CVE-2023-53192

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

vxlan: Fix nexthop hash size

The nexthop code expects a 31 bit hash, such as what is returned by

fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash

returned by skb_get_hash() can lead to problems related to the fact that

'int hash' is a negative number when the MSB is set.

In the case of hash threshold nexthop groups, nexthop_select_path_hthr()

will disproportionately select the first nexthop group entry. In the case

of resilient nexthop groups, nexthop_select_path_res() may do an out of

bounds access in nh_buckets[], for example:

hash = -912054133

num_nh_buckets = 2

bucket_index = 65535

which leads to the following panic:

BUG: unable to handle page fault for address: ffffc900025910c8

PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0

Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI

CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014

Workqueue: ipv6_addrconf addrconf_dad_work

RIP: 0010:nexthop_select_path+0x197/0xbf0

Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85

RSP: 0018:ffff88810c36f260 EFLAGS: 00010246

RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77

RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8

RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219

R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0

R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900

FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0

PKRU: 55555554

Call Trace:

<TASK>

? __die+0x23/0x70

? page_fault_oops+0x1ee/0x5c0

? __pfx_is_prefetch.constprop.0+0x10/0x10

? __pfx_page_fault_oops+0x10/0x10

? search_bpf_extables+0xfe/0x1c0

? fixup_exception+0x3b/0x470

? exc_page_fault+0xf6/0x110

? asm_exc_page_fault+0x26/0x30

? nexthop_select_path+0x197/0xbf0

? nexthop_select_path+0x197/0xbf0

? lock_is_held_type+0xe7/0x140

vxlan_xmit+0x5b2/0x2340

? __lock_acquire+0x92b/0x3370

? __pfx_vxlan_xmit+0x10/0x10

? __pfx___lock_acquire+0x10/0x10

? __pfx_register_lock_class+0x10/0x10

? skb_network_protocol+0xce/0x2d0

? dev_hard_start_xmit+0xca/0x350

? __pfx_vxlan_xmit+0x10/0x10

dev_hard_start_xmit+0xca/0x350

__dev_queue_xmit+0x513/0x1e20

? __pfx___dev_queue_xmit+0x10/0x10

? __pfx_lock_release+0x10/0x10

? mark_held_locks+0x44/0x90

? skb_push+0x4c/0x80

? eth_header+0x81/0xe0

? __pfx_eth_header+0x10/0x10

? neigh_resolve_output+0x215/0x310

? ip6_finish_output2+0x2ba/0xc90

ip6_finish_output2+0x2ba/0xc90

? lock_release+0x236/0x3e0

? ip6_mtu+0xbb/0x240

? __pfx_ip6_finish_output2+0x10/0x10

? find_held_lock+0x83/0xa0

? lock_is_held_type+0xe7/0x140

ip6_finish_output+0x1ee/0x780

ip6_output+0x138/0x460

? __pfx_ip6_output+0x10/0x10

? __pfx___lock_acquire+0x10/0x10

? __pfx_ip6_finish_output+0x10/0x10

NF_HOOK.constprop.0+0xc0/0x420

? __pfx_NF_HOOK.constprop.0+0x10/0x10

? ndisc_send_skb+0x2c0/0x960

? __pfx_lock_release+0x10/0x10

? __local_bh_enable_ip+0x93/0x110

? lock_is_held_type+0xe7/0x140

ndisc_send_skb+0x4be/0x960

? __pfx_ndisc_send_skb+0x10/0x10

? mark_held_locks+0x65/0x90

? find_held_lock+0x83/0xa0

ndisc_send_ns+0xb0/0x110

? __pfx_ndisc_send_ns+0x10/0x10

addrconf_dad_work+0x631/0x8e0

? lock_acquire+0x180/0x3f0

? __pfx_addrconf_dad_work+0x10/0x10

? mark_held_locks+0x24/0x90

process_one_work+0x582/0x9c0

? __pfx_process_one_work+0x10/0x10

? __pfx_do_raw_spin_lock+0x10/0x10

? mark_held_locks+0x24/0x90

worker_thread+0x93/0x630

? __kthread_parkme+0xdc/0x100

? __pfx_worker_thread+0x10/0x10

kthread+0x1a5/0x1e0

? __pfx_kthread+0x10/0x10

ret_from_fork+0x34/0x60

---truncated---