CVE-2022-48975 gpiolib: fix memory leak in gpiochip_setup_dev()

What is CVE-2022-48975?

CVE-2022-48975 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Oct 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

gpiolib: fix memory leak in gpiochip_setup_dev()

Here is a backtrace report about memory leak detected in gpiochip_setup_dev():

unreferenced object 0xffff88810b406400 (size 512): comm "python3", pid 1682, jiffies 4295346908 (age 24.090s) backtrace: kmalloc_trace device_add device_private_init at drivers/base/core.c:3361 (inlined by) device_add at drivers/base/core.c:3411 cdev_device_add gpiolib_cdev_register gpiochip_setup_dev gpiochip_add_data_with_key

gcdev_register() & gcdev_unregister() would call device_add() & device_del() (no matter CONFIG_GPIO_CDEV is enabled or not) to register/unregister device.

However, if device_add() succeeds, some resource (like struct device_private allocated by device_private_init()) is not released by device_del().

Therefore, after device_add() succeeds by gcdev_register(), it needs to call put_device() to release resource in the error handle path.

Here we move forward the register of release function, and let it release every piece of resource by put_device() instead of kfree().

While at it, fix another subtle issue, i.e. when gc->ngpio is equal to 0, we still call kcalloc() and, in case of further error, kfree() on the ZERO_PTR pointer, which is not NULL. It's not a bug per se, but rather waste of the resources and potentially wrong expectation about contents of the gdev->descs variable.

Weakness: CWE-401

Which versions are affected by CVE-2022-48975?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-48975?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2022-48975 being exploited?

There is no known exploitation of CVE-2022-48975 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2022-48975, GHSA-5rmx-h57x-xq29, ROOT-OS-DEBIAN-11-CVE-2022-48975, UBUNTU-CVE-2022-48975.