syzbot


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

Status: upstream: reported on 2025/08/07 13:44
Reported-by: syzbot+c2fc6d2a87ce8647c6b6@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in hci_sock_get_cookie 19 1 246d 246d 0/3 auto-obsoleted due to no activity on 2025/03/28 01:01
linux-6.1 KASAN: use-after-free Read in hci_sock_get_cookie 19 1 54d 54d 0/3 upstream: reported on 2025/06/27 19:58
upstream KASAN: slab-use-after-free Read in hci_sock_get_cookie bluetooth 19 2 469d 477d 0/29 closed as invalid on 2024/06/04 19:11
upstream KASAN: slab-use-after-free Read in hci_sock_get_cookie (2) bluetooth 19 47 100d 427d 0/29 auto-obsoleted due to no activity on 2025/08/20 20:16

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in hci_sock_get_cookie+0x41/0x50 net/bluetooth/hci_sock.c:95
Read of size 4 at addr ffff88805d0d0580 by task syz.5.1140/8082

CPU: 1 PID: 8082 Comm: syz.5.1140 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 hci_sock_get_cookie+0x41/0x50 net/bluetooth/hci_sock.c:95
 mgmt_cmd_complete+0x1f4/0x480 net/bluetooth/mgmt_util.c:163
 clock_info_cmd_complete+0x263/0x430 net/bluetooth/mgmt.c:6553
 cmd_complete_rsp+0x64/0x170 net/bluetooth/mgmt.c:1307
 mgmt_pending_foreach+0xc1/0x110 net/bluetooth/mgmt_util.c:226
 __mgmt_power_off+0x16a/0x340 net/bluetooth/mgmt.c:8638
 hci_dev_do_close+0x5c8/0x1030 net/bluetooth/hci_core.c:1791
 hci_dev_close+0xd7/0x180 net/bluetooth/hci_core.c:1877
 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1140
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbb0a552be9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbb087ba038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbb0a779fa0 RCX: 00007fbb0a552be9
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000004
RBP: 00007fbb0a5d5e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb0a77a038 R14: 00007fbb0a779fa0 R15: 00007ffc42cacef8
 </TASK>

Allocated by task 6182:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 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+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:609 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:1864
 sk_alloc+0x2f/0x310 net/core/sock.c:1917
 hci_sock_create+0xa0/0x220 net/bluetooth/hci_sock.c:2094
 bt_sock_create+0x155/0x220 net/bluetooth/af_bluetooth.c:130
 __sock_create+0x47b/0x900 net/socket.c:1486
 sock_create net/socket.c:1542 [inline]
 __sys_socket+0xe2/0x170 net/socket.c:1584
 __do_sys_socket net/socket.c:1593 [inline]
 __se_sys_socket net/socket.c:1591 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1591
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 8083:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4559
 sk_prot_free net/core/sock.c:1900 [inline]
 __sk_destruct+0x55a/0x820 net/core/sock.c:1986
 sock_put include/net/sock.h:1939 [inline]
 mgmt_pending_free net/bluetooth/mgmt_util.c:261 [inline]
 mgmt_pending_remove+0x13d/0x1a0 net/bluetooth/mgmt_util.c:269
 mgmt_pending_foreach+0xc1/0x110 net/bluetooth/mgmt_util.c:226
 mgmt_index_removed+0x119/0x280 net/bluetooth/mgmt.c:8546
 hci_sock_bind+0xa96/0xe20 net/bluetooth/hci_sock.c:1246
 __sys_bind+0x2f4/0x3f0 net/socket.c:1720
 __do_sys_bind net/socket.c:1731 [inline]
 __se_sys_bind net/socket.c:1729 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1729
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88805d0d0000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1408 bytes inside of
 2048-byte region [ffff88805d0d0000, ffff88805d0d0800)
The buggy address belongs to the page:
page:ffffea0001743400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5d0d0
head:ffffea0001743400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888016842000
raw: 0000000000000000 0000000000080008 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 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4319, ts 59857501833, free_ts 12969731604
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5474
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 __kmalloc+0x1cd/0x330 mm/slub.c:4403
 kmalloc include/linux/slab.h:609 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 tomoyo_init_log+0x19b4/0x1e40 security/tomoyo/audit.c:275
 tomoyo_supervisor+0x34e/0x10d0 security/tomoyo/common.c:2097
 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
 tomoyo_env_perm+0x146/0x1e0 security/tomoyo/environ.c:63
 tomoyo_environ security/tomoyo/domain.c:672 [inline]
 tomoyo_find_next_domain+0x1593/0x1a60 security/tomoyo/domain.c:882
 tomoyo_bprm_check_security+0xdd/0x120 security/tomoyo/tomoyo.c:101
 security_bprm_check+0x5e/0x90 security/security.c:868
 search_binary_handler fs/exec.c:1730 [inline]
 exec_binprm fs/exec.c:1783 [inline]
 bprm_execve+0x9f7/0x17d0 fs/exec.c:1852
 do_execveat_common+0x51e/0x6d0 fs/exec.c:1957
 do_execve fs/exec.c:2027 [inline]
 __do_sys_execve fs/exec.c:2103 [inline]
 __se_sys_execve fs/exec.c:2098 [inline]
 __x64_sys_execve+0x8e/0xa0 fs/exec.c:2098
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x94/0x280 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9393
 destroy_args+0xef/0x8b0 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x318/0x370 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88805d0d0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805d0d0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805d0d0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88805d0d0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805d0d0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/07 13:43 linux-5.15.y c79648372d02 04cffc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in hci_sock_get_cookie
* Struck through repros no longer work on HEAD.