CVE-2024-49985

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

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/048bbbdbf85e5e00258dfb12f5e368f908801d7b
• https://git.kernel.org/stable/c/1883cad2cc629ded4a3556c0bbb8b42533ad8764
• https://git.kernel.org/stable/c/22a1f8a5b56ba93d3e8b7a1dafa24e01c8bb48ba
• https://git.kernel.org/stable/c/894cd5f5fd9061983445bbd1fa3d81be43095344
• https://git.kernel.org/stable/c/9b8bc33ad64192f54142396470cc34ce539a8940
• https://git.kernel.org/stable/c/c2024b1a583ab9176c797ea1e5f57baf8d5e2682
• https://git.kernel.org/stable/c/d6f1250a4d5773f447740b9fe37b8692105796d4
• https://git.kernel.org/stable/c/fac3c9f7784e8184c0338e9f0877b81e55d3ef1c