Subject: CVE-2024-46782: ila: call nf_unregister_net_hooks() sooner

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

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

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

ila: call nf_unregister_net_hooks() sooner

syzbot found an use-after-free Read in ila_nf_input [1]

Issue here is that ila_xlat_exit_net() frees the rhashtable,
then call nf_unregister_net_hooks().

It should be done in the reverse way, with a synchronize_rcu().

This is a good match for a pre_exit() method.

[1]
 BUG: KASAN: use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline]
 BUG: KASAN: use-after-free in __rhashtable_lookup include/linux/rhashtable.h:604 [inline]
 BUG: KASAN: use-after-free in rhashtable_lookup include/linux/rhashtable.h:646 [inline]
 BUG: KASAN: use-after-free in rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672
Read of size 4 at addr ffff888064620008 by task ksoftirqd/0/16

CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.11.0-rc4-syzkaller-00238-g2ad6d23f465a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:93 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
  print_address_description mm/kasan/report.c:377 [inline]
  print_report+0x169/0x550 mm/kasan/report.c:488
  kasan_report+0x143/0x180 mm/kasan/report.c:601
  rht_key_hashfn include/linux/rhashtable.h:159 [inline]
  __rhashtable_lookup include/linux/rhashtable.h:604 [inline]
  rhashtable_lookup include/linux/rhashtable.h:646 [inline]
  rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672
  ila_lookup_wildcards net/ipv6/ila/ila_xlat.c:132 [inline]
  ila_xlat_addr net/ipv6/ila/ila_xlat.c:652 [inline]
  ila_nf_input+0x1fe/0x3c0 net/ipv6/ila/ila_xlat.c:190
  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
  nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
  nf_hook include/linux/netfilter.h:269 [inline]
  NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312
  __netif_receive_skb_one_core net/core/dev.c:5661 [inline]
  __netif_receive_skb+0x1ea/0x650 net/core/dev.c:5775
  process_backlog+0x662/0x15b0 net/core/dev.c:6108
  __napi_poll+0xcb/0x490 net/core/dev.c:6772
  napi_poll net/core/dev.c:6841 [inline]
  net_rx_action+0x89b/0x1240 net/core/dev.c:6963
  handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
  run_ksoftirqd+0xca/0x130 kernel/softirq.c:928
  smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
  kthread+0x2f0/0x390 kernel/kthread.c:389
  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x64620
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xbfffffff(buddy)
raw: 00fff00000000000 ffffea0000959608 ffffea00019d9408 0000000000000000
raw: 0000000000000000 0000000000000003 00000000bfffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52dc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_ZERO), pid 5242, tgid 5242 (syz-executor), ts 73611328570, free_ts 618981657187
  set_page_owner include/linux/page_owner.h:32 [inline]
  post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
  prep_new_page mm/page_alloc.c:1501 [inline]
  get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
  __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
  __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
  alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
  ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4103
  __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4130
  __do_kmalloc_node mm/slub.c:4146 [inline]
  __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4164
  __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
  bucket_table_alloc lib/rhashtable.c:186 [inline]
  rhashtable_init_noprof+0x534/0xa60 lib/rhashtable.c:1071
  ila_xlat_init_net+0xa0/0x110 net/ipv6/ila/ila_xlat.c:613
  ops_init+0x359/0x610 net/core/net_namespace.c:139
  setup_net+0x515/0xca0 net/core/net_namespace.c:343
  copy_net_ns+0x4e2/0x7b0 net/core/net_namespace.c:508
  create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
  unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
  ksys_unshare+0x619/0xc10 kernel/fork.c:3328
  __do_sys_unshare kernel/fork.c:3399 [inline]
  __se_sys_unshare kernel/fork.c:3397 [inline]
  __x64_sys_unshare+0x38/0x40 kernel/fork.c:3397
page last free pid 11846 tgid 11846 stack trace:
  reset_page_owner include/linux/page_owner.h:25 [inline]
  free_pages_prepare mm/page_alloc.c:1094 [inline]
  free_unref_page+0xd22/0xea0 mm/page_alloc.c:2612
  __folio_put+0x2c8/0x440 mm/swap.c:128
  folio_put include/linux/mm.h:1486 [inline]
  free_large_kmalloc+0x105/0x1c0 mm/slub.c:4565
  kfree+0x1c4/0x360 mm/slub.c:4588
  rhashtable_free_and_destroy+0x7c6/0x920 lib/rhashtable.c:1169
  ila_xlat_exit_net+0x55/0x110 net/ipv6/ila/ila_xlat.c:626
  ops_exit_list net/core/net_namespace.c:173 [inline]
  cleanup_net+0x802/0xcc0 net/core/net_namespace.c:640
  process_one_work kernel/workqueue.c:3231 [inline]
  process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
  worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
  kthread+0x2f0/0x390 kernel/kthread.c:389
  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff88806461ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806461ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888064620000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff888064620080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888064620100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

The Linux kernel CVE team has assigned CVE-2024-46782 to this issue.

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

	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 4.19.322 with commit 43d34110882b
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 5.4.284 with commit dcaf4e221682
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 5.10.226 with commit 93ee345ba349
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 5.15.167 with commit bda4d84ac0d5
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 6.1.110 with commit 925c18a7cff9
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 6.6.51 with commit 18a5a1694046
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 6.10.10 with commit 47abd8adddbc
	Issue introduced in 4.5 with commit 7f00feaf1076 and fixed in 6.11 with commit 031ae72825ce

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-2024-46782
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:
	net/ipv6/ila/ila.h
	net/ipv6/ila/ila_main.c
	net/ipv6/ila/ila_xlat.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/43d34110882b97ba1ec66cc8234b18983efb9abf
	https://git.kernel.org/stable/c/dcaf4e2216824839d26727a15b638c6a677bd9fc
	https://git.kernel.org/stable/c/93ee345ba349922834e6a9d1dadabaedcc12dce6
	https://git.kernel.org/stable/c/bda4d84ac0d5421b346faee720011f58bdb99673
	https://git.kernel.org/stable/c/925c18a7cff93d8a4320d652351294ff7d0ac93c
	https://git.kernel.org/stable/c/18a5a16940464b301ea91bf5da3a324aedb347b2
	https://git.kernel.org/stable/c/47abd8adddbc0aecb8f231269ef659148d5dabe4
	https://git.kernel.org/stable/c/031ae72825cef43e4650140b800ad58bf7a6a466