Stack-based Buffer Overflow Affecting kernel package, versions *
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Test your applications- Snyk ID SNYK-RHEL7-KERNEL-6633134
- published 18 Apr 2024
- disclosed 17 Apr 2024
Introduced: 17 Apr 2024
CVE-2024-26885 Open this link in a new tabHow to fix?
There is no fixed version for RHEL:7 kernel.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by RHEL.
See How to fix? for RHEL:7 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix DEVMAP_HASH overflow check on 32-bit arches
The devmap code allocates a number hash buckets equal to the next power of two of the max_entries value provided when creating the map. When rounding up to the next power of two, the 32-bit variable storing the number of buckets can overflow, and the code checks for overflow by checking if the truncated 32-bit value is equal to 0. However, on 32-bit arches the rounding up itself can overflow mid-way through, because it ends up doing a left-shift of 32 bits on an unsigned long value. If the size of an unsigned long is four bytes, this is undefined behaviour, so there is no guarantee that we'll end up with a nice and tidy 0-value at the end.
Syzbot managed to turn this into a crash on arm32 by creating a DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it. Fix this by moving the overflow check to before the rounding up operation.
References
- https://access.redhat.com/security/cve/CVE-2024-26885
- https://git.kernel.org/stable/c/4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9
- https://git.kernel.org/stable/c/1f5e352b9088211fa5eb4e1639cd365f4f7d2f65
- https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c
- https://git.kernel.org/stable/c/225da02acdc97af01b6bc6ce1a3e5362bf01d3fb
- https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691
- https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3
- https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3
- https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c
- https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html