CVE-2024-47141 Information

Description

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.

Let’s 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;

Reference

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