Message-ID: <2025050226-CVE-2023-53107-ef59@gregkh>
Date: Fri,  2 May 2025 17:56:12 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53107: veth: Fix use after free in XDP_REDIRECT

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

veth: Fix use after free in XDP_REDIRECT

Commit 718a18a0c8a6 ("veth: Rework veth_xdp_rcv_skb in order
to accept non-linear skb") introduced a bug where it tried to
use pskb_expand_head() if the headroom was less than
XDP_PACKET_HEADROOM.  This however uses kmalloc to expand the head,
which will later allow consume_skb() to free the skb while is it still
in use by AF_XDP.

Previously if the headroom was less than XDP_PACKET_HEADROOM we
continued on to allocate a new skb from pages so this restores that
behavior.

BUG: KASAN: use-after-free in __xsk_rcv+0x18d/0x2c0
Read of size 78 at addr ffff888976250154 by task napi/iconduit-g/148640

CPU: 5 PID: 148640 Comm: napi/iconduit-g Kdump: loaded Tainted: G           O       6.1.4-cloudflare-kasan-2023.1.2 #1
Hardware name: Quanta Computer Inc. QuantaPlex T41S-2U/S2S-MB, BIOS S2S_3B10.03 06/21/2018
Call Trace:
  <TASK>
  dump_stack_lvl+0x34/0x48
  print_report+0x170/0x473
  ? __xsk_rcv+0x18d/0x2c0
  kasan_report+0xad/0x130
  ? __xsk_rcv+0x18d/0x2c0
  kasan_check_range+0x149/0x1a0
  memcpy+0x20/0x60
  __xsk_rcv+0x18d/0x2c0
  __xsk_map_redirect+0x1f3/0x490
  ? veth_xdp_rcv_skb+0x89c/0x1ba0 [veth]
  xdp_do_redirect+0x5ca/0xd60
  veth_xdp_rcv_skb+0x935/0x1ba0 [veth]
  ? __netif_receive_skb_list_core+0x671/0x920
  ? veth_xdp+0x670/0x670 [veth]
  veth_xdp_rcv+0x304/0xa20 [veth]
  ? do_xdp_generic+0x150/0x150
  ? veth_xdp_rcv_one+0xde0/0xde0 [veth]
  ? _raw_spin_lock_bh+0xe0/0xe0
  ? newidle_balance+0x887/0xe30
  ? __perf_event_task_sched_in+0xdb/0x800
  veth_poll+0x139/0x571 [veth]
  ? veth_xdp_rcv+0xa20/0xa20 [veth]
  ? _raw_spin_unlock+0x39/0x70
  ? finish_task_switch.isra.0+0x17e/0x7d0
  ? __switch_to+0x5cf/0x1070
  ? __schedule+0x95b/0x2640
  ? io_schedule_timeout+0x160/0x160
  __napi_poll+0xa1/0x440
  napi_threaded_poll+0x3d1/0x460
  ? __napi_poll+0x440/0x440
  ? __kthread_parkme+0xc6/0x1f0
  ? __napi_poll+0x440/0x440
  kthread+0x2a2/0x340
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x22/0x30
  </TASK>

Freed by task 148640:
  kasan_save_stack+0x23/0x50
  kasan_set_track+0x21/0x30
  kasan_save_free_info+0x2a/0x40
  ____kasan_slab_free+0x169/0x1d0
  slab_free_freelist_hook+0xd2/0x190
  __kmem_cache_free+0x1a1/0x2f0
  skb_release_data+0x449/0x600
  consume_skb+0x9f/0x1c0
  veth_xdp_rcv_skb+0x89c/0x1ba0 [veth]
  veth_xdp_rcv+0x304/0xa20 [veth]
  veth_poll+0x139/0x571 [veth]
  __napi_poll+0xa1/0x440
  napi_threaded_poll+0x3d1/0x460
  kthread+0x2a2/0x340
  ret_from_fork+0x22/0x30

The buggy address belongs to the object at ffff888976250000
  which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 340 bytes inside of
  2048-byte region [ffff888976250000, ffff888976250800)

The buggy address belongs to the physical page:
page:00000000ae18262a refcount:2 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x976250
head:00000000ae18262a order:3 compound_mapcount:0 compound_pincount:0
flags: 0x2ffff800010200(slab|head|node=0|zone=2|lastcpupid=0x1ffff)
raw: 002ffff800010200 0000000000000000 dead000000000122 ffff88810004cf00
raw: 0000000000000000 0000000080080008 00000002ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888976250000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888976250080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888976250100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                  ^
  ffff888976250180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888976250200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

The Linux kernel CVE team has assigned CVE-2023-53107 to this issue.


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

	Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 6.1.21 with commit 717d20710596b5b26595ede454d1105fa176f4a4
	Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 6.2.8 with commit 6e755b56896df48b0fae0db275e148f8d8aa7d6f
	Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 6.3 with commit 7c10131803e45269ddc6c817f19ed649110f3cae

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-2023-53107
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/net/veth.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/717d20710596b5b26595ede454d1105fa176f4a4
	https://git.kernel.org/stable/c/6e755b56896df48b0fae0db275e148f8d8aa7d6f
	https://git.kernel.org/stable/c/7c10131803e45269ddc6c817f19ed649110f3cae

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