Resource Leak Affecting kernel-rt package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL9-KERNELRT-6677437
- published27 Apr 2024
- disclosed24 Apr 2024
Introduced: 24 Apr 2024
CVE-2024-26924 (opens in a new tab)How to fix?
There is no fixed version for RHEL:9 kernel-rt.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt package and not the kernel-rt package as distributed by RHEL.
See How to fix? for RHEL:9 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_set_pipapo: do not free live element
Pablo reports a crash with large batches of elements with a back-to-back add/remove pattern. Quoting Pablo:
add_elem("00000000") timeout 100 ms ... add_elem("0000000X") timeout 100 ms del_elem("0000000X") <---------------- delete one that was just added ... add_elem("00005000") timeout 100 ms
- nft_pipapo_remove() removes element 0000000X Then, KASAN shows a splat.
Looking at the remove function there is a chance that we will drop a rule that maps to a non-deactivated element.
Removal happens in two steps, first we do a lookup for key k and return the to-be-removed element and mark it as inactive in the next generation. Then, in a second step, the element gets removed from the set/map.
The _remove function does not work correctly if we have more than one element that share the same key.
This can happen if we insert an element into a set when the set already holds an element with same key, but the element mapping to the existing key has timed out or is not active in the next generation.
In such case its possible that removal will unmap the wrong element. If this happens, we will leak the non-deactivated element, it becomes unreachable.
The element that got deactivated (and will be freed later) will remain reachable in the set data structure, this can result in a crash when such an element is retrieved during lookup (stale pointer).
Add a check that the fully matching key does in fact map to the element that we have marked as inactive in the deactivation step. If not, we need to continue searching.
Add a bug/warn trap at the end of the function as well, the remove function must not ever be called with an invisible/unreachable/non-existent element.
v2: avoid uneeded temporary variable (Stefano)
References
- https://access.redhat.com/security/cve/CVE-2024-26924
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4EZ6PJW7VOZ224TD7N4JZNU6KV32ZJ53/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DAMSOZXJEPUOXW33WZYWCVAY7Z5S7OOY/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GCBZZEC7L7KTWWAS2NLJK6SO3IZIL4WW/
- https://git.kernel.org/stable/c/14b001ba221136c15f894577253e8db535b99487
- https://git.kernel.org/stable/c/3cfc9ec039af60dbd8965ae085b2c2ccdcfbe1cc
- https://git.kernel.org/stable/c/41d8fdf3afaff312e17466e4ab732937738d5644
- https://git.kernel.org/stable/c/7a1679e2d9bfa3b5f8755c2c7113e54b7d42bd46
- https://git.kernel.org/stable/c/e3b887a9c11caf8357a821260e095f2a694a34f2
- https://git.kernel.org/stable/c/ebf7c9746f073035ee26209e38c3a1170f7b349a
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html