Memory Leak Affecting bpftool package, versions <0:6.1.124-134.200.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (12th percentile)

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  • Snyk IDSNYK-AMZN2023-BPFTOOL-9523910
  • published27 Mar 2025
  • disclosed29 Dec 2024

Introduced: 29 Dec 2024

CVE-2024-56755  (opens in a new tab)
CWE-401  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 bpftool to version 0:6.1.124-134.200.amzn2023 or higher.
This issue was patched in ALAS2023-2025-809.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool package and not the bpftool package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING

In fscache_create_volume(), there is a missing memory barrier between the bit-clearing operation and the wake-up operation. This may cause a situation where, after a wake-up, the bit-clearing operation hasn't been detected yet, leading to an indefinite wait. The triggering process is as follows:

[cookie1] [cookie2] [volume_work] fscache_perform_lookup fscache_create_volume fscache_perform_lookup fscache_create_volume fscache_create_volume_work cachefiles_acquire_volume clear_and_wake_up_bit test_and_set_bit test_and_set_bit goto maybe_wait goto no_wait

In the above process, cookie1 and cookie2 has the same volume. When cookie1 enters the -no_wait- process, it will clear the bit and wake up the waiting process. If a barrier is missing, it may cause cookie2 to remain in the -wait- process indefinitely.

In commit 3288666c7256 ("fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()"), barriers were added to similar operations in fscache_create_volume_work(), but fscache_create_volume() was missed.

By combining the clear and wake operations into clear_and_wake_up_bit() to fix this issue.

CVSS Base Scores

version 3.1