Description

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

mlxsw: spectrum_acl_tcam: Fix possible use-after-free during activity update

The rule activity update delayed work periodically traverses the list of
configured rules and queries their activity from the device.

As part of this task it accesses the entry pointed by 'ventry->entry',
but this entry can be changed concurrently by the rehash delayed work,
leading to a use-after-free [1].

Fix by closing the race and perform the activity query under the
'vregion->lock' mutex.

[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_acl_tcam_flower_rule_activity_get+0x121/0x140
Read of size 8 at addr ffff8881054ed808 by task kworker/0:18/181

CPU: 0 PID: 181 Comm: kworker/0:18 Not tainted 6.9.0-rc2-custom-00781-gd5ab772d32f7 #2
Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019
Workqueue: mlxsw_core mlxsw_sp_acl_rule_activity_update_work
Call Trace:

dump_stack_lvl+0xc6/0x120
print_report+0xce/0x670
kasan_report+0xd7/0x110
mlxsw_sp_acl_tcam_flower_rule_activity_get+0x121/0x140
mlxsw_sp_acl_rule_activity_update_work+0x219/0x400
process_one_work+0x8eb/0x19b0
worker_thread+0x6c9/0xf70
kthread+0x2c9/0x3b0
ret_from_fork+0x4d/0x80
ret_from_fork_asm+0x1a/0x30

Allocated by task 1039:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
__kmalloc+0x19c/0x360
mlxsw_sp_acl_tcam_entry_create+0x7b/0x1f0
mlxsw_sp_acl_tcam_vchunk_migrate_all+0x30d/0xb50
ml...

Classification

CVE ID: CVE-2024-35855

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/1b73f6e4ea770410a937a8db98f77e52594d23a0
https://git.kernel.org/stable/c/e24d2487424779c02760ff50cd9021b8676e19ef
https://git.kernel.org/stable/c/c17976b42d546ee118ca300db559630ee96fb758
https://git.kernel.org/stable/c/b996e8699da810e4c915841d6aaef761007f933a
https://git.kernel.org/stable/c/feabdac2057e863d0e140a2adf3d232eb4882db4
https://git.kernel.org/stable/c/b183b915beef818a25e3154d719ca015a1ae0770
https://git.kernel.org/stable/c/79b5b4b18bc85b19d3a518483f9abbbe6d7b3ba4

Timeline