Skip to content

In the Linux kernel, the following vulnerability has been...

High severity Unreviewed Published May 1, 2024 to the GitHub Advisory Database • Updated Jun 3, 2024

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

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]
[ 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

References

Published by the National Vulnerability Database May 1, 2024
Published to the GitHub Advisory Database May 1, 2024
Last updated Jun 3, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.042%
(5th percentile)

Weaknesses

No CWEs

CVE ID

CVE-2024-27018

GHSA ID

GHSA-cm9x-gp4m-whg8

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

Learn more about GitHub language support

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.