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KASAN: slab-use-after-free Read in hci_conn_del

Status: fixed on 2023/07/01 16:05
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com
Fix commit: ca1fd42e7dbf Bluetooth: Fix potential double free caused by hci_conn_unlink
First crash: 366d, last: 337d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in hci_conn_del 0 (1) 2023/05/02 06:16

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in hci_conn_del+0x599/0x950 net/bluetooth/hci_conn.c:1142
Read of size 1 at addr ffff8880795ec039 by task kworker/u5:4/5035

CPU: 1 PID: 5035 Comm: kworker/u5:4 Not tainted 6.4.0-rc3-syzkaller-00032-g933174ae28ba #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/16/2023
Workqueue: hci5 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
 print_report mm/kasan/report.c:462 [inline]
 kasan_report+0x11c/0x130 mm/kasan/report.c:572
 hci_conn_del+0x599/0x950 net/bluetooth/hci_conn.c:1142
 hci_conn_complete_evt+0x867/0x1010 net/bluetooth/hci_event.c:3233
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x956/0xfd0 net/bluetooth/hci_event.c:7529
 hci_rx_work+0xaeb/0x1340 net/bluetooth/hci_core.c:4062
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Allocated by task 6835:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 ____kasan_kmalloc mm/kasan/common.c:333 [inline]
 __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:559 [inline]
 kzalloc include/linux/slab.h:680 [inline]
 hci_conn_add+0xb8/0x16b0 net/bluetooth/hci_conn.c:986
 hci_connect_sco+0x3c7/0x1050 net/bluetooth/hci_conn.c:1663
 sco_connect net/bluetooth/sco.c:264 [inline]
 sco_sock_connect+0x2d7/0xae0 net/bluetooth/sco.c:610
 __sys_connect_file+0x153/0x1a0 net/socket.c:2003
 __sys_connect+0x165/0x1a0 net/socket.c:2020
 __do_sys_connect net/socket.c:2030 [inline]
 __se_sys_connect net/socket.c:2027 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:2027
 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+0x63/0xcd

Freed by task 5035:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:162 [inline]
 __cache_free mm/slab.c:3389 [inline]
 __do_kmem_cache_free mm/slab.c:3576 [inline]
 __kmem_cache_free+0xcd/0x2c0 mm/slab.c:3583
 device_release+0xa3/0x240 drivers/base/core.c:2484
 kobject_cleanup lib/kobject.c:683 [inline]
 kobject_release lib/kobject.c:714 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c2/0x4d0 lib/kobject.c:731
 put_device+0x1f/0x30 drivers/base/core.c:3733
 hci_conn_del+0x1e5/0x950 net/bluetooth/hci_conn.c:1162
 hci_conn_unlink+0x2ce/0x460 net/bluetooth/hci_conn.c:1109
 hci_conn_del+0x10f/0x950 net/bluetooth/hci_conn.c:1137
 hci_conn_complete_evt+0x867/0x1010 net/bluetooth/hci_event.c:3233
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x956/0xfd0 net/bluetooth/hci_event.c:7529
 hci_rx_work+0xaeb/0x1340 net/bluetooth/hci_core.c:4062
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Last potentially related work creation:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0x7b/0x90 mm/kasan/generic.c:491
 insert_work+0x48/0x360 kernel/workqueue.c:1365
 __queue_work+0x625/0x1120 kernel/workqueue.c:1526
 __queue_delayed_work+0x1c8/0x270 kernel/workqueue.c:1674
 queue_delayed_work_on+0x109/0x120 kernel/workqueue.c:1710
 queue_delayed_work include/linux/workqueue.h:520 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1444 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1414 [inline]
 sco_chan_del+0x1f8/0x4f0 net/bluetooth/sco.c:169
 __sco_sock_close+0x178/0x740 net/bluetooth/sco.c:454
 sco_sock_shutdown+0x1dd/0x350 net/bluetooth/sco.c:1243
 __sys_shutdown_sock net/socket.c:2345 [inline]
 __sys_shutdown_sock net/socket.c:2339 [inline]
 __sys_shutdown+0xf5/0x1c0 net/socket.c:2357
 __do_sys_shutdown net/socket.c:2365 [inline]
 __se_sys_shutdown net/socket.c:2363 [inline]
 __x64_sys_shutdown+0x54/0x80 net/socket.c:2363
 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+0x63/0xcd

The buggy address belongs to the object at ffff8880795ec000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 57 bytes inside of
 freed 4096-byte region [ffff8880795ec000, ffff8880795ed000)

The buggy address belongs to the physical page:
page:ffffea0001e57b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x795ec
head:ffffea0001e57b00 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0x1()
raw: 00fff00000010200 ffff888012440900 ffffea0000db2510 ffffea0000e16090
raw: 0000000000000000 ffff8880795ec000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x3420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 6835, tgid 6834 (syz-executor.0), ts 408666015964, free_ts 408619809041
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1731
 prep_new_page mm/page_alloc.c:1738 [inline]
 get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3502
 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4768
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 kmem_getpages mm/slab.c:1360 [inline]
 cache_grow_begin+0x9b/0x3b0 mm/slab.c:2569
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
 ____cache_alloc mm/slab.c:3018 [inline]
 ____cache_alloc mm/slab.c:3001 [inline]
 __do_cache_alloc mm/slab.c:3201 [inline]
 slab_alloc_node mm/slab.c:3249 [inline]
 __kmem_cache_alloc_node+0x360/0x3f0 mm/slab.c:3540
 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1057
 kmalloc include/linux/slab.h:559 [inline]
 kzalloc include/linux/slab.h:680 [inline]
 hci_conn_add+0xb8/0x16b0 net/bluetooth/hci_conn.c:986
 hci_connect_sco+0x3c7/0x1050 net/bluetooth/hci_conn.c:1663
 sco_connect net/bluetooth/sco.c:264 [inline]
 sco_sock_connect+0x2d7/0xae0 net/bluetooth/sco.c:610
 __sys_connect_file+0x153/0x1a0 net/socket.c:2003
 __sys_connect+0x165/0x1a0 net/socket.c:2020
 __do_sys_connect net/socket.c:2030 [inline]
 __se_sys_connect net/socket.c:2027 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:2027
 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+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1302 [inline]
 free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2564
 free_unref_page+0x33/0x370 mm/page_alloc.c:2659
 slab_destroy mm/slab.c:1612 [inline]
 slabs_destroy+0x85/0xc0 mm/slab.c:1632
 cache_flusharray mm/slab.c:3360 [inline]
 ___cache_free+0x2ae/0x3d0 mm/slab.c:3423
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x4f/0x1a0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x195/0x220 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:186 [inline]
 slab_post_alloc_hook mm/slab.h:711 [inline]
 slab_alloc_node mm/slab.c:3256 [inline]
 slab_alloc mm/slab.c:3265 [inline]
 __kmem_cache_alloc_lru mm/slab.c:3442 [inline]
 kmem_cache_alloc+0x1bd/0x3f0 mm/slab.c:3451
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:140
 getname_flags+0x9e/0xe0 include/linux/audit.h:321
 vfs_fstatat+0x77/0xb0 fs/stat.c:275
 __do_sys_newfstatat+0x8a/0x110 fs/stat.c:446
 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+0x63/0xcd

Memory state around the buggy address:
 ffff8880795ebf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880795ebf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880795ec000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8880795ec080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880795ec100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/05/25 15:00 upstream 933174ae28ba 0513b3e6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in hci_conn_del
2023/05/24 21:38 upstream 9d646009f65d 4bce1a3e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in hci_conn_del
2023/05/19 06:58 upstream 2d1bcbc6cd70 3bb7af1d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in hci_conn_del
2023/05/07 06:16 upstream fc4354c6e5c2 90c93c40 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in hci_conn_del
2023/04/29 00:55 upstream 22b8cc3e78f5 62df2017 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in hci_conn_del
2023/05/19 15:37 upstream 2d1bcbc6cd70 e0257275 .config console log report info ci-qemu-upstream-386 KASAN: slab-use-after-free Read in hci_conn_del
2023/04/26 21:40 linux-next b7455b10da76 19a3dabe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in hci_conn_del
* Struck through repros no longer work on HEAD.