cacheinfo: Fix shared_cpu_map to handle shared caches at different levels

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: cacheinfo: Fix shared_cpu_map to handle shared caches at different levels The cacheinfo sets up the shared_cpu_map by checking whether the caches with the same index are shared between CPUs. However, this will trigger slab-out-of-bounds access if the CPUs do not have the same cache hierarchy. Another problem is the mismatched shared_cpu_map when the shared cache does not have the same index between CPUs. CPU0 I D L3 index 0 1 2 x ^ ^ ^ ^ index 0 1 2 3 CPU1 I D L2 L3 This patch checks each cache is shared with all caches on other CPUs.

References

• https://git.kernel.org/stable/c/2f588d0345d69a35e451077afed428fd057a5e34
• https://git.kernel.org/stable/c/dea49f2993f57d8a2df2cacb0bf649ef49b28879
• https://git.kernel.org/stable/c/198102c9103fc78d8478495971947af77edb05c1