KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache There is a potential UAF scenario in the case of an LPI translation cache hit racing with an operation that invalidates the cache, such as a DISCARD ITS command. The root of the problem is that vgic_its_check_cache() does not elevate the refcount on the vgic_irq before dropping the lock that serializes refcount changes. Have vgic_its_check_cache() raise the refcount on the returned vgic_irq and add the corresponding decrement after queueing the interrupt.

References

• https://git.kernel.org/stable/c/d04acadb6490aa3314f9c9e087691e55de153b88
• https://git.kernel.org/stable/c/ba7be666740847d967822bed15500656b26bc703
• https://git.kernel.org/stable/c/12c2759ab1343c124ed46ba48f27bd1ef5d2dff4
• https://git.kernel.org/stable/c/dba788e25f05209adf2b0175eb1691dc89fb1ba6
• https://git.kernel.org/stable/c/65b201bf3e9af1b0254243a5881390eda56f72d1
• https://git.kernel.org/stable/c/dd3956a1b3dd11f46488c928cb890d6937d1ca80
• https://git.kernel.org/stable/c/ad362fe07fecf0aba839ff2cc59a3617bd42c33f