Linux Kernel KVM SVM SEV IOCTL Interface Kernel Data Leak Vulnerability

A vulnerability in the Linux kernel's KVM SVM module related to SEV ioctl interfaces can lead to a kernel data leak. This issue arises because the length parameter for some SEV ioctl interfaces may be less than or equal to the maximum size allowed, yet still larger than the data returned by the PSP firmware. As a result, the memory allocated by kmalloc reflects the size of the input rather than the actual data received. Since the PSP firmware does not completely overwrite the allocated buffer, these SEV ioctl interfaces can inadvertently return uninitialized memory from the kernel's slab allocator.

Impact

Exploitation of this vulnerability can result in the unintentional disclosure of sensitive kernel memory, potentially leading to further exploitation or privilege escalation.