[v6.1] KASAN: use-after-free Read in hci_sock_get_cookie (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13ae963a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=0d5e09e91873efedf815
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0d5e09...@syzkaller.appspotmail.com

do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
==================================================================
BUG: KASAN: use-after-free in hci_sock_get_cookie+0x60/0x68 net/bluetooth/hci_sock.c:96
Read of size 4 at addr ffff0000d4a6e580 by task syz.4.342/5699

CPU: 0 PID: 5699 Comm: syz.4.342 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
print_address_description+0x88/0x218 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:420
kasan_report+0xa8/0xfc mm/kasan/report.c:524
__asan_report_load4_noabort+0x2c/0x38 mm/kasan/report_generic.c:350
hci_sock_get_cookie+0x60/0x68 net/bluetooth/hci_sock.c:96
mgmt_cmd_status+0x140/0x430 net/bluetooth/mgmt_util.c:149
cmd_status_rsp net/bluetooth/mgmt.c:1462 [inline]
cmd_complete_rsp+0xf4/0x1ac net/bluetooth/mgmt.c:1482
mgmt_pending_foreach+0xd4/0x148 net/bluetooth/mgmt_util.c:259
__mgmt_power_off+0x13c/0x32c net/bluetooth/mgmt.c:9549
hci_dev_close_sync+0x478/0xec8 net/bluetooth/hci_sync.c:5242
hci_dev_do_close net/bluetooth/hci_core.c:510 [inline]
hci_dev_close+0xe4/0x200 net/bluetooth/hci_core.c:535
hci_sock_ioctl+0x594/0x874 net/bluetooth/hci_sock.c:1074
sock_do_ioctl+0x100/0x258 net/socket.c:1201
sock_ioctl+0x238/0x824 net/socket.c:1320
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4521:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc+0xec/0x178 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]
sk_prot_alloc+0xc4/0x1ec net/core/sock.c:2052
sk_alloc+0x44/0x390 net/core/sock.c:2108
bt_sock_alloc+0x4c/0x140 net/bluetooth/af_bluetooth.c:148
hci_sock_create+0xa8/0x190 net/bluetooth/hci_sock.c:2142
bt_sock_create+0x14c/0x24c net/bluetooth/af_bluetooth.c:132
__sock_create+0x4b0/0x8b4 net/socket.c:1549
sock_create net/socket.c:1605 [inline]
__sys_socket_create net/socket.c:1642 [inline]
__sys_socket+0xc0/0x1ac net/socket.c:1670
__do_sys_socket net/socket.c:1683 [inline]
__se_sys_socket net/socket.c:1681 [inline]
__arm64_sys_socket+0x7c/0x94 net/socket.c:1681
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Freed by task 5701:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xbc/0x218 mm/slub.c:3700
kfree+0xd0/0x1a8 mm/slab_common.c:988
sk_prot_free net/core/sock.c:2091 [inline]
__sk_destruct+0x4dc/0x76c net/core/sock.c:2177
sk_destruct net/core/sock.c:2192 [inline]
__sk_free+0x320/0x430 net/core/sock.c:2203
sk_free+0x60/0xc4 net/core/sock.c:2214
sock_put include/net/sock.h:2085 [inline]
mgmt_pending_free+0x88/0x114 net/bluetooth/mgmt_util.c:307
mgmt_pending_remove+0xec/0x104 net/bluetooth/mgmt_util.c:315
cmd_complete_rsp+0xfc/0x1ac net/bluetooth/mgmt.c:-1
mgmt_pending_foreach+0xd4/0x148 net/bluetooth/mgmt_util.c:259
mgmt_index_removed+0x134/0x2e8 net/bluetooth/mgmt.c:9474
hci_sock_bind+0x890/0xcc0 net/bluetooth/hci_sock.c:1253
__sys_bind+0x1f8/0x2a4 net/socket.c:1810
__do_sys_bind net/socket.c:1821 [inline]
__se_sys_bind net/socket.c:1819 [inline]
__arm64_sys_bind+0x7c/0x94 net/socket.c:1819
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d4a6e000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1408 bytes inside of
2048-byte region [ffff0000d4a6e000, ffff0000d4a6e800)

The buggy address belongs to the physical page:
page:000000004724d5d7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114a68
head:000000004724d5d7 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc000312d800 dead000000000002 ffff0000c0002900
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000d4a6e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d4a6e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d4a6e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000d4a6e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d4a6e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Unable to handle kernel paging request at virtual address e0b9a094a00002c8
KASAN: maybe wild-memory-access in range [0x05d104a500001640-0x05d104a500001647]
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
[e0b9a094a00002c8] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5699 Comm: syz.4.342 Tainted: G B syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 02400005 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __list_del_entry_valid+0x78/0x158 lib/list_debug.c:59
lr : __list_del_entry_valid+0x4c/0x158 lib/list_debug.c:47
sp : ffff800021c175b0
x29: ffff800021c175b0 x28: ffff0000d0e60000 x27: ffff0000d4341378
x26: dfff800000000000 x25: ffff0000d43400a8 x24: 0000000000000000
x23: ffff0000f1d07c00 x22: dfff800000000000 x21: 05d104a500001645
x20: ffff0000d607fc00 x19: ffff0000f1d07c00 x18: ffff800011b7bf60
x17: 0000000000000000 x16: ffff800008042fdc x15: ffff8000089eda3c
x14: 0000000000000001 x13: 1ffff00002b4a6f2 x12: 0000000000ff0100
x11: ff00800010cd0b14 x10: 0000000000000000 x9 : ffff80001c465a90
x8 : 00ba2094a00002c8 x7 : ffff80000805977c x6 : ffff80000805998c
x5 : ffff0000f61ed098 x4 : ffff800021c17290 x3 : ffff80000a8d890c
x2 : dead000000000122 x1 : 0000000000000008 x0 : 0000000000000000
Call trace:
__list_del_entry_valid+0x78/0x158 lib/list_debug.c:59
__list_del_entry include/linux/list.h:134 [inline]
list_del include/linux/list.h:148 [inline]
mgmt_pending_remove+0x30/0x104 net/bluetooth/mgmt_util.c:314
cmd_complete_rsp+0xfc/0x1ac net/bluetooth/mgmt.c:-1
mgmt_pending_foreach+0xd4/0x148 net/bluetooth/mgmt_util.c:259
__mgmt_power_off+0x13c/0x32c net/bluetooth/mgmt.c:9549
hci_dev_close_sync+0x478/0xec8 net/bluetooth/hci_sync.c:5242
hci_dev_do_close net/bluetooth/hci_core.c:510 [inline]
hci_dev_close+0xe4/0x200 net/bluetooth/hci_core.c:535
hci_sock_ioctl+0x594/0x874 net/bluetooth/hci_sock.c:1074
sock_do_ioctl+0x100/0x258 net/socket.c:1201
sock_ioctl+0x238/0x824 net/socket.c:1320
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 91008902 eb0202bf 54000520 d343fea8 (38766908)
---[ end trace 0000000000000000 ]---


---
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