CVE-2022-48954

In the Linux kernel, the following vulnerability has been resolved:

s390/qeth: fix use-after-free in hsci

KASAN found that addr was dereferenced after br2dev_event_work was freed.

==================================================================

BUG: KASAN: use-after-free in qeth_l2_br2dev_worker+0x5ba/0x6b0

Read of size 1 at addr 00000000fdcea440 by task kworker/u760:4/540

CPU: 17 PID: 540 Comm: kworker/u760:4 Tainted: G E 6.1.0-20221128.rc7.git1.5aa3bed4ce83.300.fc36.s390x+kasan #1

Hardware name: IBM 8561 T01 703 (LPAR)

Workqueue: 0.0.8000_event qeth_l2_br2dev_worker

Call Trace:

[<000000016944d4ce>] dump_stack_lvl+0xc6/0xf8

[<000000016942cd9c>] print_address_description.constprop.0+0x34/0x2a0

[<000000016942d118>] print_report+0x110/0x1f8

[<0000000167a7bd04>] kasan_report+0xfc/0x128

[<000000016938d79a>] qeth_l2_br2dev_worker+0x5ba/0x6b0

[<00000001673edd1e>] process_one_work+0x76e/0x1128

[<00000001673ee85c>] worker_thread+0x184/0x1098

[<000000016740718a>] kthread+0x26a/0x310

[<00000001672c606a>] __ret_from_fork+0x8a/0xe8

[<00000001694711da>] ret_from_fork+0xa/0x40

Allocated by task 108338:

kasan_save_stack+0x40/0x68

kasan_set_track+0x36/0x48

__kasan_kmalloc+0xa0/0xc0

qeth_l2_switchdev_event+0x25a/0x738

atomic_notifier_call_chain+0x9c/0xf8

br_switchdev_fdb_notify+0xf4/0x110

fdb_notify+0x122/0x180

fdb_add_entry.constprop.0.isra.0+0x312/0x558

br_fdb_add+0x59e/0x858

rtnl_fdb_add+0x58a/0x928

rtnetlink_rcv_msg+0x5f8/0x8d8

netlink_rcv_skb+0x1f2/0x408

netlink_unicast+0x570/0x790

netlink_sendmsg+0x752/0xbe0

sock_sendmsg+0xca/0x110

____sys_sendmsg+0x510/0x6a8

___sys_sendmsg+0x12a/0x180

__sys_sendmsg+0xe6/0x168

__do_sys_socketcall+0x3c8/0x468

do_syscall+0x22c/0x328

__do_syscall+0x94/0xf0

system_call+0x82/0xb0

Freed by task 540:

kasan_save_stack+0x40/0x68

kasan_set_track+0x36/0x48

kasan_save_free_info+0x4c/0x68

____kasan_slab_free+0x14e/0x1a8

__kasan_slab_free+0x24/0x30

__kmem_cache_free+0x168/0x338

qeth_l2_br2dev_worker+0x154/0x6b0

process_one_work+0x76e/0x1128

worker_thread+0x184/0x1098

kthread+0x26a/0x310

__ret_from_fork+0x8a/0xe8

ret_from_fork+0xa/0x40

Last potentially related work creation:

kasan_save_stack+0x40/0x68

__kasan_record_aux_stack+0xbe/0xd0

insert_work+0x56/0x2e8

__queue_work+0x4ce/0xd10

queue_work_on+0xf4/0x100

qeth_l2_switchdev_event+0x520/0x738

atomic_notifier_call_chain+0x9c/0xf8

br_switchdev_fdb_notify+0xf4/0x110

fdb_notify+0x122/0x180

fdb_add_entry.constprop.0.isra.0+0x312/0x558

br_fdb_add+0x59e/0x858

rtnl_fdb_add+0x58a/0x928

rtnetlink_rcv_msg+0x5f8/0x8d8

netlink_rcv_skb+0x1f2/0x408

netlink_unicast+0x570/0x790

netlink_sendmsg+0x752/0xbe0

sock_sendmsg+0xca/0x110

____sys_sendmsg+0x510/0x6a8

___sys_sendmsg+0x12a/0x180

__sys_sendmsg+0xe6/0x168

__do_sys_socketcall+0x3c8/0x468

do_syscall+0x22c/0x328

__do_syscall+0x94/0xf0

system_call+0x82/0xb0

Second to last potentially related work creation:

kasan_save_stack+0x40/0x68

__kasan_record_aux_stack+0xbe/0xd0

kvfree_call_rcu+0xb2/0x760

kernfs_unlink_open_file+0x348/0x430

kernfs_fop_release+0xc2/0x320

__fput+0x1ae/0x768

task_work_run+0x1bc/0x298

exit_to_user_mode_prepare+0x1a0/0x1a8

__do_syscall+0x94/0xf0

system_call+0x82/0xb0

The buggy address belongs to the object at 00000000fdcea400

which belongs to the cache kmalloc-96 of size 96

The buggy address is located 64 bytes inside of

96-byte region [00000000fdcea400, 00000000fdcea460)

The buggy address belongs to the physical page:

page:000000005a9c26e8 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xfdcea

flags: 0x3ffff00000000200(slab|node=0|zone=1|lastcpupid=0x1ffff)

raw: 3ffff00000000200 0000000000000000 0000000100000122 000000008008cc00

raw: 0000000000000000 0020004100000000 ffffffff00000001 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

00000000fdcea300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc

00000000fdcea380: fb fb fb fb fb fb f

---truncated---