Subject: CVE-2024-27018: netfilter: br_netfilter: skip conntrack input hook for promisc packets

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

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

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

netfilter: br_netfilter: skip conntrack input hook for promisc packets

For historical reasons, when bridge device is in promisc mode, packets
that are directed to the taps follow bridge input hook path. This patch
adds a workaround to reset conntrack for these packets.

Jianbo Liu reports warning splats in their test infrastructure where
cloned packets reach the br_netfilter input hook to confirm the
conntrack object.

Scratch one bit from BR_INPUT_SKB_CB to annotate that this packet has
reached the input hook because it is passed up to the bridge device to
reach the taps.

[   57.571874] WARNING: CPU: 1 PID: 0 at net/bridge/br_netfilter_hooks.c:616 br_nf_local_in+0x157/0x180 [br_netfilter]
[   57.572749] Modules linked in: xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_isc si ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5ctl mlx5_core
[   57.575158] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0+ #19
[   57.575700] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[   57.576662] RIP: 0010:br_nf_local_in+0x157/0x180 [br_netfilter]
[   57.577195] Code: fe ff ff 41 bd 04 00 00 00 be 04 00 00 00 e9 4a ff ff ff be 04 00 00 00 48 89 ef e8 f3 a9 3c e1 66 83 ad b4 00 00 00 04 eb 91 <0f> 0b e9 f1 fe ff ff 0f 0b e9 df fe ff ff 48 89 df e8 b3 53 47 e1
[   57.578722] RSP: 0018:ffff88885f845a08 EFLAGS: 00010202
[   57.579207] RAX: 0000000000000002 RBX: ffff88812dfe8000 RCX: 0000000000000000
[   57.579830] RDX: ffff88885f845a60 RSI: ffff8881022dc300 RDI: 0000000000000000
[   57.580454] RBP: ffff88885f845a60 R08: 0000000000000001 R09: 0000000000000003
[   57.581076] R10: 00000000ffff1300 R11: 0000000000000002 R12: 0000000000000000
[   57.581695] R13: ffff8881047ffe00 R14: ffff888108dbee00 R15: ffff88814519b800
[   57.582313] FS:  0000000000000000(0000) GS:ffff88885f840000(0000) knlGS:0000000000000000
[   57.583040] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   57.583564] CR2: 000000c4206aa000 CR3: 0000000103847001 CR4: 0000000000370eb0
[   57.584194] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[   57.584820] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[   57.585440] Call Trace:
[   57.585721]  <IRQ>
[   57.585976]  ? __warn+0x7d/0x130
[   57.586323]  ? br_nf_local_in+0x157/0x180 [br_netfilter]
[   57.586811]  ? report_bug+0xf1/0x1c0
[   57.587177]  ? handle_bug+0x3f/0x70
[   57.587539]  ? exc_invalid_op+0x13/0x60
[   57.587929]  ? asm_exc_invalid_op+0x16/0x20
[   57.588336]  ? br_nf_local_in+0x157/0x180 [br_netfilter]
[   57.588825]  nf_hook_slow+0x3d/0xd0
[   57.589188]  ? br_handle_vlan+0x4b/0x110
[   57.589579]  br_pass_frame_up+0xfc/0x150
[   57.589970]  ? br_port_flags_change+0x40/0x40
[   57.590396]  br_handle_frame_finish+0x346/0x5e0
[   57.590837]  ? ipt_do_table+0x32e/0x430
[   57.591221]  ? br_handle_local_finish+0x20/0x20
[   57.591656]  br_nf_hook_thresh+0x4b/0xf0 [br_netfilter]
[   57.592286]  ? br_handle_local_finish+0x20/0x20
[   57.592802]  br_nf_pre_routing_finish+0x178/0x480 [br_netfilter]
[   57.593348]  ? br_handle_local_finish+0x20/0x20
[   57.593782]  ? nf_nat_ipv4_pre_routing+0x25/0x60 [nf_nat]
[   57.594279]  br_nf_pre_routing+0x24c/0x550 [br_netfilter]
[   57.594780]  ? br_nf_hook_thresh+0xf0/0xf0 [br_netfilter]
[   57.595280]  br_handle_frame+0x1f3/0x3d0
[   57.595676]  ? br_handle_local_finish+0x20/0x20
[   57.596118]  ? br_handle_frame_finish+0x5e0/0x5e0
[   57.596566]  __netif_receive_skb_core+0x25b/0xfc0
[   57.597017]  ? __napi_build_skb+0x37/0x40
[   57.597418]  __netif_receive_skb_list_core+0xfb/0x220

The Linux kernel CVE team has assigned CVE-2024-27018 to this issue.

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

	Issue introduced in 5.15.151 with commit 7c3f28599652 and fixed in 5.15.157 with commit dceb683ab87c
	Issue introduced in 6.1.81 with commit 2b1414d5e94e and fixed in 6.1.88 with commit b13db0d16bc7
	Issue introduced in 6.6.21 with commit 80cd0487f630 and fixed in 6.6.29 with commit 3f59ac29dea0
	Issue introduced in 6.8 with commit 62e7151ae3eb and fixed in 6.8.8 with commit 43193174510e
	Issue introduced in 6.8 with commit 62e7151ae3eb and fixed in 6.9 with commit 751de2012eaf
	Issue introduced in 6.7.9 with commit cb734975b0ff

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-2024-27018
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/bridge/br_input.c
	net/bridge/br_netfilter_hooks.c
	net/bridge/br_private.h
	net/bridge/netfilter/nf_conntrack_bridge.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/dceb683ab87ca3666a9bb5c0158528b646faedc4
	https://git.kernel.org/stable/c/b13db0d16bc7b2a52abcf5cb71334f63faa5dbd6
	https://git.kernel.org/stable/c/3f59ac29dea0921637053908fe99268d157bbb9d
	https://git.kernel.org/stable/c/43193174510ea4f3ce09b796e559a2fd9f148615
	https://git.kernel.org/stable/c/751de2012eafa4d46d8081056761fa0e9cc8a178