CVE-2024-36899
Description
In the Linux kernel, the following vulnerability has been resolved: gpiolib: cdev: Fix use after free in lineinfo_changed_notify The use-after-free issue occurs as follows: when the GPIO chip device file is being closed by invoking gpio_chrdev_release(), watched_lines is freed by bitmap_free(), but the unregistration of lineinfo_changed_nb notifier chain failed due to waiting write rwsem. Additionally, one of the GPIO chip's lines is also in the release process and holds the notifier chain's read rwsem. Consequently, a race condition leads to the use-after-free of watched_lines. Here is the typical stack when issue happened: [free] gpio_chrdev_release() --> bitmap_free(cdev->watched_lines) <-- freed --> blocking_notifier_chain_unregister() --> down_write(&nh->rwsem) <-- waiting rwsem --> __down_write_common() --> rwsem_down_write_slowpath() --> schedule_preempt_disabled() --> schedule() [use] st54spi_gpio_dev_release() --> gpio_free() --> gpiod_free() --> gpiod_free_commit() --> gpiod_line_state_notify() --> blocking_notifier_call_chain() --> down_read(&nh->rwsem); <-- held rwsem --> notifier_call_chain() --> lineinfo_changed_notify() --> test_bit(xxxx, cdev->watched_lines) <-- use after free The side effect of the use-after-free issue is that a GPIO line event is being generated for userspace where it shouldn't. However, since the chrdev is being closed, userspace won't have the chance to read that event anyway. To fix the issue, call the bitmap_free() function after the unregistration of lineinfo_changed_nb notifier chain.
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
| OS | Version | Status | Fixed in |
|---|---|---|---|
| rhel | 9 | fixed | |
| sles | affected | | |
| debian | bookworm | fixed | 6.1.128-1 |
| debian | bullseye | fixed | 5.10.234-1 |
| debian | forky | fixed | 6.8.11-1 |
| debian | sid | fixed | 6.8.11-1 |
| debian | trixie | fixed | 6.8.11-1 |
| linux-kernel | affected | 6.6.31 | |
| linux-kernel | 6.9 | affected | |
| almalinux | 9 | fixed | kernel-64k-devel-matched-5.14.0-427.37.1.el9_4.aarch64.rpm |
References
- https://access.redhat.com/errata/RHSA-2024:6997
- https://git.kernel.org/stable/c/02f6b0e1ec7e0e7d059dddc893645816552039da
- https://git.kernel.org/stable/c/2d008d4961b039d2edce8976289773961b7e5fb5
- https://git.kernel.org/stable/c/2dfbb920a89bdc58087672ad5325dc6c588b6860
- https://git.kernel.org/stable/c/95ca7c90eaf5ea8a8460536535101e3e81160e2a
- https://git.kernel.org/stable/c/ca710b5f40b8b16fdcad50bebd47f50e4c62d239
- https://git.kernel.org/stable/c/d38c49f7bdf14381270736299e2ff68ec248a017
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
- https://www.suse.com/security/cve/CVE-2024-36899.html
- https://security-tracker.debian.org/tracker/CVE-2024-36899
- https://bugzilla.redhat.com/2265271
- https://bugzilla.redhat.com/2273270
- https://bugzilla.redhat.com/2278167
- https://bugzilla.redhat.com/2278245
- https://bugzilla.redhat.com/2278248
- https://bugzilla.redhat.com/2278250
- https://bugzilla.redhat.com/2278252
- https://bugzilla.redhat.com/2278318
- https://bugzilla.redhat.com/2281677
- https://bugzilla.redhat.com/2283894
- https://bugzilla.redhat.com/2284549
- https://bugzilla.redhat.com/2293348
- https://bugzilla.redhat.com/2293364
CWEs
CWE-362 CWE-416
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.