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Improper Locking Affecting kernel-debug-modules-core package, versions *

Severity

 Recommended
0.0
medium
0
10

Based on CentOS security rating.

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  • Snyk IDSNYK-CENTOS9-KERNELDEBUGMODULESCORE-9445869
  • published15 Mar 2025
  • disclosed12 Mar 2025
Report a new vulnerability Found a mistake?

Introduced: 12 Mar 2025

NewCVE-2024-58088  (opens in a new tab)
CWE-667  (opens in a new tab)

How to fix?

There is no fixed version for Centos:9 kernel-debug-modules-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-core package and not the kernel-debug-modules-core package as distributed by Centos. See How to fix? for Centos:9 relevant fixed versions and status.

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

bpf: Fix deadlock when freeing cgroup storage

The following commit bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]") first introduced deadlock prevention for fentry/fexit programs attaching on bpf_task_storage helpers. That commit also employed the logic in map free path in its v6 version.

Later bpf_cgrp_storage was first introduced in c4bcfb38a95e ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs") which faces the same issue as bpf_task_storage, instead of its busy counter, NULL was passed to bpf_local_storage_map_free() which opened a window to cause deadlock:

<TASK>
    (acquiring local_storage->lock)
_raw_spin_lock_irqsave+0x3d/0x50
bpf_local_storage_update+0xd1/0x460
bpf_cgrp_storage_get+0x109/0x130
bpf_prog_a4d4a370ba857314_cgrp_ptr+0x139/0x170
? __bpf_prog_enter_recur+0x16/0x80
bpf_trampoline_6442485186+0x43/0xa4
cgroup_storage_ptr+0x9/0x20
    (holding local_storage->lock)
bpf_selem_unlink_storage_nolock.constprop.0+0x135/0x160
bpf_selem_unlink_storage+0x6f/0x110
bpf_local_storage_map_free+0xa2/0x110
bpf_map_free_deferred+0x5b/0x90
process_one_work+0x17c/0x390
worker_thread+0x251/0x360
kthread+0xd2/0x100
ret_from_fork+0x34/0x50
ret_from_fork_asm+0x1a/0x30
</TASK>

Progs:

  • A: SEC("fentry/cgroup_storage_ptr")
    • cgid (BPF_MAP_TYPE_HASH) Record the id of the cgroup the current task belonging to in this hash map, using the address of the cgroup as the map key.
    • cgrpa (BPF_MAP_TYPE_CGRP_STORAGE) If current task is a kworker, lookup the above hash map using function parameter @owner as the key to get its corresponding cgroup id which is then used to get a trusted pointer to the cgroup through bpf_cgroup_from_id(). This trusted pointer can then be passed to bpf_cgrp_storage_get() to finally trigger the deadlock issue.
  • B: SEC("tp_btf/sys_enter")
    • cgrpb (BPF_MAP_TYPE_CGRP_STORAGE) The only purpose of this prog is to fill Prog A's hash map by calling bpf_cgrp_storage_get() for as many userspace tasks as possible.

Steps to reproduce:

  • Run A;
  • while (true) { Run B; Destroy B; }

Fix this issue by passing its busy counter to the free procedure so it can be properly incremented before storage/smap locking.

CVSS Base Scores

version 3.1