Linux Kernel IOMMU NULL Pointer Dereference Vulnerability

A vulnerability in the Linux kernel's IOMMU subsystem was addressed, specifically in the 'iommu_copy_struct_from_user()' function. The issue involved improper handling of NULL pointers, which could lead to dereferencing errors. This vulnerability was identified during a review of the 'iommu_copy_struct_to_user()' helper, where it was noted that NULL pointers should be rejected before being dereferenced. Additionally, a typo was pointed out, which was also related to the 'iommu_copy_struct_from_user()' function. The vulnerability affects several versions of the Linux kernel.

Impact

The vulnerability could lead to a NULL pointer dereference, potentially causing a denial-of-service condition by crashing the system or causing the kernel to become unresponsive.