Subject: CVE-2022-48912: netfilter: fix use-after-free in __nf_register_net_hook()

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

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

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

netfilter: fix use-after-free in __nf_register_net_hook()

We must not dereference @new_hooks after nf_hook_mutex has been released,
because other threads might have freed our allocated hooks already.

BUG: KASAN: use-after-free in nf_hook_entries_get_hook_ops include/linux/netfilter.h:130 [inline]
BUG: KASAN: use-after-free in hooks_validate net/netfilter/core.c:171 [inline]
BUG: KASAN: use-after-free in __nf_register_net_hook+0x77a/0x820 net/netfilter/core.c:438
Read of size 2 at addr ffff88801c1a8000 by task syz-executor237/4430

CPU: 1 PID: 4430 Comm: syz-executor237 Not tainted 5.17.0-rc5-syzkaller-00306-g2293be58d6a1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 nf_hook_entries_get_hook_ops include/linux/netfilter.h:130 [inline]
 hooks_validate net/netfilter/core.c:171 [inline]
 __nf_register_net_hook+0x77a/0x820 net/netfilter/core.c:438
 nf_register_net_hook+0x114/0x170 net/netfilter/core.c:571
 nf_register_net_hooks+0x59/0xc0 net/netfilter/core.c:587
 nf_synproxy_ipv6_init+0x85/0xe0 net/netfilter/nf_synproxy_core.c:1218
 synproxy_tg6_check+0x30d/0x560 net/ipv6/netfilter/ip6t_SYNPROXY.c:81
 xt_check_target+0x26c/0x9e0 net/netfilter/x_tables.c:1038
 check_target net/ipv6/netfilter/ip6_tables.c:530 [inline]
 find_check_entry.constprop.0+0x7f1/0x9e0 net/ipv6/netfilter/ip6_tables.c:573
 translate_table+0xc8b/0x1750 net/ipv6/netfilter/ip6_tables.c:735
 do_replace net/ipv6/netfilter/ip6_tables.c:1153 [inline]
 do_ip6t_set_ctl+0x56e/0xb90 net/ipv6/netfilter/ip6_tables.c:1639
 nf_setsockopt+0x83/0xe0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x122/0x180 net/ipv6/ipv6_sockglue.c:1024
 rawv6_setsockopt+0xd3/0x6a0 net/ipv6/raw.c:1084
 __sys_setsockopt+0x2db/0x610 net/socket.c:2180
 __do_sys_setsockopt net/socket.c:2191 [inline]
 __se_sys_setsockopt net/socket.c:2188 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2188
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f65a1ace7d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f65a1a7f308 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f65a1ace7d9
RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 00007f65a1b574c8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 00007f65a1b55130
R13: 00007f65a1b574c0 R14: 00007f65a1b24090 R15: 0000000000022000
 </TASK>

The buggy address belongs to the page:
page:ffffea0000706a00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c1a8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001c1b108 ffffea000046dd08 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52dc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_ZERO), pid 4430, ts 1061781545818, free_ts 1061791488993
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
 __alloc_pages_node include/linux/gfp.h:572 [inline]
 alloc_pages_node include/linux/gfp.h:595 [inline]
 kmalloc_large_node+0x62/0x130 mm/slub.c:4438
 __kmalloc_node+0x35a/0x4a0 mm/slub.c:4454
 kmalloc_node include/linux/slab.h:604 [inline]
 kvmalloc_node+0x97/0x100 mm/util.c:580
 kvmalloc include/linux/slab.h:731 [inline]
 kvzalloc include/linux/slab.h:739 [inline]
 allocate_hook_entries_size net/netfilter/core.c:61 [inline]
 nf_hook_entries_grow+0x140/0x780 net/netfilter/core.c:128
 __nf_register_net_hook+0x144/0x820 net/netfilter/core.c:429
 nf_register_net_hook+0x114/0x170 net/netfilter/core.c:571
 nf_register_net_hooks+0x59/0xc0 net/netfilter/core.c:587
 nf_synproxy_ipv6_init+0x85/0xe0 net/netfilter/nf_synproxy_core.c:1218
 synproxy_tg6_check+0x30d/0x560 net/ipv6/netfilter/ip6t_SYNPROXY.c:81
 xt_check_target+0x26c/0x9e0 net/netfilter/x_tables.c:1038
 check_target net/ipv6/netfilter/ip6_tables.c:530 [inline]
 find_check_entry.constprop.0+0x7f1/0x9e0 net/ipv6/netfilter/ip6_tables.c:573
 translate_table+0xc8b/0x1750 net/ipv6/netfilter/ip6_tables.c:735
 do_replace net/ipv6/netfilter/ip6_tables.c:1153 [inline]
 do_ip6t_set_ctl+0x56e/0xb90 net/ipv6/netfilter/ip6_tables.c:1639
 nf_setsockopt+0x83/0xe0 net/netfilter/nf_sockopt.c:101
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3404
 kvfree+0x42/0x50 mm/util.c:613
 rcu_do_batch kernel/rcu/tree.c:2527 [inline]
 rcu_core+0x7b1/0x1820 kernel/rcu/tree.c:2778
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558

Memory state around the buggy address:
 ffff88801c1a7f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801c1a7f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88801c1a8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88801c1a8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801c1a8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

The Linux kernel CVE team has assigned CVE-2022-48912 to this issue.

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

	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 4.14.270 with commit 05f7927b25d2
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 4.19.233 with commit bdd8fc1b826e
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 5.4.183 with commit 49c24579cec4
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 5.10.104 with commit 8b0142c4143c
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 5.15.27 with commit bd61f192a339
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 5.16.13 with commit 5a8076e98dde
	Issue introduced in 4.14 with commit 2420b79f8c18 and fixed in 5.17 with commit 56763f12b0f0

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-2022-48912
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/netfilter/core.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/05f7927b25d2635e87267ff6c79db79fb46cf313
	https://git.kernel.org/stable/c/bdd8fc1b826e6f23963f5bef3f7431c6188ec954
	https://git.kernel.org/stable/c/49c24579cec41e32f13d57b337fd28fb208d4a5b
	https://git.kernel.org/stable/c/8b0142c4143c1ca297dcf2c0cdd045d65dae2344
	https://git.kernel.org/stable/c/bd61f192a339b1095dfd6d56073a5265934c2979
	https://git.kernel.org/stable/c/5a8076e98dde17224dd47283b894a8b1dbe1bc72
	https://git.kernel.org/stable/c/56763f12b0f02706576a088e85ef856deacc98a0