CVE-2024-43819

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

kvm: s390: Reject memory region operations for ucontrol VMs

This change rejects the KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM. This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and would thus result in a null pointer dereference further in. Memory management needs to be performed in userspace and using the ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2.

[frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/49c9945c054df4c22008e2bf87ca74d3e2507aa6
• https://git.kernel.org/stable/c/7816e58967d0e6cadce05c8540b47ed027dc2499