About vulnerability
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]
[ 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—