Subject: CVE-2022-48954: s390/qeth: fix use-after-free in hsci

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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 fb fb fb fb fb fb fc fc fc fc
>00000000fdcea400: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                           ^
 00000000fdcea480: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 00000000fdcea500: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================

The Linux kernel CVE team has assigned CVE-2022-48954 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.15 with commit f7936b7b2663 and fixed in 5.15.83 with commit db6343a5b0d9
	Issue introduced in 5.15 with commit f7936b7b2663 and fixed in 6.0.13 with commit bde0dfc7c456
	Issue introduced in 5.15 with commit f7936b7b2663 and fixed in 6.1 with commit ebaaadc332cd

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-48954
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/s390/net/qeth_l2_main.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/db6343a5b0d9661f2dd76f653c6d274d38234d2b
	https://git.kernel.org/stable/c/bde0dfc7c4569406a6ddeec363d04a1df7b3073f
	https://git.kernel.org/stable/c/ebaaadc332cd21e9df4dcf9ce12552d9354bbbe4