// For flags

CVE-2024-27018

netfilter: br_netfilter: skip conntrack input hook for promisc packets

Severity Score

7.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: netfilter: br_netfilter: omitir el enlace de entrada conntrack para paquetes promiscos. Por razones históricas, cuando el dispositivo puente está en modo promisco, los paquetes que se dirigen a los taps siguen la ruta del enlace de entrada del puente. Este parche agrega una workaround para restablecer el seguimiento de conexión de estos paquetes. Jianbo Liu informa señales de advertencia en su infraestructura de prueba donde los paquetes clonados llegan al enlace de entrada br_netfilter para confirmar el objeto conntrack. Elimine un bit de BR_INPUT_SKB_CB para anotar que este paquete ha llegado al gancho de entrada porque pasa al dispositivo puente para llegar a las derivaciones. [57.571874] ADVERTENCIA: CPU: 1 PID: 0 en net/bridge/br_netfilter_hooks.c:616 br_nf_local_in+0x157/0x180 [br_netfilter] [57.572749] Módulos vinculados en: xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat escriba xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry superposición 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] Nombre de hardware: PC estándar UEM (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 01/04/2014 [ 57.576662] RIP: 0010:br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.577195] Código: fe ff ff 41 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 &lt;0f&gt; 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: 0000000 [ 57.581695] R13: ffff8881047ffe00 R14: ffff888108dbee00 R15: ffff88814519b800 [ 57.582313] FS: 0000000000000000(0000) GS:ffff88885f8400 00(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: 00000000000000000 DR6: 00000000ffe0ff0 0000000000000400 [ 57.585440] Seguimiento de llamadas: [ 57.585721] [ 57.585976] ? __advertir+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

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-02-19 CVE Reserved
  • 2024-05-01 CVE Published
  • 2024-05-24 EPSS Updated
  • 2024-12-19 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15.151 < 5.15.157
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15.151 < 5.15.157"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.1.81 < 6.1.88
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.1.81 < 6.1.88"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.6.21 < 6.6.29
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.6.21 < 6.6.29"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.8 < 6.8.8
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.8 < 6.8.8"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.8 < 6.9
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.8 < 6.9"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
6.7.9
Search vendor "Linux" for product "Linux Kernel" and version "6.7.9"
en
Affected