init/main.c:1604
 kernel_init+0x1a/0x1d0 init/main.c:1496
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Freed by task 10:
 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:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0x103/0x140 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1681 [inline]
 slab_free_freelist_hook+0x85/0x190 mm/slub.c:1706
 slab_free mm/slub.c:3459 [inline]
 kfree+0xea/0x540 mm/slub.c:4519
 process_one_work+0x9c9/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x65b/0x1200 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xed/0x120 mm/kasan/generic.c:348
 insert_work+0x48/0x370 kernel/workqueue.c:1353
 __queue_work+0x5d1/0xf30 kernel/workqueue.c:1519
 queue_work_on+0xf6/0x110 kernel/workqueue.c:1546
 queue_work include/linux/workqueue.h:502 [inline]
 nbd_put drivers/block/nbd.c:283 [inline]
 nbd_put+0xd7/0x120 drivers/block/nbd.c:276
 nbd_genl_connect+0xc73/0x16a0 drivers/block/nbd.c:2019
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x32d/0x590 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x154/0x430 net/netlink/af_netlink.c:2504
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2403
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff8881463ee800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 688 bytes inside of
 1024-byte region [ffff8881463ee800, ffff8881463eec00)
The buggy address belongs to the page:
page:ffffea000518fa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8881463ef800 pfn:0x1463e8
head:ffffea000518fa00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea00050c7a08 ffffea00050fe608 ffff888010c41dc0
raw: ffff8881463ef800 000000000010000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 7639818470, free_ts 0
 prep_new_page mm/page_alloc.c:2424 [inline]
 get_page_from_freelist+0xa76/0x2f90 mm/page_alloc.c:4151
 __alloc_pages+0x1ba/0x510 mm/page_alloc.c:5373
 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2033
 alloc_pages+0x29f/0x300 mm/mempolicy.c:2183
 alloc_slab_page mm/slub.c:1744 [inline]
 allocate_slab mm/slub.c:1881 [inline]
 new_slab+0x321/0x490 mm/slub.c:1944
 ___slab_alloc+0x937/0x1000 mm/slub.c:2970
 __slab_alloc.constprop.0+0x51/0xa0 mm/slub.c:3057
 slab_alloc_node mm/slub.c:3148 [inline]
 kmem_cache_alloc_node_trace+0x187/0x400 mm/slub.c:3232
 kmalloc_node include/linux/slab.h:613 [inline]
 kzalloc_node include/linux/slab.h:743 [inline]
 blk_throtl_init+0x7c/0x660 block/blk-throttle.c:2420
 blkcg_init_queue+0x199/0x770 block/blk-cgroup.c:1193
 blk_alloc_queue+0x451/0x630 block/blk-core.c:567
 blk_mq_init_queue_data block/blk-mq.c:3120 [inline]
 __blk_mq_alloc_disk+0x47/0x190 block/blk-mq.c:3143
 loop_add+0x324/0x940 drivers/block/loop.c:2344
 loop_init+0x1f5/0x218 drivers/block/loop.c:2575
 do_one_initcall+0x103/0x650 init/main.c:1292
 do_initcall_level init/main.c:1367 [inline]
 do_initcalls init/main.c:1383 [inline]
 do_basic_setup init/main.c:1402 [inline]
 kernel_init_freeable+0x6b4/0x73d init/main.c:1604
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881463ee980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881463eea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881463eea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8881463eeb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881463eeb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/08/21 07:35 linux-next 86ed57fd8c93 b599f2fc .config console log report syz C ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
2021/08/25 07:30 linux-next 372b2891c15a b599f2fc .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
2021/08/24 03:28 linux-next 46debfec12b4 b599f2fc .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
2021/08/22 15:45 linux-next 86ed57fd8c93 b599f2fc .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
2021/08/21 14:49 linux-next 86ed57fd8c93 b599f2fc .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
2021/08/21 07:10 linux-next 86ed57fd8c93 b599f2fc .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in nbd_genl_connect
* Struck through repros no longer work on HEAD.