CVE-2024-47141

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

pinmux: Use sequential access to access desc->pinmux data

When two client of the same gpio call pinctrl_select_state() for the same functionality, we are seeing NULL pointer issue while accessing desc->mux_owner.

Lets say two processes A, B executing in pin_request() for the same pin and process A updates the desc->mux_usecount but not yet updated the desc->mux_owner while process B see the desc->mux_usecount which got updated by A path and further executes strcmp and while accessing desc->mux_owner it crashes with NULL pointer.

Serialize the access to mux related setting with a mutex lock.

cpu0 (process A)			cpu1(process B)

pinctrl_select_state() { pinctrl_select_state() { pin_request() { pin_request() { … …. } else { desc->mux_usecount++; desc->mux_usecount && strcmp(desc->mux_owner, owner)) {

     if (desc->mux_usecount > 1)
           return 0;
     desc->mux_owner = owner;

} }

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/2da32aed4a97ca1d70fb8b77926f72f30ce5fb4b
• https://git.kernel.org/stable/c/5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e
• https://git.kernel.org/stable/c/c11e2ec9a780f54982a187ee10ffd1b810715c85