Bug 2425103 (CVE-2023-54148)

Summary: CVE-2023-54148 kernel: net/mlx5e: Move representor neigh cleanup to profile cleanup_tx
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was identified in the Linux kernel’s Mellanox mlx5 Ethernet driver (net/mlx5e) related to the cleanup order of neighbour information when handling offloaded IP tunnel encapsulation rules in ECMP (Equal-Cost Multipath) mode. In certain scenarios — such as unloading the eswitch device while an offloaded ECMP rule is still active — the representor neighbour data for the peer uplink may be cleaned up prematurely in the profile->disable callback before the intended profile->cleanup_tx callback. This premature cleanup can result in a use-after-free condition when subsequent code attempts to access the freed neighbour data, potentially leading to kernel faults
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-12-24 14:03:12 UTC
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Move representor neigh cleanup to profile cleanup_tx

For IP tunnel encapsulation in ECMP (Equal-Cost Multipath) mode, as
the flow is duplicated to the peer eswitch, the related neighbour
information on the peer uplink representor is created as well.

In the cited commit, eswitch devcom unpair is moved to uplink unload
API, specifically the profile->cleanup_tx. If there is a encap rule
offloaded in ECMP mode, when one eswitch does unpair (because of
unloading the driver, for instance), and the peer rule from the peer
eswitch is going to be deleted, the use-after-free error is triggered
while accessing neigh info, as it is already cleaned up in uplink's
profile->disable, which is before its profile->cleanup_tx.

To fix this issue, move the neigh cleanup to profile's cleanup_tx
callback, and after mlx5e_cleanup_uplink_rep_tx is called. The neigh
init is moved to init_tx for symmeter.

[ 2453.376299] BUG: KASAN: slab-use-after-free in mlx5e_rep_neigh_entry_release+0x109/0x3a0 [mlx5_core]
[ 2453.379125] Read of size 4 at addr ffff888127af9008 by task modprobe/2496

[ 2453.381542] CPU: 7 PID: 2496 Comm: modprobe Tainted: G    B              6.4.0-rc7+ #15
[ 2453.383386] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 2453.384335] Call Trace:
[ 2453.384625]  <TASK>
[ 2453.384891]  dump_stack_lvl+0x33/0x50
[ 2453.385285]  print_report+0xc2/0x610
[ 2453.385667]  ? __virt_addr_valid+0xb1/0x130
[ 2453.386091]  ? mlx5e_rep_neigh_entry_release+0x109/0x3a0 [mlx5_core]
[ 2453.386757]  kasan_report+0xae/0xe0
[ 2453.387123]  ? mlx5e_rep_neigh_entry_release+0x109/0x3a0 [mlx5_core]
[ 2453.387798]  mlx5e_rep_neigh_entry_release+0x109/0x3a0 [mlx5_core]
[ 2453.388465]  mlx5e_rep_encap_entry_detach+0xa6/0xe0 [mlx5_core]
[ 2453.389111]  mlx5e_encap_dealloc+0xa7/0x100 [mlx5_core]
[ 2453.389706]  mlx5e_tc_tun_encap_dests_unset+0x61/0xb0 [mlx5_core]
[ 2453.390361]  mlx5_free_flow_attr_actions+0x11e/0x340 [mlx5_core]
[ 2453.391015]  ? complete_all+0x43/0xd0
[ 2453.391398]  ? free_flow_post_acts+0x38/0x120 [mlx5_core]
[ 2453.392004]  mlx5e_tc_del_fdb_flow+0x4ae/0x690 [mlx5_core]
[ 2453.392618]  mlx5e_tc_del_fdb_peers_flow+0x308/0x370 [mlx5_core]
[ 2453.393276]  mlx5e_tc_clean_fdb_peer_flows+0xf5/0x140 [mlx5_core]
[ 2453.393925]  mlx5_esw_offloads_unpair+0x86/0x540 [mlx5_core]
[ 2453.394546]  ? mlx5_esw_offloads_set_ns_peer.isra.0+0x180/0x180 [mlx5_core]
[ 2453.395268]  ? down_write+0xaa/0x100
[ 2453.395652]  mlx5_esw_offloads_devcom_event+0x203/0x530 [mlx5_core]
[ 2453.396317]  mlx5_devcom_send_event+0xbb/0x190 [mlx5_core]
[ 2453.396917]  mlx5_esw_offloads_devcom_cleanup+0xb0/0xd0 [mlx5_core]
[ 2453.397582]  mlx5e_tc_esw_cleanup+0x42/0x120 [mlx5_core]
[ 2453.398182]  mlx5e_rep_tc_cleanup+0x15/0x30 [mlx5_core]
[ 2453.398768]  mlx5e_cleanup_rep_tx+0x6c/0x80 [mlx5_core]
[ 2453.399367]  mlx5e_detach_netdev+0xee/0x120 [mlx5_core]
[ 2453.399957]  mlx5e_netdev_change_profile+0x84/0x170 [mlx5_core]
[ 2453.400598]  mlx5e_vport_rep_unload+0xe0/0xf0 [mlx5_core]
[ 2453.403781]  mlx5_eswitch_unregister_vport_reps+0x15e/0x190 [mlx5_core]
[ 2453.404479]  ? mlx5_eswitch_register_vport_reps+0x200/0x200 [mlx5_core]
[ 2453.405170]  ? up_write+0x39/0x60
[ 2453.405529]  ? kernfs_remove_by_name_ns+0xb7/0xe0
[ 2453.405985]  auxiliary_bus_remove+0x2e/0x40
[ 2453.406405]  device_release_driver_internal+0x243/0x2d0
[ 2453.406900]  ? kobject_put+0x42/0x2d0
[ 2453.407284]  bus_remove_device+0x128/0x1d0
[ 2453.407687]  device_del+0x240/0x550
[ 2453.408053]  ? waiting_for_supplier_show+0xe0/0xe0
[ 2453.408511]  ? kobject_put+0xfa/0x2d0
[ 2453.408889]  ? __kmem_cache_free+0x14d/0x280
[ 2453.409310]  mlx5_rescan_drivers_locked.part.0+0xcd/0x2b0 [mlx5_core]
[ 2453.409973]  mlx5_unregister_device+0x40/0x50 [mlx5_core]
[ 2453.410561]  mlx5_uninit_one+0x3d/0x110 [mlx5_core]
[ 2453.411111]  remove_one+0x89/0x130 [mlx5_core]
[ 24
---truncated---