CVE-2024-26885
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | 5.10.214 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.7.12-1 |
| sid | Fixed | 6.7.12-1 |
| forky | Fixed | 6.7.12-1 |
| bullseye | Fixed | 5.10.216-1 |
| bookworm | Fixed | 6.1.85-1 |
References
- https://git.kernel.org/stable/c/1f5e352b9088211fa5eb4e1639cd365f4f7d2f65
- https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c
- https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691
- https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3
- https://git.kernel.org/stable/c/4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9
- https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3
- https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c
- https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737
- https://git.kernel.org/stable/c/225da02acdc97af01b6bc6ce1a3e5362bf01d3fb
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
- https://www.suse.com/security/cve/CVE-2024-26885.html
- https://security-tracker.debian.org/tracker/CVE-2024-26885
CWEs
CWE-119
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.