CVE-2024-49874

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

i3c: master: svc: Fix use after free vulnerability in svc_i3c_master Driver Due to Race Condition

In the svc_i3c_master_probe function, &master->hj_work is bound with svc_i3c_master_hj_work, &master->ibi_work is bound with svc_i3c_master_ibi_work. And svc_i3c_master_ibi_work can start the hj_work, svc_i3c_master_irq_handler can start the ibi_work.

If we remove the module which will call svc_i3c_master_remove to make cleanup, it will free master->base through i3c_master_unregister while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows:

CPU0 CPU1

                                | svc_i3c_master_hj_work

svc_i3c_master_remove | i3c_master_unregister(&master->base)| device_unregister(&master->dev) | device_release | //free master->base | | i3c_master_do_daa(&master->base) | //use master->base

Fix it by ensuring that the work is canceled before proceeding with the cleanup in svc_i3c_master_remove.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/27b55724d3f781dd6e635e89dc6e2fd78fa81a00
• https://git.kernel.org/stable/c/4318998892bf8fe99f97bea18c37ae7b685af75a
• https://git.kernel.org/stable/c/4ac637122930cc4ab7e2c22e364cf3aaf96b05b1
• https://git.kernel.org/stable/c/56bddf543d4d7ddeff3f87b554ddacfdf086bffe
• https://git.kernel.org/stable/c/61850725779709369c7e907ae8c7c75dc7cec4f3