CVE-2024-26866

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

spi: lpspi: Avoid potential use-after-free in probe()

fsl_lpspi_probe() is allocating/disposing memory manually with spi_alloc_host()/spi_alloc_target(), but uses devm_spi_register_controller(). In case of error after the latter call the memory will be explicitly freed in the probe function by spi_controller_put() call, but used afterwards by devm management outside probe() (spi_unregister_controller() <- devm_spi_unregister() below).

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070 … Call trace: kernfs_find_ns kernfs_find_and_get_ns sysfs_remove_group sysfs_remove_groups device_remove_attrs device_del spi_unregister_controller devm_spi_unregister release_nodes devres_release_all really_probe driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/1543418e82789cc383cd36d41469983c64e3fc7f
• https://git.kernel.org/stable/c/2ae0ab0143fcc06190713ed81a6486ed0ad3c861
• https://git.kernel.org/stable/c/996ce839606afd0fef91355627868022aa73eb68
• https://git.kernel.org/stable/c/da83ed350e4604b976e94239b08d8e2e7eaee7ea
• https://git.kernel.org/stable/c/1543418e82789cc383cd36d41469983c64e3fc7f
• https://git.kernel.org/stable/c/2ae0ab0143fcc06190713ed81a6486ed0ad3c861
• https://git.kernel.org/stable/c/996ce839606afd0fef91355627868022aa73eb68
• https://git.kernel.org/stable/c/da83ed350e4604b976e94239b08d8e2e7eaee7ea