Memory Leak Affecting kernel-default-livepatch package, versions <6.4.0-150600.23.33.1
Threat Intelligence
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Test your applications- Snyk IDSNYK-SLES156-KERNELDEFAULTLIVEPATCH-8647875
- published18 Jan 2025
- disclosed17 Jan 2025
Introduced: 17 Jan 2025
CVE-2024-56755 (opens in a new tab)How to fix?
Upgrade SLES:15.6 kernel-default-livepatch to version 6.4.0-150600.23.33.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch package and not the kernel-default-livepatch package as distributed by SLES.
See How to fix? for SLES:15.6 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.
References
- https://www.suse.com/security/cve/CVE-2024-56755.html
- https://bugzilla.suse.com/1234920
- https://git.kernel.org/stable/c/22f9400a6f3560629478e0a64247b8fcc811a24d
- https://git.kernel.org/stable/c/539fabba965e119b98066fc6ba5257b5eaf4eda2
- https://git.kernel.org/stable/c/8beb682cc9a0798a280bbb95e3e41617237090b2
- https://git.kernel.org/stable/c/8cc1df3113cb71a0df2c46dd5b102c9e11c8a8c6
- https://git.kernel.org/stable/c/ddab02607eed9e415dc62fde421d4329e5345315