CVE-2024-49985 i2c: stm32f7: Do not prepare/unprepare clock during runtime suspend/resume
A deadlock in the STM32F7 I2C driver can cause a denial of service when specific clock controllers are attached to the bus.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-49985?
CVE-2024-49985 is a medium-severity 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:
i2c: stm32f7: Do not prepare/unprepare clock during runtime suspend/resume
In case there is any sort of clock controller attached to this I2C bus controller, for example Versaclock or even an AIC32x4 I2C codec, then an I2C transfer triggered from the clock controller clk_ops .prepare callback may trigger a deadlock on drivers/clk/clk.c prepare_lock mutex.
This is because the clock controller first grabs the prepare_lock mutex and then performs the prepare operation, including its I2C access. The I2C access resumes this I2C bus controller via .runtime_resume callback, which calls clk_prepare_enable(), which attempts to grab the prepare_lock mutex again and deadlocks.
Since the clock are already prepared since probe() and unprepared in remove(), use simple clk_enable()/clk_disable() calls to enable and disable the clock on runtime suspend and resume, to avoid hitting the prepare_lock mutex.
Weakness: CWE-667
Which versions are affected by CVE-2024-49985?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-49985?
Apply the vendor's patch.
Is CVE-2024-49985 being exploited?
There is no known exploitation of CVE-2024-49985 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-51774, BELL-CVE-2024-49985, DEBIAN-CVE-2024-49985, GHSA-qfhj-q535-jf9w, UBUNTU-CVE-2024-49985.